Cummins has been doing "laps" around the United States in Cummins-powered Dodge Ram Heavy-Duty 2500 and 3500 series pickups since July. The laps are being used to field test the re-engineered Cummins Turbo Diesel engine and the Dodge Ram combination in extreme operating conditions "to ensure that reliability and durability are unmatched" in this vehicle class.

Each lap is about 9,000 miles and covers all types of road and weather conditions. Each truck pulls fully loaded trailers to increase the demands placed on the engines.

For testing purposes, the vehicles typically are operated with 90% load on the engine, which Cummins said is much greater than the demands of an average user.

Cummins has compiled more than a quarter-million miles of testing through this system.