Higher Speed Limits Cost Lives
[Writer] This is research news from UIC – the University of Illinois at Chicago.
Today, Lee Friedman, assistant research professor at the UIC School of Public Health, talks about a project to evaluate the impact repealing the National Maximum Speed Law has had on road fatalities and injuries in crashes.
Here’s Professor Friedman:
[Friedman] I’ve recently conducted a research project evaluating the impact of the repeal of the National Maximum Speed Law, which occurred in 1995. The law was initiated in 1974 in response to the oil embargo of 1973, and during its first year there was a drop of almost 17 percent in fatalities when they reduced speed laws to 55 miles per hour.
In 1995, those mandatory speed laws of 55 miles per hour were revoked and it allowed states to set any speed limit that they felt was suitable based on the needs of their population or public officials.
The primary finding of our study was that over ten years following the repeal of NMSL, which is the National Maximum Speed Law, we found that there was an excess of 12,500 deaths that resulted to the increased speed limits across the United States of America.
The only states we did not include in our study were Hawaii and Massachusetts, and we also excluded the District of Columbia because of circumstances related to our statistical analysis.
Some people wonder if there has been a long-term impact related to the policy of increasing speed limits nationally or within states. The primary flaw of previous studies has been that they’ve only focused on selected states, select regions, and also they’ve used a very crude analysis of simply analyzing before versus after.
If you look at my data analysis, the impact actually in just a simple before or after, was almost twice as high as when I used a mixed regression model. And the importance of using a mixed regression model is that we control for the characteristics of each state, because Florida is not the same as Wyoming. There’s different density issues in terms of car volume densities, population densities, and also the type of vehicles on the road. You have different fleet sizes, different variations of fleet sizes, and vehicle quality in terms of newer vehicles versus older vehicles in every single state, as well as driver characteristics, rules for who can hold onto a license, who can’t hold onto a license. So the important thing is to control for the within state and between state characteristics.
Previously everyone just said ‘ok, every state’s the same,’ we’ll just go and throw them all together, even though everyone had different starting dates and with this methodology we’re controlling for the variation between the states as well as within each state. And that’s an important factor that has never been done previously, and on top of that this is the first study to actually look at long-term effects. Every study previously has, I think, gone now more than 2 or 2.5 years from the starting point and this study we’ve done ten years following the starting point.
One of the previous arguments was that people have said this will only have an immediate impact and it will fade over time. Well we have shown that it actually persists across time, and ten years is a very long time.
These policy changes that appear basically harmless to the public, they say ‘oh, it’s so much better, it will be good for commerce because we’ll improve delivery times, it will reduce costs,’ but in fact what we show is that 12,500 people died, most likely in terms of our estimates, as a result of this policy, and it’s a failed policy because it was, in essence, an experiment over ten years of saying that nothing will happen; that was the hypothesis.
We’ve shown that something has happened and it’s quite dramatic.
If you think about the twin towers, even though it’s a very dramatic event, 3,000 people died on September 11th, and that has in essence led to a whole foreign policy which is quite dramatic.
We make decisions based on human lives for certain policies, and foreign policy, we have made certain decisions based on human lives and it was very dramatic for the nation.
What we did now, we know that 12,500 people died, which is four times what happened on September 11th, and yet probably in the end there will be no dramatic effect whatsoever, no one will even look at it. It will be just washed away. People will go, oh it’s just part of the circumstance of driving, it’s just the risk of driving.
What we know from both Europe and from this research is that policy has a major impact on the lives of people within any road system, whether it’s a city, within a state, or across the country.
I hope that policy makers read this in order to re-evaluate the national policy on speed and road safety. Two things that would really impact road safety, or public safety in terms of on the roads, would be implementing a national speed camera program — which has been implemented in England, France and Australia. They’ve shown immediate reductions in fatalities in motor vehicle crashes following national speed camera programs. Also, to have a national speed policy enforcement of speed unilaterally across road systems would have a great impact as well.
[Writer] Lee Friedman is an assistant research professor in environmental and occupational health sciences at UIC.
For more information on this research, go to www.uic.edu, click on “news releases” and look for the release dated July 16, 2009.
This has been research news from UIC – the University of Illinois at Chicago.
