It's something that almost every parent has worried about at some point: what if my child is left behind on the school bus?
Administrators with the National School District in National City are hoping to prevent that with a new security system for school buses.
An upgraded alarm, called the Child Check Mate, prompts bus drivers to check the vehicle for students. It ensures no child is left unattended at the end of the route.
"We installed it on ten buses and the project costs about 8000 dollars," said Antonio Perez, Director of Transportation with the National School District.
The alarm system is designed so that bus drivers must sweep the bus to look for students who have not disembarked. The new child-check alarm activates when the engine is turned on.
"Drivers were a bit hesitant at first but it has been going very well," added Perez.
The alarm can only be deactivated at the back of the bus and only after the key is removed from the ignition.
New state regulations require 25,000 school buses to be equipped with the security system by the state of the 2018-2019 school year.
If a bus driver tries to exit the bus without deactivating the system, a horn is triggered to sound for a half hour or until the safety check is completed.
"It's going to be loud," said Perez. "It's designated to be heard from a distance of 200 feet so the driver would hear it and we would hear it."
All 10 buses in the National City School District now have the equipment.
The Paul Lee School Bus Safety Law was passed in 2016 after a non-verbal student with autism died on a school bus in Whittier, California. He was left on the bus on a hot day with the windows shut.