When Cal is in the hospital after his accident, just before he fully wakes up he is shown with an oxygen tube going to his nose. In the shot right after that and all subsequent shots, the oxygen tubes are gone.
Ilene says the jars of broken glass are from windshields. Windshields are made from laminated glass, two layers of glass with a sheet of very tough plastic inside. This is what keeps the glass together when the windshield is broken. The side windows are made from tempered glass which breaks into "diamonds" instead of the long sharp shards typical in house windows.
When they look at the video footage of Cal's crash the two cars are in the wrong position. The cars are positioned as if they stopped at the moment of impact. This would only happen if they were both going very slowly. Cal was going slow, having just started again after waiting for the light. The other car was going much faster because his light was already green. They hit hard enough that they would have bounced leaving Cal's car close to the other side of the intersection on the same side Cal came from. The other car would have been knocked slightly off course by the impact but would have continued in the same general direction, ending up on the far side of the road from where Cal's car would have ended up.