Other reasons, reported by drivers include:
• personal comfort
• listening to the radio
• parking illegally
• convenience

Q: What is the "profile" of the typical idler?
A: It's safe to say that most motorists do some amount of idling. However, Canadian research shows some interesting trends. For example, the amount of idling a driver does tends to increase with the number of people in the household. A driver living with children is more likely to idle than one without children. As well, the frequency of idling appears to decrease as a person ages - a retiree is the least likely to idle. A person living in a rural area is more likely to idle than a driver living in an urban center.

Q: With modern emissions technology and more fuel-efficient cars, why do I have to worry about a small matter like idling?
A: It's true that automakers have succeeded in cleaning up most of the harmful substances emitted by vehicles. Compared with unregulated vehicles 30 years ago, today's new cars generate 98 percent fewer hydrocarbons, 96 percent less carbon monoxide and 90 percent fewer nitrous oxides. But one element in tailpipe emissions can't be "cleaned up" - carbon dioxide (CO2). This is the principle greenhouse gas linked to climate change. Every gallon of fuel that is burned produces about 19 pounds of CO2. The bottom line: the more fuel you use, the more CO2 you produce. And one of the best ways to cut fuel consumption is to avoid idling. After all, it gets you nowhere.

Q: How can only one gallon of gasoline burned by a car or light truck produce 20 lbs of carbon dioxide (CO2)?
A: Two factors contribute to the high output of carbon dioxide (CO2) per gallon of fuel burned. First, fuel burns in the presence of oxygen that it gets from air. Since air is only one-fifth oxygen, large quantities of air are needed to burn gasoline. Second, gasoline is rich in carbon, which is converted to CO2 when burned in the presence of oxygen. Because large quantities of air are required to burn gasoline, large amounts of CO2 are produced. If you're a typical motorist who drives 13,000 miles each year, you're emitting about four and a half tons of CO2 per year - that's three times the weight of your car!

Q: Is it important to idle my vehicle for a few minutes to warm up the engine, especially in winter?
A: No. Although this is a common practice among motorists, it's also wasteful and damages the environment. Tests show that you need no more than 30 seconds of idling to circulate the engine oil before you can drive away on cold days. Anything more just wastes money and produces needless greenhouse gas emissions. Remember, more than the engine needs to be warmed - so do the tires, transmission, wheel bearings and other moving parts. As well, the catalytic converter doesn't function at its peak until it reaches between 400°C and 800°C. The best way to warm the engine and all other components is to drive your vehicle.

Q: Is it more economical and fuel-efficient to leave my car running for a few minutes than to constantly turn it off and on? A: No. If you're going to be stopped for more than 10 seconds (except in traffic), you'll save fuel and money by turning off the vehicle and then restarting it when you're ready to drive again. Every 30 minutes of idling costs you nearly one-tenth of a gallon in wasted fuel - and more than three-tenths of a gallon if your vehicle has an eight-cylinder engine. As well, restarting a car many times doesn't wear out the battery and starter motor too soon. And catalytic converters stay warm for up to 25 minutes after you turn off the engine, so frequent stops and starts don't produce the large amount of harmful emissions seen with cold starts. There's no question about it - idling gets you nowhere. Instead, it wastes fuel and money and damages the environment.

Q: Are the "start-up" emissions after a long shut-down period more than if the engine just idled?
A: Much depends on the age and maintenance of the engine, but it's safe to assume that the start-up emissions are negligible after either a short or long period of time. In other words, the start-up emissions are not as great as the idling emissions, so it's always better to shut down. Of course this ignores the main reason for idling which is to provide cab comfort.

For example, we assume a truck consumes about 1 gallon per hour at idle and emits 135 g/hr of NOx and 3.68 g/hr of PM. If one were to argue that it is better to just idle overnight for 10 hours instead of shutting down, then one would have to claim that the start-up emissions (i.e., the amount of emissions over the time it took the engine to warm up) exceeds the idling emissions for 10 hours. If the truck idled for 10 hours it would emit 1,350 g of NOx (135 g/hr x 10 hours). So the question is would the start-up emissions exceed 1,350 g? While this question has not been answered with test data, a fairly strong argument can be made based on common sense that the start-up emissions would not exceed this amount.

Here are some tips that you can do yourself:
Reduce vehicle warm-up idling to 30 seconds, yes, even in subfreezing temperatures. People usually idle their cars more in the winter than in the summer. But even in winter, you don't need to let your car sit and idle for five minutes to "warm it up" when 30 seconds will do just fine.

Driving away slowly to moderately fast to get lubricants flowing is best for the engine. The only way to adequately warm up the transmission, wheel-bearings, steering, suspension, and tires is to actually drive.

10 seconds of idling can use more fuel than turning off the engine and restarting it. And when you start your engine, don't step down on the accelerator, just simply turn the key to start.

Avoid using a remote vehicle starter, which encourages unnecessary idling.

Consider the purchase of a gas/electric hybrid vehicle which seldom idles when stopped.

Spread the word to family and friends.

If you're in a drive-through restaurant/business line or waiting for someone and you'll be parked and sitting for 10 seconds or longer turn off your car's engine (except in traffic). For every 2 minutes a car is idling, it uses about the same amount of fuel it takes to go about one mile.

Research indicates that the average person idles their car 5 to 10 minutes a day. If you're not going anywhere, idling gets zero miles per gallon on top of your zero miles travelled.

A simple alternative to idling on errands is to park your car and just turn it off. You will rarely get back to your car faster than the time it takes to restart it.

Q: What are the most common reasons for idling?
A: Warming up a vehicle is the most common reason drivers give for idling - in both winter and summer! We also idle a lot at drive-through windows, when we are waiting on someone, and when we wait at railway crossings, wait to park, run quick errands, stop to talk to an acquaintance or friend, prepare to leave the house, wait to get gas - even wait in line to get our car washed. All of these situations waste energy and produce needless greenhouse gas emissions - and they are all avoidable.

Q: Can idling damage my car's engine?
A: You bet it can! Because the engine isn't working at its peak operating temperature when it's idling, the fuel doesn't undergo complete combustion. This leaves fuel residues that can contaminate engine oil and damage engine parts. For example, fuel residues tend to deposit on spark plugs. As the amount of engine idling increases, the plugs' average temperature drops, and they get dirty more quickly. This, in turn, can increase fuel consumption by 4 to 5 %. It's a vicious circle of wasted fuel and needless greenhouse gas emissions. Excessive idling can also let water condense in the vehicle's exhaust. This can lead to corrosion and reduce the life of the exhaust system.

Q: What are the truck maintenance and engine wear costs at idle?
A: The trucking industry has analyzed the impact of idling on engines, both in terms of maintenance and engine wear costs. Long-duration idling causes more oil and oil filter deterioration and increases the need for more oil and filter changes. Similarly, the longer the idling time, the sooner the engine, itself, will need to be rebuilt. The trucking industry estimates that long-duration idling costs the truck owner $1.13 per day, based on the need for more oil changes and sooner overhaul costs.