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The Guidelines

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9.5.1

The RSA practitioner needs to keep in mind a number of implications of the unique dynamics of motorcycles that are key to optimising safety for motorcyclists.

Awareness of the line that motorcyclists take through bends and junctions, keeping them clear of:

  • Service covers and gully gratings. Locating ironwork out of the wheel tracks of twin track vehicles or on the outside of bends can place them on the line used by motorcycles.

    This presents a sudden change in road surface properties leading to stability problems. It should also be noted that water on service covers freezes sooner than water on the surrounding road surface. If the cover cannot be moved, it should be provided with a surface finish compatible with the skid resistance of the surrounding road.

  • Large areas of road marking. Thermoplastic road marking material should be laid to an acceptable standard of skid resistance and retro-reflectivity. In practice, newly laid markings are rarely tested, and even if they are, the values often fall long before the road surface requires maintenance (see below).This leads to markings that are slippery when wet. Large areas of such markings, especially in areas likely to be used by motorcycles, can present a serious safety hazard.

    This has to be balanced against a realistic assessment of any road safety benefits to be gained from using large areas of road markings.

Awareness of the “clear zone” around the outside of bends, keeping it clear of:

  • Unprotected street furniture. Best practice in street scene management recommends auditing of street furniture to see if, for example, signs can be rationalised into single assemblies to avoid a proliferation of posts.

    This should be taken a stage further, with sign locations considered carefully to make sure they do not present a collision hazard for a falling motorcyclist. If it is unavoidable to have street furniture in the “clear zone”, every effort should be made to make it as ‘impact friendly’ as possible.

  • Safety barrier products that have only been tested on twin track vehicles. These can represent a serious hazard to a dismounted rider.More investigation is needed into aftermarket collision mitigation measures in locations where there is a higher risk of motorcycle loss of control (Chapter 4).

Awareness of the effects of unpredictable surface irregularities, such as:

  • Poor surface tie-ins. This is yet another example of a problem that can be a cause of mild irritation to a twin track vehicle driver, and yet potentially cause a motorcyclist to suffer a sudden shift in balance, with loss of control and possibly a crash to follow.

  • Badly designed or located traffic calming features. As already described, motorcycles are machines that, to a point, become better balanced with increasing speed. Conversely, travelling at low speed can require more of rider and machine. In this situation, poor location, design or maintenance of traffic calming features can contribute to loss of balance, reduced control or even a crash (see Chapter 8).
  • Areas likely to retain surface detritus. Motorcycles form just over 1% of the traffic mix by distance travelled in the UK [DfT 2003a].Other vehicles tend to push surface detritus, chippings, broken lens glass and so on, into areas of the road they do not use.

    These same areas can be used by motorcyclists, either because it forms the correct line for a motorcyclist to take or because other, heavier traffic has pushed them there. In any case, motorcycles require the road to facilitate grip and braking; areas covered in road detritus facilitate neither.

    This subject is covered in more detail in Chapter 6.

  • Poorly designed drainage. It should be self-evident that motorcyclists suffer sooner and more severely when surface water is not dealt with by carriageway drainage systems.

Awareness of the importance of consistent skid resistance properties:

  • Terminating anti-skid surfacing on straight sections.

    Sudden changes in road surface properties on bends or junctions, especially skid resistance, can lead to stability problems as the rider tries to cope with the sudden change in the dynamics and response of the motorcycle.

  • Not using innovative road markings too close to bends. This includes:

    • Dragon’s teeth markings.
    • Speed limit roundels or other surface “signs”.
    • Transverse markings or “jiggle” bars.

9.5.2

The same principle about sudden changes in road surface properties applies here: road markings rarely have the same skid resistance value as the surrounding road surface.

Placing markings in areas of the road likely to be used for braking or cornering by motorcyclists can significantly increase the risk of stability problems.

This can often be avoided by relocating the marking, rather than losing its general road safety benefit by deleting it altogether.

Using road-marking material that has an acceptable level of skid resistance and remains close to that level for the life of the marking.

This implies:

• Using profiled lining instead of flat lining.
• Using material that has a similar skid resistance to the surrounding surface.
• Using material that has retro-reflectivity that enables a rider to maintain good forward visibility at night, especially in the wet, when riding conditions and retroreflectivity are both at a minimum.
• Setting high, achievable standards for retro-reflectivity and skid resistance – and testing for them.
• Using new marking materials and methods of laying, for example polymethylmethacrylate materials, that make it more likely that good skid resistance and retroreflectivity levels are met and maintained.

The extra cost of these materials and methods should be set against the penalty to be paid for permitting poor standards: increased injury accidents.

Measures to ameliorate the problems caused by mud or leaves on the road.

This should include:

• Location of new field accesses away from bends and junctions.
• Providing warning signs at locations where mud is likely to be a recurring problem.
• Considering leaf fall problems when designing landscaping and the “soft estate” on new schemes.

Awareness of the need for street lighting:

Motorcycle headlights are weaker than those of other motor vehicles.

Refer to guidance from the local authority street lighting team or the Institution of Lighting Engineers (ILE 1995).

Awareness that the eye height of a motorcyclist is much higher than a car driver:

Usually this is a good thing, affording the rider a better view of the road ahead or any developing traffic situation.

However, check sight lines at RSA Stage 2 and Stage 3, taking account of the increased eye height of the motorcycle rider.

An object may intrude into the visibility splay at rider eye height that may not obstruct a car driver’s view.