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Automobile exhaust is a large contributor of atmospheric nitrogen and wet deposition on paved surfaces runs off quickly without any absorption by soils . The algorithms presented here were tested on 4K and 16K processor MasPar MP-1 and on 4K , 8K , and 16K processor MasPar MP-2 parallel machines and were used to drive Carnegie Mellon 's testbed vehicle , the Navlab I , on paved roads near campus . A small portion of rollover crashes occur on paved surfaces , but a much larger number occur when a vehicle runs off the road and strikes a tripping mechanism such a soft soil , a curb or guard rail ( FHWA is conducting related research on these physical attributes ) . However , that effect is limited to the untripped rollovers on paved surfaces .