Nearly every state DOT is grappling with how to reduce traffic and carbon emissions—many states developed official , and congestion relief is often at the top of a DOT’s priority list. But a new study from Swedish researchers says that some of the most common ways to address these challenges—using only “carrots” rather than “sticks,” in the researchers’ words—may leave states struggling to achieve their goals.
Focus Areas
Caltrans review finds outdated and misunderstood models hinder project analysis
In California, where travel demand models often guide project-level decisions and analysis, a new report finds many are outdated, poorly documented, and ill-suited to the purposes agencies sometimes use them for.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.
Repairing highways is better for the economy than expanding them
The U.S. faces a $1 trillion backlog of roads and bridges needing repair, according to FHWA. Yet we still spend roughly $27 billion per year (25% of the total) expanding and building new highways. Mounting evidence shows that shifting those dollars toward maintenance and rehabilitation could yield greater benefits.
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.
More transit means safer streets
To reduce traffic deaths, public transit should be seen as a core part of safety infrastructure, not just an alternative mode of travel. Every day, thousands of car crashes occur in the U.S., resulting in injury or death, yet they receive far less attention than the much rarer crashes involving public transit. For city planners working to reduce roadway fatalities, understanding how these perceptions influence travel choices is critical.
More states are moving away from the 85th percentile rule to set speeds
States are increasingly moving past the outdated “85th percentile rule” for setting speed limits, weighing factors other than the observed traffic flow in those calculations. The AP recently highlighted Ohio among a wave of efforts to consider roadway context and the presence of walkers and bikers in allowing lower speeds to ensure safer roads. For states looking to follow suit, a newly released report from the Center for Pedestrian and Bicyclist Safety offers states a data-driven, objective framework to set speed limits based on roadway context, not just vehicle movement.
State action spurs local parking reform
Earlier this month, Denver, Colorado eliminated minimum parking requirements from its zoning code for all developments across the city. We’ve promoted the benefits of reforming outdated parking policies, including lower construction costs and better traffic management. In Denver and many other cities, changes at the state level helped catalyze the city’s reforms.
Emotional perceptions can be a tool for predicting street safety
How a street feels can matter just as much as how it’s physically built. A new study shows that emotional perceptions about whether a street seems inviting, secure, or rundown can help explain safety for people walking or biking—a reminder that planners should think beyond conventional design standards. Road designers should also consider the character and aesthetics of the spaces they create.
California will let agencies pay for housing to offset increased driving
A new California law gives transportation agencies the option to pay into an affordable housing fund to offset the increased travel demand associated with major road projects. The approach could achieve several goals at once: mitigating emissions from highway expansions, creating a new funding stream for affordable housing, and helping more people live in accessible neighborhoods, reducing their transportation costs.
For better mental health, researchers recommend walking and biking
Staying grounded and mentally fit can be challenging these days. While some people turn to meditation or self-medication, a large and growing body of research points to a simpler solution: walkable neighborhoods and bike-friendly streets. Not only can they improve physical health, but they also offer meaningful benefits to our social and emotional well-being. As we’ve noted, extended periods driving can have the opposite effect.