Texas made headlines recently when it approved an 85 mph speed limit on a stretch of toll road between Austin and San Antonio. As some incredulous media types pointed out, that’s the highest posted speed limit in the Western Hemisphere. Gasp!
The phones at NMA HQ rang off the hook: reporters from across the country looking for our perspectives on this evil plot to end the universe as we know it. Is 85 mph safe, they asked? Won’t higher speeds lead to more accidents, they asked? Why, oh why, did they do it? And so on. A typical phone conversation went something like this:
Media Type: Is 85 mph safe a safe speed at which to drive?
NMA: Based on the traffic engineering studies conducted by the Texas DOT, it is. TX DOT pointed out that people are already driving 85 mph on other stretches of this particular road without increased safety risks.
This points to how speed limits should be set in the first place—based on the 85th percentile speed, which factors in the speeds that people naturally drive. When set this way, speed limits almost always go up (because they’ve been set artificially low to begin with), and accidents almost always go down.
MT: Accidents go down? How can that be?
NMA: Setting speed limits correctly reduces the speed differential among vehicles, meaning that you have more vehicles traveling at about the same speed. This reduces vehicle conflicts (tailgating, quick lane changes, sudden braking, etc.) and lessens the chance for accidents.
MT: But that nice man from the Insurance Institute for Highway Safety (IIHS) said that when speed limits go up, accidents do as well.
NMA: Look at what’s happened nationwide. When the 55 mph national maximum speed limit was repealed in 1995, highway fatality rates started declining, and they have been ever since. So, as more and more states have raised highway speed limits to 70, 75 and beyond, our roads have actually gotten safer. That’s the benefit of setting speed limits correctly.
MT: But that nice man from the IIHS has a study showing just the opposite.
NMA: We dissected that study when it first came out in 2009 and revealed some major flaws, the primary one being that the researchers failed to look at fatality rates. Actual fatalities may have increased on some roads, but when you factor in an increasing number of vehicle miles traveled the fatality rate is actually trending down.
MT: Do you have examples to back that up?
NMA: Sure. When Ohio raised the speed limit on the Ohio Turnpike last year from 65 mph to 70 mph, detractors predicted death and mayhem. It turns out that the turnpike had its safest year ever with fatalities and fatality rates reaching historic lows.
In 2009, Utah began testing an 80 mph speed limit on a stretch of I-15. Accidents actually went down and there have been no fatalities. Utah DOT just made the higher limits permanent and is now looking at posting 80 mph limits on other stretches.
Look at the German Autobahn. Two-thirds of it has no fixed speed limit, yet the 2009 fatality rate was only 0.7 per 100 million vehicle miles traveled (VMT). The lowest recorded fatality rate in the United States was 1.09 per 100 million VMT in 2011.
MT: Yeah, but raising speed limits to such levels will only encourage people to drive 90 or 95, right?
NMA: Nope. People drive at a speed they feel is safe and comfortable and they don’t exceed it. That’s what the 85th percentile is all about. Most people intuitively know what a safe speed is. When Utah raised the speed to 80 mph, actual driving speeds didn’t change. They stayed right around 85 mph. But, raising speed limits does allow more drivers to be in compliance with the law, which cuts down on violations.
MT: But accidents that occur at higher speeds can be more serious and cause greater damage and injury.
NMA: True, but setting speeds correctly, based on the 85th percentile, will lessen the chances that those accidents will happen in the first place. Setting speeds in this way actually has a preventative effect.
This exchange not only provides a refresher on setting proper speed limits, but shows what we’re up against. The insurance industry shills and the “safety advocates” have an easy (though incorrect) story to tell: speeds go up, accidents go up. Who can argue with that?
We can, and do, very effectively. Because the facts are on our side. Maybe that’s why, despite the media ballyhoo, public opinion favors higher speed limits.
Still, many speed limits remain artificially low, resulting in unsafe driving conditions and unnecessary citations. And policymakers have no incentive to make necessary changes.