With three accidents on "autopilot" in a short period, the defects in Tesla's design are becoming clear.
1. Tesla's "hands on wheel" enforcement is much weaker than their competitors. BMW, Volvo, and Mercedes have similar systems, but after a few seconds of hands-off-wheel, the vehicle will start to slow. Tesla allows minutes of hands-off time; one customer reports driving 50 miles without touching the wheel. Tesla is operating in what I've called the "deadly valley" - enough automation that the driver can zone out, but not enough to stay out of trouble.
The fundamental assumption that the driver can take over in an emergency may be bogus. Google's head of automatic driving recently announced that they tested with 140 drivers and rejected semi-automatic driving as unsafe. It takes seconds, not milliseconds, for the driver to recover situational awareness and take over.
2. Tesla's sensor suite is inadequate. They have one radar, at bumper height, one camera at windshield-top height, and some sonar sensors useful only during parking. Google's latest self-driving car has five 3D LIDAR scanners, plus radars and cameras. Volvo has multiple radars, one at windshield height, plus vision. A high-mounted radar would have prevented the collision with the semitrailer, and also would have prevented the parking accident where a Tesla in auto park hit beams projecting beyond the back of a truck.
Tesla is getting depth from motion vision, which is cheap but flaky. It cannot range a uniform surface.
3. Tesla's autopilot behavior after a crash is terrible. It doesn't stop. In the semitrailer crash, the vehicle continued under power for several hundred feet after sheering off the top of the Tesla driving under the semitrailer. Only when it hit a telephone pole did the car stop.
The Pennsylvania Turnpike crash is disturbing, because it's the case the "autopilot" is supposed to handle - divided limited-access highway under good conditions. The vehicle hit a guard rail on the side of the road. That may have been an system failure. Too soon to tell.
The NTSB, the air crash investigation people, have a team investigating Tesla. They're not an enforcement agency; they do intensive technical analysis. Tesla's design decisions are about to go under the microscope used on air crashes.
Tesla's spin control is backfiring. They tried to blame the driver. They're being sued by the family of the dead driver, and being investigated by the NHTSA (the recall people), and the NTSB. In comparison, when a Google self-driving car bumped a bus at 2mph, Google admitted fault, took the blame, and Urmson gave a talk at SXSW showing the data from the sensors and discussing how the self-driving car misjudged the likely behavior of the bus.