If you apply that reliability percentage directly to time driven (inaccurate, I know, but for the sake of argument), a system which takes care of 99% of driving

If you apply that reliability percentage directly to time driven (inaccurate, I know, but for the sake of argument), a system which takes care of 99% of driving problems will still abandon you to chaos for 18 seconds out of every 30 minute drive. This is an eternity in a moving vehicle where milliseconds can draw the line between life & death. The only systems safe enough to allow fully automated vehicles in the near future will have to be on dedicated lanes or roads, probably with additional safety mechanisms on the roadway itself.