Comprehensive Transport Emission Reduction Planning
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Comprehensive Transport Emission Reduction Planning
Guidelines for Evaluating Transportation Emission Reduction Strategies
7 June 2022
Todd Litman
Victoria Transport Policy Institute
Most current emission reduction plans devote far more funding to electric vehicle subsidies than to active
and public transport improvements, despite these modes’ large co-benefits. That is inefficient and unfair.
Abstract
Many jurisdictions have ambitious greenhouse gas emission reduction targets and plans. This study
critically evaluates the methods used to develop these plans. It finds that the analysis is often biased in
ways that exaggerate the benefits of clean vehicles such as hybrid and electric automobiles, and
undervalue vehicle travel reduction strategies such as transportation demand management (TDM)
programs. Many plans are overly-optimistic about clean vehicle fleet implementation speed and
effectiveness, and underestimate TDM effectiveness. They often overlook the slow pace of fleet
electrification (particularly for fuel intensive vehicle types such as SUVs and light trucks), clean vehicle
lifecycle emissions, rebound effects, plus the high costs and inequities of clean vehicle subsidies. Most
plans overlook some of the most effective TDM strategies and their co-benefits, and underestimate the
price elasticity of vehicle travel. As a result of these biases, most current emission reduction plans
overemphasize clean vehicles and underemphasize vehicle travel reductions compared with what is
optimal. This study suggests that to be efficient and equitable, transportation emission reduction plans
should rely at least as much on vehicle travel reductions as on clean vehicle strategies, with particular
emphasis on “quick win” strategies. It provides recommendations for improving analyses.
Todd Alexander Litman © 2021-2022
You are welcome and encouraged to copy, distribute, share and excerpt this document and its ideas, provided the author is given
attribution. Please send your corrections, comments and suggestions for improvement.
Comprehensive Transportation Emission Reduction Planning
Victoria Transport Policy Institute
Introduction
Many jurisdictions and organizations have ambitious climate change (also called Greenhouse Gas or
GHG) emission reduction goals and targets, and are developing plans to achieve them (1, 2). For
example, President Biden recently established a target to reduce U.S. GHG emissions 50-52% by 2030
(3). Since transportation is one of the largest emission sources, it is a major component of such plans.
There are many possible ways to reduce transportation emissions. These include “clean vehicle”
strategies that reduce emission rates, and transportation demand management (TDM) and Smart
Growth policies that reduce total vehicle travel, as summarized in Table 1.
Table 1 Examples of Emission Reduction Strategies (4, 5, 6, 7, 8, 9)
Clean Vehicles Vehicle Travel Reductions
Technologies and policies that reduce emission TDM and Smart Growth policies that reduce
rates per vehicle-mile total vehicle travel
Multimodal planning (improve walking, bicycling,
Shifts to more efficient and alternative fuel vehicles
public transit, ridesharing, etc.)
(e.g., hybrid, electric and hydrogen).
Smart Growth policies that create more compact
High emitting vehicle scrapage programs.
and multimodal communities.
Efficient driving and anti-idling campaigns.
Transportation Demand Management programs
Switching to lower carbon and cleaner fuels. (commute trip reduction, freight transport
Inspection and maintenance programs. management, etc.)
Resurface highways. More efficient road, parking and vehicle pricing.
Roadside “high emitter” identification Vehicle parking policy reforms.
Increase fuel prices by reducing subsidies and increasing taxes (encourages both types of strategies)
“Cleaner vehicles” reduce per-mile emission rates. Vehicle travel reductions reduce total motor vehicle travel.
Fuel price increases help achieve both.
Which strategies are most effective and beneficial overall? That depends on how they are analyzed. This
study critically evaluates the analysis methods used in typical emission reduction plans, including the
types of strategies considered, models used to predict their effects on travel and emissions, and the
scope of benefits and costs considered in analysis.
This is an important and timely issue. Large and rapid emission reductions are needed to protect the
world’s climate. It is important to identify the most effective and beneficial ways to achieve these goals.
Transportation policies have broad economic, social and environmental effects; it is important that
emission reduction analysis be comprehensive, accounting for all impacts. This study provides specific
recommendations for improving emission reduction planning methods.
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Comprehensive Transportation Emission Reduction Planning
Victoria Transport Policy Institute
Emission Reductions Plans Reviewed
Below are summaries of emission reduction plans evaluated in this study.
