Boise Police say the 33-year-old rider crashed into the corner barrier on the raised highway above 15th Street in downtown, skidded along it for about 100 feet, then flipped over the barrier and fell down 30 feet to Rhodes Skate Park below.
Dispatch says the rider was taken to the hospital with unknown injuries.
A witness at the skate park who ran over to the rider after watching him fall tells us he was wearing a helmet and was conscious, but appeared severely injured.
Boise Police say the evidence on scene leads them to believe excessive speed may have been involved.
The inbound Connector was closed and traffic was forced to exit onto River Street while the crash was under investigation.