Variety of controllers have been developed to improve driving as well as operating conditions of vehicles, such as to provide smooth throttle movement, zero steady state speed error, good speed tracking over rod slopes, and robustness to system variation and operating conditions. The complexity of the speed control algorithms has increased through the years to meet the Growing demands on more stringent automotive performance criteria. Only with the recent availability of inexpensive microprocessors more sophisticated control strategies have been implemented. The clutch-less automatic gear transmission system utilizes a gearbox that automatically changes the gear ratio, which allows the driver to simply select one gear to move or park the vehicle. There are two main types of transmission in cars: manual transmission and automatic transmission. The key difference between a manual and an automatic transmission is that the manual transmission locks and unlocks different sets of gears to the output shaft to achieve the various gear ratios, while in an automatic transmission the same set of gears produces all of the different but discrete gear ratios. The planetary gear set is the device that makes this possible in an automatic transmission. Manual transmissions can be very tiring to drive in heavy stop and-go traffic. It has the problem of Worn or slipping clutches. In cold weather manual transmissions can become sluggish and hard to shift. Also in the beginning can be difficult to learn.