CCC Mitigation Monitoring Framework

Assessing UK progress in reducing emissions

29 June 2022

Type of publication:
Progress reports

Country focus:

Carbon budgets, targets and progress

2. Surface transport

Key messages

  • Electric and other zero-emission vehicles. The biggest share of abatement in this sector will come from the transition to zero-emission vehicles. These are likely mostly to be electric (i.e., battery-powered), especially for cars and vans, for which the Government is targeting a full switchover in sales of new vehicles by 2030. Hydrogen is also a possibility, primarily for larger vehicles like heavy goods vehicles. The key indicators that we will use to monitor this are the share and number of new vehicles of each type being sold each year.
  • Forward indicators for zero-emission vehicles. Beyond these headline numbers, we will also monitor a suite of indicators of the key enablers of this transition. This includes measures of the underlying supply chains, public attitudes to these vehicles, and prices.
  • Charging infrastructure. It will also be vital for high-quality charging infrastructure to be widely available in all areas of the country, so that drivers can have confidence that they will be able to charge their vehicles even if they don’t have access to private charge points. We will monitor this through indicators on quantity, quality, and geographic coverage of the public charging network.
  • Conventional vehicle efficiency. Alongside the transition to zero-emission vehicles, it will be important to continue to improve the CO2 intensities of the conventional vehicles that continue to be sold. We will monitor both these intensities directly and key enablers such as the average size of vehicles and the use of biofuels in road transport.
  • Travel demand. The sector’s pathway also relies on demand-side action leading to reduced traffic growth. Our framework includes both high-level indicators monitoring overall vehicle traffic levels and supporting indicators looking at demand for and public attitudes towards alternative lower-carbon modes of travel. These outcomes are a crucial part of the sector’s transition, as they can deliver near-term emissions savings and help realise a range of co-benefits.

How we monitor surface transport

The Net Zero transition for the surface transport sector is dependent on both technological transitions to reduce vehicle emissions across all vehicle types and demand-side actions to reduce growth in road traffic levels.

  • The Monitoring map for surface transport reflects this through its two main branches – the first covering reductions in average vehicle emissions intensities and the second covering travel demand (Figure 2.1).
  • In the long-term, improvements in fleet intensities through the uptake of zero-emission vehicles will deliver the majority of the sector’s abatement. However, demand-side actions have an important supporting role. They can deliver significant emissions reduction in the medium-term while vehicle fleets are still largely fossil-fuelled. And longer term, demand-side actions can limit growth in electricity demand and embedded production emissions while bringing a range of co-benefits (e.g. to air quality, health, and congestion) even once zero-emission vehicles are widespread.

The Monitoring map shows how the Government’s policies, supported by relevant contextual enablers, can put in place the conditions for success required to realise the outcomes that deliver the transition.

  • On the technological side, the Government’s key policy is the zero-emission vehicle mandate, which will be introduced from 2024. This will be supported by investment in UK manufacturing, targeted support where necessary for vehicle purchasers, and trials of early-stage technologies (e.g., for HGVs). Provided supply chains are able to scale up and expected price reductions are realised, this should drive a robust supply of high-quality zero-emission vehicles which are attractive to consumers, leading to the uptake trajectories that are needed.
  • Widespread provision of high-quality charging infrastructure will be essential to enabling this. Delivery of the Government’s EV Charging Infrastructure Strategy, through action to maximise private-sector investment and targeted support where necessary, is designed to deliver such a network. These will need to be affordable, reliable, and widely available in order to ensure universal willingness to switch over to zero-emission vehicles.
  • In parallel, the Government intends to maintain a system of CO2 intensity regulations for new vehicles (i.e., regulations that require ongoing improvement in the efficiency of new conventional vehicles), alongside incentives for blending of biofuels into petrol and diesel, to ensure that carbon emissions from the remainder of the fleet are also managed until these vehicles switch over to zero-emission options.
  • On the demand side, progress depends on policies designed to shift journeys away from private car use onto more sustainable modes of transport. The Government has committed investment for walking and cycling infrastructure and to improve public transport systems. Schemes to increase car occupancy and dissuade car use where competitive alternatives are available can also play a role. These need to form a holistic package that makes lower-carbon modes more affordable, more reliable, and better quality, offering a compelling alternative. If that occurs, then consumers and businesses will be more willing to adopt these alternatives and travel more sustainably, reducing demand for high-carbon modes of travel. Technological and societal shifts, such as the advent of hybrid working, can also play a role in enabling this.


Figure 2.1 Monitoring map for surface transport

Source: CCC analysis.
Notes: The emissions reduction figures show the reductions required by 2035 in both the Government’s Carbon Budget Delivery Plan and the CCC’s Balanced Pathway. The vehicle intensity assumptions show the rough ranges in fleet-average CO2-intensities that will be needed to meet these pathways, while the road traffic growth assumption is based on the increase in road traffic in the CCC’s Balanced Pathway compared to current levels, before the impact of rebound effects.


This section sets out the indicators we will use in our progress monitoring for the surface transport sector. For each indicator we assign an ID number and identify a current data source. We explain why each indicator is important and what we are looking to see in our monitoring. The historical data and, where available and relevant, the benchmark trajectories against which we compare them are presented in the supporting data alongside our Progress Reports.

We follow the order laid out in the Monitoring map (Figure 2.1), taking each main branch in turn to lay out required outcomes, enablers, and contextual factors. We discuss policy needs (flagged as ‘Policy’) alongside the most relevant outcomes and enablers, while specific recommendations are made in our annual Progress Reports to Parliament.

We first cover the supply side – the need to reduce the emissions intensity of vehicles – and then the demand side – the need to reduce growth in emissions-intensive travel modes.

(a) Supply-side indicators

Required outcome: Reduced vehicle emissions intensities

Progress on vehicle technologies and efficiencies should lead to reductions in the average emissions intensities across the fleet, which are captured by this group of indicators. These indicators effectively merge all supply-side progress – uptake of zero-emission vehicles, improving efficiency of conventional vehicles and uptake of biofuels.

Indicators: Fleet-average vehicle CO2 intensity

ID: ST1, ST2, ST3
Source: DESNZ Final UK greenhouse gas emissions national statistics; DESNZ Provisional UK greenhouse gas emissions national statistics; DfT Road Traffic statistics
Unit: gCO2

  • These indicators track the average CO2 intensity of all cars, vans, and HGVs that are on the road in the given year. We calculate real-world emissions intensities by dividing the total emissions allocated to each vehicle type in the emissions inventory by the total kilometres driven by that vehicle type, according to DfT’s published statistics. These indicators represent the average intensity across the entire vehicle fleet, including both conventional and zero-emission vehicles.
  • The Government has not set out a trajectory for either fleet efficiency or vehicle-kilometres, so we are unable to compare these indicators against a Government pathway. Instead, we have produced a benchmark trajectory for these indicators by dividing the residual emissions by vehicle type in our Balanced Pathway by our Balanced Pathway assumptions for total vehicle-kilometres. This trajectory falls steadily to very close to zero across all vehicle types by 2050.
  • Reducing the average CO2 intensity of vehicles across the fleet is the fundamental outcome required on the left-hand branch of Figure 2.1. This can be achieved through accelerating the uptake of zero-emission vehicles and improving the intensities of new conventional vehicles entering the fleet.

Required outcome: Rapid uptake of zero-emission vehicles

This group of indicators covers tracking progress on sales of zero-emission vehicles (ZEVs) and the number of ZEVs in the fleet.

