- Speed hump
A speed hump (also called a road hump or undulation,cite web |author=ITE
title=Traffic Calming Measures – Speed Hump
publisher=Institute of Transportation Engineers] and in Ireland called a speed ramp) is a rounded
traffic calmingdevice used to reduce vehicle speed and volume on residential streets. Humps are placed across the road to slow traffic and are often installed in a series of several humps in order to prevent cars from speeding before and after the hump. Common speed hump shapes are parabolic, circular, and sinusoidal.
Generally, speed humps are 12 to 14 feet (3.7 to 4.25 m) in length and span the width of the road. The height of humps ranges from 3 to 4 inches (7.5 to 10 cm). The length and height of the speed humps determine the speed at which traffic will travel over the devices. Shorter lengths and greater heights slow cars most drastically. When placed in a series 350–550 feet (100–170 m) apart, humps will reduce 85 percentile speeds by 8–10 mph (13–15 km/h). [cite web|author=Peter Partington
Speed humps are used in locations where very low speeds are desired and reasonable. [cite web |author=trafficcalming.org
publisher=Fehr and Peers] Speed humps are typically placed on residential roads and are not used on major roads, bus routes, or primary emergency response routes. Placement is generally mid-block between intersections.
Comparison to speed bumps
While similar to
speed bumps, humps are less aggressive than speed bumps at low speeds and are used on actual streets, as opposed to bumps which are primarily placed in parking lots. While speed bumps generally slow cars to 5 – 10 mph (8 – 15 km/h), humps slow cars to 10 – 20 mph (15 – 30 km/h). The narrow nature of speed bumps often allows vehicles to pass over them at high speed while only perturbing the wheels and suspension, hardly affecting the vehicle cab and its occupants. The relatively long slopes of speed humps gradually accelerate the entire vehicle in vertical direction, causing the perturbation of the cab to become progressively more severe at higher speeds.
Speed humps are constructed of
asphalt, concrete, or rubber. While traditionally most humps were constructed of asphalt or concrete, rubber is becoming increasingly common in some regions for several reasons. Asphalt and concrete can be difficult to construct precisely while rubber products are pre-shaped to standardized sizes and thus consistently meet industry standards. An additional advantage is ease of installation, which is particularly beneficial when a city wants to test streets before deciding where to keep the devices.Fact|date=April 2008 The simple installation process also allows for relocation during the winter when snow is a concern, which prevents damage to the humps by snowplows.Fact|date=April 2008 In addition, unlike concrete and asphalt, which necessitate frequent and high cost replacement, rubber products are longer lasting and thus more cost-efficient.
One criticism of speed humps is their effect on
emergency vehicles. Response time is slowed by 3–5 seconds per hump for fire trucks and up to 10 seconds for ambulanceswith patients on-board. Speed humps are thus usually not placed on primary response routes. Speed cushions may be placed on these routes instead.
Occasionally, there is an increase in traffic noise from
brakingand accelerationof vehicles on streets with speed humps, particularly from buses and trucks. Other effects include increased vehicle fuel consumption and emissions – as most fuel injection systems in modern internal combustion engines operate in open-loop mode (fuel rich) when accelerating – as well as increased wear and tear on brakes, engine and suspension components.
Damage caused by
snow plows during the winter months is an additional concern.
Speed tables are longer than speed humps with a flat section in the middle. Cars are slowed less compared to speed humps.
Speed cushions are a series of three humps that are ideal for use on streets when emergency vehicle response time is a concern.
Speed bumps are significantly smaller than speed humps and used in areas where speed must be slowed nearly to a halt.
* [http://www.ci.austin.tx.us/roadworks/rwspdhmp.htm Questions and Answers about Speed Humps]
* [http://www.transalt.org/press/magazine/042Spring/12speedhumps.html Speed Humps Protect Children from Injury]
* [http://www.trafficlogix.com/speed-humps.asp Traffic Logix Rubber Speed Hump Description]
Wikimedia Foundation. 2010.
Look at other dictionaries:
speed hump — speed bump or speed hump noun A low hump across a road intended to slow down traffic • • • Main Entry: ↑speed speed hump see ↑speed bump above. • • • Main Entry: ↑speed * * * noun, pl ⋯ humps [count] Brit : ↑ … Useful english dictionary
speed hump — (SPEED hump) n. A low ridge that runs across a street and that is designed to slow down cars. A speed hump is a longer, flatter version of a speed bump. Example Citation: New York City, prepare for the speed hump. A hump, not to be confused,… … New words
speed hump — /ˈspid hʌmp/ (say speed hump) noun → road hump … Australian English dictionary
speed hump — noun speed bump … Wiktionary
speed hump — bump in a road or driveway made to decrease drivers of vehicles speed … English contemporary dictionary
Speed hump — (jocular) (amongst boaties) skindiver … Dictionary of Australian slang
speed hump — Australian Slang (jocular) (amongst boaties) skindiver … English dialects glossary
So slow smb. couldn't get a job as a speed hump — dull witted person … Dictionary of Australian slang
so slow smb. couldn't get a job as a speed hump — Australian Slang dull witted person … English dialects glossary
Speed cushion — 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… … Wikipedia