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Community Environmental Health

IDEM Environmental Health > Vehicle Idling Vehicle Idling

An idling car produces air pollution, even though the car is not going anywhere. Ten minutes of idling per day adds more than 50 pounds of carbon monoxide, particles, nitrogen oxides, and other toxic gases to the air per year. If you idle more than 30 seconds, your car will emit more air pollution than if you turn it off and on again. Check out the ISDH Great Reasons Not to Idle brochure [PDF] for more reasons to turn your car off.

Diesel Exhaust and School Bus Idling

Diesel exhaust from idling school buses poses a health risk to both drivers and students. As idling buses wait for students at schools, they emit exhaust fumes which concentrate at ground level and which can enter both passenger compartments of the buses and school classrooms through ventilation systems. Numerous scientific studies indicate that exposure to diesel exhaust can cause lung damage, respiratory problems, premature death, and lung cancer. Although everyone can be affected by diesel exhaust, children are more susceptible to these health problems because their respiratory systems are not fully developed.

Benefits of Reducing School Bus Idling:

  • Helps protect the health of drivers and students from the harmful effects of diesel exhaust fumes.
  • Reduces air pollutants that contribute to ozone, smog and fine airborne particle formation.
  • Reduces fuel consumption and saves money. A typical diesel vehicle burns approximately one gallon of fuel for each hour it idles. If each bus reduces its idling time by 30 minutes per day, a corporation operating 16 buses could save more than $2,500 per school year in reduced fuel costs.
  • Reduces wear and tear on the engine – saving on maintenance costs and increasing the life of the engine!

School Bus Drivers Can Make a Difference

School bus drivers can make a significant impact on protecting the health of their passengers and their own health by limiting engine idling whenever practical. Here are some simple guidelines for school bus drivers to follow:

  • Turn off engines when you reach the school or other destination, unless you will be leaving within a few minutes.
  • Do not allow buses to idle while waiting for passengers.
  • During morning start-up, buses should idle no longer than necessary to bring them to proper operating temperature and to defrost all windows.

Certain exceptions may be made (consistent with school policies or state regulations) under the following conditions:

  • It is necessary to run the engine in order to operate safety equipment.
  • When the outside temperature is between 32 and 20 degrees, idling is allowed for up to 15 minutes.
  • When the outside temperature is below 20 degrees, idling is allowed for up to 30 minutes or until windows are defrosted.

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