  • These are important indicators to monitor, given that the transition to zero-emission road vehicles is responsible for around 80% of surface transport abatement in the Government’s Net Zero Strategy pathway in 2035.
  • It will be important to monitor sales both as a percentage of all vehicle sales and in absolute number, given that the Government’s ZEV mandate targets are set in terms of percentage market share, but the pace of the ZEV transition is dependent on the actual number of vehicles being replaced. If the overall new vehicle market is smaller, then the transition will take longer for a given percentage market share.
Indicators: Sales of electric cars and vans

ID: ST4, ST5, ST6, ST7, ST8, ST9
Source: DfT vehicle statistics; SMMT new car and van registrations
Unit: %

  • These indicators measure the number of new electric vehicle sales and their market share of total sales, with separate indicators for cars and vans. Total new vehicle sales are also recorded to give a sense of the overall market size. These indicators represent a direct measure of the pace of technological transition in the sector based on DfT’s published figures on new vehicle registrations by propulsion and fuel type. Early insight into current-year performance can be obtained from Society of Motor Manufacturers and Traders’ (SMMT’s) monthly market summaries.
  • The Government has committed to ending sales of new petrol and diesel cars and vans by 2030. These indicators track whether sales of battery-electric vehicles (BEVs) and plug-in hybrid electric vehicles (PHEVs) are ramping up at the necessary pace to achieve this.
    • Policy. The transition should prioritise BEVs over PHEVs, both as PHEVs in real-world usage can often generate similar emissions to conventional vehicles and because we expect fully electric options to represent a more cost-effective solution for consumers and for society as a whole.
    • We also present our Balanced Pathway uptake trajectories for comparison. These were based on a consumer decision model under the assumption that BEVs reach cost-parity with conventional vehicles by 2030.
  • Policy. The Government will need to make sure that both car and van sales grow at the pace required. The separate ZEV mandates applying to cars and vans should achieve this, but the Government must also ensure that the wider policy landscape supports this.
    • While EVs are more expensive to purchase than conventional vehicles, this should include targeted grants and subsidies, while effective policy will also need to ensure a robust supply of EVs to meet demand. Other EV policy needs are covered within the enabling indicators below.
Indicators: Sales of zero-emission HGVs and buses

ID: ST10, ST11, ST12, ST13
Source: DfT vehicle statistics
Unit: %

  • These indicators monitor sales of new zero-emission HGVs and buses (including coaches), both in terms of the volume of new vehicles sold and market share. Again, total new vehicle sales are also recorded for context. They are based on DfT’s published data on new vehicle registrations by propulsion and fuel type.
  • ZEV HGVs are at an earlier stage of market development. However, the Government’s commitment to phasing out new sales of diesel HGVs by 2035 for those below 26 tonnes and 2040 for those above aligns with what modelling we commissioned as part of our Sixth Carbon Budget advice expects to be feasible, provided that a supportive policy and incentive environment is in place.
    • The HGV indicators track progress towards these goals, with our Balanced Pathway uptake trajectory again presented for comparison.
    • Policy. Detailed delivery plans are required to set out how these phase-out dates will be achieved. An effective plan should build on thinking around the ZEV mandate for cars and vans as well as emerging findings from the ongoing zero-emission freight trials, and should cover the roles for regulation, support, and incentives.
  • Sales of all remaining new non-zero-emission vehicles must end by 2040. For buses, the Government proposes bringing this date forward to between 2025 and 2032. This reflects that many urban bus routes are already suitable for electric or hydrogen options. However, some longer-distance routes and coaches face decarbonisation challenges similar to those for HGVs.
    • This indicator is compared against a straight line towards an indicative 2030 end-of-sales date and also our Balanced Pathway uptake assumptions.
    • Policy. Effective bus policy must enable actions at a local level. Local authorities should be encouraged to work with bus operators to deliver fleet decarbonisation in parallel with service improvements.
    • Policy. At the same time, DfT should seek opportunities to share the data gathered from the zero-carbon HGV trials with bus and coach operators.
Indicators: Share of zero-emission vehicles in the fleet

ID: ST14, ST15, ST16, ST17
Source: DfT vehicle statistics
Unit: %

  • The objective of policies to drive the uptake of ZEVs is to ensure that, by 2050, the vast majority of the entire fleet of vehicles operating on UK roads produces zero emissions at the tailpipe. These indicators monitor progress towards this goal, through tracking of the percentage of cars, vans, HGVs, and buses on the road that are ZEVs. They are based on figures published by DfT on the number of licenced vehicles operating by propulsion and fuel type.
  • The Government’s Net Zero Strategy set out five-yearly assumptions for the share of zero-emission vehicles in the fleet for each vehicle type. These indicators are compared against these benchmarks.
  • Policy. The pace of this transition will depend on the volume of sales of ZEVs across each vehicle category, as monitored by the previous indicators. The Government will need to evaluate whether these are progressing sufficiently fast to deliver the ZEV penetration, and hence emissions savings, that are required. Later in the transition, incentives to replace older vehicles (for example scrappage schemes) may play a role.

Required outcome: Conventional vehicle efficiency

These indicators ensure that new conventional vehicles continue to deliver improving efficiency. This is important as the majority of new vehicles are still currently conventionally powered and because vehicles that are sold in the late 2020s could remain in the fleet well into the 2040s.

Indicators: New vehicle emissions intensities

ID: ST18, ST19, ST20, ST21, ST22, ST23, ST153, ST154
Source: SMMT (unpublished)
Unit: gCO2/km

  • These indicators track the average emissions intensities of new cars and vans, as measured under the Worldwide Harmonised Light Vehicle Test Procedure (WLTP) test-cycle. Past data (up to 2020) was compiled under the New European Driving Cycle (NEDC) test-cycle, and for comparability more recent data for cars have been converted from WLTP to NEDC-equivalent figures. No such conversion has been performed for vans, so data before and after this change may not be directly comparable. They are based on data collected by SMMT from vehicle manufacturers. If possible, we will expand these indicators in future to cover other vehicle types as well.
  • The indicators monitor averages across all new vehicles, across new conventional vehicles and across new non-ZEVs separately, in order to enable us to assess progress across the new vehicle fleet towards the requirement of 0 gCO2/km by 2035 and to simultaneously monitor progress in the remaining portion of conventional vehicle sales against our Balanced Pathway assumption on conventional vehicle CO2.
  • Since 1990, manufacturers delivered considerable improvements to vehicle intensities. These were largely driven by EU regulations, which required car and van emissions to reach specified standards by 2020 and set specifications for heavy-duty vehicle emissions. However, the improvements offered by these technological advancements were largely lost to two factors:
    • Increases in demand for road transport across all modes, which meant that vehicles were driving more kilometres, even if their grams emitted per kilometre was lower.
    • A trend towards larger, heavier cars such as SUVs during the 2010s. The larger weight of these vehicles makes them less fuel-efficient than smaller models.
  • Policy. Effective policy should continue to drive improvements in conventional vehicle efficiencies, particularly in market sectors where the ZEV transition will proceed more slowly, such as HGVs. At a minimum, it must avoid any regression in emissions intensities of conventional vehicles while manufacturers are prioritising investment into development of ZEVs. Furthermore, manufacturers should also be required to prioritise lighter, more efficient vehicles where possible.
Indicators: Average age of vehicles in the fleet

ID: ST24, ST25, ST26, ST27
Source: DfT vehicle statistics
Unit: Years

  • These indicators monitor the average age of all cars, vans, HGVs, and buses on the road, as reported in DfT’s registrations data.
  • Efficiencies of comparable vehicles have tended to improve over time. Furthermore, zero-emission vehicles have only become prevalent recently. Therefore, older vehicles are likely to be less fuel-efficient and have higher tailpipe emissions. It will be important to monitor this indicator to make sure that restrictions on the sale of new conventional vehicles do not have the unintended consequence of causing drivers to hold onto their existing vehicles for longer.
  • Policy. To counter this risk, policies such as the ZEV mandate should be supported by appropriate messaging and subsidy and taxation gradients that are targeted at groups for whom perceptions or cost present barriers to ZEV adoption. Later in the transition, there may be a role for rewards or scrappage schemes to encourage reluctant consumers to switch to less carbon-intensive choices.

Enablers: Robust supply of quality zero-emission vehicles

To achieve mass-market uptake, ZEVs must be widely available, reliably obtainable, and high-quality. These indicators aim to monitor these factors.

