Their spatial demands can require removal of parking spaces and create difficulties for pedestrians. Chicanes and Chokers Chicanes also change a roadway's character. They are essentially islands or curb extensions built into the street in alternating pairs, like the teeth of a zipper, which force drivers to slow their cars. They provide opportunities for landscaping and refuges for pedestrians, both of which calm traffic by reminding drivers to share the roadway. They work best on low-volume streets and must be designed with care to prevent bicycles from being forced into too close proximity to motorized vehicles.
Chokers are scaled-down chicanes and work singly.
They require extensive pre-implementation study of their possible effects to avoid spillover on nearby streets. They are also generally very costly and their use must be reconciled with the objections of emergency and other services providers who will lose direct access to the closed off blocks. Mechanized Enforcement Mechanized traffic rule enforcement is gaining popularity. Its most common use is to catch red-light runners. A camera snaps pictures of an offending vehicle's license plate as it passes through the intersection, and the registered owner subsequently receives a summons or warning in the mail.