Austroads has produced many good and useful standards. One of the best is Guide to Road Design Part 6A: Paths for Walking and Cycling (AGRD06A). The ACT Active Travel Standards (MIS05) are compliment by the Austroads AGRD06A. The Austroads National Standard is more detailed than the ACT equivalent and complements the local standard.
- Path width recommendations
- Copenhagen style protected cycle lanes
- Cost of bike paths
Path width recommendations
The Australian Austroads cycle path standard includes recommendations on path widths. Most of the shared paths in Canberra are much too narrow, when we consider these Austroads recommendations.
How wide does a path need to be? Cyclists know that narrow paths result in conflicts between pedestrians and cyclists. Wider is better. AGRD06A explains the types of things that we should consider which include:
- the travelling speed of the cyclists,
- whether the path used in both directions,
- the mix between bikes and pedestrians
- frequently used paths are wider, such as a commuting route
Figure 1 shows a couple walking and two bikes passing each other from the opposite direction. This is a common occurrence for all the pretty lakes of Canberra. The Australian standards recommend a 4 m wide paths in these areas. This scenario is corresponds to the ACT Main Community Routes (MCR) or Main Recreational Routes (MRR). Separating the paths is not mandated, but any cyclist will attest that a line along the track between cyclists and pedestrians areas make a big difference in pedestrians behaviour. It also reminds the pedestrians to watch their dogs.
Figure 2 shows a ONE-WAY path and that the separation between cyclists and pedestrians needs to be BIGGER for the higher cycle speeds that are typical of commuting to work. Here 1 m separation is recommended between commuters and pedestrians as commuters can ride at speeds of 30kmh or more. This example is for ONE-WAY paths, TWO-WAY would need to be wider still.
Copenhagen style protected cycle lanes
Have you ever wonder what is meant by Copenhagen style protected cycle lanes? This term appears in a number of ACT Government document, one of note is the Molonglo Group Centre Concept Plan. They should not be confused with bike paths which are grade separated and the better solution. Copenhagen style protected cycle lanes are popular in big cities as they can be retrofitted in old suburbs as part of urban renewal. What are we doing building them in green field suburbs instead of bike paths? The information shows the way Copenhagen style protected cycle lanes have been built in Melbourne.
GETTING IT RIGHT 4. DESIGN FOR SAFETYCopenhagen style protected cycle lanes, Changing lane multimodal in Melbourne, ADM Case Study St Kilda Melbourne Victoria, (Auckland Design Manual), 10.
1. The speed limit is 60kph with the St Kilda Masterplan (2007-09) recommending a reduction to 50kph to improve pedestrian safety.
2. For most of its length St Kilda Road has a wide, shared footpath which provides a safe environment separated from vehicles by the majestic trees.
3. The Masterplan recommended creating “Copenhagen style” (protected) cycle lanes adjacent to the kerb rather than in their current traditional location which is between the parked cars and the vehicle lane.
4. It was also recommended that the cycle lanes be increased in width from 1.2m to 2.0m with the addition of a “safety strip” (1m wide) to allow space for car passenger doors to open.
Cost of bike paths
The cost of a bike path depends on many factors. The material used to make the bike path is one of those factors and Austroads provides a guide in the AGRD06A. Several materials are used to build paths in Canberra but most common are concrete or asphalt.
ACT data for the construction cost of bike paths is discussed here.
Appendix C.4 of the AGRD06A has information about path costs. As expected, the exact costs can vary depending on the jurisdiction but the relative costs for different paths types are clear from the Austroads data.
Figure 3 compares the cost of the path over a 20-year period for three different materials: decomposed granite, asphalt, concrete and boardwalk. The capital costs for construction for an unpaved decomposed granite is the cheapest of these types, but unpaved surfaces erode easily and therefore the maintenance for unpaved paths is high. Paved surfaces are more expensive to build but are hardier so that the maintenance costs are better. The capital costs of asphalt are only a little more than decomposed granite but more expensive than concrete to maintain. Nevertheless, despite concrete being almost twice the price per km of asphalt, the “lifetime cost” over twenty years concrete and asphalt paths are similar.
Asphalt or concrete, which is better?
It depends. In wet areas and areas prone to flooding concrete appears to be a better option. It also does not get as hot in the summer, but glare can be a problem. Moisture can cause longitudinal cracks in asphalt and roots can cause cracking across the path. Both can be reduced by root and moisture guards (600 mm deep) as is required for all new paths (estates) under ACT planning standards (MIS05 and ACTSD). The ACT specification for paths is ACTSD-0501 (figure 4 below).
What about maintenance?
A well-constructed asphalt will last 20 years. Canberra’s paths are of poor quality due to lack of maintenance and maybe in some cases older than 20 years. Primary and Main Community Routes are likely to be asphalt. Why would the ACT government leave a path unpaved if asphalt is cheaper in the long term? Unpaved paths are very expensive as they erode with every storm. It seems strange that the ACT government would build them. The only reason appears to be that in a “natural” environment an unpaved may have better “amenity”. In other words, the reason is aesthetic, certainly not because it is cheaper. Unpaved paths may also be chosen to discourage bike use as their poor traction qualities make riding more difficult.