A while back, a friend of mine texted our group chat and left the following message:

“Hey guys…a bus just passed and its lights were flashing ‘call 911.’ Should I have called?”

Even through text, she sounded worried. Faced with a possibly dangerous situation, she froze, like a deer caught in headlights, as the bus quickly raced past her.

None of us had ever seen a distress signal coming from a public bus before.

“I think you should have called,” one friend messaged her.

“But the bus was full of people and everything seemed okay,” she replied.

Curious about the topic, I decided to do some investigative reporting and was able to uncover a few things. First off, the “CALL 911” or “EMERGENCY CALL POLICE” light display is indeed a distress signal. It is a silent alarm, triggered by the driver, that goes through Central Control to the police.

For the most part, it is used when disruptive or threatening behavior occurs on the bus. In the event of a hostage or hijacking situation, for example, the bus operator cannot visibly call for help and needs the light to signal surrounding drivers.

Incidentally, the signal can also be accidently triggered, resulting in a “false alarm” type scenario. Hopefully, that’s what actually happened in my friend’s case.