There were no serious injuries, but a four-vehicle crash on Interstate 180 West at the Hepburn Street interchange late Thursday afternoon during the height of rush hour caused an extensive traffic jam on the interstate, city police said. Three of the vehicles had to be towed, including a Chrysler Town and Country van at left and a Jeep Compass, police said. All those involved declined medical treatment following the 4:20 p m. accident, police said. City firefighters also responded. Motorists entering I-180 West at Hepburn Street had a difficult time getting on the highway.