This is just beyond me. How did the radars not see the front portion of the truck, the front wheels, the underbody of the container isn't that high to let the entire car go through?
I'm not even sure the radar has a height dimension, I suspect they just focused it at bumper height to catch most cars.
The car also has a single camera in the front to see the lane markers, and a short range ultrasonic system to give it a 360 degree view, out to a few meters.
For the amount of confidence drivers are putting into the system, Tesla don't have anywhere enough sensor data.
And I absolutely agree with your last sentence - these cars need more sensors.