Vehicle miles traveled (VMT) is a measure often used to define the usage of light duty (and occasionally heavy-duty) vehicles. Reducing VMT, a conservation approach to transportation planning, can result in significant GHG and local criteria emission reductions. The national VMT trend is increasing largely due to development sprawl: since 1980, the number of miles Americans drive has grown three times faster than population and nearly twice as fast as vehicle registrations. If this trend continues, it could result in a nearly 50 percent increase in national VMT between 2005 and 2030. To meet GHG targets and other goals, states will need to identify opportunities to slow and reverse this trend. For example, NRDC projects that to meet nationwide 80 percent below 2050 targets, VMT would have to fall per capita by 24 percent (coupled with significant increases in efficiency and a transition to electrified transportation).

There are myriad policies that can be implemented or designed to reduce VMT, including many of those discussed in this section and in other reports. These strategies may lead consumers to use alternative forms of transportation (such as walking, carpooling, or public transportation) or reduce the need for transportation at all (through land use and urban design policies). Policy options fall into four general categories:

• Pricing mechanisms: more accurately reflecting the costs of individual vehicle use can lead consumers to alternative forms of transportation. As discussed above, these mechanisms may include congestion pricing, parking policies, or VMT-based fees (that may replace fixed fee vehicle registration fees or even gas taxes). For example, Oregon is piloting a voluntary VMT-based charge to replace traditional fuel taxes, under which participants would pay a road usage charge for the amount of miles they drive, instead of the fuel tax.
• Alternative transportation support: policies that make alternative transportation easier can help reduce VMT in individual vehicles. These can include bicycle planning and incentives, transit investment and prioritization, and outreach efforts to encourage the use of these modes of transit.
• Transportation demand management: these programs provide incentives or requirements to reduce transportation demand. One example of such a policy would be a fleet- or company-wide VMT reduction requirement, though such a target would likely require complementary policies to support its achievement. Other demand reducing programs could include workplace programs, such as telecommuting, incentives for living near work (particularly effective for organizations with multiple locations, such as restaurant franchises, banks, or grocery stores), compressed work week, or incentives for carpooling. Universal access transit pass programs are often a core element of transportation demand management programs. One city in which a combination of such policies has been successful is Seattle, Washington—achieving a 75 percent non-single occupancy vehicle (SOV) mode share as of 2017 through transit, rideshare, pedestrian, and bicycle policies and programs.
• Shared mobility programs: these programs including car-sharing, ride-sharing, bike- and scooter-sharing, car-hailing, and ride-sourcing. These programs can also be considered transportation demand management programs though, as discussed in “Ride Sharing Opportunities” above, policymakers may need to consider carefully the possible rebound effects of such programs. Shared mobility alternatives can provide users more transportation choices, offer first and last mile solutions for riders to connect with transit, reduce traffic congestion, lessen parking pressures, and reduce vehicle miles traveled and GHG emissions. They can also reduce household transportation costs by allowing individuals to forego the cost associated with purchasing and maintaining a vehicle. At the same time, car owners can earn extra income by renting out excess vehicle capacity.
• Development standards and policies: development standards and policies can help states, cities, and other local areas to proactively manage VMT growth by targeting compact development and integration of alternative forms of transport (see Transportation-Oriented Development below, as well). Such standards can focus on “infill” of existing developed areas as well as requirements for expanding development. For example, a state or local city government could create a series of tax credits or other incentives to encourage development in existing areas and the rehabilitation of existing buildings to encourage infill rather than building in greenfields and contributing to sprawl. Policymakers could also provide financial support, such as discounted loans or increased tax deductions, for housing and other private development projects in locations where VMT will be minimized. Downtown revitalization programs can also help draw new investment to already developed areas and incentivizes denser, more efficient development. Finally, states and local governments could require GHG and/or VMT evaluations in land use policymaking, regulation, and legislation. Resources such as the LEED Neighborhood Development Guide can provide a high-level overview of possible best practices for such evaluations.
• Improvements to local zoning laws: in many areas, local zoning laws typically prohibit denser development. These laws may limit the impact of VMT reduction efforts through development height limits, minimum parking requirements, or other zoning requirements that limit the ability to expand housing and development in urban areas. This has historically lead to an increase in sprawl to accommodate growing populations. Revisions to zoning laws may be an important precursor to VMT reduction policies that depend on improving development of housing near urban areas or other employment and commercial centers. In California, for example, State Senator Scot Weiner introduced a measure to encourage denser development in part by prohibiting local zoning restrictions on residential development within half a mile of transit lines. Though the measure failed, it may serve as a model for other measures, such as Los Angeles’ Exposition Corridor Transit Neighborhood Plan.

For references and sources for this policy background and these case studies, please see the full report, Toolkit for Advanced Transportation Policies http://www.mjbradley.com/sites/default/files/mjba_transportation_toolkit.pdf