In this case, AP was not even engaged, so the radar nor AP cannot be blamed in this case. I don't think there have been any T-bone accidents while on AP for the past two years, so I don't know that the issue still exists in the current software. In fact, the V9 FSD beta release coming in April will not even use RADAR.A skirt (in this case) or a solid cement median divider (in the Mountain View fatal Model X Autopilot case) won't help.
That's because current Tesla's automation system is still using RADAR which is designed to label moving obstacles running in the same direction as Tesla are dangerous.
If the obstacles are stationary or moving but in a different direction (Lateral Turn Across Path--LTAP, in this case), then the current RADAR is designed to ignore them and the car would go ahead and slam right into them as proven in previous Autopilot accidents (not just fatal but also non-fatal Autopilot accidents too: Police cars, fire trucks, vans...).
That's why other companies are using LIDARS for those above cases.