In racing sports, the ideal line is the path that a competitor takes through a race course, the line that allows the competitor to travel at the highest average speed. The ideal line is often used in motorsports, though other racing sports such as skiing and bicycling have similar concepts of an ideal line.
When analyzing a single corner, the optimum line is one that minimizes the time spent in the corner and maximizes the speed as the vehicle leaves the corner.
The apex is the point in the turn where the vehicle runs closest to the inside edge of the track. Hitting the apex allows the vehicle to take the straightest line and maintain the highest speed through that specific corner.