UTSA Smart Stop Sign (IMAGE) University of Texas at San Antonio Caption The next-generation stop sign uses a multi-pixel passive infrared sensor that detects a vehicle as it approaches an intersection. Once the vehicle is within the sensing range, a signal beacon triggers the stop sign's flashing system. Credit Courtesy of UTSA Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.