Tracking devices as the name implies track a vehicle’s location. Tracking devices commonly use GPS for locating a vehicle. Vehicle tracking systems are commonly used by urban public transit authorities, particularly in large cities. Several types of vehicle tracking devices exist, mainly passive and active. Tracking systems are commonly used by fleet operators for fleet management functions such as fleet tracking, routing, dispatch, on-board information and security. Other applications of tracking device include monitoring driving behavior, such as an employer of an employee, or a parent with a teen driver. Vehicle tracking systems are popular in theft prevention and retrieval device. Vehicle Tracking System can also be used a security system. Some vehicle tracking systems also control vehicle remotely, including block doors or engine in case of emergency.