So who decides speeds on a stretch of highway should be 70, or motorists in a neighborhood should drive 25?
Meet Don Davis. He sets the limits in Wake, Durham, Franklin, Granville, Vance, Person and Warren Counties.
That's right, theDepartment of Transportationhas one speed limit specialist for seven counties.
Davis uses some high-tech equipment, like a slope meter to check for safe speeds in curves. Most of the analysis is low-tech.
"One thousand one, one thousand two, one thousand three, one thousand four, one thousand five," Davis counts as a car drives by.
Davis says he responds to every speed limit complaint that comes in to the DOT. But with one man checking all those roads there are some mistakes. And most of the errors are on the side of caution.
"We have some speed limits out there that are probably not the correct speed limit, but generally they're on the slow side rather than on the fast side," Davis says. "We have a lot of speed limits out there that probably are unjustifiably slow."
Drivers agree. One of the speed limits they call the most unjustifiable is on a road in west Raleigh: Centennial Parkway from Lake Wheeler to Avent Ferry.
People who drive the road every day say the speed limit started at 50, then dropped to 45. Now it is posted at 40. Speed limit setters say this is just one of those roads.
"Sometimes just the magnitude of it, roads can get lost in the shuffle, but it has become apparent now that this one is in the works and is going to be corrected," says Tom Gould.
Gould is the DOT's top man in the seven-county district that includes Wake County. He says the confusion for drivers was caused by confusion between governments.
"That roadway was opened to the public initially without any actual speed limit sign placed on it," Gould says. "It was then incorporated into the city of Raleigh basically without the state realizing it, and I understand the city was then enforcing their statutory 35."
Many drivers who got tickets when the speed limit changed say they think the new speed limit on Centennial Parkway does not make sense.
"I think it should be at least 45-50. Forty is a little slow for that road, at least now, when there's more traffic, more people, more stuff going on," one driver says.
The man who sets the speed limit says he gets lots of complaints, and he can't keep everyone happy. Davis wants people to know one thing: "I personally put a lot of thought into it. We don't just arbitrarily put a speed limit up."
If you are concerned about the speed limit on a particular road, you can reach Don Davis or his supervisors at (919) 560-6856.