Beginning next week, state highway personnel will take down signs displaying one speed for big trucks and another speed for other vehicles on rural-area interstates.
The Arkansas Highway Commission on Wednesday adopted an order eliminating the different speeds, which have been in place for almost 20 years.
Since 1996, trucks traveling in Arkansas have been limited to 65 mph on those sections while other vehicles could go 70 mph. Research has shown that the different speeds don't promote efficient traffic flow, and none of the states surrounding Arkansas use the different speeds, according to the order.
Under the commission order, all vehicles on rural interstates will have a 70 mph speed limit, once the signs are removed, said Tony Sullivan, the assistant chief engineer for operations at the Arkansas Highway and Transportation Department.
"We actually will do this on Monday of next week when ALL state sign crews can hit the interstate[s] at one time and make the change," Danny Straessle, a department spokesman, said in an email.
All vehicles have the same speed limits on suburban interstates [65 mph] and urban interstates [60 mph].
Arkansas and other states have set their own speed limits since passage of the National Highway System Designation Act of 1995, which repealed federal speed limits. At the time, federal speed limits were 55 mph and 65 mph.
The change comes as crash fatalities on Arkansas highways have dropped to historic lows. Fatalities in Arkansas in 2013 fell to an estimated 490. Final results for 2014 aren't available, but preliminary figures show about 465 fatalities, according to the Arkansas State Police preliminary fatal crash summaries.
Some studies show that, in general, the faster that heavy trucks go, the longer it takes them to stop.
A Federal Highway Administration study published in September 2004 found that different speed limits for heavy trucks and for cars did not have a significant effect on safety in comparison with uniform speed limits.
The commission order cited traffic flow as a factor in the decision.
Scott Bennett, the Highway Department director, said he saw firsthand the effect of the different speed limits on traffic flow during a trip on Interstate 40 to Memphis a few weeks ago.
"There was a couple of times that I was in the left lane behind a truck that was going about 65.1 mph and trying to pass a truck in the right lane going 65.0 mph," he told commission members.
"It took me about somewhere around 17 minutes to get around one of those trucks. It took me about 15 minutes to get around the other one.
"It is actually causing congestion out in the rural areas, especially I-40 between here and West Memphis."
Sullivan said the change is a common-sense one.
"We're just trying to get everyone to move along at the same speed," he said, adding that only five other states still have different speed limits for big trucks and cars.
The trucking industry opposed the 1996 commission decision to impose the different speed limits. It welcomed the change Wednesday.
"It stands to reason that all of the vehicles in traffic need to be playing by the same rules," said Shannon Newton, the president of the Arkansas Trucking Association.