Autonomous driving system

A method comprising:

• recognizing a traveling road on which an own vehicle is traveling, the traveling road having a plurality of lanes;
• recognizing speeds of other vehicles traveling on an own lane on which the own vehicle is traveling and speeds of other vehicles traveling on an adjacent lane that is adjacent to the own lane;
• determining a vehicle density in the adjacent lane based on the speeds of other vehicles traveling on the adjacent lane, positional information of three or more continuous vehicles that travel on the adjacent lane, and by assigning weights to respective inter-vehicle distances between the three or more continuous vehicles that travel on the adjacent lane and taking an average value of the weighted inter-vehicle distances after excluding inter-vehicle distances of a threshold value or more;
• and
• determining whether to perform a lane change to the adjacent lane based on the vehicle density in the adjacent lane and a threshold density.