GM recycles water bottles to make part for Chevy Equinox, coat insulation for the homeless, air filters
TECAT announces first wireless torque sensor model featuring shunt calibration

IIHS: Speed limit increases in US caused 33,000 deaths over 20 years

A new Insurance Institute for Highway Safety (IIHS) study shows that increases in speed limits over two decades have cost 33,000 lives in the US. In 2013 alone, the increases resulted in 1,900 additional deaths, essentially canceling out the number of lives saved by frontal airbags that year.

Charles Farmer, IIHS vice president for research and statistical services and the author of the study, looked at deaths per billion miles traveled by state and roadway type. Taking into account other factors that affected the fatality rate—including changes in unemployment, the number of potential young drivers (ages 16-24) and per capita alcohol consumption—he found that each 5 mph increase in the maximum speed limit resulted in a 4% increase in fatalities. The increase on interstates and freeways, the roads most affected by state maximums, was 8%.

Comparing the annual number of fatalities in the 41 states with the number that would have been expected if each state's maximum speed limit had remained unchanged since 1993, Farmer arrived at the estimate of 33,000 additional fatalities over the 20-year period. That number is approximately equal to the nationwide annual tally of fatalities during recent years.

Although fatality rates fell during the study period, they would have been much lower if not for states’ decisions to raise speed limits.

—Charles Farmer

As large a number as it is, 33,000 is likely an underestimate, Farmer says. In his analysis, he considered only increases in the maximum speed limit, which often applies only to rural interstates, but many states also increased speed limits on urban interstates. Other states increased speed limits on one section of road and later extended the higher limit to other sections. Those subsequent changes weren't factored in.

The study doesn’t include the increases of the past three years. In 2013, only Texas and Utah had limits above 75 mph. Five more have joined that club since then, and others have abandoned 65 mph limits for 70 mph.

Maximum speed limits January 1993. Click to enlarge.   Maximum speed limits Januaary 2003. Click to enlarge.

Background. Maximum speed limits are set by the states, and they have been on the rise since 1995. However, during most of the 1970s and 1980s, the threat of financial penalties held state speed limits to 55 mph. In 1973, Congress required that states adopt 55 mph as their maximum speed limit in order to receive their share of highway funds. Concerns over fuel availability, rather than safety, had prompted Congress to pass the measure, known as the National Maximum Speed Limit, but the most significant result was a decrease in fatalities.

In 1987, with energy concerns fading, Congress relaxed the restriction, allowing states to increase speed limits to 65 mph on rural interstates. The law was completely repealed in 1995.

Proponents of raising the speed limit often argue that such increases simply bring the law in line with reality, since most drivers exceed the limit. Once the limit is raised, however, drivers go even faster.

IIHS researchers found that travel speeds increased following the repeal of the National Maximum Speed Limit. They also found that fatalities went up, first on rural interstates with the law’s partial repeal and later on all interstates after the full repeal.

The increases have continued apace. Today, six states have 80 mph limits, and drivers in Texas can legally drive 85 mph on some roads.

The new study looked at the effect of all speed limit increases from 1993 to 2013 in 41 states. Nine states and the District of Columbia were excluded because they had relatively few vehicle miles traveled each year, leading to wide fluctuations in their annual fatality rates.



I think that this is overly simplistic. If you have an accident at a higher speed, the consequences can be worse as the energy involved goes as the square of the speed. However, the cars have become better at handling higher speeds and the overall safety systems have become better. I live in one of those states with an 80 mph rural interstate speed limit (and 70 mph urban interstate speed limit) and our overall fatality rate has gone down and is even lower if you consider it in terms of fatalities per mile instead of just fatalities per year.


Nobody cares. They're too worried about "important things" like stopping gay marriage. So 40,000+ people a year die in car wrecks...that's just not important to the average moron. LOL


Car bullets are killers but gun bullets are killing more in USA?

Immigration will compensate?

Trevor Carlson

Give me an example of an "accident" where a fatality was "caused" by speed and I'm pretty sure if you were to actually look at all the factors in those specific accidents, speed was a by-product not the cause in 99.9% of those fatalities. True accidents are caused by things like debris falling on you or something unexpected happening to another driver who then goes out of control. Most times, if something unexpected happens to you while driving then you were very likely not paying well enough attention. Of course this would be impossible for the state to prove and no driver would admit it in court but it doesn't make it un-true.
Risky driving behavior such as inattentiveness, inexperience/overconfidence, recklessness, and poor road conditions are the true causes of most accidents that are instead attributed to excessive speed by cops as the "cause" of the so-called accident (that could've easily been prevented).
Speed only kills when the vehicle transitions from a well-controlled state to an under-controlled or over-corrected state of motion. The speed itself is not the cause of the lack of control (except when aerodynamic lift reduces traction - not a factor for road cars on public roads) but it may become a factor in how long it takes for the vehicle to get back under control. Crash investigators are not allowed to rule the cause of an accident was due to driver error or inattention unless the evidence is over-whelming but excessive speed is allowed to be the "cause" that does not need evidence other than the fact that there was an accident to make the claim as being self-evidently true.
Speed Limits are mostly just easy guidelines put in place to keep most vehicles at the same speed. It is the difference in speed between vehicles the same road that is the real danger but that is difficult to enforce or legislate. Plus speed limits give enforcement agencies an easy source of revenue with very low risk (danger to the officers per $ collected).

The comments to this entry are closed.