Description - Gradual rise and fall in pavement surface over a varied distance
Objective - Reduce vehicle speed by the change in vertical movement of the vehicle
Constraint - May not reduce the speed of all vehicles; some discomfort to occupants of vehicles at all speeds across the device
Speed Dip/Swale
Description - Gradual depression in the pavement surface over a varied distance
Objective - Reduce vehicle speed by the change in vertical movement of the vehicle
Constraint - May not reduce the speed of all vehicles; some discomfort to occupants of vehicles at all speeds across the device
Description - Raised island placed generally in the middle of an intersection
Objective- Reduce vehicle speed and provide predictable traffic flows
Constraint - May not reduce the speed of all vehicles. Can force traffic closure to adjacent properties if installed as a retrofit
Description - Extension of curb into the paved roadway to narrow the street, generally into the parking area
Objective - Increase pedestrian safety by reducing distance to cross street, slow traffic and increase awareness of neighborhood environment
Constraint - Reduce parking in an area, may impact turning movements; may impact drainage of the street
Description - Artificial curving of the street by installation of offset curb bulbs or by offset curb parking
Objective - Reduce traffic speed
Constraint - Reduces parking, may not slow down all vehicles, may increase speed of some motorists
Description - Raised curbs or other means at intersection approaches to force or prohibit certain traffic movements. Can also be accomplished by adopting and enforcing certain regulations such as no left or right turns, one-way streets, etc.
Objective - Reduce traffic volume by diverting traffic
Constraint - Changes traffic patterns and diverts traffic onto other streets
Description - Closing roads at mid block to create block that has traffic ingress and ingress at one end(s) only
Objective - Reduce traffic volume and traffic speed on the specific block
Constraint - Changes traffic patterns and diverts traffic onto other streets
Description - Partial narrowing of a street at an intersection by the fencing of a portion of the road
Objective - Slow traffic and increase awareness of neighborhood environment
Constraint - May not slow all vehicles; may make turning into the street more difficult
Description - Installation of signs to make motorists aware that they are entering residential streets. Usually used in conjunction with other devices such as entry gates
Objective - Increase awareness of motorists of the neighborhood environment
Constraint - Effect may diminish over time and affect can also be diminished by overuse of the signs
F:\USERS\ADMIN\Board of Supervisors\June 4, 2002\Summary of Traffic Calming Devices Attachment May 6.doc