Drivers were scrambling to get their cars up to snuff minutes before the Demolition Derby was scheduled to start Friday.

They were removing bolts, cutting metal and detaching plates — all violations of the of Douglas County Fair’s Demolition Derby rules.

“The rules, there are holes in them called gray areas,” said Nick Rockhold, 22, who has been a derby driver for six years. “You try to push the gray area … to make your car stronger because it’s not specifically spelled out in the rules. Everything is up to the officials. They look at your car, and if they find something that’s not supposed to be there, then you have to fix it or you don’t run.”

Six officials inspected derby cars. And some cars didn’t make the cut.

But Rockhold was not worried. Wearing a Kansas University shirt with the sleeves cut off, Rockhold stood near his car before the event, a composed look on his face.

About an hour later, when officials signaled the start of the derby, that composed look surely slid away.

For Rockhold, the Demolition Derby is a way of venting frustrations. Legal road rage, you could say.

“It helps me get rid a bunch of aggression,” Rockhold said. “You get to go out and just beat everyone up and just bang, and the look in people’s eyes when you’re coming for them — they get to be about the size of softballs.”

For similar reasons, Cody Anno, of Lawrence, has been running in derbies for five years. But Anno’s interest in derbies bloomed long before that. His father competed, and Anno has been watching the mud-slinging, noisy competition since he was knee high.

Competing has only strengthened Anno’s love for derbies.

“I do it for the adrenaline rush,” Anno said.

The first heat of the Demolition Derby started around 8 p.m., the sun still setting. Thousands of people watched as the first batch of cars careened and crashed into one another. Smoke billowed from hoods, and engines chugged and crackled. One car caught fire.

Drivers get bruises and whiplash, but serious injuries are rare. And because of that, Rockhold rarely gets nervous.

“It’s just another day at the office,” he said.