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Cycle pathspath networks around the outside of a roundabout may provide a suitable alternative for peopleto cyclists who do not wish to cycle in the roundabout. Off-road path alternatives at roundabouts will generally be shared paths, iei.e. pedestrian volumes and needs should be included when determining path width and alignment.
This section includes:
- Appropriateness of off-road paths
appropriateness of off-road paths - Platform design
platform design - Grade-separated crossings at roundabouts
grade-separated crossings at roundabouts.
Appropriateness of off-road paths
Appropriateness of off-road paths
Where an off-road path network is provided, it should not be assumed that cyclists will (or should) use these, unless cycling is specifically prohibited on the roadway. these. Off-road path networks may seem too indirect to some cyclists. Thus all roundabouts should also be designed with on-road cyclists in mind.
The bi-directional nature of off-road paths can result in safety implications for cyclists crossing roundabout approaches and departures as motorists may not expect cyclists coming from the “wrong” direction (i.e. cycling anti-clockwise around an off-road path network). ThereforeThus it is preferable that off-road paths are one-way only for cyclists and circulate in the same direction as the circulating traffic. It is also particularly importantcritical to reduce speeds of motor vehicles entering and exiting the roundabout where cyclists may be crossing the legs. Also,legs. Also, sufficient intervisibility between path users and motorists should be ensured at crossings on roundabout departure legs.
The suitability of an off-road path network to provide for cyclists depends on the gaps available in traffic. Iftraffic; if flows are too heavy, cyclists will not be able to find a gap to cross the approach and departure lanes. Tolanes. To determine the suitability of a crossing point for cyclists, the Austroads ‘Pedestrian Facility Selection Tool’ can be used, with some adaptations toadaptations[AH1] to account for cyclists. Thecyclists. The tool will yield a level of service rating for specific crossing provisions which will help in determining the suitability of path crossings at roundabouts.
Platform design
The design criteria for pedestrian platforms presented in the New Zealand Pedestrian planning and design guide areNew Zealand Pedestrian Planning and Design Guide[AH2] are appropriate for crossings shared by pedestrians and cyclists on path networks at roundabouts; note that this includes the criteria that the speed limit is 50 km/h or less, and that the crossing platforms should be preceded by a feature that causes vehicles to slow. For the exit the roundabout provides this. For the approach, an extended splitter island, narrowed lane,slow, and where the close proximity of the roundabout would meet this requirement.speed limit is 50 km/h or less. Design information is also available in the Traffic Control Devices Manual Part 6.
Because platforms at roundabouts are separated by islands, uni-directional designs are feasible with departure ramps more gentle than approach ramps.
For a 'small' roundabout‘ small[AH3] ’ roundabout (i.e. inscribed diameter 25-30 m; see section 0) the crossing is usuallycrossings should be located 6m fromimmediately outside of the circulating lane. roundabout area. For compact roundabouts,larger roundabouts (i.e. inscribed diameter greater than 30 m) the platform and an associated zebra crossing permit the setback to be further. The crossings should be set back at least 6 m5 m but no greater than 20 m from the circulating lanes. A set back of 6 m5 m allows one vehicle to queue without blocking the crossing or intruding into the circulating lanes, and 12 m permits two vehicles to do so. Researchwhereas research has shown that further than 20 m20m from the limit line vehicle speeds are too high to allow for pedestrians and cyclists to cross safely (Campbell et al., 2012). The Austroads Guide to Road Design Part 4B recommends a distance of 12 m (2 car-lengths) across both approach and exit.
Grade-separated crossings at roundabouts
If it is deemed appropriate to provide an off-road path network at a roundabout but crossing one or more approaches and departures is difficult and high risk, grade separated crossings should be considered. For path design refer to Austroads Guide to Road Design part 6; Paths.( Campbell et al., 2012 ).
Cycle lane transition to off-road path
Grade separated crossings at roundabouts
If it is deemed appropriate to provide an off-road path network at a roundabout but sufficient opportunities to cross approach and departure lanes at roundabouts are not available, grade separated crossings should be considered.