Accelerating Decarbonization of the U.S. Energy System (https://bit.ly/3mBYh5k) by the National
Academy of Sciences. This major study identifies actions needed to reach net-zero emissions by
2050. Its transportation goals include 50% zero-emission vehicle sales by 2030, more multiple
occupancy vehicle trips, and urban planning changes to facilitate biking and walkability. It ignores
rebound effects, parking policy reforms, and efficient transportation pricing.
Accelerating Climate Action in Israel: Refocusing Mitigation Policies (doi.org/10.1787/fb32aabd-en)
by the OECD. This study emphasizes the need to reduce vehicle travel and encourage electrification
using efficient pricing, multimodal transport planning, and more compact, accessible development.
All Hands on Deck: An Assessment of Provincial, Territorial and Federal Readiness to Deliver a Safe
Climate (https://bit.ly/3CRU2sA) by the Pembima Institute. It evaluates Canadian emission reduction
policies. It recommends vehicle electrification but does not mention vehicle travel reductions.
An Actionable Vision of Transport Decarbonization, (https://bit.ly/2mBWtZm) by the Global Climate
Action Agenda Transport Team. This study identifies ways to achieve significant emission reductions
and other sustainable development goals. It identifies “quick win” actions that include transport
planning reforms, electric vehicle recharging infrastructure, freight efficiency, car- and bike-sharing,
active and public transport (particularly bus) improvements, better traveler information systems,
phase-out fossil fuel subsidies, carbon taxes, and more efficient road and parking pricing.
Blueprint 2030: An All-In Climate Strategy for Faster, More Durable Emissions Reductions
(www.americaisallin.com/blueprint-2030) describes a whole-of-society approach to cut emissions by
at least 50% by 2030 and set the stage for full decarbonization before mid-century. Transportation
policies emphasize vehicle electrification, but also include public transit investments and more
compact and multimodal community development.
Canada’s Net Zero Future: Finding Our Way in the Global Transition (https://bit.ly/3pgk29c) by the
Canadian Institute for Climate Choices. This report recommends electric vehicle and biofuel
development, plus increased use of public transit and active transportation.
Clearing the Air: Transportation, Land Use and Carbon Emissions in Metro Vancouver
(https://bit.ly/3rJjkE3) by the David Suzuki Foundation. This study evaluates a relatively small set of
transportation emission reduction strategies using an outdated transportation model. It concludes
that TDM and Smart Growth policies provide small emission reductions in Vancouver, Canada.
Climate Action Plan for Transportation Infrastructure (CAPTI) (https://calsta.ca.gov/subject-
areas/climate-action-plan) by the California State Transportation Agency. This report provides
specific guidance for changing transportation investments to support sustainability goals.
The Compact City Scenario (www.itdp.org/multimedia/the-compact-city-scenario) by ITDP and the
University of California, Davis. Analysis concludes that achieving emission reduction targets will
require both compact cities developed for walking, cycling and public transit, as well as a rapid and
strategic transition to electrified vehicles, as illustrated in Figure 1.
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Comprehensive Transportation Emission Reduction Planning
Victoria Transport Policy Institute
Figure 1 The Compact City Scenario, The Only Way to 1.5° (https://bit.ly/33LCy45)
Decarbonising Transport (https://bit.ly/3t9zsB6) by the UK Department for Transport identifies ways
that Britain will achieve its target of eliminating climate emissions by 2050. These include
accelerating a shift from automobile to active and public transport (with the goal that by 2030, half
of all urban journeys will be by bicycle or walking), more efficient goods delivery, fleet
decabonization, behaviour change and community-based emission reduction programs.
Draft Advice for Consultation (https://bit.ly/3jQJTDC) by the New Zealand Climate Change
Commission. This study evaluates emission reduction strategies based on the degree they support
other strategic goals. It recommends urban planning reforms, active mode improvements, freight
management, reliable and affordable shared transport, plus electric or low-emission vehicles.
Driving Down Emissions: Transportation, Land Use and Climate Change, (https://bit.ly/3tLZBEw) by
Transportation for America and Smart Growth America. This report argues that large emission
reductions are possible by meeting the demand for housing in accessible, multimodal communities.
Driving California’s Transportation Emissions to Zero (https://escholarship.org/uc/item/3np3p2t0)
by the University of California’s Institute of Transportation Studies. This study identifies ways that
California can achieve carbon-neutral transportation by 2045. It states that, “Reducing VMT in
California from light, medium, and heavy-duty vehicles is a critical part of reducing transportation
system GHG emissions.” It identifies some TDM strategies such as carsharing and ridehailing, public
transit improvements and road pricing, but overlooks parking reforms and Smart Growth policies.
