KEVLAR IS A HEAVY DUTY CORD MATERIAL THAT HAS BEEN USED FOR BLOWOUT-RESISTANT TIRES. IT IS FIVE TIMES AS STONG AS STEEL THREAD OF THE SAME DIAMETER. BY VARYING THE WEAVE AND LAYERING THE FABRIC, A LIGHTWEIGHT VEST CAN BE FASHIONED THAT WILL STOP A BULLET. TAILORS FIND KEVLAR DIFFICULT TO WORK WITH, BUT 16 FIRMS ARE MAKING VESTS AND OTHER GARMENTS FROM THE MATERIAL. APPROXIMATELY 200,000 VESTS HAVE BEEN SOLD, MOST OF THEM TO THE LAW ENFORCEMENT COMMUNITY. TO EVALUATE THE MATERIAL, LEAA EQUIPPED 5,000 OFFICERS WITH VESTS IN 15 CITIES. DURING THE FIRST 2 YEARS OF THE PROJECT, FIVE OFFICERS WERE ASSAULTED WHILE WEARING THE VEST, AND IN ALL FIVE CASES THE VESTS PREVENTED SERIOUS INJURY. TWO OF THE OFFICERS WERE ASSAULTED WITH GUNS, TWO WITH KNIVES, AND ONE WITH A CANE. LEAA SUGGESTS THAT KEVLAR VESTS HAVE CONTRIBUTED TO THE RECENT DECLINE IN THE NUMBER OF POLICE OFFICERS KILLED AND IS CONDUCTING RESEARCH TO VERIFY THIS BELIEF. KEVLAR, HOWEVER, LOSES 60 PERCENT OF ITS EFFECTIVENESS WHEN WET, CREATING A PROBLEM DURING CHASES ON HOT DAYS. LEAA FOUND IN ITS 15-CITY EXPERIMENT THAT OFFICERS WORE THE VESTS ONLY 55 PERCENT OF THE TIME IN COOLER WEATHER AND ONLY 38 PERCENT OF THE TIME IN WARMER WEATHER. FACTORS AFFECTING THE ON-THE-BEAT ACCEPTANCE OF THE VEST WERE THE OFFICERS' PERCEPTIONS OF THE NEED FOR PROTECTION, COMFORT, THE OFFICERS' VANITY SINCE THE VEST DETRACTS FROM THE NEAT LOOK OF THE UNIFORM, AND THE OFFICERS' BELIEFS IN A PREDESTINED DATE WITH DEATH--THE IDEA THAT WHEN YOUR NUMBER'S UP, THERE'S NOTHING YOU CAN DO ABOUT IT. THERE IS THE ADDITIONAL PROBLEM OF WHO SHOULD BEAR THE COST OF THE $100 TO $150 VEST, AND IN MOST CITIES IT IS THE INDIVIDUAL OFFICER HIMSELF. (KJM)