THE PLAINS, Va. — The National Association of State Directors of Pupil Transportation Services (NASDPTS) recommends that school districts evaluate loading zones for proximity to idling school buses and, as funding permits, replace older buses with cleaner-burning new buses.

The recommendations are included in an information paper on air quality released by NASDPTS in March. The full report can be read at www.nasdpts.org.

Reducing engine idling, especially in areas where schoolchildren congregate, would curtail students’ exposure to exhaust emissions, but the association stops short of recommending that states target school buses for idling laws. “These programs should not be applicable only to school buses, since school buses make up a very small percentage of all commercial motor vehicles,” the paper states.

The association recognizes, however, that the school transportation industry can reduce its level of exhaust emissions by replacing older buses with new ones or by retrofitting older buses with emission control technologies.

Funding constraints faced by many school districts across the country create obstacles to these objectives. “The expectation for accelerated school bus replacement programs or retrofit programs to occur in large numbers without significant increases in funding for such programs is unreasonable,” the paper states.

NASDPTS also suggests that school bus drivers be aware that following large vehicles such as commercial trucks or other school buses too closely can compromise air quality within their vehicles. “Several studies clearly show that as much as 50 percent of the exhaust emissions that end up inside a motor vehicle is directly attributable to the exhaust from the vehicle(s) immediately in front,” the report says.