Speed and survival
A few miles per hour decides whether a person hit by a car walks away, ends up in the hospital, or dies.
This page is a draft. Every fact links to its source, so you can check it yourself.
When a car hits a person walking or biking, speed is the biggest thing that decides what happens next.
The numbers
A large study of US crashes looked at how fast the car was going at the moment it hit someone walking. (AAA Foundation for Traffic Safety, 2011)
| Car speed at impact | Risk the person dies | Risk of severe injury or death |
|---|---|---|
| 16 mph | 10% | |
| 23 mph | 10% | 25% |
| 31 to 32 mph | 25% | 50% |
| 42 mph | 50% | |
| 46 mph | 90% | |
| 58 mph | 90% |
Blank cells mean the study did not give that exact pair. The study reports each risk level at a set speed, so the two columns use slightly different speeds.
The Federal Highway Administration (FHWA) puts it another way. A driver going 30 mph who hits a person has a 45% chance of killing or seriously hurting them. At 20 mph, the chance drops to 5%. (FHWA)
Faster cars need much more room to stop
Caltrans designs roads so a driver can see far enough ahead to stop. Here is how much road a driver needs, counting the time to notice and react plus braking. (Caltrans Highway Design Manual, Table 201.1)
| Speed | Stopping distance |
|---|---|
| 25 mph | 150 feet |
| 30 mph | 200 feet |
| 35 mph | 250 feet |
| 40 mph | 300 feet |
| 45 mph | 360 feet |
| 50 mph | 430 feet |
Going from 30 to 40 mph adds about 100 feet. A child who steps out 250 feet ahead can be missed at 30 mph and hit at 40 mph.
Why it matters here
- The Sacramento-Roseville-Folsom area is tied for 19th worst of the 101 biggest US metro areas for people killed while walking, at 3.21 deaths per 100,000 people a year from 2020 to 2024. (Smart Growth America, Dangerous by Design 2026)
- In 2023 the City of Sacramento ranked worst of California's 15 biggest cities for speed-related injury crashes. (California Office of Traffic Safety)
What cities and counties can do now
California changed its speed limit rules so local agencies have more say.
- AB 43 (2021) lets a city or county lower a limit by an extra 5 mph on a "safety corridor" or next to places with many people walking or biking, like schools and senior centers. (California Legislature, AB 43; Vehicle Code 22358.7)
- AB 1938 (2022) lets an agency keep its current speed limit, or go back to the one before, instead of raising it after a new speed survey. (California Legislature, AB 1938)
- Speed cameras are allowed only as pilots in six cities: Los Angeles, San Jose, Oakland, Glendale, Long Beach and San Francisco. Sacramento-area cities would need a new state law. (California Legislature, AB 645)
Signs alone do not slow most drivers. Road design does the real work. See Road design.
What to ask for
- "Please use AB 43 to lower the limit on [road], which serves [school, park, senior center]."
- "Please keep the current limit on [road] under AB 1938 instead of raising it."
- "Please add design changes that slow traffic, not only new signs."
Sources for this page
- Impact Speed and a Pedestrian's Risk of Severe Injury or Death (Tefft, 2011), AAA Foundation for Traffic Safety, 2011
- Appropriate Speed Limits for All Road Users (FHWA-SA-21-034), Federal Highway Administration, 2021
- Highway Design Manual, Chapter 200, Table 201.1 Sight Distance Standards (July 1, 2020), California Department of Transportation (Caltrans), 2020
- AB 43 (2021) Traffic safety; Vehicle Code 22358.7, California Legislature, 2021
- AB 1938 (2022) Traffic safety: speed limits, California Legislature, 2022
- AB 645 (2023) Vehicles: speed safety system pilot program, California Legislature, 2023
- Dangerous by Design 2026: rankings, Smart Growth America, 2026
- OTS Crash Rankings: Sacramento, 2023, California Office of Traffic Safety, 2023
Last checked 2026-11-02.