The Defense Advanced Research Projects Agency (DARPA) has successfully completed the largest test of its kind involving vehicle-mounted nuclear and radiological detectors. Conducted in cooperation with Fire and Emergency Medical Services (EMS) in Washington, D.C., the test involved placement of DARPA’s SIGMA devices on the agency’s fire trucks and ambulances last July. By the time the test concluded in February, the vehicles logged in more than 100,000 hours using the devices, as the vehicles traveled more than 150,000 miles. They detected thousands of radiation sources, emanating from harmless items like granite rocks in construction sites and residual materials from medical treatments. The SIGMA device can distinguish between harmful and benign sources, DARPA said. The agency plans to expand testing to other metropolitan areas during the next two years.