Braking Efficiency of Modern Motor-Cars

Abstract

AN abstract of a speech made by Prof. R. A. Moyer at the Annual Safety Congress, held at the Iowa State College, has been issued by Science Service, Washington, D.C. Prof. Moyer considers that on ordinary roads the present-day braking power of motor-cars when driven at their highest speeds is insufficient, and that they are decidedly unsafe. Safety lies mainly in providing low stopping distances. To provide the same stopping distance when travelling at 60 miles an hour as at 40 miles an hour requires brakes two and a half times as powerful. In Prof. Mover's opinion, to maintain traffic speeds at about 45 miles an hour on open stretches of road would eliminate many of the risks arising from high speed. A study of traffic statistics shows that half the risk of accident would be eliminated if cars were forbidden to run at more than 55 miles an hour. If speeds greater than this are necessary, it would be far cheaper and probably equally safe to use an aeroplane. Prof. Moyer points out that Sir Malcolm Campbell needed a 2,500 horse-power motor to average 300 miles an hour on the salt beds of Utah? probably the most perfect race course in the world. On the other hand, an aeroplane with a 1,000 horsepower motor can reach 350 miles an hour in the air.