Handbook for Analyzing Greenhouse Gas Emission Reductions, Assessing Climate Vulnerabilities, and
Advancing Health and Equity (www.caleemod.com/handbook/index.html), by the California Air
Pollution Control Officers Association. The Handbook provides methods to quantify GHG emission
reductions from a specified list of measures, primarily focused on project-level actions. The
Handbook also includes a method to assess potential benefits of different climate vulnerability
reduction measures, as well as measures that can be implemented to improve health and equity.
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Comprehensive Transportation Emission Reduction Planning
Victoria Transport Policy Institute
Halfway There: Energy Efficiency Can Cut Energy Use and Greenhouse Gas Emissions in Half by 2050,
(https://bit.ly/3yiQuwM) by the American Council for an Energy-Efficient Economy. This report
identifies ways to halve pollution emissions through various government policies and investments. It
concludes that the largest transportation savings come from more efficient and electric vehicles,
plus new mobility options including ride sharing, car sharing, public transit improvements, telework,
pedestrian- and bike-friendly streets, and more compact development.
Better Access to Urban Opportunities: Accessibility Policy for Cities in the 2020s
(https://bit.ly/3mBCf2B) by the LSE Cities and the OECD for the Coalition for Urban Transitions. This
report identifies public policies to integrate climate emission reduction and social equity goals into
pandemic recovery programs by creating more accessible and efficient cities.
50 Steps Toward Carbon-Free Transportation: Rethinking U.S. Transportation Policy to Fight Global
Warming (https://bit.ly/3j7G10N) by the Frontier Group. This report provides an agenda for
reforming current policies that increase vehicle emissions. It recommends vehicle electrification,
Smart Growth development policies, more shared mobility, active and public transport
improvements, road space reallocation, efficient transport pricing, and deployment of new
technologies that reduce emissions.
Net Zero by 2050: A Roadmap for the Global Energy Sector, International Energy Agency. This report
describes various changes in energy production and consumption required to achieve net zero by
2050. The proposed pathways rely primarily on fuel shifting and energy efficiency gains, including
shifts to low carbon fuel vehicles (particularly electricity). Behavior changes, “such as replacing car
trips with walking, cycling or public transport, or foregoing a long‐haul flight” are expected to
achieve an estimated 4% of emission reduction targets.
Project Drawdown (https://drawdown.org) is a major planning exercise that identifies and evaluates
various emission reduction technologies. It identifies outcome, such as cleaner vehicles and mode
shifting, but gives little attention to the policies and incentives needed to achieve these outcomes,
such as TDM incentives and Smart Growth development policies.
Transport and Climate Change Global Status Report (https://tcc-gsr.com), by Sustainable Low
Carbon Transportation (SLOCAT). This detailed (365-page) report evaluates transport’s contribution
to climate change, ways to reduce emission, and various success stories. It emphasizes the
importance of balancing climate action with other development goals, and so advocates avoid-shift-
improve prioritization which favors vehicle travel reductions over clean vehicle strategies.
Transport Climate Action Directory, (www.itf-oecd.org/tcad-measures) by the International
Transport Forum. This website describes over 60 climate mitigation strategies, including their
emission reductions, costs and co-benefits. It includes many TDM and Smart Growth policies.
Transport Strategies for Net-Zero Systems by Design (https://bit.ly/31Qi1Ll) by the OECD. This report
applies a well-being lens to transport emission reduction planning. It concludes that induced
demand, urban sprawl and the erosion of active and shared transport modes results in car
dependency and high emissions. It recommendations emission strategies that improve well-being
such as street redesign, compact development and shared mobility. It concludes that these policies
increase the effectiveness and public acceptability of carbon pricing and vehicle electrification.
5Comprehensive Transportation Emission Reduction Planning
Victoria Transport Policy Institute
Updated NDCs – What Do They Say About Transport? (https://bit.ly/3febltV) by Changing Transport.
This study evaluates National Determined Contributions (NDC), which identify how countries plan to
achieve their emission reduction targets. Of 47 submissions only eight include specific transport
emission reduction targets, 11 specify other transport targets such as electric-vehicle adoption
rates, 57% shift travel to resource-efficient modes, while only 6% aim to reduce total travel.
