"because inevitably an earthquake is going to make a self driving car crash where nobody could have prevented it"
Maybe not. On March 11, 2011, a magnitude 8.9 earthquake hit Japan.
The first seismometer to detect it (out of 92 in the system) was on Kinkazan Island, just off the eastern coast of Japan. Each seismometer has some compute power and is constantly computing a hazard level based on the waveforms of earth movements. The Kinkazan unit did what it was supposed to, and sent an emergency shutdown signal to the Shinkansen high speed rail system. Not through the signaling system; the circuit breakers at power substations were immediately tripped and power to the trains cut. The trains treat a power cut as an emergency stop situation and apply the brakes hard. All trains stopped safely.
Maybe not. On March 11, 2011, a magnitude 8.9 earthquake hit Japan. The first seismometer to detect it (out of 92 in the system) was on Kinkazan Island, just off the eastern coast of Japan. Each seismometer has some compute power and is constantly computing a hazard level based on the waveforms of earth movements. The Kinkazan unit did what it was supposed to, and sent an emergency shutdown signal to the Shinkansen high speed rail system. Not through the signaling system; the circuit breakers at power substations were immediately tripped and power to the trains cut. The trains treat a power cut as an emergency stop situation and apply the brakes hard. All trains stopped safely.
[1] http://www.railway-technology.com/features/feature122751/