VMT Reduction Branch
Rethinking How We Build So Californians Can Drive Less
Technical Resources
Caltrans provides resources for developers, local governments, and others seeking information on how to implement projects that support the goals of SB 743 and benefit their communities.
Housing, transportation, and the environment are all intertwined. When we address one, we must consider the effects on the others. Challenges like congestion, affordable housing, and climate change require rethinking how we build and support our communities.
In 2020, Caltrans implemented Senate Bill (SB) 743. SB 743 changes the way the Department evaluates transportation projects, aiming to reduce the amount of time people have to spend behind the wheel.
A Better Approach: VMT
The legislation has prompted a change in the way the state measures the impacts of new development and transportation projects. In the past, projects were evaluated based on the potential increase in traffic in the immediate area. The new approach (called "Vehicle Miles Traveled" or "VMT") looks at the number and length of car trips induced by development projects and transportation.
The Old Way
Measured how fast cars go during rush hour
Compelled communities to expand highways
Induced more driving, creating more congestion and emissions
The New Way
Measures distance vehicles travel, measured as VMT (Vehicle Miles Traveled)
Encourages walkable communities with less traffic and more transportation options
Avoids expensive expansions
A VMT-based approach encourages thoughtful development with better connections to jobs, schools, and commercial centers. It supports active transportation, creates healthier communities, and helps us reach our climate goals.
Induced Demand: Why Wider Highways Often Don't Work
One of the goals of the new approach is to avoid the problem of induced demand, also known as induced travel. What is induced demand?
For many years, California tried to solve the problem of congestion by building bigger roads. Unfortunately, that approach didn't work for many communities. In fact, widening highways often had the opposite effect.
When highways are expanded, a series of changes occur, often resulting in more trips and longer travel times, as people are forced to drive farther to get to work and other destinations.
Induced demand creates more traffic at greater cost to people and the environment, while worsening congestion.
Click here to view the image to the right and learn more about induced demand.
The Impact of Induced Travel – Sunnytown, CA
Trends In Vehicle-Miles Traveled (VMT)
Caltrans' new approach comes as VMT is trending upward, undercutting policy goals around climate, equity, and safety. On a per capita basis, which accounts for population growth, VMT is flatter but still trending higher in recent years - and is still far above the level needed to meet the state's climate goals. Caltrans and its partners are striving to improve these trends by working to provide access to destinations with less driving required.
Note: VMT not shown for pandemic years 2020-21.
SB 743 Hot Topics
SB 743 at 10: The environmental effects of traffic
NCST Calculator truck adjustment
VMT analysis of auxiliary lanes
When are VMT impacts from a project acceptable?
Use of percentages in assessing induced VMT
Data updates completed in the NCST Induced Travel Calculator