What are the rubber strips that are sometimes placed on busy roads that come from a metal box on the side and lay across the lanes of traffic?

What are the rubber strips that are sometimes placed on busy roads that come from a metal box on the side and lay across the lanes of traffic?
The rubber strips are sensors that connect to traffic counters (the metal boxes). The counters record the number of axles that pass by a certain point on the road. Your local transportation agency uses the counts to figure out how many cars are using that particular road. The traffic counts tell the agency when to plan for road improvements and where to spend traffic funds.