Perhaps they are the signs nobody notices: A yellow stripe on the top says in bold letters “notice,” and an orange stripe on the bottom says “work zone.” The white part sandwiched in between has a little drawing that purports to be a camera with the words “speed photo enforced.”

A number of drivers on Maryland highways have ignored that warning. How many? More than 1.3 million between 2013 and 2016, earning the state almost $54 million in revenue from fines.

In the past year alone, speed cameras in the work zone where the Capital Beltway crosses Suitland Road have recorded 124,477 people speeding, according to a report compiled by AAA. At $40 a pop, those work zone tickets would earn the state close to $5 million.

“That’s a three-year project that’s going to go on for two more years,” said John B. Townsend II, spokesman for AAA Mid-Atlantic. “There have been other work zones on the Beltway, but that’s the only current one.”

Statewide, there are 15 active work zones on state highways. Cameras in those locations have generated 495,222 tickets with a face value of $19.9 million.

Overall, however, the revenue from work-zone speed cameras in Maryland has declined in recent years from a high of $16.4 million to just over $9 million in 2016.

“The revenue drops because people become accustomed to where the work zones are,” Townsend said. “About 40 percent of the people who get these tickets are repeat offenders.”

The purpose of lowering the speed limit in work zones is twofold. It protects construction workers on the job, and it helps drivers negotiate through terrain that may differ from the normal highway, such as lanes that change or narrow suddenly. The latter explains why speed cameras remain in place even after work crews have departed for the day.

The number of work-zone speed cameras depends on how many maintenance jobs the Maryland Department of Transportation has going at any given time on the Beltway.

The department said that in 2016, six people died in work zones, including one construction worker, and dozens more were injured in crashes.

“In Maryland, most work zone crashes across the state occur in the Washington, D.C., metro area and the Baltimore metro area,” Townsend said.

While Maryland law permits speed cameras in “construction zones on expressways or controlled access highways on which the speed limit is 45 mph or greater,” they are not allowed under Virginia law.

The Virginia state Senate this year approved a measure that would have allowed troopers to use handheld speed cameras in or near work zones, but the bill died in a House subcommittee.