Zero Carbon Action Plan (ZCAP) for the United States (www.unsdsn.org/Zero-Carbon-Action-Plan) by
the Sustainable Development Solutions Network. This major study recommends that 30% of new
vehicles be electric by 2030 and per capita vehicle travel be reduced 25% by 2050. To achieve those
targets it recommends shifting funds from roadways to resource-efficient modes, plus more
compact development. It recommends linking transportation funding to VMT reductions. It states,
“Transportation is generally seen as the most challenging sector to decarbonize, but it may also
prove one of the least costly—even eventually providing large economic saving. It is also the sector
with the greatest opportunity to provide a large number of associated co-benefits to travelers and
society and to create a more environmentally sustainable and equitable society.”
The report, Changing Transport, Summary Analysis evaluated the commitments and goals to
decarbonise transport in the Nationally Determined Contributions (NDCs) submitted to the United
Nations Framework Convention on Climate Change found that more than half of emission reduction
actions encourage fuel shifting and less than a quarter encourage vehicle travel reductions.10
Most studies focus on technical solutions, such as shifts to hydrogen and electric vehicles, with the
assumption that these fuels will be produced by renewable electricity. Many mention transportation
demand management, such as active and public transport improvements, but they are often assumed to
have limited potential, high costs, and little public support. A few studies recognize other sustainable
development goals and co-benefits of vehicle travel reduction strategies such as social equity (and
therefore improving accessibility for non-drivers), public health and safety, and reducing sprawl-related
costs. A few apply avoid-shift-improve prioritization which favors vehicle travel reductions over other
strategies. Few recognize rebound effects (the additional vehicle travel) caused by energy efficient and
alternative fueled vehicles. Some such as California’s Climate Action Plan for Transportation
Infrastructure, describe major planning and funding reforms required to achieve sustainability goals.11, 12
These studies also vary in the perspective and scope of strategies that are considered. Some only
consider outcomes, such as people driving less or using electric vehicles, while others consider the policy
reforms and incentives that will required to motivate these changes, such as more multimodal
transportation planning, carbon taxes, road pricing and parking policy reforms.
A critical analysis of current transportation planning practices finds that the majority of government
investments continue to favor automobile transportation, as illustrated below, contradicting strategic
goals to reduce vehicle travel.
6Comprehensive Transportation Emission Reduction Planning
Victoria Transport Policy Institute
Common Analysis Biases
This section describes various biases found in the emission reduction plans evaluated.
Unrealistic Fleet Turnover Predictions
Many plans use overly optimistic fleet turnover predictions. For example, the Clearing the Air report
assumes that current policies will eliminate conventional vehicles by 2030 and cause 90% of vehicle
travel will be electric by 2050, as illustrated below. These assumptions are unrealistic.
Figure 2 Percentage of Different Types of Personal Vehicles on the Road (13)
The “Clearing the Air” report assumes,
unrealistically, that all vehicles will be
efficient or zero emission vehicles by
2030. This exaggerates clean vehicle
benefits.
(ICE = Internal Combustion Engine; VES
= Vehicle Emission Standard)
Electric vehicles are relatively costly and face obstacles including limited range and limited recharging
infrastructure (14). Since only about 5% of vehicles are replaced each year, it takes decades for new
technologies to fully penetrate a fleet unless many operable vehicles are scrapped prematurely. Electric
vehicles currently represent less than 2% of new vehicle sales. Although new vehicles tend to be driven
more annual miles than older vehicles, this is offset by the fact that electric versions of fuel-intensive
vehicle types (SUVs, light truck and vans) are developing more slowly than cars, so the remaining fossil
fuel fleet will be extra energy intensive. Optimistically, half of new vehicles could be electric by 2030, but
realistically it will probably take longer, and remaining fossil fuel vehicles will skew to low fuel economy
(15). With current policies, the fleet is unlikely to be fully electric by 2050, as illustrated below (16).
Figure 3 Optimistic and Realistic Electric Vehicle Sales and Fleet Penetration
100%
Optimistically, half of new
15-20 year lags
vehicle sales could be electric
80% Optimistic by 2030, but realistically it will
Sales Optimistic probably take longer, and
Realistic Fleet since only about 5% of vehicles
60%
Percent
Sales are replaced each year, it
takes 15-20 years before a
40% Realistic Fleet percentage of vehicle sales are
reflected in the fleet. With
20% current policies it is unlikely
that the fleet will be full
0% electric before 2050.