Indicators: Availability of electric car and van models

ID: ST28, ST29
Source: Office for Zero Emission Vehicles (unpublished)
Unit: Number

  • These indicators assess the number of different models of electric car and van available each year. This is based on data provided to us by the Office for Zero-Emission Vehicles (OZEV).
  • They act as a proxy for the availability of electric options, given that it will reflect increases in manufacturers offering EVs and in the breadth of their ranges. Ultimately, what we want to see is EVs becoming widely available across all market segments and at all price points. This will be vital to making EVs accessible and affordable to all consumer groups, allowing them to be adopted by the mass market.
  • Policy. An effective ZEV mandate should monitor these sorts of factors, with scope to tailor the certificate regime to encourage manufacturers to produce and sell vehicles in categories or at price points where availability is limited.
Indicator: Availability of zero-emission HGV models

ID: ST30
Source: Office for Zero Emission Vehicles [not published]
Unit: Number

  • This indicator would mirror the previous one, but for zero-emission HGVs. We hope to include this indicator in future versions of this framework once the ZEV HGV market develops and reliable data is collected.
  • Trials of ZEV HGVs at commercial scale, with vehicles in operation across a variety of operational use cases, should help stimulate this emerging market and give manufacturers confidence to invest in production of ZEVs.
Indicators: Sales of used electric cars and vans

ID: ST32, ST33
Source: SMMT used car sales data
Unit: %

  • The average car is resold three times and remains in the fleet for 14 years. Consequently, around three times as many used cars are bought every year as new cars, with many consumers only ever contemplating used options. Therefore, a robust supply of electric cars to the used car market is essential to enabling the benefits of the electric transition to be accessible to all. These indicators track sales of battery-electric and plug-in options in the used car and van markets. They are based on SMMT data on used vehicle sales.
  • Policy. Effective policy should aim to ensure that actions to drive EV uptake in the new car and van markets flow through to deliver this robust supply to the second-hand market in a timely manner. The availability and affordability of electric options across all market segments should be monitored to ensure that all consumers will be able to participate in the transition and that no groups are subject to disproportionate costs or impacts. If necessary, subsidies and grants could play a role in this market as well.
  • Clear, consistent, and trusted information on battery condition is essential to enable consumers to make confident purchases, particularly of used EVs. Research has found that EV battery capacities are typically eroded only relatively slowly, with the vast majority of range still available for the second owner and beyond. All manufacturers should make this information easily available to ensure that consumers are able to make informed decisions.

Enablers: Charging infrastructure

These indicators monitor the provision, distribution, and reliability of public EV chargers across the country. Research shows that concerns around battery range and about where to charge vehicles are the two biggest barriers to people switching to EVs. Widespread provision of high-quality, reliable public charging infrastructure will be key to addressing this.

Indicators: Number of public chargers and rapid chargers

ID: ST34, ST35
Source: OZEV EV charging devices statistics
Unit: Number

  • These indicators report on the number of public charge points available across the country, plus the share of these that are rapid chargers. They are based on OZEV’s annual publication of electric vehicle charging device statistics, with the figures for 1st January being recorded as year-end totals for the previous year.
  • These figures are compared against two benchmark trajectories:
    • A straight-line from 2021 levels to reach the minimum ambition of 300,000 public charge points by 2030 stated in the Government’s Electric Vehicle Infrastructure Strategy.
    • Our assessment of the public charging network required in our Balanced Pathway, which is based on models of local parking-based and national inter-urban charging demand developed by Systra.[1]
  • To deliver these ambitions, investment in public charging infrastructure will need to continue throughout the 2020s and 2030s to ensure that the charging network develops at a pace and quality that encourages the uptake of EVs.
    • This needs to include a mix of rapid chargers along major roads, to enable people to recharge quickly during longer journeys, and local chargers to enable people who can’t charge at home to recharge day-to-day.
    • Charging infrastructure needs to be delivered ahead of need, to ensure that drivers have the confidence to switch to an EV. This will be particularly important for enabling widespread uptake of EVs among households without private off-street parking.
    • Policy. The Government should produce clear guidance for local authorities on how to develop local charging infrastructure strategies commensurate with these ambitions. This should include both sharing of best practice between similar areas and provision of long-term, predictable funding streams to enable local authorities to develop and retain dedicated resource to tackle this challenge. Published guidance, regional expertise-sharing, and advice and resource from national bodies such as the UK Infrastructure Bank can play a role here.
    • Policy. Much of the investment in the public charging network is likely to come from the private sector, given the substantial business opportunity presented by the transition to electric vehicles. The Government’s role should be to enable and direct this investment, through appropriate regulation and de-risking, and to identify and mitigate market failures. This includes taking action to support infrastructure deployment in areas where private-sector business models are less viable.
Indicator: Reliability of public charge points

ID: ST37, ST141
Source: Zap-Map (unpublished)
Unit: %

  • Reliability is also vital to deliver consumer confidence in the ability to recharge an EV. These indicators will monitor this, separately assessing reliability of the network as a whole and of rapid charge points. They are based on an extract from Zap-Map’s national database of public chargers, showing what percentage were operational at the end of Q1 in 2022.
  • The reliability across the rapid network will be compared against the Government’s stated minimum reliability level of 99%. The indicator for the whole network should be expected to show signs of improvement over time as well, given the requirement for all charge point operators to provide support for customers who experience charging issues.
  • Policy. The Government must ensure that this does occur, so that low reliability levels do not become detrimental to public perceptions of EVs and thereby hinder uptake. This should be considered in developing local charging strategies, with local authorities funded and advised on how to ensure that new chargers will be operated and serviced reliably and how to procure support for existing networks. It could also be appropriate to extend reliability targets to wider portions of the network.

Enablers: Public and business attitudes to electric vehicles

It is not enough to deliver robust supply; people need to be willing to buy electric vehicles for uptake to proceed at the pace required. This willingness must become widespread and sceptical views not become too widespread or entrenched.

Indicators: Awareness of electric vehicles

ID: ST38, ST39
Source: DfT Transport and transport technology: public attitudes tracker
Unit: %

  • These indicators track the proportion of individuals surveyed as part of DfT’s regular public attitudes tracker who identify themselves as being aware and being knowledgeable about EVs.
  • Awareness is defined as all those who have heard of EVs, while knowledge is defined as those who say they know at least a little about them.
  • Both indicators should increase naturally as a result of car manufacturers increasing their focus on EVs, as advertising and marketing will seek to sell products to consumers. There may be a role for policy in ensuring that consumers have access to easily intelligible information to allow them to make informed purchasing decisions.
    • Policy. For example, policy could encourage vehicle manufacturers to clearly display real-world range figures and provide battery health indicators, or charge point operators to display prices in a clear, easily comparable metric.
Indicators: Next vehicle intention

ID: ST40, ST41
Source: DfT Transport and transport technology: public attitudes tracker
Unit: %

  • DfT’s public attitudes tracker also records the stated next vehicle intention of those surveyed who are planning to buy, lease or replace a car or van. These indicators record the proportion of these who say that they intend to purchase or lease either a battery-electric or any hybrid/electric model.
  • This is a self-reported intention, so it is not clear the extent to which this translates into reality. Furthermore, it gives no indication of the timescales associated with the planned purchase. Nonetheless, the evolution of the metric should give a sense of the extent to which EVs are developing mass-market appeal.
  • Achieving mass market appeal is dependent on both consumer awareness and the availability and affordability of compelling electric products.
Indicators: User experience of public EV charging

ID: ST42
Source: None

  • This indicator – depending on availability – will report the average consumer rating of the largest public charging operators.
  • This is a proxy for the user experience of the public charging network, reflecting how users are reviewing their experience of using the most common types of charge point on the network. While shifts in this indicator may reflect genuine improvements in the consumer experience, they may also be driven by evolving consumer expectations or different operators moving in or out of the subset of the network covered. Therefore, care will need to be taken in interpreting this data.
  • The Government aims to deliver an easier, more transparent, and more interoperable charging experience for EV drivers.
    • Clear public messaging on pricing and charge point capabilities (as well as on other things such as EV range) will be important in helping the mass market understand and make the switch to EVs.
    • Drivers need to be able to have confidence that they will be able to use chargers (both in terms of the payment means they have available, the user registration accounts they hold, and whether the charger is occupied) when they need them. This extends to non-EV drivers, for whom the charging experience must not appear overly complicated in order to offer a compelling alternative to driving their existing vehicle.
Indicator: Zero-emission vehicles in Government fleets

ID: ST43, ST142
Source: Defra and Cabinet Office Greening Government Commitments
Unit: %

  • The Government should aim to lead the way in implementing a transition to zero-emission mobility. These indicators track this, through the share of vehicles operating in central Government fleets that are either zero-emission or ultra-low emission.
  • The Greening Government Commitments set targets for 25% of the fleet to be ultra-low emission by the end of 2022 and 100% to be zero-emission by the end of 2027. These indicators are therefore compared against the straight-line trajectories required to meet these commitments.
  • Policy. Government departments should put in place long-term plans to transition their fleets to zero-emission vehicles, as part of a coherent cross-Government strategy led from the Cabinet Office and funded by the Treasury. Opportunities should be sought to extend these beyond central Government fleets to cover all public sector vehicles.

