We all know “The Arm of Safety,” aka “Mom Arm” aka “The Original Seatbelt.”

The driver’s arm, usually parental, flings out unbidden against the chest of the passenger, usually filial, when unexpected braking occurs.

Science hasn’t quite yet determined how many lives are saved by this uncontrollable, yet heroic act, although eye rolls appear to be the primary passenger response.

But another “arm of safety” does save lives: the arms on a school bus that lower when making a stop.

This arm clears all lanes of traffic for children to cross the road and get on the bus, or get off the bus and cross the road. Some buses have a stop sign that flips out, others just use their red flashers.

No matter the signal, each one is an arm of safety — one that drivers need to recognize and respect.

The routine-throwing holiday break precipitated a bus safety reminder from Northwest Education Services, the intermediate school district, last week. Their headline? “Red lights mean no passing.”

It is that simple.

If one forgets, if one is late for work and stewing, if one thinks the kids have already crossed, or the driver is too slow — whatever one thinks in those situations — and then opts to pass that bus, there are potential consequences.

In Michigan, anyone who passes a stopped school bus with its red lights flashing may be subject to a civil infraction and fines of up to $500. Violators also may be required to perform up to 100 hours of community service at a school. (May we suggest cleaning up school buses?)

That is just for violating that law.

The real consequence comes when a child, nearly impossible to see, crosses the road lawfully to go to school/home and an impatient driver, passing the bus illegally, strikes that child.

It happens — and worse — one law firm calls it “an alarming trend,” citing National Highway Traffic Safety Administration data. From 2006 to 2015, 301 school-age children died in school-transportation-related crashes. Of those 301 fatalities, 102 children — nearly a third — were killed while they were approaching or leaving the bus.

In several cases, drivers were young and inexperienced, not much older than the students they killed. But not all.

Buses are extremely safe; they are the most regulated form of transportation out there, and they are uniquely designed to prevent injuries once inside. But the drivers around them — us — have no such oversight.

Michigan State Police offer safety tips for both drivers and students, along with other helpful information on its website.

Tips for Drivers

— Prepare to stop when a slowing bus has its overhead yellow lights flashing.

— Stop at least 20 feet away from buses when red lights are flashing, unless driving in the opposite direction on a divided highway.

— Slow down in or near school and residential areas.

— Look for clues — such as safety patrols, crossing guards, bicycles and playgrounds — that indicate children might be in the area.

— Watch for children between parked cars and other objects.

Tips for Students

— Always stay in sight of the bus driver.

— Don’t hurry off the bus; check traffic first.

— Don’t go back to the bus after exiting.

Mind those red flashers and never pass. Make mom proud.

— Traverse City Record-Eagle