Clean air — Utah Permit Test

A Utah driver saves gas by turning the engine off and restarting it if they expect to idle for more than 30 seconds.

Half a minute is the break-even point. Past it an idling engine burns more than a restart does.

IDLING—you will save gas by turning the engine off and restarting it again if you expect to idle for more than 30 seconds.

The most effective way to reduce vehicle emissions is to use the vehicle less.

No amount of careful driving beats a trip not taken, which is why the list starts with combining errands.

The most effective way to reduce vehicle emissions is to use it less.

Keeping tires inflated to the recommended pressure minimizes tire wear and helps a Utah vehicle get the best fuel economy.

Soft tires cost fuel every mile and wear out early. A pressure gauge is the cheapest tool in the trunk.

It’s also important to keep the tires inflated to the recommended pressure. This will minimize tire wear and help your car get the best possible fuel economy.

Octane measures how much a fuel can be compressed in an engine before it spontaneously combusts, and is not a measure of fuel power or quality.

Premium fuel is not stronger or cleaner. Buying it for a car that does not need it buys nothing at all.

Octane is a measure of how much a fuel can be compressed in an engine before it spontaneously combusts. It is not a measure of fuel power or quality.

Using a vehicle air conditioner increases the load on the engine, which can increase emissions and decrease fuel economy.

The compressor is driven by the engine, so cooling the cabin is paid for in fuel and in exhaust.

AIR CONDITIONING—using a vehicle air conditioner increases the load on the engine.

Modern Utah vehicles need little warm-up and are most efficient when being driven, and idling for long periods in cold weather can cause excessive engine wear.

Warming a car up on the driveway wears the engine and pollutes for nothing. Driving gently does the job better.

Modern vehicles need little warm-up; they’re most efficient when being driven. Idling for long periods in cold weather can cause excessive engine wear.

After how long idling should a Utah driver switch the engine off?

30 seconds. Half a minute is the break-even point. Past it an idling engine burns more than a restart does. Utah Driver Handbook 2026-2027, p.99: “IDLING—you will save gas by turning the engine off and restarting it again if you expect to idle for more than 30 seconds.”