Backup warning systems are common on new vehicles, but older cars and commercial vehicles can also be retrofitted. Rostra Precision Controls manufactures the Rostra Obstacle Sensing System (ROSS) that alerts drivers to obstacles that come within 12 feet of the rear and sides of their vehicles while backing up. That includes cars, buildings, trees and people and pets. The company says the motion-sensing unit uses the latest microwave technology to provide both audible and visual alerts in all weather conditions. The ROSS also remains completely hidden when installed behind a non-metal (plastic) bumper. Get full details from www.rostra.com and order for about $240 from online outlets including www.summitracing.com.