The Dangers of Unintentional Idling

If you don’t think your engine’s still running, you might forget to turn it off. Well, you might forget to push the ignition button off because the engine isn’t running right now. It seems to be off.

So you think it is, don’t push Off and leave the car.

Which might start running again a few minutes after you leave.

This can and is happening because of Automated StartStop (ASS) the new “feature” many new cars come standard with as a fuel-saving measure.

Whenever the car stops, so does the engine—the idea being that a non-running motor doesn’t burn any gas or emit any gas. The gains and reductions are almost immeasurably small per car but necessary from the standpoint of regulatory compliance—the fuel economy and emissions edicts that are becoming otherwise impossible to comply with—without switching over to electric cars, which is another story.

So ASS automatically turns the engine off whenever the car isn’t moving, as at a red light or at a standstill in traffic. When the driver takes his foot off the brake and depresses the gas pedal, the engine automatically restarts itself, and the car resumes running.

That’s the theory, but here’s the problem:

ASS can’t tell the difference between stopping for a red light or because traffic has temporarily stopped or because you’re parking.

If you forget to push the ignition button off—which is easy to do when the engine has already turned itself off—the motor will restart after a while, even if the car isn’t moving (and you’re no longer in it). When this happens, the battery will run down — because electrically powered accessories will still be powered if the ignition is still on.

If the engine kicks itself back to life when the car is outside, it’s no big deal. Gas will be wasted and emitted as the engine idles.

But if it idles for hours in your garage, it could be a very big deal, if the gasses emitted find their way into your house.

Several people have already been killed by the gasses emitted from cars left unintentionally idling — a modern problem that first arose when the keyless/push-button ignition system came online in mass-marketed vehicles in the early 2000s.

People sometimes forget to push the Off button or thought they did push it and leave the car with its ignition still on.

This is easy enough to do when you’re in a hurry or preoccupied with other things. Modern car engines are very quiet, even when they are running.

And pushing a button isn’t the same as turning and removing a key.

A physical key in a physical lock has to be physically turned to the Off position before the key can be removed from the lock. Most people who are parking their car will not leave the key in the ignition. The act of removing the key automatically entails the act of turning off the ignition and thereby, the engine.

This has been a failsafe against unintentional idling for the past 100 years until about ten years ago when keyless/pushbutton ignition systems became popular.

People in a hurry or not paying attention no longer had to shut off the engine to remove a physical key. It was now possible for them to assume they’d shut off the engine because they thought they’d pushed the Off button and walked away from a still-running car.

If you’ve had a chance to drive a car with pushbutton ignition, you already know all about this.

Some systems require an extended push to register the driver’s intentions. If you don’t push and hold the button long enough, the engine sometimes stays on despite your best efforts. Or it comes back on (if you press the button too long).

You have to make sure the engine is, in fact, off in a way that was never necessary when keys were used to turn an engine on and off.

ASS has compounded this problem by actually shutting off the engine temporarily.

But the ignition is still on, and if that’s not very deliberately turned off, the engine will come back on.


The driver, in a hurry or just distracted, rolls into his garage, his mind on other things. Before he even puts the gear selector into Park, the engine has already shut itself off. So he assumes it is off, doesn’t push the button to turn the ignition off, leaves the car, and goes inside.

After a while, the engine he thought was off, turns itself back on and continues to run, emitting gasses that can lead to the Big Sleep.

An easy solution would be to go back to physical keys which make infinitely more economical and functional sense than overteched fobs and would eliminate the problem of engines that turn themselves on and turn their owners off.

Physical keys are also much more durable and far less expensive than electronic key fobs, and being physical keys will never stop working because the battery died or you put them through the wash.

Keyless ignition is convenient, of course. But how inconvenient is it, really, to put a key in a lock and turn it? Are we really that lazy? That gadget-addled?


So, rather than the cost-effective/simple fix, we’ll get the complicated, expensive, and a wholly unnecessary one.

Discussion among those who govern is already under way. Instead of going back to keys, keyless ignition/ASS-equipped cars to have another system to warn drivers about the engine they just left running. Some of these would send a nag message to the driver’s phone since he’s already left the car.

It makes me want to take the Big Sleep.

Wake me when it’s over.


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2 Responses to “The Dangers of Unintentional Idling”

  1. David Holzman says:

    Thanks for making me even more glad I have a car that predates most of this garbage. Given that I use a house key every day, and never leave home without my keys, and that I’m probably not unusual in this, I can’t see any advantage to these keyless systems.