Enablers: Use of biofuels

In the long term, we expect that zero-emission technologies will be suitable for virtually all vehicles on the road, so consumption of fossil fuels will almost disappear in the surface transport sector. However, for some vehicle types, this transition will take a relatively long time, and so measures that can reduce emissions from these vehicles in the short-to-medium term continue to have value.

Indicator: Consumption of low-carbon road transport fuels

ID: ST44
Source: HMRC Hydrocarbon Oils Bulletin, DESNZ Greenhouse gas reporting: conversion factors
Unit: % of road transport fuel used by volume

  • This indicator monitors the percentage of road transport fuel that is supplied through biofuels.
  • Progress on this indicator is tracked against the assumed levels of low-carbon fuel used in road transport in the Government’s Net Zero Strategy and in our Sixth Carbon Budget Balanced Pathway.
  • Biofuels can be produced from waste or from specially grown crops and can be blended into petrol and diesel to displace consumption of fossil fuels. This reduces lifecycle emissions associated with the operation of the vehicle.
  • The use of biofuels to displace fossil fuel consumption in the remaining fleet of conventional vehicles is therefore sensible. Incentives and obligations to produce and sell these fuels are a valuable means of encouraging investment in these emissions-reducing fuels.
  • However, in the longer term it is important that such investment doesn’t lock-in dependency on combustion engines, since our cross-economy assessment is that the limited quantities of biomass available for biofuel production are likely to be better used in other sectors in which fully zero-emission options are not expected to become viable or where the carbon content can be sequestered (for example in construction).

Enablers: More resource-efficient vehicles

Manufacturers can lower the emissions footprint of their vehicles by producing and selling vehicles that are smaller, lighter, and make more efficient use of natural resources. This is an important part of a sustainable transport sector and is relevant to both conventional and zero-emission vehicles. These indicators reflect this.

Indicator: New vehicle size

ID: ST45
Source: SMMT (unpublished)
Unit: %

  • These indicators track the percentage of new vehicles sold that are categorised as sports utility vehicles (SUVs). This is based on data collected by SMMT from vehicle manufacturers.
  • During the 2010s, the size and weight of the average car sold increased, offsetting much of the improvements in vehicle efficiency and leading to small increases in overall sectoral emissions. This was largely manufacturer advertising of and consumer demand for SUVs.
  • This will continue to present a risk during the transition to EVs, both because of the risk of continued sales of heavy, highly polluting conventional vehicles and because heavier EVs require larger batteries (embedding more emissions and consuming larger quantities of raw materials) and produce more particulate emissions from their brakes and tyres.
  • Policy. Policies that are designed to deliver the transition to ZEVs and improve conventional vehicle intensities should also consider how they can incentivise manufacturers and consumers to prioritise more resource-efficient vehicles. This could be designed into the certification scheme for the ZEV mandate or take the form of weight-based taxation gradients, for instance.
Indicator: EV battery capacities

ID: ST46
Source: EV Database
Unit: Miles

  • This indicator monitors the real-world battery range of new EVs being sold each year. This is based on data on models available each year sourced from EV Database.
  • Increasing battery capacities lead to greater independent range, allowing EVs to travel further without needing to recharge. This is beneficial for drivers and is likely to make EVs more appealing to the mass market.
  • However, larger batteries also require more raw materials input and embed more emissions in their production, increasing the environmental impact of the vehicle. While this impact is still considerably smaller than the tailpipe emissions from conventional vehicles, it is important to balance against the benefits provided by increasing range.
  • Efficiency improvements and reductions in vehicle size can also deliver similar range increases without the need for ever-larger batteries. Furthermore, more widespread, more reliable charge points can give consumers confidence to accept lower-range models. These steps can also reduce the cost of the vehicle.

Contextual factors: Battery supply and prices

Using a battery to power a vehicle, rather than a fuel tank, entails dependency on new supply chains and materials. These indicators will track whether these are scaling up and reducing in cost at the pace required through the 2020s and 2030s.

Indicator: UK battery manufacturing capacity

ID: ST47
Source: Faraday Institution Annual Gigafactory Study

  • This indicator tracks the capacity for producing EV batteries in the UK. It is based on the Faraday Institution’s monitoring of UK battery manufacturing capacity, and records the capacity of operational battery manufacturing plants in the UK.
  • The benchmark against which this indicator is compared is provided by the Faraday Institution’s trajectory to reach nearly 200 GW of domestic production by 2040.
  • Developing and growing the EV industry within the UK will be important both in realising the economic benefits of the transition and in ensuring a smooth supply of vehicles to meet the required sales ramp-up.
    • The Faraday Institution’s trajectory was based on its assessment that gigafactories should be based in the UK, at the scale indicated, in order for the UK to reach its job-creation potential in the surface transport sector. In the absence of gigafactories, it is likely that the sector will see job losses.
    • Policy. Policy and regulation should seek to offer the industry sufficient clarity on expected demand to enable significant private-sector investment in this growing industry. Trade policy should consider how to localise as much of this investment as possible within the UK, to enhance security of supply and reduce embedded emissions within the supply chain.
Indicator: UK battery recycling capacity

ID: ST48
Source: None

  • This indicator – depending on availability of reliable data – will monitor the development of a UK battery recycling industry.
  • EV batteries require considerable quantities of valuable raw materials. If these batteries are simply disposed of at end-of-life, then these materials will be lost. Battery recycling offers a route to develop a circular economy that makes more efficient use of these resources.
  • Policy. To enable this, regulations requiring manufacturers to make batteries recyclable in a straightforward, non-proprietary manner are essential. Such policies are required before mass-market scale-up of EV uptake, to provide potential investors with confidence in future supply volumes.
    • The European Union introduced recycling requirements for EV batteries in 2021. As a result, it saw an upspring of recycling facilities.
Indicators: Raw materials supplies

ID: ST49, ST50, ST51, ST52, ST53, ST54, ST55, ST56, ST57
Source: US Geological Survey statistics
Unit: Million tonnes (known reserves) and thousand tonnes (global production)

  • These indicators monitor the annual production, and the known global reserves, of four key raw materials that are contained within EV batteries. They are based upon the US Geological Survey’s annual minerals reports.
  • The data on annual global production should give an indication of the current level of materials availability and the pace at which this is scaling up. The supporting indicator on known global reserves places this in some context, showing the amount of this material thought to be available.
  • However, it is important to note that a core aim should be to minimise the portion of these resources that need to be mined – through improving battery chemistries, recycling, and demand-side measures – to reduce potential environmental damage and embedded production emissions.
  • Policy. Good policy should regularly evaluate the availability of raw materials and take proactive steps to mitigate approaching backlogs. Furthermore, it should incentivise or require vehicle manufacturers to develop ethical supply chains, including robust measures to prevent human exploitation and reduce environmental and social impacts.
Indicator: Battery cell prices

ID: ST58
Source: Bloomberg NEF
Unit: $/kWh (real 2019)

  • The battery is the highest-cost component of an EV. Therefore, this indicator tracks the average price of an EV battery cell. It reports Bloomberg New Energy Finance’s annual data on the average cost per kilowatt-hour, converted to real US dollars for 2019.
  • We compare this indicator against the prices assumed within our Sixth Carbon Budget analysis, which were based on Bloomberg New Energy Finance’s 2020 market forecast and were the basis for our assessment that EVs will reach cost-parity with conventional vehicles by 2030.
  • Battery prices fell dramatically through the 2010s, and this decline is expected to continue (although the gradient will level off). Alongside improvements to manufacturing efficiency and economies-of-scale, this should enable manufacturers to reduce the price of the EVs they produce, bringing EVs towards cost-parity with conventional vehicles.