2020 2025 2030 2035 2040 2045 2050
7Comprehensive Transportation Emission Reduction Planning
Victoria Transport Policy Institute
A recent study by the Carnegie Mellon University, Decarbonizing US Passenger Vehicle Transport Under
Electrification and Automation Uncertainty has a Travel Budget, also concluded that vehicle travel
reductions are needed to reduce automobile emissions 80% by 2050 (17). Similarly, detailed analysis by
the State Smart Transportation Initiative predicts that current vehicle electrification efforts will fail to
achieve emission reduction targets, particularly if vehicle travel continues to grow, as illustrated below.
Figure 4 Predicted Emissions Based on U.S. EIA’s Annual Energy Outlook (18)
With current vehicle travel growth, due in part to rebound effects from vehicle electrification and
automation, fleet electrification will not achieve 2050 emission reduction targets.
Outdated Transportation Models
Emission reduction plans use transportation models to predict how a policy will affect vehicle travel and
emissions. Many of these models are outdated and inaccurate. For example, a major study, The Impacts
of Land Use and Pricing in Reducing Vehicle Miles Traveled, predicted that a 25₵ per mile VMT fee,
equivalent to a $5 per gallon fuel tax, would reduce affected vehicle travel just 15% (19). It explains,
“This is due to the low price-elasticity of vehicle travel demand – a known feature of travel behavior that
can be attributed partially to the lack of competitive alternative modes of travel in much of the region.”
Such low elasticity values are based on studies performed in the U.S. during the last quarter of the
Twentieth Century when employment rates and wages were increasing, and fuel prices were relatively
low, which showed very low price elasticities (20). More recent studies indicate that vehicle travel is two
or three times more price sensitive than older models assume (21, 22). These biases can significantly
affect analysis results. For example, if an older model predicts that a price change will reduce vehicle
travel 5%, the actual long-term impact is likely to be 10-15%. Similarly, if it predicts that electric vehicles
will be driven 10% more annual miles than comparable fossil fuel vehicles, the true rebound effect is
probably 20-30%. Older models also underestimate TDM and Smart Growth emission reductions (23).
8Comprehensive Transportation Emission Reduction Planning
Victoria Transport Policy Institute
Rebound Effects
Because cleaner vehicles generally have lower operating costs they tend to increase total vehicle travel
and associated costs. For example, electric cars cost are about half as much to operate as a comparable
fossil fuel car, which typically increases vehicle-miles 10-30% (24, 25). This is called a rebound effect, and
the additional vehicle-miles are called induced vehicle travel. Although there are still net emission
reductions – a 10-30% rebound effect leaves 70-90% net savings – the induced travel increases
congestion, infrastructure costs, crashes, and sprawl-related costs. The additional travel provides user
benefits, otherwise motorists would not drive more miles, but these tend to be modest since the
additional travel consists of marginal-value vehicle-miles that users are most willing to forego if their
costs increase.
Lifecycle Emissions Figure 5 Life-cycle GHG Emissions (24)
Many plans exaggerate clean vehicle benefits by Tailpipe
250
Emission Grams Per Km
ignoring embodied emissions emitted by vehicle and Battery Production
fuel production, plus the additional weight of 200 Vehicle Production
electric vehicles (their batteries typically add 500 to 150 Fuel Production
1,200 pounds), which increases tire particulate
100
emissions and crash risks (26, 27). Hybrids typically
reduce emissions by a third and electric cars by two- 50
thirds compared with comparable fossil fuel vehicles 0
(28, 29), as illustrated right. This is good, but it is an Avg. Prius Hybrid Nisson Leaf Nisson Leaf
exaggeration to call them “zero emission” vehicles. European Car Europe U.S.
By increasing total vehicle travel and sprawl they Electric vehicles typically reduce emissions 60-80%
increase emissions from road and parking compared with a comparable fossil-fuel vehicle. It is an
infrastructure and by displacing carbon- exaggeration to call them “zero emission vehicles.”
sequestering natural lands.30
High Costs and Subsidies of Cleaner Vehicles
Electric vehicles are currently expensive and receive various subsidies, as summarized in Table 2. Since a
typical gasoline car produces about seven annual tonnes of carbon, compared with two for an electric
car, electric vehicle emission reductions cost $100-400 per tonne, which is higher than many other
strategies (31). These costs may decline as electric vehicle technologies improves, but until a vehicle-
miles tax is applied, electric vehicles they will continue to receive approximately $300 annual subsidy in
avoided road user taxes, representing approximately $60 cost per ton of emissions reduced.
