Research is underway to bring out the best speed limiting road humpMany drivers have a problem of too violent reaction of their vehicle when passing poorly constructed road humps, even at allowed speed. General methods developed by SP within the framework "Dynamic Metrology" have now been applied to investigate and improve the height profile of these common road humps.
Dynamic Metrology aims to evaluate dynamic measurements in different contexts. A somewhat odd but nevertheless very common type of "dynamic measurement ' is performed daily by quite many people when passing over various speed humps with different vehicles, cars, buses or bicycles.
Evaluation and optimization of speed humps and other mechanical speed limiting measures
Road humps are supposed to be designed to expose the drivers of the vehicles with a controlled amount of discomfort, in proportion to how much the speed limit is exceeded. For maximum benefit for all, the discomfort should thus be minimized below but maximized above the speed limit. In addition, it is also important that there is no risk that neither the driver, passengers or vehicles gets damaged during repeated passages.
The profiles of the road humps are presently based on general studies and very often mostly on visual appearance. Their speed limiting effect is generally hardly known in any detail at all. In the best cases, very limited tests are made. Sometimes new road humps must be modified to avoid unwanted effects. Wear is often underestimated as well as how small deviations in shape can be allowed. Nearby wells and subsidence can amplify the impacts on the vehicles substantially when the height profile deviates from the intended one. Only in rare occasions when a large amount of complaints from drivers have been reported systematic studies are made to determine the risk of injury potentially caused by the humps.
SP makes an evaluation possible
SP proposes a unique but relatively simple method which can be utilized to determine how an entire fleet of cars, buses and trucks etc. of different brands, types and ages behave when they pass over a road hump or an arbitrarily shaped profile/roughness of the road.
New types of mechanical speed limiting barriers such as speed corrugated waveforms of the running surface can also be investigated and optimized. The cumulative risk of spinal cord injury in the repetitive passage of several humps may be determined. If routes and their road height profiles as well as vehicles and speed restrictions are known, a bus driver’s total accumulated risk of injury throughout his/her life can for instance be determined, as both professional driver and private motorist.
At SP, methods have also been developed to determine the best shape of road humps according to the desired speed limiting effect, the vehicles, permitted speed etc.
With regard to the hundreds of humps found in many cities, all different variants of vehicles and the variation of speed limits, it is virtually impossible to measure how the impact on vehicles may vary. The novel methods of evaluation proposed by SP which combine simple measurements and mathematical analysis, not only makes this evaluation possible but also includes methods to find the best profile of new designs of road humps.