Speed humps as traffic calming measures which significantly affect traffic flow. Recent studies mostly investigated traffic flow parameters such as speed, density, traffic volume, capacity and safety parameters. In this research, impact of speed hump on speed of different kinds of vehicles and also passenger-car equivalent impact for heavy vehicle is studied. Emam Khomeini Avenue as a major arterial in Isfahan was selected as its traffic stream consists of almost all types of vehicles. Data was collected by videotaping of the traffic stream.