Table 2 Typical Electric Vehicle Subsidies (32)
Subsidy Annual Value
Corporate Average Fuel Economy (CAFE) credits ($4,700 over 15 years) $313
Purchase subsidy ($5,000 over a 15-year vehicle life) $333
Electric vehicle recharging stations (50 free annual recharges costing $2.50) $125
Road user fee exemption (12,500 annual miles, 20 mpg, 50₵ tax per gallon) $310
Total Annual Subsidy $1,081
Electric vehicles receive various subsidies that currently total more than $1,000 per year.
Many analyses overlook battery replacement costs. Batteries typically last 80,000 to 160,000 miles and
cost $5,000 to $15,000, averaging about 5₵ to 15₵ per vehicle-mile (33). Costs per Kwh are declining,
but battery sizes and costs are increasing to improve performance and range.
9Comprehensive Transportation Emission Reduction Planning
Victoria Transport Policy Institute
Scope of Vehicle Travel Reduction Strategies Considered
Most emission reduction plans consider a limited set of vehicle travel reduction strategies, and omit
some of the most effective. They often include active and public transport improvements, vehicle
sharing, telework, and sometimes road pricing and transit-oriented development, but few include least-
cost transportation planning, pay-as-you-drive (PAYD) pricing, efficient parking pricing, comprehensive
Smart Growth policies, and targeted travel reduction programs (34, 35).
Large vehicle travel reductions are certainly possible. Automobile-oriented transport planning,
underpriced parking, low fuel prices, and sprawl-oriented development policies cause U.S. residents to
drive far more annual miles than in peer countries (36). An integrated package of cost effective
transportation demand management (TDM) strategies can reduce per capita vehicle travel by 30-50%,
provided it includes both carrots and sticks (37).
Figure 6 Projected Portland Region TDM Program GHG Reductions (38)
The Portland region’s proposed
TDM program is predicted to
reduce vehicle travel and
associated emissions by 45%. It
includes carrots (improvements
to resource-efficient modes and
more affordable housing in
walkable neighborhoods) and
sticks (efficient pricing and road
space reallocation).
Many cost-effective vehicle travel reductions can be implemented quickly. For example, to reduce
vehicle travel and emissions 20% by 2030, a jurisdiction could:
Shift transportation funding from roadway expansions to walking, bicycling and public transit
improvements. Establish active and public transport service quality targets.
Eliminate parking minimums, require parking unbundling and cash out (people who don’t drive
receive the cash equivalent of parking subsidies provided to motorists), plus public parking fees with
revenues invested in resource-efficient transportation programs.
Support and require commute trip reduction, school transport management, transportation
management association, and other targeted TDM programs.
Implement PAYD vehicle insurance, taxes and registration fees by 2025.
Implement a fuel or carbon tax that starts at $20 per tonne of carbon (20₵ per gallon of gasoline)
and increases 10% annually.
Reform development policies to allow affordable housing in compact, multimodal neighborhoods.
Establish strong logistic management programs to increase freight transport efficiency.
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Victoria Transport Policy Institute
Co-Benefits
Cleaner vehicles conserve fossil fuel and reduce emissions but provide few other benefits, and by
inducing additional vehicle travel they can increase external costs such as congestion, infrastructure
cost, crashes and sprawl-related costs. Vehicle travel reductions and Smart Growth provide a far greater
range of benefits, as illustrated below. For example, Maizlish, Rudolph and Jiang conclude that active
transportation improvements could reduce transportation emissions 24% and by reducing local
pollution and increasing physical activity cold avoid 167,000 deaths, providing $1.6 trillion in monetized
health benefits, compared with 1,400 deaths avoided and $13 billion health benefits from fleet
electrification (39). Few emission reduction plans consider all of these impacts.
Table 3 Comparing Impacts
Planning Objectives Clean Vehicles TDM and Smart Growth
Vehicle Travel Impacts Increased Reduced
Congestion reduction
Roadway cost savings
Parking cost savings
Consumer savings and affordability Higher purchase, lower operating
Traffic safety
Improved mobility for non-drivers
Fossil fuel conservation
Pollution reduction
Physical fitness and health
Strategic development objectives (reduced sprawl)
(= Achieve objectives. = Contradicts objective.) Cleaner vehicles help conserve fossil fuel and reduce
pollution emissions but provide few other benefits. Vehicle travel reductions and more compact,
accessible community development provide far greater ranges of benefits.
Latent Demand for Less Automobile-Dependent Lifestyles
Some emission reduction plans assume that most people want to live automobile-dependent lifestyles,
so vehicle travel reductions harm consumers and are difficult to implement (40). For example, the
Clearing the Air report implies that Smart Growth may reduce livability for families with children, and
mode shifts are difficult and costly to achieve. There are good reasons to be skeptical of such claims.