Contextual factors: Energy prices

These indicators will monitor the cost of charging an EV and the operational savings that EVs provide.

Indicators: Cost of petrol versus electricity

ID: ST59, ST155
Source: RAC Foundation Charge Watch, ZapMap Price Index, DESNZ Domestic Energy Price Indices, DESNZ Gas and Electricity Prices in the Non-Domestic Sector
Pence per mile (nominal)

  • These indicators compare the cost of driving a typical EV and a typical conventional car. This is based on typical fuel and energy efficiency figures and average current electricity and petrol prices. Costs are presented in nominal terms.
    • Costs are based on the RAC’s assumed efficiency assumptions for a typical car – 8.8 miles/litre for petrol/diesel and 3.5 miles/kWh for an EV.
    • Domestic charging prices are based on quarterly domestic electricity prices, while public charging costs are based on the ZapMap’s current cost per mile, scaled by historical quarterly non-domestic electricity price data.
  • Separate indicators are calculated for two indicative profiles of EV driver charging behaviour. In the first profile, the driver has access to a home charger and uses this for 80% of charging, with the remaining 20% at public rapid chargers (e.g. during longer journeys). In the second, the driver does not have a home charger, and so relies on public slow/fast chargers for 80% of charging, with the remaining 20% again at public rapid chargers.
  • The operating savings demonstrated by this indicator are expected to form a key part of the emerging economic case for choosing an EV over a conventional vehicle. This will be especially true for higher-mileage drivers, where the operating savings could outweigh any upfront cost premium relatively quickly.
    • Given that most new cars are bought on financing arrangements, spreading the cost over a series of monthly payments, these ongoing savings are relevant alongside the upfront cost.
  • Policy. Drivers who do not have access to private off-street parking will generally be reliant on the public chargepoint network for charging their vehicles. Effective policy should aim to reduce the cost of public charging for local residents to help these drivers realise similar operating cost savings to drivers who can charge at home, which is important for enabling mass-market EV uptake and delivering a fair transition.
Indicator: Cost of charging at a public charge point versus home charging

ID: ST60
Source: None

  • Subject to the availability of data, this indicator aims to track the average comparison between the cost of charging an EV on the public network and at home.
  • If public charging is considerably more expensive, this risks deterring those without access to private off-street parking from switching to an EV. Furthermore, it could lead to regressive distributional impacts, forcing those without the means to purchase or rent a property with a driveway to pay more for running a car.
  • Policy. It is important that the Government monitor this comparison and take policy action if competition between charge point operators alone proves insufficient to narrow this difference.
    • There are a variety of options available to address this issue, ranging from tax changes to equalise costs to connectivity and pavement infrastructure designed to enable more drivers to use their home energy supply in public settings.

(b) Demand-side indicators

Required outcomes: Reduced demand for carbon-intensive modes of travel

Even with the phase-out of new fossil-fuelled cars and vans by 2030, most of the vehicle fleet will be operating on petrol and diesel power until at least the mid-2030s. Therefore, reducing demand offers significant potential to cut emissions in the medium-term. These indicators will track this.

Furthermore, even once the fleet is fully zero-emission, demand reduction will still offer emissions reductions by lowering the need for electricity and reducing embedded production emissions, as well as a range of co-benefits such as reduced congestion, lower particulate emissions from tyres and brakes, and cost savings.

Indicators: Kilometres travelled by road vehicles

ID: ST61, ST62, ST63
Source: DfT Road traffic statistics
Unit: Billion kilometres

  • These indicators monitor the total vehicle-kilometres travelled on UK roads. They also report this separately for England, Scotland, and Wales to allow early identification of any divergent trends between nations. The data for these indicators is based on DfT’s published road traffic statistics.
  • This is a direct measure of the level of demand for road travel. Note, however, that DfT’s publication covers Great Britain only – to enable comparison with our Balanced pathway, we have scaled this up by 4% to approximate additional traffic from Northern Ireland.
  • These indicators are tracked against the levels of demand assumed in our Balanced Pathway. Our aim is to assess progress against the Government’s expected demand trajectories once they are made available.
  • Road traffic has increased gradually since 1990 across all modes, with cars dominating overall volumes but vans showing the largest growth.
  • Policy. Clear messaging, coupled with deliverable policy, is needed to reverse these long-standing trends.
    • Effective implementation policy can consist of a combination of measures to improve the availability, attractiveness, and affordability of alternatives to car, van, and HGV use and measures to remove distortions that encourage driving.
    • Sustainable transportation should be a core principle embedded within the planning system. This should take a whole-system approach, considering all modes of transport together, and making it easier to implement solutions that work best locally and maximise synergies between low-carbon modes.
Indicators: Car usage per person

ID: ST64, ST65
Source: DfT Road Traffic Statistics, DfT National Travel Survey, Scottish Household Survey
Unit: Billion tonne-kilometres

  • The set of headline indicators on kilometres travelled by road vehicles reflect not just individual decisions whether or not to travel by road, but also population growth. In some cases, this can mask progress, so these indicators also track the annual distance travelled by car per person.
  • This data is calculated by multiplying the total car-kilometres driven by surveyed average car occupancy levels and then dividing by population. The indicators are compared against the implied car usage per person within our Sixth Carbon Budget Balanced Pathway.
  • This approach allows us to calculate comparable estimates for England and Scotland (no occupancy data is available for Wales or Northern Ireland), which will allow us to compare performance between nations to identify any emerging divergent trends.

Required outcomes: Shift to low-carbon modes

Modal shift to lower-carbon forms of transport can reduce the emission footprint of journeys. This will be assessed through these indicators.

Indicators: Demand for active travel

ID: ST71, ST72, ST143
Source: DfT Walking and Cycling Statistics, DfT Road Traffic Statistics
Unit: Journey stages (journey stages travelled by walking and cycling) and km (km travelled by bicycle)

  • These indicators track the total number of journey stages[1] travelled by walking and cycling in England, and the total number of kilometres cycled across Great Britain. DfT’s Walking and Cycling statistics cover England only, while the Road Traffic Statistics capture cycling activity across Great Britain.
  • The Government’s Net Zero Strategy introduced two targets – to double total cycling stages (relative to 2013 levels) and increase annual walking stages to 365 per person by 2025. The indicators on cycling and walking stages will be tracked against these goals. The supporting indicator on cycling kilometres will monitor the overall impact on the total distance cycled.
  • Policy. Achieving this will require credible policy to encourage greater participation in active travel.
    • To maximise emissions savings, policy should focus on how to enable car drivers to switch their journeys to walking or cycling.
    • An effective policy landscape to enable this requires sustainable transport to be embedded centrally within spatial planning approaches, so that all developments must properly consider how they can increase the ability of residents to access local services and public transport systems actively.
    • In addition, high-quality walking and cycling facilities should be provided for existing residents that are safe and separated from traffic where possible.
  • Increasing walking and cycling also offers a variety of important co-benefits, including improved health, better air quality, lower transport costs, and reduced congestion.
Indicators: Personal travel by mode

ID: ST73, ST74, ST75, ST76, ST77, ST78, ST79, ST80, ST81, ST82, ST83, ST84, ST85, ST86, ST87
Source: DfT National Travel Survey, Scottish Government Scottish Household Survey, Northern Ireland DfI Travel Survey for Northern Ireland
Unit: %

