JEFFERSON CITY, Mo. — Across the country, states are stepping on the accelerator: Nearly a dozen of them have raised their maximum speeds allowed on interstate highways from numbers like 65 and 70 mph.
State Rep. Mike Kelley, R-Lamar, wants to add Missouri to the list.
For a second year, Kelley has filed a bill that would allow the Missouri Department of Transportation to raise the speed limit from 70 mph to 75 mph on interstates.
“I feel it will help the traffic flow on a lot of our interstates, help keep us competitive in the trucking market as well as the traveling market,” he said. “Faster interstates have better reputations as roads which are safer to travel and popular for companies doing business travel and people traveling on vacation.”
In its current form, the bill would be limited to three traffic arteries: Interstate 70, which runs through mid-Missouri from Kansas City to St. Louis, Interstate 44, which runs from the Oklahoma border in Southwest Missouri to St. Louis, and Interstate 49, which has been assigned to the former U.S. Highway 71 that runs north-south along the western edge of the state.
In 1996, Missouri raised its maximum speed on interstates from 65 to 70. Kelley’s bill would not make it mandatory for MoDOT to raise the limit, but it would raise the ceiling for the agency.
A speed limit is often developed after traffic studies through a figure known in the traffic planning world as the 85th percentile, said John Bowman, a spokesman for the National Motorists Association. The figure, in many ways, is based on psychology as much as science. The idea, he said, is that a driver will drive as fast as they feel comfortable. Using the 85th percentile, engineers can set a speed limit where 85 percent of the drivers studied feel comfortable driving.
“Traffic engineering principles, when it comes to speed limits, are that you look at speeds people are already traveling,” he said. “It tends to be the prevailing speed on the highway that should set the speed limit, not the other way around.”
If people are already going a few miles per hour over the posted speed limit, the prevailing speed for the highway could be higher than the listed speed. Kelley said the interstate near Springfield is a perfect example of this.
“On Interstate 44 in Springfield, it suddenly drops to 60 mph,’ Kelley said. ‘Does the speed of all the traffic suddenly drop? No. They keep going because they still feel comfortable and safe at the speed they were already going. Drivers in St. Louis and Kansas City do the same thing.”
Last year, Kelley’s measure passed out of a House committee but did not pass out of the General Assembly. As he revs up his legislative engines this time, Kelley is facing a formidable foe in the transportation world: MoDOT, where officials have raised concerns about the bill.
“MoDOT is opposed to legislation that has the potential to increase the traffic incident crash rate as well as the severity of traffic crashes,” spokeswoman Holly Dentner said. “Crash severity increases with increased speeds — the faster you drive, the more severe the crash, if you crash.”
Kansas is a potential example of this. The state raised its speed limit to 75 in 2012. After the change, the state’s highway crash rate hardly changed, but there was a spike in the number of fatalities. According to a report in The Kansas City Star, highway crash deaths jumped 54 percent since the law was enacted.
Speed limits tend to follow regional trends. In the Northeast, speed limits are lower — about 65 mph in many New England states. In the South and Midwest — all the way to Missouri — speed limits average about 70 mph. In Western states (with the exception of California, Oregon and Washington) speed limits average higher, between 75 and 80 mph.
“Out West, you have these wide-open, straight interstates. It’s safer to drive faster, as opposed to New England with the congestion,” said Bowman, whose organization studies the issue.
Officials in Kansas said they have not had enough time to study the effect of the speed limit change — they want to look at five years of data — and that they are still reviewing whether other factors, such as seat belt use, are in play.
Kelley shrugged off criticism, adding that he thinks other factors — particularly distractions like texting or eating while driving — contribute to the dangers on the road more than speeding.
“Speed is very rarely the cause of an accident,” he said.
State lawmakers in Missouri have filed five bills that aim to prohibit drivers from sending, reading or writing a text message while operating a motor vehicle. It now is only banned for motorists under 21. Two of the bills include exemptions for hands-free technology.