  Since DARPA started Grand Challenges in 2004 and Urban Challenges in 2007,
autonomous driving has been the most active field of AI applications. This
paper gives an overview about technical aspects of autonomous driving
technologies and open problems. We investigate the major fields of self-driving
systems, such as perception, mapping and localization, prediction, planning and
control, simulation, V2X and safety etc. Especially we elaborate on all these
issues in a framework of data closed loop, a popular platform to solve the long
tailed autonomous driving problems.
