Bicycle Network: Good Design Guides
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- Detours, detour, Detour signing, Detour signage
Access for bike riders needs to be maintained during major construction works that block bicycle routes (as it is for motor vehicles and pedestrians). Detours for bike riders around construction works need to be clear, smooth and safe. They should be as short as possible in length and duration. Planning for major works must include provision of effective detours for the life of the project.
What’s the problem?
Without a well designed detour people could get lost or injured while trying to navigate around construction works that close a path or bike lane.
What are the risks?
Construction works sometimes require bike riders (and pedestrians) to be detoured around the site. If no detour or substandard detour is provided bike riders could:
• get lost trying to find an alternate route
• take an unintentionally longer route
• be forced to take a dangerous route (e.g. onto a busy road) and risk a crash or injury.
Crashes can also happen while negotiating a substandard detour route, many due to:
• Slippery or unstable surfaces – detours which use uncompacted gravel as the path surface see riders slip or get bogged in the soft gravel
• Narrow path – narrow detours force riders into the path of others and leave less room for error or manoeuvrability
• Windy path – sharp bends and curves on detours narrow the usable path and reduce sight lines
• Rough paths – detours with steps and holes can catch bike tyres and cause crashes.
What is the solution?
Plan ahead when programming works to provide a detour for bike riders that is safe and easy to use. A Traffic Management Plan should be prepared for major works. Make sure the detour meets the guidelines for width, smoothness and alignment. Give people enough notice, both in time and space, of the upcoming detour. Make sure all connections are kept open – for instance detouring bike riders to the south of works may deny them access to a path to the north of the site.
Keep detours as short as possible, both in distance and in duration. Consider scheduling works for non peak hour times on bicycle commuter routes to minimise disruptions to bike riders.
Make sure they are clearly marked and unambiguously signed so people do not get last. A clear, smooth path is paramount. When existing footpaths and roads are being used then linemarking, pavement stenciling and signage can help make the alignment more visible.
Well considered efforts (such as preparation of a Traffic Management Plan) made early in the project can be rewarded by less downtime handling complaints, dealing with bad PR and in having to redo a poorly signed detour route.
Distinctive white text on blue background is becoming the standard for path and trail detours around Melbourne. The alternative is black text on yellow background. Such signs placed at regular intervals to reassure riders and pedestrians that they are on the right track are the key to success. At decision points such as intersections and changes in direction the instruction needs to be unambiguous. Major destinations must be clearly marked.
Equally important as clear signs on route are route maps at approach points to any detour. A coloured map with clear legend can give path users confidence that the detour will return them to their intended route and an appreciation of what directions to expect along the way.
For best results treat detours seriously, plan the route well, carefully select signs required, provide advance notice, implement, monitor and be prepared to respond and adjust as necessary.
What do the guidelines say?
The guidelines are clear on the need to provide clear detours that do not present a hazard to bike riders. Part 6A of the Austroads Guide to Road Design Part 6A: Pedestrian and Cyclist Paths (2009) states in Appendix B:
"When construction and maintenance work is carried out involving trenching or other construction work across roads and paths, access for cyclists (and pedestrians in the case of shared paths) should be maintained, and to a satisfactory quality to avoid the use of alternative routes which may be hazardous or inconvenient for cyclists (and pedestrians).
"Construction and maintenance works should be undertaken in such a way that these activities do not place cyclists at risk during the works period. This is particularly important, for instance, where a sealed shoulder is closed for maintenance on freeways of other high speed roads where cyclists may be permitted. "
Having a smooth surface (i.e. not gravel) is also recognised as important:
"As a principal objective of provision for cyclists adjacent to the works site, the riding surface should be maintained in a clean and smooth state.... Temporary paths should be sealed. "
Lighting is also important on detours as rider may use it at night and not be expecting a detour or new alignment:
"Where works are carried out for a period exceeding one day, the works should be made sufficiently visible for night-time path travel, so that path users are able to observe conditions under low ambient light conditions including temporary access paths, and take appropriate action. In addition, as a general principle, lighting on temporary access paths should not be less than the existing level on the original path. "
What do we say about the guidelines?
We agree with guidelines and their emphasis on maintaining safe access for bike riders during construction works which block a bike route.
Examples, Good and Bad
Most people can't ride on steps
Main Yarra Trail, Southbank at Convention Centre/Charles Grimes Bridge - the detour here while the new convention centre is being constructed is not rideable. Neither is there enough notice given to allow bike riders to avoid a long back track to an alternate route if they are unable to carry their bikes over the steps. No wheel ramps are provided to make the steps easier to negotiate. A poorly planned and executed detour on a major cycle route.
Detour M1 Freeway widening at Tooronga Rd. The path detour is smooth, wide, straight path with clear signage. Unfortunately the route signage for the detour at the end of this section was unclear and many users became lost. Clear signage at the start and end of the detour, and at all turns, is essential as the route may be unclear if it crosses driveways and roads.
East Malvern Bridge replacement detour of Scotchmans Creek path. Notice the map showing the full detour alignment and multiple signs at the turn in background. Maps enable people to plan their route, especially those who don't plan to follow the full detour and need to turn off to another destination. This is especially important for longer detours.
|East Malvern Bridge replacement detour. The detour was well planned and implemented. Detour maps helped guide people through the route and let them plan their trip.|
Detour for Manningham St bridge construction, Parkville, Melbourne. The bridge eradicated a set of stairs but meant the Capital City Trail was detoured for some months. The only available detour was circuitous and involved use of existing footpaths and several crossings of freeway off ramps and major roads that were crossed by the existing bridge that needed to be closed. Lack of planning resulted in a poorly signed and marked detour. Here the foreman has drawn arrows on the footpath in an attempt to delineate the route.
Stencils on the ground can supplement signage which can be removed by vandals. Notice the new asphalt laid to smooth the path.
Docklands, Melbourne. The detour uses the existing footpath and uses signage to guide bike riders. However this can lack clarity at crossing points, especially if one sign goes missing. A centre line and stencils can make the route clearer.
Swanston St, Melbourne. Building works required a gantry and closure of the bike lane. The detour is narrow with curves but the surface is relatively smooth, hazards clearly marked and the route clearly signposted and marked with green pavement. Unfortunately on this day construction workers blocked the path with a generator with no forewarning at the entrance. Bike riders were forced to turn onto the road at a tight point with merging traffic. Planning should take into account these situations and provide an alternate route or at least have a plan for dealing with additional works.
Below - figures from Austroads Guide to Road Design Part 6A: Pedestrian and Cyclist Paths. Appendix B.