High Definition Maps are essential for autonomous driving cars, these maps have very high accuracy of object detection and locations which are accurate up to centimeter levels. HD maps provide high accuracy and precise location of traffic lanes, traffic signals, speed limits, bike lanes, height and location of the curb and other useful data. Autonomous cars have a number of sensors like LIDAR, GPS, IMU and radars to assist them and they also act as a redundancy in the event if any censor fails.