July 1, 2002
The latest news about school buses.


A study has found that children are exposed to diesel exhaust from school buses at levels greater than what is predicted by government monitoring.

Environment and Human Health Inc., a non-profit group made up of doctors, public-health professionals and policy experts, conducted the study in Connecticut using portable monitoring devices worn by students. Fine particulate concentrations on diesel buses often were five to 15 times higher than average levels at fixed-site monitoring stations.

Researchers found that levels of fine particles and black carbon were higher under certain circumstances: when buses were idling with doors or windows opened; when buses moved through heavy traffic; and especially when buses were lined up and idling to load or unload students.

The report urges the federal government to require installation of air filtration equipment to prevent bus exhaust from entering the passenger cabin and retrofitting of diesel buses to reduce emissions; mandate the use of low-sulfur fuel; provide financial support for replacing diesel fleets with low-emission vehicles; order periodic testing of tailpipe emissions; and establish air-quality standards for the passenger cabins of school buses.


Students riding in a school bus are nearly eight times safer than those riding in a car, the National Highway Traffic Safety Administration (NHTSA) says.

In a report to Congress, the NHTSA says the fatality rate for school buses is 0.2 fatalities per 100 million vehicle miles compared with 1.5 fatalities per 100 million vehicle miles for cars.

The agency attributes the safety record to compartmentalization on school buses. Compartmentalization is the protective envelope created by strong, closely spaced seats that have energy-absorbing high seat backs that protect occupants in a crash.

The NHTSA report also found that mandating lap belts on large, new school buses appears to have little, if any, benefit in reducing serious injuries in severe frontal crashes.

In small school buses, the report says, any increased risks associated with the use of lap belts are more than offset by the number of ejections prevented. These buses weigh less, have different crash dynamics, and are more prone to rollover than large school buses.

The use of combination lap/shoulder belts, if used properly, could improve safety somewhat on both large and small school buses. But lap/shoulder belts also could reduce school bus capacity by up to 17 percent because of seat redesign, and add between $40 and $50 per seating position to the cost of a new vehicle.


The National School Transportation Association acknowledges that exposure to diesel fumes can be risky. It encourages cooperating with school officials to try to diminish the dangers. The NSTA's suggestions:

  • Offer to work with administrators to see how school-loading times can be reduced.

  • Consider whether a school can modify the way buses line up at the school.

  • Make customers aware of the costs involved in moving to cleaner buses, so that they can figure those costs into their budgets.

  • Partner with administrators to lobby school boards and legislatures for reasonable conversions to clean vehicles and for financial support.

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