Vehicle Miles Traveled

Long commutes, dangerous bike lanes, and poor air quality all have one thing in common: our transportation system’s overreliance on cars. Most of us are so used to taking a car everywhere that we hardly notice the subtle ways they make our lives worse.

Despite their ubiquity, cars are both hazardous for our health and bad for the environment. Over 3,000 Californians are killed in motor vehicle crashes each year and our transportation sector generates 50% of the greenhouse gas emissions released into the atmosphere. Car exhaust also emits air pollutants, which can cause health problems such as asthma, lung and heart disease, and cancer.

Encouraging households to switch away from single-occupant driving and to using other modes of transportation could be the key to solving the climate crisis and making our streets safer. We envision a California where traveling by using carpooling, transit, biking, or walking is more affordable and accessible than driving. This is why the Coalition for Clean Air supports government actions that reduce our reliance on cars by reducing vehicle miles traveled.

What is VMT?

Vehicle Miles Traveled (VMT) is defined as one vehicle traveling on a road for one mile. Policymakers often use this metric to determine how land-use patterns might impact travel. The Coalition for Clean Air is particularly interested in VMT as a metric since it is correlated to air pollution and climate change. As VMT from combustion engines increases, so do climate-forcing greenhouse gas (GHG) emissions due to increased tailpipe emissions.

How can California effectively reduce VMT?

The Coalition for Clean Air works closely with California’s transportation agencies to encourage the construction of projects that reduce the reliance on single-occupancy vehicles. Simply by building protected bike lanes, sidewalks, and bus shelters, increasing the reliability of transit, lowering fares, and slowing down traffic in residential areas, we can encourage households to reduce their driving in favor of using transit, walking, or bicycling. If a government does propose a project that increases VMT by increasing the number of cars on the road, the above strategies can help mitigate some of that impact. The Coalition for Clean Air also supports better land use and transportation practices, such as the creation of 15-minute cities where all basic needs are located no more than 15 minutes away, reducing the need to travel long distances.

VMT & Zero-Emission Vehicles

Looking to the future, many wonder how VMT will change as zero-emission vehicles (ZEVs) become the preferred mode of transportation in California. Zero-emission vehicles are a critical part of the solution to the air and climate crises as they reduce greenhouse gas emissions and combustion-related pollutants. However, both strategies are needed if we are to fully address the climate crisis. ZEVs do not solve all air quality issues, as brakes and tires release particulate matter into the air. Additionally, reducing VMT can provide health benefits, as walking and bicycling have been found to improve physical and mental health. Finally, studies have found that it will be impossible for California to meet its climate targets without also addressing VMT as it is projected to continue to increase as a result of population and GDP growth. Thus, the Coalition for Clean Air is committed to addressing both pieces of the puzzle by promoting policy decisions that encourage Californians to switch to zero-emission cars and drive less. For more information on our work on ZEVs, click here.

CCA Actions

While there is much to be done in this field, here are a few examples of projects we have worked on.

CCA supports the implementation of SB 743 (Steinberg). Before SB 743, the primary travel-measuring metric was Levels of Service (LOS), which tended to promote sprawl and highway expansions due to its focus on reducing traffic. SB 743 directs the Governor’s Office of Planning and Research to establish an alternative metric, which is how VMT became the primary metric we use today for the environmental analysis of new development projects under the California Environmental Quality Act (CEQA).
CCA was a key supporter of AB 285 (Friedman), which required the Strategic Growth Council (SGC) to conduct a study of the effects of all Sustainable Community Strategies (SCSs) and how they have influenced the current transportation system. SGC submitted a report in January 2022, where it found that only 2% of the current transportation funding is invested in sustainable transportation projects that would reduce VMT.
In 2022, CCA strongly supported AB 2237 (Friedman) and AB 2438 (Friedman), which would have required the state to align transportation projects and transportation funding with the state’s climate goals. Unfortunately, due to strong opposition from the road-building industry and their allies, neither of the bills were signed into law.
Sustainable transportation advocates also succeeded in stopping SB 1410 (Caballero), which threatened to limit the use of VMT as a transportation metric by requiring it to only be used for projects near transit stops.
CCA supports the California Air Resources Board’s (CARB) Electric Bicycle Incentive Program, which will provide monetary incentives for the purchase of electric bicycles, and we encourage the agency to focus incentives on low-income communities.
CCA and 22 other transportation and environmental organizations asked the newly appointed Director of Caltrans to stop building highway expansions and focus funding instead on building sustainable projects that align with California’s climate and air quality targets. Click here to read the letter we sent to Caltrans.
Additionally, the Coalition for Clean Air and a coalition of environmental groups helped successfully stop Caltrans from expanding the 710 freeway, marking a shift away from continuously funding new roads and road expansions.

How can you get involved?

Building more accessible and safe communities will take everybody’s effort. If you would like to help us create this vision for California, here are a few actions you can take:

Consider replacing your next car trip with using public transportation, bicycling, or walking.
Participate in your local politics by attending your local metropolitan planning organization’s meetings and voicing your support for walkable and bikeable infrastructure. You can find a list of MPOs
Participate in CCA’s California Clean Air Day and pledge to take action to improve air quality and reduce vehicle miles traveled. The next Clean Air Day is on October 4th, 2023.
Subscribe to the Coalition for Clean Air’s newsletter to learn more about ways to engage.