Traffic radar emits microwaves, and the issue is whether these microwaves can cause cancer in those human tissues with which they come in contact. A group of German scientists conducted experiments that used microwaves of the type transmitted by traffic radar (continuous wave transmitted at very low power density). These experiments produced scientific proof that athermal low-power effects can occur. Dr. W. Ross Adey, Chief of Research at the Jerry Pettis Memorial Veterans Hospital in Loma Linda, Calif., has been involved in medical and scientific research in the area of cancer promotion and microwaves for over 30 years. Based on his experience and the German research, Dr. Adey has stated that police radar "may carry a significant biological and biomedical risk based on both the physical evidence and the biological evidence." Dr. Henry Kues of Johns Hopkins University Applied Physics Laboratory has described his research on the effects of microwaves on the eye. He has concluded that under certain circumstances, police officers using hand-held radar are exposed to levels higher than those allowed under the 100 microwatts per square centimeter JHU-APL exposure standard. These findings and other research findings reported in this article are sufficient to produce a presumption of risk for police officers who use hand-held radar. Departments should require that all traffic radar antennas be placed outside the patrol vehicle.