Bicycle Network: Good Design Guides
Shared paths: Key Criteria
Shared paths are used by a variety of users. Often they are incorrectly called bike paths when they are actually (and legally) used by people walking, running, riding bikes and other wheeled vehicles. Engineering guidelines state that a shared path should be: - wide enough (2.5 min width up to 4.0m for popular paths); - relatively straight with clear sight lines; - clear of obstacles in the middle of the trail and alongside it; - preferable sealed (so people on wheels can use it safely).
Shared paths are popular with families, commuting and recreational cyclists. They often follow waterways or run through parkland, offering a picturesque and pleasant riding experience.
In Victoria, Parks Victoria plays the lead role in developing the arterial trail network in Melbourne, known as the Metropolitan Trail Network (MTN). Local councils are responsible for constructing paths that complement the MTN in Melbourne.
In regional Victoria councils construct local networks, often with the help of the Department of Sport and Recreation funding.
|Austroads Guide to Road Design - Part 6A: Pedestrian and Bicycle Paths outlines the design of shared paths so they are constructed to a good quality level of service and minimise conflict between various users. VicRoads Cycle Notes offer a simplified summary of the guidelines.||
Key criteria for designing shared paths
- Adequate width. Paths need to allow space for pedestrians to walk two abreast and leave room for on-coming traffic or bike riders to overtake. 2.5m is the desired minimum for local access paths but 3m is the preferred minimum on paths with moderate levels of useage (See Cycle Notes 12 PDF 337KB). Whatever the width of your path you will need a good reason not to paint a centre line. Part 14 says "It is recommended that shared use paths are designated with a separation line".
- Gentle gradients and turns. Steep grades can create a hazard for cyclists travelling downhill and difficulty when riding up. Sharp turns should be avoided as they are detrimental to the riding experience and are a potential conflict point when people cut the corner.
- Clearance from obstacles. Recommended minimum clearance from fixed objects alongside the path such as trees, rocks or poles is 1.0m. This allows space for path users to move off the path when stopped and provides a verge for dog walking. It is important that plantings are kept well back from the path (2m) so that as they grow they will not encroach on the path.
The minimum vertical clearance from overhead structures such as underpasses or overhanging tree branches is 2.4m .
- Sight distances. For safety path users need to be able to see what's up ahead to enable them to stop or take evasive action. 'Blind' corners can cause crashes and bushy trees at road crossings can prevent users from seeing approaching cars.
- Appropriate surface - Sealed vs Unsealed? Paths with a good quality surface will attract more users than a poorly surfaced path. The High Country Rail Trail in Tallangatta has a sealed surfaced trail heading east from town and a gravel surface trail heading west from town. The sealed section gets 5 times more use than the gravel section, including disabled and wheelchair users. A good quality gravel surface may be appropriate to maintain a more 'natural' experience but is likely result in less people using the path.
- Sealed - Concrete vs Bitumen? When comparing sealed treatments our preference is for concrete over bitumen. Whilst concrete is initially more expensive it will last far longer than bitumen thus requiring less ongoing maintenance and represents a far lower "whole of life" cost. It has the added benefit of being more visible at night and can be coloured with the surrounding enviroment.
Centre line marking
A broken centre line serves a number of purposes:
- Reminds path users to keep left and helps to reduce conflict
- Clearly distinguishes shared paths from footpaths
- Assists trail users to follow the main trail and not take a wrong turn
Anniversary Trail survey
In 1999 the City of Boroondara surveyed 366 residents to understand how people use the Anniversary Outer Circle Trail, specifically asking how people used the path and if there were conflicts between users.
55% of respondents supported the use of centre line marking as a means to improve path behaviour and reduce conflict. A survey was carried out to observe path users before the centre line was marked and another survey done afterwards. After the centre line was marked there was an increase in the number of path users keeping left.
White line survey
In November 1995 Nicholas Walter carried out a report for Bicycle Network Victoria on the impact of a centre white line and directional arrows in modifying trail use behaviour called The White Line Project. Observations and surveys were carried out at Jells Park, on the Yarra Trail at South Yarra, Westerfolds Park and the Moonee Ponds Creek Trail.
Yarra Trail - Before the white centre line was marked almost half of trail users travelled in the centre or to the right of the path. With the introduction of a white line 84% of users kept to the left.
The response from trail users after a centre line was installed included "it is easier to overtake" and "the behaviour of users is more predictable".
Path users suggested centre lines, widening the paths and improving the surface as a way to improve the trails.
The conclusion found that "many potential conflicts between users could be avoided or alleviated through the introduction of the white line and arrows".
See Directional and route signage for more information on improving navigation on trails and guidelines for centre line installation.
Intersections of paths with roads
Shared paths should be aligned to intersect roads at approximately 90 degrees to maximise sight distances. Path terminal devices such as bollards are not recommended as they can be a safety hazard to cyclists, particulary bollards that are located in the middle of the path.
See Bollards and other obstacles and Smooth kerb ramps and Path crossings of roads for examples of good and poor terminal device treatments including fencing, ramps, chicanes, line marking and holding rails.