In California, where travel demand models often guide project-level decisions and analysis, a new report finds many are outdated, poorly documented, and ill-suited to the purposes agencies sometimes use them for. Transportation agencies rely on models to forecast traffic and guide billions of dollars in infrastructure investment. Without updates, these tools risk locking in old assumptions about growth and travel behavior rather than helping agencies plan for a more sustainable and efficient future.
travel demand modeling
Despite efficiency gains, rising travel demand pushes emissions higher
Advances in technology have made transportation more energy efficient in recent decades, lowering emissions per mile and per unit of freight. But according to a new study, those efficiency gains haven’t been enough to offset the rise in emissions from new transportation demand. To hold transportation emissions steady going forward, the study says, global transportation demand must not continue rising, or we must make a more dramatic shift toward electrification than currently imagined.
Advanced models can’t replace sound judgment
The investments made by transportation agencies are often guided by increasingly sophisticated models and forecasts, which strive to account for more factors and become more accurate in predicting travel patterns. These improvements, while promising for the future, also highlight the many ways that most agencies’ existing models miss the mark. Values-based decision-making can help agencies achieve the outcomes they have set out in their long-range plans more effectively than relying on models alone.
USDOT could advance travel modeling and help planners account for induced demand
A provision of the Bipartisan Infrastructure Law (Sec. 11205) requires USDOT to review existing travel demand models and, among other things, consider the potential implications of induced travel. Federal officials, committed to that mandate, were at the TRB annual meeting last week to learn from modeling experts and practitioners. This blog post offers one perspective on the issues and lays out several opportunities gleaned through discussions at TRB.
New study finds households with constrained parking drive fewer miles
More studies over the years have shown us that the price and availability of parking has a strong influence on people’s travel choices. A ten-year-old study from New York, for instance, called attention to the influence of parking availability on people’s decision to drive to work. Several years later, I led a study connecting long-term parking growth to citywide increases in car commuting. Now a new study by a cohort of researchers across North America, including myself, makes that connection even clearer by drawing a direct line from residential parking ratios to household VMT.