Current methods of screening vehicles for explosive threats primarily rely upon what the agents can see 
during physical inspections. These approaches have proven both time consuming and expensive. To improve the ability to screen for threats within a vehicle at federal buildings or at large public events, S&T is developing technologies that could rapidly screen vehicles at a distance, including systems that would allow for non-contact or standoff detection of explosive residues.
Screening people for explosive threats and conventional weapons has also been a challenge away from airport-style checkpoints. S&T is developing technologies that would allow screening of people outside the constraints of the conventional checkpoint. These advances will improve security at mass transit systems and large public events. In addition to the detection of explosive residues, S&T is examining non-invasive imaging systems which would detect anomalies that could be explosives or conventional weapons such as guns. Both imaging and trace detection technologies could be used to screen people before they enter buildings or public areas.