Imagine the following situation: a narrow residential street with vehicles passing by at speed incompatible with safety. What is the ideal solution such as speed bumps offer pointed out by the residents and usually adopted by the transit agencies? Build a speed bump! In particular, it is not considered the alternative inappropriate under certain circumstances. The problem is the way it is built.
They are transverse undulations and can be used where it is necessary to reduce the speed of the vehicle imperatively, in cases where a technical study of traffic engineering shows a significant index or potential risk of accidents whose determining factor is the speeding practiced in the place and where other traffic engineering alternatives are ineffective.
It is not enough to gather the necessary material and build a spine; the implementation of the transverse undulation on the public road will depend on the express authorization of the Transit Authority (director/president of the transit agency) with jurisdiction over the road.
There are two types of speed bumps, Type A and Type B. The first can be installed in places where there is a need to limit the maximum speed to 30 km/h on roads with urbanized sections, on urban collector roads, and places that are, in rule, low movement. The second type can be installed on a local urban road, whose intention is to reduce the speed to 20 km/h, as long as there are no regular lines of collective passenger transport.
If the spine is installed close to an intersection, a minimum distance of 15 meters from the curb alignment or the edge line of the transversal road must be respected. The Type A spine should be 8 to 10 cm high and 3.70 m long, while the Type B spine should be 6 to 8 cm high and 1.5 m long. In both cases, the width is the same as the track.
In addition, there is mandatory signage, that is, there must be “maximum speed permitted,” two “protrusion or spine” signs in place, one before the transverse undulation and the other with a position arrow next to the undulation, which it must be painted completely or with stripes interspersed in yellow.It is strictly forbidden to use tacks, studs, and similar devices applied across the public road, which are those famous yellow “bricks” are sometimes used to replace the spine.
There are cases in which people build the spine and, due to the lack of technical requirements and proper signage, accidents can occur, and obviously, those who improperly placed the obstacle will be held responsible.