A spike strip is a device used to impede or stop the movement of automobiles by flattening their tires. Generally, the strip is composed of collection of 1.5" to 3" long metal barbs pointing upward. The barbs are designed to puncture and flatten rubber automobile tires when an automobile is driven over them.
Spike strips are also used to control ingress and egress to certain areas where automobiles travel. A one-way spike strip will allow an automobile to travel over them in one direction; the spikes are hinged so that they collapse harmlessly when driven over in one direction, but remain upright when driven in another.
A light-weight variant used by various police forces is the Federal Signal Corporation's Stinger. It is packaged in a concertina form, with a tough frame of nylon strips holding hollow, pointed steel rods. In use it is spread out across a surface or even thrown towards approaching vehicles, spreading out during flight, an attatched rope means it is easy to regather after use. The construction of the strip points the spikes into the tires as they pass over, the spikes then detach and remain in the tires, their hollow construction assisting in the venting of air over 10 to 20 seconds.
