Yole Developpement research "Sensors and Data Management for Autonomous Vehicles report 2015" shows the roadmap from manned driving to "feet off" to "hands off" to "mind off" and the sensors needed for that:
"Currently, the most advanced commercial car with autonomous features embeds in the order of 17 sensors. Yole anticipates 29+ sensors by 2030. Today, two sensor businesses dominate: ultrasonic sensors and cameras for surround. Together they are worth a $2.4B market value, but ultrasonic sensors comprise 85% of current market volume. By 2030, cameras for surround will lead the market at $12B, followed by ultrasound sensors and long-range radar ($8.7B and $7.9B respectively), and then short-range radar ($5B). Overall 2030 market value is estimated at $36B.
All of these evolutions will likely lead to mass-market adoption of semi-autonomous vehicles by 2030. We expect more than 22M units (18% of all vehicles sold) of level-2 vehicles and 10M units of level-3 vehicles by 2030, along with 38M units of level-2 vehicles and 1M units of Level-4 vehicles."