It used to be that it took more gas to start a car than to operate it. It used to be that when you started a car, it had to idle for a while before it could safely go anywhere. That was back in the days of starting motors and carburetors.
In this day of electronic ignition and fuel injection, it is better to start the car and start driving right away. It is also better, and much cheaper, to turn the engine off if you will be sitting still for any longer than 10 seconds!
We waste too much gas idling for at least two reasons these days. First, drivers’ knowledge of cars hasn’t kept up with technology. Too many people think that the old rules that they learned way back when are still valid. Second, there are even more reasons to idle during the course of a drive than there were before.
For every two minutes that you idle, while you’re getting zero miles per gallon, you use about the same amount of gas as you do when you drive a mile. The average driver idles at least five minutes a day. In that time, small cars use about half a cup of gas; cars with V8 engines use about a cup.
Does that seem like too little to bother with? It amounts to 10-20 gallons a year, or somewhere in the neighborhood of a full tank of gas. For those who are keeping track of greenhouse gasses, wasting those 10-20 gallons of gas also adds between 220 and 440 pounds of carbon dioxide to the atmosphere.
That’s for one driver. If everyone in the US cut idling by five minutes a day, that would save 3.8 million gallons of gas and 40,000 tons of carbon dioxide every day. And 1.4 billion gallons of gas and 13 million tons of carbon dioxide annually.
Excess idling on startup
Here’s a silly little thought experiment.
With older technology, people started their cars, sat for a while, and then began to drive. When seat belts became mandatory, they used the idling time to fasten them. I’ll bet most people still start the car before they fasten their seat belts. Lets’ suppose that every one in the country does that. Let’s further suppose that everyone starts to fasten their seat belts before starting the car on one day. What difference will it make?
It takes about 5 seconds to fasten a seat belt. When you leave the house, go someplace, and go back home, you have started the car twice. If you stop for gas or any other errand one way or the other, you start the car once again each time.
I don’t have any statistics about how often, on average, people start their cars every day, but consider the case of parents of teenagers. The teenagers are likely to have extracurricular activities before school, after school, and in the evening.
Supposing a teenager who doesn’t drive and therefore can’t conveniently take the bus, a stay-at-home parent might have this routine
- Start the car at home and drive to school.
- Do one errand on the way on the way home, which means starting the car again.
- Start the car at home again and drive to school. Instead of going home, go to the piano teacher’s studio.
- Do one errand during the lesson, which means starting the car one more time.
- Return to the studio and turn off the engine while waiting for the end of the lesson. Restart the car and drive home.
- Start the car at home to drop teenager off for an evening activity and return home.
- Start the car at home to pick up teenager after the evening activity and return home.
That adds up to starting the car seven times that day. If the driver starts the car before putting on the seat belt, that 35 seconds of unnecessary idling. Not everyone starts their car that often in a day, but plenty of people do that much and more.
Changing that one little habit can make a good start on reducing daily idling by five minutes.
Other excess idling
I said earlier that there are new occasions for idling that didn’t exist before. Before I mention them, here’s some of what’s not new:
- Traffic lights, or stop signs at a busy street
- Railroad crossings
- Traffic jams on highways or arterial streets
- The pick-up lane at schools
- Trying to get out of the parking lot after a concert or sporting event where hundreds of others may be trying to get to the same exit.
Here are two new ones that can use up a lot of gas if you’re not mindful:
- Drive thru lanes at fast food restaurants, drug stores, banks, ATMs, etc.
- Pulling over to the side of the road to use a cell phone safely
It may be illegal in your jurisdiction to turn off the motor at a traffic light. It’s probably pointless at a stop sign, where you’re waiting for a very brief window of opportunity to move.
But remember: if you’re going to idle for more than 10 seconds, it’s actually better for the car and uses less gasoline to shut the motor off. It should be very easy for most people to eliminate five minutes of idling every day. Avoid the drive thru lanes entirely. Those things can easily waste more than five minutes at a time.
Otherwise, if it looks like you’ll be sitting in more than one place for a while, turn the motor off. You’ll use less gas. And if enough other people in the same place turn their motors off, everyone will have less exhaust fumes to breathe.
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