Surveys indicate that many North Americans would like to drive less, rely more on non-auto modes, and
live in more multimodal communities, provided that these alternatives are convenient, comfortable and
affordable (41). TDM and Smart Growth respond to those demands. There are many examples of
integrated TDM and Smart Growth programs that provide large travel reductions and benefits (42, 43).
Of course, TDM and Smart Growth face obstacles, costs and uncertainties, but so do clean vehicle
strategies. As previously discussed, electric vehicles, particularly larger types such as SUVs, light trucks
and vans, are currently costly and will require decades to fully penetrate fleets. They receive large and
regressive subsidies, and by encouraging more driving and sprawl they exacerbate traffic problems and
sprawl. Their emission reductions are difficult to predict due to uncertainties concerning their future
performance and costs, market penetration, rebound effects, annual mileage and scrapage rates.
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Victoria Transport Policy Institute
Comparing Impacts
The figure below compares potential emission reductions provided by vehicle electrification and vehicle
travel reductions. Fleet electrification takes decades, and considering vehicle and fuel embodied
emissions, additional vehicle weight, plus rebound effects, only reduces a vehicle’s emission 60-80%. A
set of TDM and Smart Growth policies can reduce North American per capita vehicle-miles to those in
peer countries such as Germany, Norway and Sweden. Many of these strategies can be implemented
quickly, and by reducing total vehicle ownership and sprawl, provide additional emission reductions.
Figure 7 Comparing Emission Reductions (44)
100% Considering embodied
emissions and rebound effects,
electrification typically reduces
80%
emissions about 70% compared
with similar fossil fuel vehicles,
Emission Reductions
and will take decades to
achieve significant results.
60% Vehicle
Electrification Many vehicle travel reductions
(364 PPYs) can be implemented quickly,
40% and by reducing vehicle
ownership and sprawl provide
indirect as well as direct
20% Vehicle Travel emission reductions.
Reductions
(467 PPYs) As a result, travel reductions
provide more total percentage
0%
point years (PPY) of emission
2020 2025 2030 2035 2040 2045 2050
reductions than electrification.
This analysis indicates that both fleet electrification and vehicle travel reductions are needed to achieve
zero emissions by 2050. Because of the 15-20 year lag between new vehicle sales and achieving that
level of vehicle fleet penetration, vehicle electrification cannot provide significant emission reductions
before 2040. In contrast, many TDM and Smart Growth policies can be implemented quickly, providing
earlier and more total emission reductions during the three decade period.
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Victoria Transport Policy Institute
Summary and Recommendations
The table below summarizes various planning biases, their impacts, and ways to correct them.
Table 4 Comparing Impacts
Planning Bias Impacts Corrections
Exaggerates the speed of clean vehicle Overestimates clean vehicle Use realistic predictions of clean
market penetration. impacts and benefits. vehicle deployment.
Underestimates clean vehicle
Use of outdated travel models that rebound effects and undervalues Use newer and better modes for
underestimate travel impacts. vehicle travel reductions. predicting travel impacts.
Ignores rebound effects (increased Overestimates clean vehicle
travel by clean vehicles), and the benefits and underestimates their Account for rebound effects and the
increased external costs that result. community costs. additional external costs that result.
Overlooks embodied and upstream Overestimates clean vehicle Apply lifecycle analysis that accounts
emissions emission reductions and benefits. for all emissions.
Failure to account for all clean vehicle Estimate and compare unit emission
subsidies, and compare them with other Underestimates clean vehicle reduction costs (dollars per tonne of
emission reduction strategies. costs and regressivity. emission reductions).
Only considers a limited and ineffective Undervalues TDM and Smart Consider a broad range of potential
set of vehicle travel reduction strategies. Growth impacts and benefits. vehicle travel reduction strategies.
Overlooks TDM and Smart Growth co- Undervalues TDM and Smart Account for all significant co-
benefits, besides emission reductions. Growth benefits. benefits.
Assumes that TDM and Smart Growth Undervalues vehicle travel Consider consumer preferences for
harm consumers and are unpopular. reduction impacts and benefits. more multimodal lifestyles.
Current emission reduction planning practices are biased in ways that tend to exaggerate clean vehicle
benefits and undervalue TDM and Smart Growth strategies. These can be corrected.
Recent studies conclude that vehicle travel reductions can provide greater benefits than commonly
recognized (45, 46). For example, a New York Times article “There’s One Big Problem with Electric Cars.
