THE TESTS WERE CONDUCTED JOINTLY BY THE GENERAL SERVICES ADMINISTRATION (GSA) AND THE NATIONAL BUREAU OF STANDARD'S LAW ENFORCEMENT STANDARDS LABORATORY (LESL). THE IMPETUS FOR SUCH TESTS AND FOR A RESULTING USER GUIDE CAME FROM A REPORT ON TWO FATAL ACCIDENTS IN WHICH STEEL-BELTED RADIAL TIRES ON STATE HIGHWAYS PATROL CARS HAD FAILED DURING HIGH SPEED CHASES. FOR THE JOINT TESTING PROGRAM, GSA CONDUCTED THE HIGH SPEED ENDURANCE AND TREAD WEAR TESTS; THE NATIONAL BUREAU OF STANDARDS, TOGETHER WITH STAFF OF THE NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, THE TRACTION TESTS. RESULTS SHOWED SUBSTANTIAL VARIATIONS IN TRACTION PERFORMANCE DURING THE DIFFERENT TESTS. TRACTION CHARACTERISTICS STUDIED INCLUDE BRAKING, CORNERING, ACCELERATING, AND SPINNING. THE 10 TYPES OF TIRES WERE RANKED IN GROUPS RANGING FROM 'GOOD' TO 'POOR.' SIX OF THE 10 BRANDS PERFORMED ACCEPTABLY IN THE TREAD WEAR TESTS. RESULTS SHOWED THAT CLIMATE AND/OR ROAD CONSTRUCTION HAVE MAJOR EFFECTS ON TREAD WEAR. IN MOST GEOGRAPHIC REGIONS, TREAD-WEAR PERFORMANCE OF FABRIC AND STEEL RADIALS WAS NEARLY EQUAL. ON THE AVERAGE, BIAS-PLY TIRES LASTED ABOUT 13,200 MILES; BIAS-BELTED, ABOUT 15,900 MILES; FABRIC RADIALS, ABOUT 22,800 MILES; AND STEEL RADIALS, ABOUT 24,200 MILES. ANALYSIS OF MANUFACTURERS' TESTS AND THOSE OF OTHER ORGANIZATIONS SHOWED WIDE VARIATIONS IN TEST PROCEDURES. THE ANALYSIS CONCLUDED THAT VARIATIONS CRITICAL TO A TIRE'S PERFORMANCE SHOULD BE ELIMINATED. A SURVEY OF LAW ENFORCEMENT AGENCIES ALSO SHOWED FREQUENT DEFICIENCIES IN PATROL CAR MAINTENANCE PROCEDURES. TABLES AND FOOTNOTES ARE INCLUDED. (CFW)