VMT Explained
Focusing on the broader impacts of driving rather than just the drivers’ experience on the road.
California introduced VMT as a transportation impact metric with Senate Bill 743 (SB 743), and now its use is expanding to other states—all in pursuit of improved public health outcomes like reducing greenhouse gas (GHG) emissions, encouraging infill development, and promoting active transportation.
Watch What is VMT to learn how it’s calculated and how this metric can help researchers understand the impacts of travel.
Why reducing VMT matters
VMT helps cities and communities improve:
Car Use and Travel Experience
- Tracks how much and where people are driving
- Identifies car dependency in communities
- Evaluates the efficiency of land use and transportation networks
Transportation Planning and Safety
- Shows how new roads increase driving (induced vehicle travel)
- Identifies high VMT per capita areas at greater risk of collisions
Environmental Impact
- Identifies the contribution that vehicle travel makes to GHG and air pollutant emissions
- Informs forecasts of fuel and energy consumption from driving
- Examines how efficiently land is being used
Health and Equity
- Encourages walking and biking for better public health
- Helps reduce collisions and their severity
Question
Why Move from LOS to VMT?
For years, cities have measured traffic using Level of Service (LOS), which focuses on congestion. But LOS misses the bigger picture—failing to account for multimodal accessibility, environmental impacts, and travel safety.
Answer
A More Complete Picture
VMT considers the broader effects of driving, such as emissions, energy use, and safety while also providing insights to land use efficiency and the availability of multimodal travel choices. Shifting to, or adding, VMT as an impact metric provides communities a more complete picture of their transportation network performance.
VMT vs LOS:
A Better Approach
| Measurement | LOS (Driver Delays) | VMT (Impact of Driving) |
|---|---|---|
| Greenhouse Gas Emissions |
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| Air Pollution |
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| Fuel Consumption |
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| Energy Use |
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| Safety (Collisions) |
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| Speed (Driver Delays) |
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| Intersection Wait Times |
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| Overall Travel Experience |
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VMT Metrics in Action
Want to dive deeper? Check out our VMT Lexicon, a simple guide to understanding key VMT metrics and their impact.
VMT+: Supporting Smarter Planning
One example of our work is VMT+, a first-of-its-kind visualizer developed with 2019 StreetLight data. VMT+ equips planners with detailed insights into VMT at the state, regional, and local levels, helping communities better understand VMT generation rates. While currently available for public use in California, the tool is designed as a template for visualizations in other states.
Building Expertise in VMT and Expanding Nationwide
Public Agencies
Jurisdictions across California
Additional Resources
- Criteria for assessing travel models for environmental review
- Methods for verifying travel model sensitivity and quantifying highway project impacts (FHWA)
- Guidance for FHWA reviewers on NEPA document development (FHWA)
- Handbook on analyzing on-road GHG emissions, integrating findings into planning, and evaluating VMT forecasting methods (FHWA)
Navigating the Change
Implementation Guidance
- Criteria for assessing travel models for environmental review
- Methods for verifying travel model sensitivity and quantifying highway project impacts (FHWA)
- Guidance for FHWA reviewers on NEPA document development (FHWA)
- Handbook on analyzing on-road GHG emissions, integrating findings into planning, and evaluating VMT forecasting methods (FHWA)
Induced VMT
Mitigation Strategies
Let’s Connect
Have questions? We’re here to help.
Ron Milam
Direct of Evolving the Status Quo
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Matt Goyne
Principal
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