Tesla FSD - This is Why Self-Driving Needs Lidar (or Other Ranging)
A nameless submitter writes:
Motor Trend is reporting that a Tesla FSD owner/beta tester wondered why his car was stopping well before the end of the off ramp...where there is a stop sign before the surface street. It was so far ahead of the sign that he had to quickly switch to manual before getting rear ended by the next car down the off ramp.
His theory is that these stop signs are larger than the normal ones--and a tape measure confirms it. So the Tesla (by whatever mechanism) seems to be using the apparent size of the stop sign to determine where to stop.
This is why (imo) any sort of self driving needs ranging information. There are options, stereo cameras (which may be hard to keep aligned?), radar for certain types of objects (but stop signs might not be a good target??) or the original choice, lidar.
Also reported here with the following quote:
As they suspected, the stop sign on the exit ramp is, in fact, significantly larger. Many of these signs measure just over 48 inches tall, which is around 60 percent larger than the 30-inch signs in their neighborhood.
"60 percent larger to the camera gets interpreted as 60 percent closer?" asks the Tesla owner on Twitter. "I still have the slow creep problem here [...] and it'll come to a complete stop while sitting in the near lanes even if no cars are around!"
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