MICHIGAN'S SKID TESTING PROGRAM

A COOPERATIVE SKID TESTING PROGRAM WAS UNDERTAKEN WITH GENERAL MOTORS PROVIDING GROUND AND THE MICHIGAN STATE HIGHWAY DEPARTMENT. SKID TESTS WERE PERFORMED USING THE TWO TRAILER TESTING EQUIPMENTS. APPROXIMATELY 2,400 SKID TESTS WERE PERFORMED BETWEEN JUNE AND NOVEMBER, 1957. DYNAMIC AND STATIC COMPARATIVE TESTS OF THE TWO SKID EQUIPMENTS WERE MADE. IN GENERAL, THE DEPARTMENT'S EQUIPMENT GIVES SLIDING COEFFICIENTS ABOUT 20% HIGHER THAN GENERAL MOTOR'S AT 30 MPH IN THE SAME TEST AREAS. THIS DIFFERENCE IS BEING INVESTIGATED. TWO HIGH-ACCIDENT INTERSECTION AREAS IN DETROIT WERE GIVEN ANTI-SKID TREATMENTS UTILIZING ALUMINUM OXIDE GRAIN WITH ASPHALT AND LATEX EMULSIONS OR EPOXY RESIN BOND COATS. THESE AREAS WILL BE RETESTED PERIODICALLY TO DETERMINE THE AFFECTIVENESS IN PERMANENCE OF EACH COATING UNDER NATURAL WEATHERING AND TRAFFIC.