Statement: New Study Reveals Results of Lowering Speed Limits

  • March 28, 2023
150 150 Advocates for Highway and Auto Safety

Media Contact: Helen Jonsen 202-977-7534


Statement of Cathy Chase, President of Advocates for Highway and Auto Safety (Advocates): 

New Study Reveals Results of Lowering Speed Limits.

Proven Safeguards Must Be Advanced with Urgency to Reduce this Killer on the Roadways.

(Washington, D.C.—March 28, 2023) A new speed limit study done in Seattle, Washington by the Insurance Institute for Highway Safety (IIHS) illustrates how a small decline in speed limits can make an big impact on road safety. The new study and focus on speed are especially timely as road fatalities and injuries remain egregiously high. In 2021, nearly 43,000 people died in motor vehicle crashes in the U.S., and nearly 12,000 of them died in speeding-related crashes, according to the National Highway Traffic Safety Administration (NHTSA). This is a five percent increase from 2020.

IIHS found lowering default speed limits reduced the likelihood a crash would involve an injury by one-fifth on arterial roads. The findings in this study are in keeping with IIHS research that shows a modest five mile-per-hour (mph) speed increase can have a serious impact on a driver’s risk of injury or even death.

Advocates has been calling for states to lower speed limits and enact other proven safeguards. To the contrary, at least nine states are or have considered raising speed limits this legislative session. They include: Indiana; Iowa; Massachusetts; New York; North Carolina; North Dakota; Ohio; Tennessee; and, West Virginia. We strongly urge them to prioritize public safety over high speeds. In Ohio, Gov. Mike DeWine (R) did just this and opposed an amendment to the Transportation Funding Bill to raise the speed limit. The amendment was subsequently removed, and we urge the Ohio Legislature to ensure this language is not restored.

The new IIHS study also expresses concern about the practice of setting speed limits based on the 85th percentile free-flow speeds. Advocates agrees. Instead, what is needed is the implementation of an overall “Safe Systems Approach,” including infrastructure changes to slow vehicles down and curb speeding. Speed humps, road diets where roads are narrowed, speed-reduction zones and other measures can save lives.

Another critical component of a Safe Systems Approach is the adoption of technology to curb speeding and related crashes. We continue to call on the U.S. Department of Transportation (DOT) to issue standards for advanced driver assistance systems (ADAS) with urgency. These include requiring automatic emergency braking (AEB) that detects all people in the roadway environment be standard equipment on new cars and trucks. Earlier IIHS research shows vehicles equipped with automatic emergency braking (AEB), lane departure warning (LDW), blind spot detection (BSD) and other ADAS experience fewer crashes.

Other needed technologies include widespread use of automated enforcement (AE), speed limiters for commercial motor vehicles, and intelligent speed assist. Advocates supports federal action to incentivize state use of AE and to remove remaining restrictions on the use of federal funds to do so. Currently, a bill to repeal use of AE in Arizona passed the Senate and is pending a House vote. We urge the Arizona State Legislature to oppose the bill and retain use of this vital technology.

Advocates joins the National Transportation Safety Board (NTSB) in its call to “Implement a Comprehensive Strategy to Eliminate Speeding-Related Crashes,” which is on the 2021-2023  NTSB Most Wanted List of Transportation Safety Improvements. The release of today’s IIHS study is yet more evidence of successful strategies to reduce the deadly practice of speeding and the urgency to implement them.


Editors’ Note:

In 2021, AAA, Advocates, Governors Highway Safety Association, IIHS and the National Safety Council jointly released the Automated Enforcement (AE) Checklist to convey support for the proven technology and to help communities implement successful AE programs.

 About Advocates

Advocates for Highway and Auto Safety is an alliance of consumer, medical, public health, law enforcement and safety groups and insurance companies and agents working together to make America’s roads safer.  Advocates’ mission is the adoption of federal and state laws, policies and programs that prevent motor vehicle crashes, save lives, reduce injuries, and contain costs.