The Environmental Protection Agency (EPA) has announced a new testing program for on-highway diesel truck and bus engines that uses a portable device to measure emissions while the vehicles are on the road.

A pilot program was initiated last month, using fleets or owner-operator volunteers recruited by engine makers to test '07 engines in-use for hydrocarbon, carbon monoxide, oxides of nitrogen, and particulate matter.

An on-highway measurement of engine emissions should provide a more accurate assessment than the current method, in which engines were physically removed from vehicles and tested in a lab.

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