DENVER (CBS4) – School bus drivers may be under so much pressure to stay on schedule some of them could be breaking the law and speeding through school zones to get students dropped off on time.

For his investigation into the matter, CBS4’s Rick Sallinger stood behind a tree with a calibrated radar gun in hand that was aimed on school buses. Violators were not hard to spot.

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“Thirty-four mph in a 25 mph zone,” Sallinger said after a bus went by.

The radar gun captured driver after driver accelerating in the school zone, with many drivers going at least 30 mph in a 25 mph zone.

Denver Public Schools has 34,000 students transported to and from school each day on 320 buses.

School bus drivers do not have an easy job. Their job description includes keeping the students under control while dropping off and picking up dozens more before and after school. There are also many distractions for drivers, including traffic and the additional pressure of keeping to a strict timetable.

When CBS4 asked Transportation Department Executive Director Nicole Portee the No. 1 question school bus drivers are asked, she responded, “Why are you late?”

“I always tell them, this is your license, this is not DPS’s license and you need to drive as safely as possible,” said Amalgamated Transit Union President Barbara O’Donnell.

City photo radar records also reflect school bus drivers speeding. One shows a bus traveling 48 mph in a 35 mph zone. Another captured a driver traveling 33 mph in a 20 mph zone.

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Denver Public Schools said only five school bus drivers have received speeding tickets in the past year.

If a driver is caught speeding the incident is verified through the district’s GPS devices. The drivers are supposed to discuss if they have problems keeping on time.

“It’s the driver’s responsibility to say, ‘Hey, I’m not getting there on time. What can we do to add some additional time to my route?'” said Portee.

Often those drivers do not call attention to the issue because they are afraid.

“Job security. They’re afraid of losing their jobs,” said O’Donnell.

Portee insists safety is the main concern.

“We tell drivers they need to obey the laws of the road,” she said. “They should abide by all speed limits and be safe.”

In the past year, CBS4 found DPS received 19 photo radar tickets, including 11 in safety zones. Statistics from the city of Denver do not itemize how many of those vehicles that received the tickets were buses.

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Drivers who receive tickets are given a written reprimand and one-day suspension without pay.