What speed bump heights mean for vehicle speeds
The height of the speed bump will generally determine what speed the driver will have to slow down to avoid an uncomfortable drive. Lower heights will mean higher speeds, while more elevated bumps will mean lower speeds.
50mm high tends to be the go-to option for general car traffic. This height is enough to slow cars to 10mph or less. Severe options, like 75mm high-speed bumps, will slow cars to as low as 5mph. More elevated speed bumps like the 75mm option can reduce speed in areas with immediate danger to pedestrians. However, using them in areas where the traffic needs to flow may cause more of a hindrance than a solution.
Recommended speed bump installation
Generally, multiple speed bumps should be kept at least a vehicles length or more apart on roads. Today's standard cars work out at approximately 14.7 feet or 4600mm.
The installation of the speed bumps can significantly affect how well they work at slowing vehicles. Therefore, to get the best out of them, installing them in the right areas and in the right way is crucial.
If working with one particular type of vehicle, for example, a truck yard and trucks, this would be approximately the length of an average truck.
This gap allows the vehicle enough time to recover while avoiding it bouncing back and forth from multiple bumps. The smaller the gap, the slower drivers will have to go, which may be suited for housing estates and similar places. Longer intervals may be better suited to public roads or town centres where traffic will keep flowing.
When installing speed bumps, be sure to avoid placing them too close to
- Junctions - speed bumps that are too close to junctions may effect drivers that are driving too fast on approach to the bump.
- Entrances or exits to a premises - place speed bumps in optimal places so that they can slow traffic before they get to the entrance or exit
- Bends and corners - most speed bumps are designed to be installed in a 180 degree manner. If drivers are turning while moving over the speed bump they may risk the car sliding or damaging the speed bump.
- Pedestrian crossings - avoid putting standard speed bumps directly beside crossings. Again, place it further back to encourage drivers to slow before the reach the crossing. Some speed table systems can be used as a traffic calming and pedestrian crossing system in one.
Speed humps for emergency vehicles
Emergency vehicles can be significantly affected by speed bump placements. Traffic calming systems provide increased safety, but they can ironically slow emergency vehicles and hinder response times.
Responding to emergency calls quickly can mean the difference between life and death in some circumstances.
Speed humps, similar to speed bumps, slow vehicle traffic but work differently. A speed hump is longer from front to back and provides a gentle curve or bump instead of an immediate bump. The design of a speed hump allows traffic to flow smoothly without slowing the vehicle to a near stop.
Speed humps are typical in towns or cities where traffic needs to remain flowing at a reasonable speed.
There are two key ways to install speed humps to help emergency vehicle response.
- An offset layout of the speed humps can also improve response times for emergency vehicles. By installing the humps in a staggered manner in opposite lanes, these larger vehicles can drive around them without touching the hump.
- A side-by-side layout will allow the emergency vehicle's larger axles to fit around the speed hump and continue unimpaired.