The Gelegotis Bridge is a four-lane 7,300-foot -long structure, which began operation in 2003. The new elevated design allows auto traffic to move faster, while vessels pass under a 65-foot  clearance and through 90 feet  of horizontal clearance between the bridge supports. This bridge is named after Paul Gelegotis, a James Island businessman and politician. Paul Gelegotis is also known as "The Father of EMS", as it was he who created the Emergency Medical System in South Carolina. The "9-1-1" line, and medically equipped ambulances resulted. The South Carolina Department of Transportation opened two lanes to vehicles in November 2003, and opened the remaining two lanes in June 2004. Three construction accidents delayed the opening by six months, two of these were caused by cranes falling onto the structure; the third was a worker falling 30 feet  from a crane. The new bridge incorporates vehicle emergency lanes, but no demarcated bicycle lanes or sidewalks. It is the first bridge designed to include the South Carolina Department of Transportation's new seismic design criteria. In total, construction of the bridge cost approximately $41.5 million. The bridge was dedicated June 17, 2004. As a result of increased traffic flow and speed over the new bridge, Charleston is considering spending approximately two million dollars to build a tunnel beneath the bridge approach ramps so golf carts and pedestrians are able to safely cross.
Question: How many accidents were caused by cranes falling onto the structure?
Answer: 2