Editorial: First, let’s see how 70 mph on I-93 goes
Should New Hampshire raise the speed limit along most of Interstate 89 to 70 miles per hour?
The matter has been debated repeatedly over the years. Our view has long been that for reasons of public safety, not to mention reducing energy consumption and combating pollution and climate change, the answer should be no. In 2014, our message to state lawmakers will be slightly different: Wait and see.
At issue is yet another new bill to raise the speed limit. But lawmakers took a big step in that direction just this past year. Signed by Gov. Maggie Hassan, the measure raising the speed limit on Interstate 93 north of Concord will take effect Wednesday.
Before the Legislature turns its attention to I-89, why not see what happens on I-93? A little information will go a long way toward helping lawmakers make a good decision.
This time of year – when the state highways can turn treacherous in a matter of minutes, and the Department of Transportation is already fretting that without more money it will be unable to keep the roads as clear as motorists demand – arguments in favor of driving faster can sound like madness. But in general, proponents say that since most drivers already go 70 mph, the law should be changed to recognize that reality; that’s the argument that won the day when lawmakers considered I-93.
Trouble is, if the state raises the speed limit to 70, those same drivers are likely to push it to 75 or 80 mph – too fast when drivers are inexperienced, elderly or, say, talking on cell phones, illegally texting, or otherwise distracting themselves from the task at hand.
Estimating vehicle stopping distances at different speeds is a crapshoot, given variables like road, tire and brake condition, vehicle weight and driver reaction time. But at 65 mph, coming to a full stop after noticing danger takes the length of a football field and more – 344 feet on a dry surface and 399 on a wet one, according to one government study. Increase the speed to 70 mph, and those distances grow by about 50 feet.
In other words, the chance of an accident increases.
The state of Iowa increased the speed limit on its rural interstates to 70 mph in 2005. The number of drivers exceeding the speed limit by 10 mph decreased by more than 50 percent, but the number of serious crashes increased by about one-third and the number of serious cross-median crashes increased by 80 percent.
Would the same happen on I-89?
Fortunately, New Hampshire has a point of comparison far closer to home. We suggest legislators give the new 70 mph limit on I-93 at least a year before expanding the experiment to I-89.
When it comes to a measure likely to increase the danger on New Hampshire roads and damage the environment without much upside, taking it slow seems like the right approach.