S.C. drivers say police give them a cushion for speeding — and they might be right.

Studies by AAA Carolinas show motorists in South Carolina — which leads the nation in speed-related traffic deaths — drive about 10 miles an hour over the speed limit, on average, because they believe officers won’t pull them over.

There is no written policy about how fast is too fast. If you’re 1 mile an hour over the limit, you’re breaking the law.

But there aren’t enough troopers to pull over everyone who breaks the speed limit. So officers running radar on S.C. interstates can pick and choose.

On a Thursday night in late August, Lance Cpl. C.M. Coats parked his police cruiser under an overpass on I-77, cut his lights off and had his pick of speeders. Of the first 10 cars that passed, all 10 were going faster than the 60 mph limit. Some were at 62, one was at 71, and two were at 80.

So what was it that made Coats whip his cruiser around, “Dukes of Hazzard” style, and chase down the 11th car, a woman driving 80 mph?

“It’s up to the officer,” he said.

The woman was from Pennsylvania. She told Coats she was trying to find Fort Jackson in her rented Mazda when she went the wrong way on I-77 and ended up in Charlotte. She was on her way back when Coats got her. Coats dropped the charges down to 69 mph in a 60 mph zone.

He also was set to write the woman another ticket for not having a child in a safety seat in the back seat but changed his mind. “I’ve made her wait long enough,” he said.

About an hour later, on I-20 this time, Coats was driving about 5 miles under the speed limit in the right lane and letting cars pass him on the left side. It’s a maneuver he can do only at night because most drivers don’t notice he’s a trooper until it’s too late. A man driving 72 — 12 miles over the 60 mph limit — got pulled over.

He told Coats he just got on the interstate from S.C. 277 and didn’t know how fast he was going. He got a ticket.

Both speeders were more than 10 miles over the limit. Coats would not say he had a personal limit, — how fast you have to be going before he gives chase — only that each case was “up to the officer.”

Roderick Bailey, traffic safety manager for AAA Carolinas and a former police officer, said officers do have limits, but they vary.

“I had my own limit,” Bailey said, “and that changes throughout the day on that same highway.”

Usually, Bailey would stop motorists driving 10 mph over the speed limit. During rush hour, he bumped it down to eight over. On weekends, it was anything 14 mph or faster over the limit. He said writing someone a ticket for driving 1 mph over the speed limit would “look pretty stupid in court, so it’s the reason people do what they do.”

From January to June of this year, troopers wrote 66,671 speeding tickets, down from 71,647 during the same period a year ago — a nearly 5,000 drop, according to figures from the Department of Public Safety.

Why the drop?

There are fewer troopers on the road, department spokesman Sid Gaulden said. Friday afternoon, 28 troopers graduated from the 80th Highway Patrol Basic Class, bringing the number of troopers statewide to 783. That’s down from the 961 troopers who were on the road in 2000.

LaShawn Pendergrass of Kingstree said she feels comfortable at about 7 miles over the speed limit — any more than that, and she gets nervous.

Her 19-year driving career has yielded one warning from a Lake City police officer who doubled as her family plumber when she was 18.

Pendergrass’ personal speeding limit varies based on the posted speed limit. If she thinks it’s low, like 60 miles an hour on the highway, she has no problem stretching her seven-over rule to 10 over. If it’s a “high” limit, like 70 mph, she’ll stay at 75.

Esther Kramer, of Columbia, said she is a consistent speeder. She uses cruise control to limit her speed to a strict 7-mile-over rule.

“That’s absolutely critical for me,” she said. “I’m not as nervous about police officers because I’m only going 7 miles over the speed limit.”

Just like state troopers, not every driver is the same.

Midlands resident Mike Hood said he tries to stay at 5 miles over because, at 22 years old, his insurance costs go up when he gets tickets. Chuck Groff said he doesn’t speed, but he notices the people passing him on the highway.

“When I was in college, the speed limit was 75, so not too many people were speeding,” he said. “You had to go really fast.”

Reach Beam at (803) 771-8405 or abeam@thestate.com.