  • This is a large collection of indicators tracking the share of journeys that people make using each form of transport as the main mode, allowing a comparison between car use, active travel, and the various forms of public transport. This is collected through travel diaries as part of the National Travel Survey in England, the Scottish Household Survey, and the Travel Survey for Northern Ireland.
  • These survey data provide insight into modal choices for journeys across the nations of the UK. Due to small sample sizes and the fact that data are collected over a three-year period rather than annually, care should be taken in comparing the Northern Irish data. No comparable data is publicly available for Wales.
  • This indicator will allow us to compare progress between the nations of the UK, identifying where divergent policy approaches are having an impact.
  • Policy. Town planning should pay particular attention to providing safe spaces for walking and cycling, including through dedicated cycle routes, low traffic neighbourhoods, and pedestrianised zones (particularly around schools), and reducing pavement obstructions.
    • Enabling people to walk or cycle instead of driving can be particularly important in delivering co-benefits in urban areas, through reductions in congestion and improvements in air quality.
Indicators: Bike and scooter sharing participation

ID: ST88, ST89
Source: CoMoUK Bike Share Survey
Unit: Number

  • Bicycle sharing schemes have become widespread across urban areas of the UK. These indicators monitor the availability of and utilisation of these.
  • Similar schemes for sharing e-bikes and e-scooters are also beginning to appear. We intend to extend these indicators to cover such schemes subject to the availability of data.
  • Policy. Shared bikes can make cycling more easily accessible to urban communities. Furthermore, they can help link up public transport networks, potentially forming a more joined-up transport system that is more viable as an alternative to car travel for local residents. Local transport policy should consider the role that such schemes can play in reducing car dependency.
Indicators: Demand for bus and rail travel

ID: ST92, ST93
Source: DfT Bus Statistics, ORR Rail Passenger Statistics
Unit: Billion-km

  • These indicators monitor the number of passenger-kilometres travelled by bus and rail each year in Great Britain. They are based on DfT bus statistics and Office for Rail and Road passenger rail usage statistics.
  • The bus statistics have been converted from a financial-year to calendar-year basis, by taking three quarters of one financial year and one quarter of the previous financial year.
  • Policy. Effective policy should aim to increase bus and rail ridership through modal shift from cars. Achieving this will require making public transport services more reliable, affordable, and interconnected. This requires good coordination between national and local policy, with central Government offering clear guidance and the necessary funding to support local authorities to work with local transport operators to deliver improvements.
    • National rail policy should ensure that new links maximise opportunities for modal shift, while Great British Railways should explore opportunities to improve quality and affordability along existing routes.
    • Enhanced bus partnerships between local authorities and bus operators should focus on delivering service improvements and trialling approaches to reduce fares.
    • Increasingly, local transport systems should be viewed holistically rather than as a collection of separate modes. Linking services, aligning timetables, and joining public transport routes to active travel and shared mobility infrastructure can provide more options for alternatives to car travel.
Indicators: Tonne-kilometres of freight moved by mode

ID: ST66 ST67, ST68
Source: DfT Road Freight Statistics, ORR Rail Freight Statistics
Unit: Billion tonne-kilometres

  • These indicators track the amount of freight moved by road and by rail within Great Britain. Respectively, these are based on DfT’s road freight statistics and the Office for Rail and Road’s rail freight statistics.
  • The Government has committed to introduce a rail freight growth target. Once the level of this target is confirmed, then the rail freight indicator will be compared against it.
  • Policy. Rail freight volumes are considerably lower than road freight volumes, and trends through the 2010s were broadly away from rail. Policy should seek to reverse this, to encourage greater use of lower-carbon modes for freight transport. This should seek to enhance the flexibility offered by rail freight, for instance through effective logistics and by designing connections with low-carbon vehicles for last-mile delivery (e.g., e-cargo bikes).
Indicators: Low-carbon modal share of travel demand

ID: ST151, ST152
Source: DfT Road Traffic Statistics, DfT Bus Statistics, DfT Walking and Cycling Statistics, ORR Passenger Rail Usage Statistics, DfT National Travel Survey, Scottish Household Survey
% of passenger-km travelled

  • These indicators show the share of total passenger-kilometres travelled that is undertaken, respectively, by public transport and active travel.
  • These shares are calculated by multiplying the total vehicle-kilometres travelled by car by the average car occupancy to estimate road passenger-kilometres, and then comparing this against published figures for walking, cycling, bus and rail passenger-kilometres.
  • These indicators will allow us to track whether policies to support alternative modes are succeeding in shifting passenger demand away from cars onto lower-carbon modes of transport.

Required outcomes: More efficient use of vehicles

For some journeys, road travel is likely to continue to be the most reasonable choice. In that case, emissions reductions can still be realised through measures that improve the efficiency of this choice, such as sharing and logistics.

Indicators: Car occupancy rates

ID: ST94, ST144
Source: DfT National Travel Survey, Scottish Household Survey
Unit: Occupants per car

  • These indicators track the average number of occupants travelling in each car per journey, for England and Scotland. They are based on the National Travel Survey and Scottish Household Survey, respectively. Similar data for Wales and Northern Ireland are not available.
  • The Transport Decarbonisation Plan committed to increasing car occupancy by 2030 but did not provide any measurable target. Therefore, these indicators will be compared against the car occupancy trajectories within our Balanced Pathway (which see a 6% increase by 2030), as a proxy for the Government’s expected increases.
  • Policy. Businesses should be encouraged to implement incentives for employees to lift share, reducing their commuting emissions footprint. This could be encouraged through more widespread reporting of business scope 3 emissions. Multiple-occupancy vehicle lanes have also proved effective in incentivising people to pool journeys.
Indicators: Shared mobility uptake

ID: ST95, ST96
Source: CoMoUK annual report
Unit: Number

  • As well as active travel and public transport, car sharing presents a viable alternative to private car travel. These indicators track the membership of car clubs and the number of such vehicles available across the UK, based on figures published in CoMoUK’s annual reports.
  • The average private car is in use only 4% of the time, so there is significant potential to improve the efficiency of this asset. Car clubs help to do this – each car club vehicle is estimated to avoid the purchase of 18.5 private cars.
    • This reduces the number of cars needing to be produced, avoiding the emissions embedded within manufacture.
    • In urban areas, this can help rebalance use of road space, making for a safer and more appealing environment for walking, wheeling, and cycling.
  • Policy. Effective policy should view shared mobility as part of a wider whole-system approach to the future of transport. While it is difficult for any single mode to provide an alternative to the flexibility afforded by a private car, high-quality public transport systems and local services connected to active travel infrastructure, supported by access to shared cars when longer/heavier-duty trips are required, could make for a viable competitor.
    • Such a vision should be embedded within guidance to local authorities and the tools (e.g., the planning framework) that they have at their disposal to deliver it. This should include provision for conveniently sited parking and charging infrastructure to ensure that car clubs are able to lead the transition to zero-emission vehicles.
Indicator: Utilisation of HGV capacity

ID: ST97
Source: DfT road freight statistics
Unit: Fraction

  • This indicator tracks the average loading factor for all HGV journeys in the UK. This is presented as a fraction of available capacity that is utilised, as published in DfT’s road freight statistics.
  • This reflects the efficiency with which the UK’s road haulage sector is operating, and therefore is important to monitor. Increases will mean that fewer HGV journeys are needed to move the same volume of goods.
  • Policy. Policy should aim to enable this to occur. This should include legal mechanisms to enable greater consolidation between competitors where vehicles are travelling on similar routes, as well as local restrictions to reduce the number of trucks entering densely populated areas each day.

Enablers: Competitive low-carbon alternatives

To offer a viable alternative to car travel, infrastructure and facilities for low-carbon travel need to be widely available. Moreover, these need to be affordable and desirable to the public in order for them to be adopted at scale. These indicators monitor these key enablers.

