|Pictures related to Rumble strips|
No pictures uploaded (Upload?)
Rumble Strips are a type of traffic calming that take a variety of forms. The general principle is to create a short piece of road where it is uncomfortable for motorists to travel at speed, due to a mixture of high road noise and additional vibrations caused by the strips. In all cases, designers have to be careful to match the requirements of creating a nuisance for drivers exceeding the desired speed and at the same time minimising any additional road noise for local residents. As such, they are perhaps more common in rural than urban settings.
In many cases, whilst the strips are described below as 'full width', they do in fact stop short of the kerb or verge line by a few inches. This helps to maintain drainage flow, and also provides a slightly easier passage for cyclists. However, where the gap left is too big, it also tempts drivers into trying to keep one wheel on flat tarmac, so bringing vehicles close to the kerb.
Some early rumble strips, of the patch type described below, proved to be ineffective at slowing traffic, with drivers realising that the design meant that passing over them at 40mph was less uncomfortable than 30mph. While it is true that 20mph was often equally smooth as 40, few drivers slowed sufficiently to find this out! The reason behind this is not clear, but may be related to the distance between the strips creating different resonance in the vehicles, which sometimes fell more smoothly with the existing resonance of the engine.
Full lane width rumble strips are a common feature on the approach to Roundabouts and other busy junctions. They are often spaced at decreasing intervals for a considerable distance in advance of the junction to try and slow traffic on the approach. They normally consist of a series of yellow-painted stripes across the road, not dissimilar to a thickly painted yellow line albeit across instead of along the road.
The approaches to un signalled crossing points are another common site for rumble strips. They are particularly common on fast roads in more rural areas where the use of the crossing is insufficient for the installation of a signalled crossing. In recent years they have also proliferated at crossing points on the National Cycle Network. There are two common designs for such strips. The first is a series of full-lane width yellow lines as described above for Junction approaches, albeit not so many. They typically appear in groups of approximately 6-8, and depending on the road there can be more than one group in each direction, spaced apart. If there is more than one group, the ones closer to the crossing point are generally more severe.
The most common alternative is a patch of different coloured and courser tarmac overlaid on the road surface. Typically Yellow or Red, the patch can also incorporate a series of ribs laid as a lower course to aggravate the effect.
The third main use of rumble strips is as 'Gateways', typically where a speed limit changes, or in a school zone. They are more usually of the patch style described above, but painted strips are also used, set apart at decreasing distances over short lengths. In all cases they tend to span the full carriageway, to both slow down drivers approaching the gateway and prevent those leaving from accelerating too early. Rumble Strips in Gateway locations are often combined with verge / pavement build outs to reduce the width of the road, further slowing traffic.
There are of course many other uses for rumble strips across the country, but the basic principles and designs remain the same, with minimal adaptation required to meet a variety of needs. Many private roads use them as a slightly cheaper alternative to full Speed bumps, whilst they can also be used within car parks.