The article first describes advanced technologies that preempt programmed traffic lights to give the green light to emergency vehicles on call. The author advises that current traffic signal preemption systems are helpful, but have limitations. They are limited in range and usually affect only the traffic lights at the next and closest intersection. Preemption systems that detect flashing lights and sirens cannot "see" well around corners or "hear" in noisy areas. Pedestrians crossing at intersections are another problem. Visual warnings help, but pedestrians often do not see them in time. In noisy and crowded urban areas, lights and sirens on emergency vehicles are often not noticed until a few seconds before the vehicles arrive at the intersection. The author describes the features of specific warning and traffic-light preemption systems that are currently available on the market, followed by the technological features anticipated for the future. The latter discussion notes that vehicle-to-vehicle and infrastructure-to-vehicle communication are now being developed under the Vehicle Infrastructure Integration (VII) initiative, which involves the participation of transportation officials at the Federal and State levels as well as vehicle manufacturers. The core of VII is dedicated short-range communications (DSRC) based on wireless, local area network technology. Although traffic-signal preemption is not currently a primary objective of the VII initiative, it could benefit from the technologies being developed. With DSRC technology, emergency vehicles could communicate with roadside units, which in turn send out warnings to individual vehicles or preempt traffic lights.