Demand Management

Rising automobile use presents many challenges for DOTs and the communities they serve. People’s tendency to drive longer distances, for instance, has more than offset the benefits of highway improvements in fighting traffic delay and of cleaner vehicles in lowering greenhouse gas emissions. This growth, however, has also become less predictable in recent years. More transportation agencies are now exploring opportunities to manage travel demand and accommodate people’s daily needs with fewer and shorter car trips.

Vehicle Miles Traveled

Driving is often measured in terms of vehicles miles traveled (VMT). This number has generally increased faster than population growth in the U.S., but it tends to level off with economic and cultural shifts. It is important to track because of its effects on traffic congestion and its strong connection to related outcomes like traffic deaths and greenhouse gas emissions (shown in the adjacent panel).

Read our latest update on national VMT trends here.

Improving Policy and Practice

Best practices in transportation demand management (TDM) touch everything from employee-based commuter programs to system operations and land use regulations. SSTI supports DOTs and stakeholders in understanding how steps like road pricing, transit investments, and strategic bicycle and pedestrian improvements can reduce automobile travel. We also work with local officials to craft land use regulations that minimize the impacts of new development.

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Modernizing Mitigation

TDM strategies can range from ride-sharing services and improved transit service, to road use and parking fees. Transportation agencies can take many important steps toward effective TDM, but development patterns also play a critical role in supporting fewer, shorter trips and better multimodal options.

Local governments, in particular, can rethink how they evaluate traffic impacts and require developers to mitigate those impacts by reducing traffic instead of continually adding new capacity. Modernizing Mitigation, a report by SSTI and the Mayors Innovation Project, outlines that approach.

Big Data and TDM in Northern Virginia

Leveraging location-based data from connected vehicles and mobile devices, SSTI helped identify low-cost opportunities throughout Northern Virginia where reducing short or unnecessary car trips could address major traffic issues. This study, developed with Michael Baker International for Virginia’s Office of Intermodal Policy, also informed the early development of StreetLight Data’s Traffic Diagnostics tool.

Reducing VMT in Hawaii

Hawaii’s ambitious climate goals call for major reductions in transportation emissions, which cannot easily be achieved through electrification alone. SSTI’s technical guide, developed with Smart Growth America for Transcending Oil, lays out a replicable, data-driven approach to reducing vehicle travel through transportation investments, land use polices, and financial incentives.