As far as any Limestone County schools official knows, no sleeping child has been left on a bus at the end of a route.

But the school system is no longer willing to take that chance.

On Friday, county Transportation and Maintenance Supervisor Darryl Adams said all 114 buses in the county fleet would receive an alarm system that calls a driver back to inspect his bus at the end of a route.

“Our drivers are trained to walk to the back to check the bus at the end of each route, but this will alert the driver if he didn’t walk to the back,” Adams said.

Once the driver activates the bus’s lights, if he attempts to open the door after shutting down the motor without first walking to the back of the bus to press the alarm button, a loud horn will repeatedly blast.

“Safety is our obvious concern,” Adams said.

In the 2 1/2 years he has been transportation supervisor, Adams has not heard of a child being left on a bus.

“But I have talked with other supervisors in other towns and they have had this problem,” he said.

Very young children, especially those in kindergarten, are the most likely to fall asleep at the end of the school day, Adams said. With the compartmentalized design of modern buses, which include higher seat backs for safety purposes, it is nearly impossible to see smaller children from the front of the bus.

The cost of installing the alarms is $40 per bus. Twenty-five of the buses already have the alarms.

Limestone County buses travel a total of 6,500 miles per day, Adams said.

“Our goal is to transport kids safely and efficiently,” he said. “With the recent bus accident in Huntsville, it has made us all more aware of safety issues.”

Superintendent Barry Carroll said the sleeping-child alarm system is not mandated by the state Board of Education.

“We’d heard about it in other systems and wanted to be proactive,” Carroll said. “Even before the Huntsville accident, as early as August, we had been planning to do this.”

For some time, county drivers have had magnetic strips that read, “Empty Bus,” which they apply to back windows when they park buses at the school bus garage on Elm Street, but the alarm system would be a double precaution, Adams said.

“We learned from other persons’ mistakes,” said Carroll.