General Motors is using an array of visible and infrared cameras to study the spread of fires in cars, recently adding two new thermal imagers for improved resolution and dynamic range. The snow outside the building nears blizzard proportions, but inside the structure the huge concrete chamber is quiet and dark, except for the glare of arc lamps aimed at a raised platform in the center. On the simulated asphalt platform sits a new Honda Accord with wrecked rear and trunk compartments. In the surrounding shadows, 25 operators and observers form a ring around the platform, standing by with more than 30 instruments, including an array of visible and infrared imagers. With clocks synchronized for all the instruments, recording begins. All await the action of a hooded, suited figure holding an ignition torch. At a signal, the figure ignites a fuel leak near the rear end of the sedan. The burn is on. As the blaze rapidly envelops the car, data recording begins. Minutes later, a horn sounds. Suited figures armed with extinguishers surround the car, leaving behind only a blackened, smoking hulk. The scene was set in February inside Factory Mutual Research Corp.'s test facility in West Glocester, R.I. The latest in a series of "fire initiation and propagation tests," it was a controlled, instrumented automobile fire conducted by General Motors Corp. in conjunction with the National Highway Traffic Safety Administration and the National Institute of Standards and Technology.