Indicators: Rail network electrification

ID: ST98, ST99
Source: ORR rail infrastructure statistics
Unit: Kilometres

  • These indicators track the proportion of Great Britain’s rail network that is electrified, as well as the number of new track-kilometres that have been electrified each year. They are based on the Office for Rail and Road’s annual infrastructure statistics.
  • The Government’s Net Zero Strategy set out an assessment of how many kilometres of the rail network would need to be electrified each year, based on Network Rail’s Traction Decarbonisation Network Strategy’s vision for a future decarbonised rail network. This provides the benchmark against which these indicators are compared.
  • Track electrification represents a mature technology which can be used to reduce the extent of the network that cannot be traversed by electric trains. This enables more passenger service operators to procure electric trains and allows freight operators to be more confident that electric freight trains will be able to reach the areas of the network they require.
  • Policy. To achieve this, a clear delivery plan is needed based on the Net Zero Strategy vision. A rolling programme of network electrification can ensure that gradual progress is made at the pace required and can deliver value-for-money in investment in skills and equipment. All new railway lines that are constructed must be fully electrified from inception.
Indicator: Usage of low-carbon trains

ID: ST100, ST156
Source: DfT, rolling stock database
Unit: %

  • These indicators track the percentage of the rail vehicle fleet that are powered by fuels other than diesel, and that are zero-emission. It is based on data provided by DfT, based on their rolling stock database.
  • There will likely remain portions of the rail network where full electrification does not make financial sense. Therefore, trains operating on these stretches will need to be powered through onboard fuel. At present, this often means diesel or diesel-electric hybrid trains, but in future it could include hydrogen or battery-electric locomotives.
  • DfT have set an objective to remove all diesel-only trains from service by 2040. Therefore, this indicator is assessed against the straight-line trajectory that would be needed to ensure that all trains are powered by alternative sources by this date.
  • Policy. As mentioned above, increasing the portion of track that is electrified should give operators more confidence to purchase electric rolling stock. Beyond this, investment in research and development of alternatively fuelled locomotives and incentives or mandates for adoption may be required to help operators who need to traverse non-electrified portions of the network move away from diesel options.
Indicators: Availability of high-quality cycling infrastructure

ID: ST90, ST91
Source: Sustrans data and OpenStreetMap
Unit: Kilometres

  • These indicators monitor the length of dedicated cycle routes across the UK as well as the portion of the National Cycle Network that is assessed as being in “very good” condition. The length data comes from a query applied to extract cycle route data from Open Street Map, while the network quality data is based on Sustrans’s annual reports.
  • Policy. Provision of high-quality cycling facilities is fundamental to enabling people to cycle more. Routes that are off-road or physically separated from traffic are more desirable and likely to lead to more uptake of cycling.
Indicators: Relative costs of different modes of transport

ID: ST101, ST102, ST103
Source: ONS Inflation and price indices
Unit: Index against 2010

  • These indicators track the ONS’s cost indices for motoring, bus travel, and rail travel, adjusted for inflation and indexed to 2010 to allow comparison of how these have changed in real terms.
  • The freeze in fuel duty during the 2010s stood in contrast to the typically above-inflation increases to public transport fares. As a result, public transport became more expensive in real terms, while driving became cheaper. Such developments present a barrier to modal shift away from the car. It is therefore important to track how these relative prices evolve, to see whether investments and policy decisions on public transport are helping to rebalance these costs.
  • Policy. Effective policy should include a mixture of subsidisation of low-carbon modes of travel, investment to enable private-sector competition, regulation, and guidance on better integration across the system, and measures to reduce the appeal of driving where alternatives are viable.
    • More simplified transport fares and more integrated ticketing should be used to allow the affordable use of multiple services. Previous schemes have been overly complicated, often charging for the route taken or number of services used rather than the journey from origin to destination.
    • Concessionary fares, such as railcard schemes and free bus passes, can help reduce costs for targeted groups.
    • In areas where high-quality public transport and active travel facilities are available, financial penalties (e.g., congestion charging and low-emissions zones) and non-financial ones (e.g., low-traffic neighbourhoods and parking restrictions) should be considered to reflect the wider costs of driving. These schemes should always be designed in consultation with the local communities who will be affected.

Indicators: Public transport service provision

ID: ST146, ST147
Source: DfT Bus Statistics, ORR Key Statistics by Operator
Unit: Million vehicle-kilometres

  • These indicators monitor the total kilometres driven by local buses and passenger trains across Great Britain, which acts as a proxy for the provision of public transport services.
  • The availability of regular, reliable services is vital to enable people to make the choice to switch journeys away from private cars. Service reductions and cancellations make this choice less appealing, hindering the contribution of modal shift to the sector’s decarbonisation pathway and the realisation of co-benefits.

Enablers: Public willingness to travel more sustainably

To achieve the required amount of demand reduction and modal shift, people need to be willing to travel more sustainably. The transition will need to be managed well, ensuring that sustainable transport modes are affordable, reliable, widespread, frequent, and integrated compared to carbon-intensive modes of travel.  These indicators monitor public decisions and perceptions around lower-carbon modes of travel.

Indicators: People choosing more sustainable modes

ID: ST109, ST148
Source: DESNZ Public Attitudes Tracker
Unit: %

  • These indicator track the proportion of people that are opting to walk, cycle, or take public transport instead of using a car. This is self-reported data on whether people are doing this more than they used to, as captured through DESNZ’s annual public attitudes tracker.
  • This indicator is self-reported based on individuals’ perceptions of whether they are doing this more than they used to. As such, if people’s baseline expectations evolve, then achieving an increase in these indicators could become more or less challenging. This should be borne in mind when interpreting trends in these indicators.
  • Policy. As the Government strategies push for improvement and greater usage of sustainable transport modes, public willingness to switch their journeys to these modes should increase. Public engagement strategies should ensure that people are aware of these improvements and that they understand the actions they can take to reduce their transport emission footprints.
Indicators: Support for encouraging alternative modes of travel

ID: ST110, ST111
Source: DESNZ Public Attitudes Tracker
Unit: %

  • DESNZ’s public attitudes tracker also asks questions on support for the Government to encourage the use of alternative modes. These indicators track the responses to these question on support for increasing active travel and public transport instead of driving.
  • As the public become more aware of the dangers of climate change, the damaging emissions generated by fossil-fuelled vehicles, and the alternatives available through active travel and public transport, we would expect to see this indicator increase. The comparison between the indicators for the two modes also provides interesting insights into consumer preferences between modes.
Indicator: Attitudes towards car-sharing

ID: ST112
Source: DESNZ Public Attitudes Tracker
Unit: %

  • This indicator monitors public attitudes to car sharing through a similar question from DESNZ’s public attitudes tracker on support for the Government to encourage more use of car-sharing.
  • Expanding availability and understanding of car-sharing schemes will be important to growing public appreciation of the role that shared mobility can play in the future transport system. The most effective role of such schemes is likely to be as part of a wider transport system that allows consumers to use a mix of modes for their day-to-day activities, in place of the flexibility of private car ownership.

Enablers: Supportive tax and spending regimes

A key enabler of progress on both the demand and supply sides is that Government taxation and spending plans should be designed to incentivise consumers to adopt less carbon-intensive modes of travel. These indicators monitor the focus and outcomes of Government spending.

More broadly, the transition to electric mobility is likely to require fundamental changes to the UK’s transportation tax regime, to offset the reduction (and eventual elimination) of fuel duty receipts (Main Report, Box 3.3).

Indicators: Transport investment by mode

ID: ST104, ST105, ST106
Source: DfT Transport Statistics Great Britain
Unit: £ million (outturn prices)

  • The Government makes capital investments in infrastructure for a variety of transport modes. These indicators track the magnitude of these investments, based on their annual publication in Transport Statistics Great Britain.
  • How these investments compare across modes can give a sense of the political priority being given to providing alternatives to high-carbon travel.
  • The Road Investment Scheme 2 allocated £24 billion of funding to the national road network over the period 2020-2025. While nearly half of this was for ongoing operations and maintenance, a significant portion was allocated towards construction of new road links which may induce more demand.
    • Modelling and case studies have found evidence that road network expansion tends to lead to increases in road travel demand. European studies typically suggest an induced demand ratio of around 0.2 – that is, a 10% increase in road capacity leads to a 2% increase in traffic.
    • Moreover, UK studies have found that reductions in road capacity often lead to decreases in overall traffic (Cairns, S. et al. (2002)).
  • Policy. Decisions on roadbuilding should take these factors into account and consider how such implications can be consistent with a Net Zero-aligned future transport system.
    • Effective policy does not necessarily have to preclude all new roads but should ensure that these can only be approved subject to rigorous analysis of their lifetime emissions impacts and thorough assessment of alternative approaches that could deliver similar benefits with lower emissions.
    • Approaches that could mitigate induced demand should be considered as part of this analysis. For instance, this could include concurrent investment in local public transport systems or introduction of tolls or traffic/parking restrictions to manage road usage.
Indicators: Length of the road network

ID: ST107, ST108
Source: Transport Statistics Great Britain; Road Condition Statistics
Unit: Kilometres (length of road network), % (condition of road network)

  • This indicator tracks the length of roads across Great Britain.
  • This indicator is a direct measure of the length of new road being constructed every year, which is likely to induce additional traffic demand as discussed above.

