Speed bump
The use of vertical deflection devices is widespread around the world, and they are most commonly used to enforce a speed limit under 40 km/h (25 mph).
Each of these devices can be made from a variety of materials, including asphalt, concrete, recycled plastic, metal, or vulcanized rubber.
Temporary bolt-down installations can be ideal for planners in testing the use and positioning of speed bumps before implementing them in a larger project.
Bolt-down products can also be removed or relocated during winter snow periods—where speed bumps are easily concealed and may be damaged by snowplows.
On June 7, 1906, The New York Times reported on an early implementation of what might be considered speed bumps in Chatham, New Jersey, which planned to raise its crosswalks five inches (13 cm) above the road level: "This scheme of stopping automobile speeding has been discussed by different municipalities, but Chatham is the first place to put it in practice".
[1] The average automobile's top speed at the time was around 50 km/h (30 mph), but braking was poor by modern standards.
[citation needed] Arthur Holly Compton was a physicist and winner of the Nobel Prize in physics in 1927 for his discoveries resulting in major changes in electromagnetic theory.
[2] The British Transport and Road Research Laboratory published a comprehensive report in 1973 examining vehicle behavior for a large variety of different bump geometries.
According to a publication by the Institute of Transportation Engineers, the first speed bump in Europe was built in 1970 in the city of Delft in the Netherlands.
[10] In Sweden, an evaluation of spinal stress in bus drivers against ISO 2631-5 required on health grounds that:[11] Speed bumps can also have adverse environmental impact.
A study found that in one north London street with a speed limit of 20 miles per hour (32 km/h; 8.9 m/s) and fitted with road humps, a petrol driven car produced 64 per cent more nitrogen dioxide (NO2) than in a similar 20 miles per hour (32 km/h; 8.9 m/s) street fitted with road cushions.
The Actibump system, successfully used in Sweden, is based on powered equipment integrated into the road surface, which operates a platform that is lowered a few centimeters when a speeding vehicle approaches.
[14] In another design, a rubber housing is fitted with a pressure relief valve that determines the speed of a vehicle.
The valve can also be set to allow heavy vehicles, such as fire trucks, ambulances, and buses to cross at higher speeds.
Humps generally have pavement markings to enhance visibility and a taper edge near the curb to allow a gap for drainage.
Occasionally, there is an increase in traffic noise from braking and acceleration of vehicles on streets with speed humps, particularly from buses and trucks.
Thin cuts are sometimes placed in the middle of a hump in order to allow bicycle traffic to pass through.
In these jurisdictions, narrower speed cushions are sometimes placed between lanes to allow ambulances to pass unobstructed while driving over the centre line during an emergency.
In some jurisdictions, narrower speed cushions are placed at more frequent intervals to allow ambulances to pass while driving over the centre line.
Emergency vehicles still feature a wide track width, and the difference between them makes speed cushions more applicable.
The additional tires limit track width to as narrow as 1,200 millimetres (48 in), meaning speed cushions may not be suitable for their intended use.
[25] The long, flat design allows cars to pass without slowing as significantly as with speed humps or cushions.
[25] In the UK, vertical deflection in highways for the purpose of traffic calming typically takes one of the following forms: The Department for Transport defines the regulations for the design and use of road humps.
[30] UK news sources reported a cyclist being killed in a crash while attempting to avoid a speed bump.