They’re Still Cars,” highlights problems caused by automobile traffic (47). A New Scientist article,
“Electric Cars Won't Shrink Emissions Enough - We Must Cut Travel Too,” argues that vehicle travel
reductions are needed to achieve emission reduction targets (48). An academic study, “Electrification of
Light-Duty Vehicle Fleet Alone Will Not Meet Mitigation Targets,” concluded that current policies are
insufficient to achieve emission reduction targets (49). Our Driving Habits Must Be Part of the Climate
Conversation, concludes that vehicle travel must decline 20% to limit global warming to 1.5° (50, 51).
The Climate Change Mitigation Effects of Daily Active Travel in Cities, found that shifts from automobile
to active modes can provide larger and quicker emission reductions than fleet electrification (52).
Some jurisdictions are implementing vehicle travel reduction policies in order to reduce pollution
emissions, traffic congestion and crashes, and support more multimodal transportation. For example,
the state of California has targets to reduce per capita vehicle travel 15% by 2050. To help achieve that
goal it sponsored extensive research on how various policy and planning decisions affect vehicle travel,
and how to achieve VMT reduction targets. That included the Climate Action Plan for Transportation
Infrastructure (CAPTI)53 and the Vehicle Miles Traveled-Focused Transportation Impact Study Guide.54
13Comprehensive Transportation Emission Reduction Planning
Victoria Transport Policy Institute
Conclusions
Many jurisdictions and organizations have ambitious emission reduction targets and are developing
plans to achieve them. This study finds that the analysis methods used to develop these plans are often
biased in ways that favor clean vehicles (e.g., hybrid, electric and hydrogen) over vehicle travel
reduction strategies (i.e. transportation demand management [TDM] and Smart Growth policies). Some
of these biases have been identified in previous publications but this study is more comprehensive and
systematic. It identifies eight common biases and ways to correct them.
Many plans assume that clean vehicle strategies are more effective, cost effective, fast, reliable, and
popular than vehicle travel reductions. This study challenges those assumptions. Optimistically, half of
new vehicles could have zero tailpipe emissions 2030, but these will primarily be cars; SUV, light trucks
and van electrification is likely to lag by several years, and without strong scrapage programs many high-
emitting vehicles will continue to operate for decades. As a result, clean vehicle programs will not
provide large emission reductions before 2040, and are unlikely to be complete by 2050.
On the other hand, an integrated set of TDM and Smart Growth strategies could reduce transportation
emissions by 40% in ways that are cost-effective overall, considering all impacts. Many current policies
favor automobile travel over more resource-efficient modes. In most communities, the majority of
transportation resources – money and roadway space – are devoted to automobile facilities to the
detriment of other modes; most roads and parking facilities are unpriced; fuel prices are low; and
development policies discourage infill. These policies cause people to own more vehicles, drive more,
and spend more time and money on transport than they would if given better accessibility options and
efficient incentives. Although few motorists want to give up driving altogether, surveys indicate that
many would like to drive less, rely more on alternative modes, and live in more walkable communities,
provided that they are convenient, safe and affordable. TDM and Smart Growth respond to those
demands, and increase rewards to travellers for choosing more resource-efficient options. Many TDM
strategies can be implemented quickly, reducing emissions far faster than shifts to clean vehicles.
The assumption that clean vehicle solutions are superior to vehicle travel reductions reflects an old
planning paradigm which assumed that vehicle travel reductions are harmful (55, 56). A new paradigm
recognizes that there is significant latent consumer demand for non-auto modes and living in more
compact, multimodal communities, and serving these demands provides many direct and indirect
benefits. This new perspective is particularly important for achieving social equity goals. Clean vehicle
strategies tend to be unfair and regressive because they depend on large subsidies to car buyers, and
exacerbate automobile dependency which harms people who rely on other modes (57). In contrast,
many TDM and Smart Growth strategies improve affordable mobility options and reduce the external
costs that driving imposes on other people.
This analysis suggests that to be efficient and equitable transportation emission reduction plans should
rely at least as much on vehicle travel reductions as on clean vehicle strategies, with particular emphasis
on “quick win” strategies that can be implemented in a few years.
There is a positive message here. With better analysis we can identify true win-win emission reduction
strategies that also help achieve other economic, social and environmental goals.
14Comprehensive Transportation Emission Reduction Planning
Victoria Transport Policy Institute
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www.vtpi.org/cterp.pdf
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