Same thing happened to my DH this time last year- almost dark, he was merging to the left because his lane turned into a right-turn-only, and a yahoo in a pickup passed him and moved over to turn right, knocking my husband to the pavement. No one stopped to help him as he dragged his bike out of the street. The driver walked back and chewed my husband out, saying it was all bullsh*t. Then he left. Someone called the police. By the time they showed up he was having a hard time breathing. He ended up in an ambulance and to the hospital with a broken rib and punctured lung. He ended up needing a chest tube because the lung continued to collapse through the night, and was in the hospital for five days. They never found the driver. But we did file a claim against our uninsured motorist policy and received a settlement from them.
The interesting thing is no one stopped except a homeless guy on a bike. Everyone else drove by. We joked that if it was a dog someone would have stopped, but no one likes cyclists.