Mercedes and Nissan already have self-driving cars on the road and journalists have already seen many successful demonstrations as a passenger.
Tesla has shown a speedup video of what their system can do in the future...
At the moment, Tesla is not leading imho.
But at this very day.... They have the biggest fleet running today of l3/l4 capabele cars at the moment. No expensive multiple lidar setup, but just camera's/ radar and ultrasonic sensors.
That's a good solid base to reach a similar goal. Let's hope the software development can catch up before 2020.