Contextual factors: Technological and societal shifts

The COVID-19 pandemic accelerated previous trends towards remote working and the use of videoconferencing. These trends allow for reductions in commuting and business travel. Similarly, increases in online shopping allow for lower personal travel to retail locations. These indicators monitor the impacts of such trends.

Indicators: Travel by purpose

ID: ST113, ST114, ST115, ST116, ST117
Source: DfT National Travel Survey
Unit: %

  • These indicators monitor the percentage of car-kilometres driven for each purpose.
  • The overall aim is to reduce (or limit growth in) the total number of car-kilometres travelled.
  • Policy. As well as supporting investments in alternative modes and taking actions to restrict driving where appropriate, effective policy to limit growth in car-kilometres should be flexible to respond to new opportunities to lower the need for driving for particular purposes.
    • The advent of hybrid forms of working during the pandemic was one such example. This enabled some workers to commute less often, or at more flexible times, potentially reducing emissions. When such shifts emerge, the Government should rigorously assess the associated benefits and impacts and provide clear messaging on consumer behaviours that can realise emissions savings and co-benefits in response.
    • In future, further technological and societal shifts, such as the advent of connected and autonomous vehicles, could further transform our transportation landscape. Policy will need to adapt in response to any such changes, emphasising the importance of robust monitoring and evaluation.
Indicators: Goods ordered for delivery

ID: ST118, ST119, ST120, ST121, ST122
Source: DfT National Travel Survey
Unit: %

  • These indicators track shifts in households’ frequency of ordering goods by telephone, post, or online.
  • They demonstrate the rapid growth in online shopping since the early-2000s, providing contextual explanations for the gradual fall in car-kilometres for the purpose of shopping and the rapid rise in van traffic (particularly in urban areas).
  • Reducing the need for people to drive to retail outlets is a positive. However, the resulting growth in van and HGV traffic offsets much of this, and poses risks in terms of urban congestion, air quality, and disruption to local streetscapes.
  • Policy. Policy should seek to minimise the number of vehicles and trips needed to deliver goods, while still enabling consumer participation in e-commerce.
    • As mentioned in the section on utilisation of HGV capacity above, improved logistics and better use of consolidation, including between competitors where appropriate, have a role here. Consolidation centres could also be linked to rail freight terminals.
    • More micro-consolidation centres could allow more widespread use of e-cargo bikes to make the last mile of deliveries greener.
    • Consumer expectations and decision-making are also important. Incentives to choose slower delivery or delivery to shared lockers could allow delivery routes and scheduled to be planned more efficiently, reducing the number of length of trips that are required.


[1] These are described in Box 2.6 in our Sixth Carbon Budget Methodology Report.

[2] A stage is a portion of any journey undertaken using the transport mode specified.

Future improvements

Planned updates to the indicator framework

Our approach for monitoring progress in surface transport is evolving, and we anticipate adding the following indicators to our framework:

  • Vehicle cost comparisons. We have updated our framework this year to include a comparison of the cost per mile of driving an EV versus a petrol car. This is based on the efficiencies of typical vehicles and assumptions around user charging behaviour, which will vary for each driver. We also attempted to develop an indicator on the purchase cost surplus of EVs based on an ad-hoc comparison between the top-10 selling EVs and roughly comparable conventional cars. However, we have not included this indicator in this Monitoring Framework due to the difficulty in ensuring a robust like-for-like comparison that is meaningful for year-to-year comparison. We will continue to explore opportunities to refine the methodology to make it sufficiently robust for inclusion as more data becomes available. As EVs become more widely available across all market segments, market-wide averages will become more meaningful.
  • Demand in urban settings. Various metropolitan transport authorities publish data on levels of traffic and demand for other modes (e.g., public transport and active travel) in their towns and cities. It could be beneficial to monitor these data to identify places where local policies are having a positive impact on transport usage patterns and to track progress towards the Government’s goal of half of journeys in towns and cities being walked or cycled by 2030.
  • Air quality metrics. Electric vehicles will continue to have impacts on air quality through brake, tyre, and road wear. It will therefore be important to monitor levels of particulates, particularly in congested areas and near major roads.

Data gaps

There are also areas where lack of granular or regular data is impeding our ability to measure progress. This is particularly the case for monitoring demand-side actions and the fairness of and perspectives on the transition for surface transport. We intend to add the following areas to our framework when credible data sources are available:

  • UK battery recycling capability. Sustainable and cost-effective production of batteries is vital to delivering the EV transition. The Government should set out a strategy to delivering this, including regulations to ensure recyclability of batteries and development of an onshore recycling industry, and should publish data to enable tracking of progress.
  • EV ownership costs. Reliable, comprehensive data on the cost of owning an EV, as well as how this compares to the cost of a conventional vehicle, would help in tracking the affordability of the transition. Ideally, this would include purchase and fuel costs (which could be used to replace our ad-hoc comparisons described above) as well as wider costs such as annual servicing and maintenance costs and insurance premiums.
  • EV charging costs. We have included data on average costs of EV charging, based on third-party sources which aggregate prices across the industry. However, commercial confidentiality issues hinder our ability to compare the electricity prices available to drivers in different locations and at different types of charger. It would be useful to be able to monitor this, ideally separately for different types of charger and different regions, to identify risks to the fairness of the transition and understand what sorts of business models are able to mitigate these.
  • Public attitudes. While the DESNZ Public Attitudes Tracker and the DfT Transport and Transport Technology surveys do collect some useful data on consumer awareness and decision-making, a greater breadth of attitudinal data, ideally collected on a regular basis with consistent questions, would allow us to spotlight potential opportunities and identify emerging barriers.
  • Demand-side targets. The UK Government[3] needs to set more measurable targets, particularly on overall vehicle-kilometres, to help contextualise our indicators on transport demand. This would allow monitoring of whether policies are having sufficient impact to deliver the demand-side contribution to the sector’s decarbonisation pathway.
  • Demand-side data. The devolved nature of many aspects of transport demand policy mean that many data sources are collected separately for each nation of the UK. As such, it can be difficult to obtain consistent data across the country. In particular, Northern Ireland does not currently collect and report data on vehicle-kilometres travelled by mode.
  • Modal shift. Modal shift is a difficult concept to understand through the available data. For instance, we are not aware of any time series tracking changes in transport usage directly – that is, how many new users of active or public transport have shifted from a journey that they would previously have undertaken by car. This understanding may prove particularly important as we try to assess the role of novel transport modes such as e-bikes and e-scooters.
  • Usage and uptake of novel transport modes. Usage and uptake of e-bikes, e-cargo bikes, and e-scooters are not currently captured through DfT’s or the devolved administrations’ road traffic, travel, or vehicle statistics publications. Similarly, data on zero-emission HGVs and buses is less granular than for cars. As these novel modes become more prevalent, it will be important for these data collections to be extended to retain relevance.
  • Demand by vehicle type. One concern about the transition to EVs is the potential for rebound effects, whereby drivers drive more as a result of the lower ongoing costs. We have not been able to find any data tracking the total mileage driven by vehicle type – this would be useful to assess the potential scale of these effects and enable quantification of the co-benefits of demand reduction.

[3] The Scottish Government has introduced a 20% demand reduction target by 2030.

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