We're now getting a much better picture—literally—as to what happened with the fatal Tesla crash from earlier this year. First off, yesterday the National Transportation Safety Board released findings from their preliminary investigation. The unfortunate driver was in fact using Tesla's Autopilot features, with both the Traffic-Aware Cruise Control and Autosteer features being engaged. He was also, the report notes, speeding—doing 74 miles per hour in a 65-m.p.h. zone.

This photo of the aftermath gives you an idea of how horrific the accident was:

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To refresh your memory, the Tesla was traveling along a divided highway when a tractor trailer coming the other way made a left turn directly into its path. The Tesla passed beneath the trailer at 74 miles per hour and the top of the car was sheared off. Reuters explains the violent nature of the crash:

…The force of the initial impact of the crash resulted in the battery disengaging from the electric motors powering the car. After exiting from underneath the truck, the car traveled 297 feet, then collided with a utility pole. The car broke the pole and traveled an additional 50 feet.

This diagram put together by Electrek makes it even more clear:

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The big question is, how did Autopilot fail to sense such a large obstacle? The earlier explanation provided by Tesla was that the car's camera could not pick up the white body of the trailer against the brightly-lit sky. But what about the radar? Here's a Twitter exchange where Musk is challenged and answers:

Clearly there are kinks to work out. The tricky part here is that regulations will likely outpace actual investigations; for instance, Automotive News reports that "[The] NHTSA is expected to announce guidelines as soon as this month that will set some parameters for self-driving cars on U.S. roads," whereas the NTSB states that "The preliminary report does not contain any analysis of data and does not state probable cause for the crash…. While no timeline has been established, final reports are generally published 12 months after the release of a preliminary report."

This means that laws will emerge before we have all of the data required to craft them. Transportation Secretary Anthony Foxx is apparently aware of this challenge, according to AN: "[Foxx] told reporters Wednesday the agency would be as exact as it could without being overly prescriptive. 'We're crafting a Declaration of Independence, not a Constitution,' Foxx said."