A state highway speed camera attached to an SUV can be seen behind a port-a-potty on the southbound lanes of Interstate 270 in Gaithersburg, Md. (Ricky Carioti/The Washington Post)

Drivers in the Washington region have become accustomed to speed and red-light cameras. But a new speed camera keeping tabs on drivers on Interstate 270 in Maryland — from behind a roadside port-a-potty — has some motorists crying foul.

The gray and blue port-a-john on the southbound shoulder, just south of Middlebrook Road, shields a silver SUV with a camera attached to its front grill. Maryland highway officials say they’re trying to keep motorists to a safe speed through the work zone for an interchange being built at Watkins Mill Road in Gaithersburg.

So why does the camera need to be behind a port-a-john, where motorists can’t see it until they pass it? Because, highway officials say, the camera operators need a safe bathroom nearby. Both the portable toilet and SUV are behind a concrete barrier.

John Schofield, a spokesman for the Maryland State Highway Administration, said the setup has nothing to do with “camouflage” or “trickery.” He noted that highway signs warn of speed-camera enforcement in the area.

“We are not — and will never be — in the business of camouflaging enforcement cameras, particularly using a port-a-john to cover a full-sized vehicle with a mounted camera,” Schofield said. “We are in the business of saving lives and slowing drivers down in the work zone.”

Though state highway officials say speed camera operators need a safe place to use the restroom, some motorists say the port-a-potty is used to hide the camera, creating a speed trap. (Ricky Carioti/The Washington Post)

But some motorists are skeptical.

“I honestly think it’s just a really good spot where people won’t see it, and it’s easy to catch people with tickets,” Clarksburg resident Abdullah Abdou said as he filled his car at a nearby gas station last week.

Abdou said he spotted the camera a couple of weeks ago while driving to his D.C. catering job.

“I started seeing all these flashes,” he said. “You can’t see it from far away. You don’t see it at all until you’re right there passing it.”

Rob Mance of Potomac said he’s all for slowing down traffic in the narrow construction zone, which he drives through frequently. But it seems “kind of sneaky,” he said, to put a speed camera behind a port-a-john. It could appear to have been hidden, he said, even if that wasn’t the intention.

“I think it would be more effective if they just put it out in the open where people can see it because people respond to that,” Mance said. “If you see a port-a-potty, who slows down? The objective is to get people to slow down, to keep people safe, rather than as a moneymaker.”

Schofield said the SUV can’t park north of the port-a-john, where oncoming motorists would see it more easily, because the portable toilet would block the camera’s line of sight. Putting the toilet to the side, he said, would put the SUV closer to highway traffic.

He said he didn’t know how many warnings the camera’s system sent after it started there Jan. 3. On Thursday, it began issuing citations with $40 fines for vehicles traveling 12 mph or more above the posted 55 mph speed limit.

AAA Mid-Atlantic spokesman John Townsend said the motorist advocacy group generally supports speed cameras in work zones to make them safer “as long as it’s not established as a moneymaker.” He said he believes the Maryland highway agency’s explanation about needing a port-a-john close by because it’s one of the few agencies in the Washington region that staffs its portable speed cameras.

He said he’s also seen cameras flash behind port-a-johns in other Maryland construction zones, including on the Capital Beltway and Indian Head Highway.

“I always tell people, ‘If you want to be able to spot the speed camera, just look for the port-a-john,’ ” Townsend said. “When you see a port-a-john, slow down.”