Speed cushion
Encyclopedia
Speed cushions are traffic calming
devices designed as several small speed humps installed across the width of the road with spaces between them. They are generally installed in a series across a roadway resembling a split speed hump. The design of speed cushions forces cars to slow down as they ride with one or both wheels on the humps. However, the wider axle of emergency vehicles such as fire engines and ambulances allows them to straddle the cushions without slowing down or increasing response times.
Although the newest available traffic calming
device, speed cushions are rapidly growing in popularity due to their ability to slow cars without affecting emergency vehicles.
devices. Many municipalities are challenged by opposition to speed humps and speed tables since they slow down emergency vehicles. Speed cushions address this problem by allowing larger vehicles to straddle the cushion without slowing down. This is also an advantage for bus
es, as lower floor vehicles can sometimes ground out on traditional humps.
Speed cushions are also often less costly than speed humps or tables
while most cities report them to be just as effective.
, concrete
, or rubber
. Several trade-offs must be made when selecting the material for a new speed cushion. It is easier and more temporary to apply preformed rubber devices; prefabricated rubber cushions must simply be assembled and bolted down to meet standard specifications. Some cities feel that asphalt or concrete construction has more permanence and greater effect in slowing traffic, due to the material's rigidity and durability.
Speed tables are longer than speed humps with a flat section in the middle. Cars are slowed to higher speeds than with speed humps.
Speed bumps are significantly smaller than speed humps and used in areas where speed must be slowed nearly to a halt.
Traffic calming
Traffic calming is intended to slow or reduce motor-vehicle traffic in order to improve the living conditions for residents as well as to improve safety for pedestrians and cyclists. Urban planners and traffic engineers have many strategies for traffic calming...
devices designed as several small speed humps installed across the width of the road with spaces between them. They are generally installed in a series across a roadway resembling a split speed hump. The design of speed cushions forces cars to slow down as they ride with one or both wheels on the humps. However, the wider axle of emergency vehicles such as fire engines and ambulances allows them to straddle the cushions without slowing down or increasing response times.
Although the newest available traffic calming
Traffic calming
Traffic calming is intended to slow or reduce motor-vehicle traffic in order to improve the living conditions for residents as well as to improve safety for pedestrians and cyclists. Urban planners and traffic engineers have many strategies for traffic calming...
device, speed cushions are rapidly growing in popularity due to their ability to slow cars without affecting emergency vehicles.
Advantages
Speed cushions have several distinct advantages over similar traffic calmingTraffic calming
Traffic calming is intended to slow or reduce motor-vehicle traffic in order to improve the living conditions for residents as well as to improve safety for pedestrians and cyclists. Urban planners and traffic engineers have many strategies for traffic calming...
devices. Many municipalities are challenged by opposition to speed humps and speed tables since they slow down emergency vehicles. Speed cushions address this problem by allowing larger vehicles to straddle the cushion without slowing down. This is also an advantage for bus
Bus
A bus is a road vehicle designed to carry passengers. Buses can have a capacity as high as 300 passengers. The most common type of bus is the single-decker bus, with larger loads carried by double-decker buses and articulated buses, and smaller loads carried by midibuses and minibuses; coaches are...
es, as lower floor vehicles can sometimes ground out on traditional humps.
Speed cushions are also often less costly than speed humps or tables
Speed table
A speed table is a traffic calming device designed as a long speed hump with a flat section in the middle. Speed tables are generally long enough for the entire wheelbase of a passenger car to rest on top. The long, flat design allows cars to pass without slowing as significantly as with speed...
while most cities report them to be just as effective.
Composition
Speed cushions can be constructed of asphaltAsphalt
Asphalt or , also known as bitumen, is a sticky, black and highly viscous liquid or semi-solid that is present in most crude petroleums and in some natural deposits, it is a substance classed as a pitch...
, concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
, or rubber
Rubber
Natural rubber, also called India rubber or caoutchouc, is an elastomer that was originally derived from latex, a milky colloid produced by some plants. The plants would be ‘tapped’, that is, an incision made into the bark of the tree and the sticky, milk colored latex sap collected and refined...
. Several trade-offs must be made when selecting the material for a new speed cushion. It is easier and more temporary to apply preformed rubber devices; prefabricated rubber cushions must simply be assembled and bolted down to meet standard specifications. Some cities feel that asphalt or concrete construction has more permanence and greater effect in slowing traffic, due to the material's rigidity and durability.
Similar measures
Speed humps are similar to speed cushions although they are solid units spanning the width of the road.Speed tables are longer than speed humps with a flat section in the middle. Cars are slowed to higher speeds than with speed humps.
Speed bumps are significantly smaller than speed humps and used in areas where speed must be slowed nearly to a halt.