One of the big factors that make a bike path rideable is the gradient of the path. Too steep and we will find ourselves pushing uphill. Bike paths, poorly designed, are too steep to ride. A case study of Whitlam active travel network
Updated 23 April 2021 “Road 01” named
The “Road 01”, mentioned in this article, has now been named Sculthorpe Avenue.
Description of active travel routes
Main Community Routes: Important Main Community Routes are on either side of Whitlam running north-south, but the utility of the routes will be reduced by the very high gradients traversing the deep river valley. Both Coppins Crossing to the east, and the other route to the west, are low-level crossings. Unless measures are taken the gradients on these paths could exceed Austroads guidelines.
Local Community Routes: The Local Community Routes along the streets are steep in places but should be rideable. The utility is then dependent on the treatments for the frequent crossing of the adjacent side roads. These side roads were the subject of a recent email Whitlam Stage 2 estate design falls short on active travel. The emails message is now strengthened as most rideable paths across Whitlam are along a street. The Local Community Route in figure 6 through a park is too steep to be rideable (Austroads standards). The path is therefore poorly labelled a Local Community Routes but would be better referred to as a Recreational Route, for which gradients are much less important. There are no direct east-west Main Community Road through Whitlam so that the Local Community Routes adjacent to the streets increase in importance. The schools and shops in Molonglo 3 are along an east-west axis. This is likely to add to the popularity of these Local Community Routes.
Commuting to work from Whitlam: Whitlam is the extreme end of the Molonglo Valley Stage 3 development. It is a dead-end which is a bit unfortunate. With time the Main Community Route to the west may be connected to Whitlam as part of Whitlam Stage 4 (and preserving the Kama Reserve corridor). Commuting to Woden and Tuggeranong is hampered until the completion of the John Gorton Drive Bridge over the Molonglo. Commuting to Belconnen is hampered by the lack of off-road cycle paths directly north of William Hovell Drive. There is no direct off-road route to commute to the city until the completion of the Main Community Routes through Molonglo 3 East. Commuting from Whitlam is therefore unlikely to be popular for some years.
One of the big factors that make a bike path rideable is the gradient of the path. Too steep and we will find ourselves pushing uphill. Bike paths, poorly designed, are too steep to ride. Whitlam is a new suburb, north of the Molonglo River, and part of the Molonglo Valley Stage 3. Whitlam Residential Estate is now under construction by the ACT Suburban Land Agency.
The Molonglo River Reserve: Reserve Management Plan 2019 (ACT Government, 26 July 2019) notes that the terrain is a narrow river corridor with steep drops down to the river. See figure 1.
Not surprisingly the housing estates are being built either side of the Molonglo River on the “flatter” sections. The strong erosion by creeks means that it is by no means flat. Below (figure 2 and figure 3) are gradients of a natural landscape from a survey of the area of Whitlam in 2014 before the ACT Urban Land Agency had a chance to iron the creases out of it. Gradients of 5-10% are most common, but gradients of 15-20% and around Deep Creek the gradients exceed 25%.
The Austroads standards for bike path design recommend that a bike path never exceed 12% (children cannot ride down this gradient safely). The same standard recommends that riders struggle with prolong section of riding uphill of gradients of just 5%. The bike path up Aranda hill from the Glenloch Interchange has for a short 100 m section a gradient of 8%. Otherwise, the gradient is much more moderate. Nevertheless, most people regard the 70 m rise to the saddle as enough (only to get rattled riding down the other side to Belconnen).
I have more to say about gradients in Titbits: Horizontal Curvature and path gradients Part 3.
The Whitlam Residential Estate Concept Master Plan 2018 (CONCEPTMASTER-201834628-01 20180706) shows that the estate has been flattened by moving dirt from the high bits to the low bits. This makes it flatter and more even but not flat. Almost everywhere in Whitlam, there is a significant slope. The slope is such a problem for Molonglo Valley Stage 3 that the district playing field has been moved to be built north of William Hovell Drive on the paddocks where you will currently see horses grazing.
Here are three views in quick succession.
- Figure 4: Overview of the Whitlam Residential Estate
- Figure 5: Deep Creek Pond and drop into the Molonglo Valley, Whitlam Residential Estate
- Figure 6: Local Community Route from Deep Creek to the centre of the suburb
Note here that the yellow areas where the houses are to be built are generally flatter than the green surrounds (figure 4). The edge of the estate drops off into the river valley (figure 5). And finally, the big hills could not be removed, so they have turned them into parks (green) and have built around them (figure 6). These parks are often the steepest sections of the estate and where you will find some Local Community Routes.
My conclusion is that some paths in Whitlam are very steep. I will use the example here of the Local Community Route starting at Deep Creek and ascending the hill from “Road 01”. “Road 01” is the label for the still-unnamed road of Stage 2 of the Whitlam estate. This road has already been mention in my email, Whitlam Stage 2 estate design falls short on active travel, to the Minister for Housing and Suburban Development, Yvette Berry.
Unfortunately, it is not possible to calculate the gradient of these paths at this time as the terrain is yet to be capture as a Digital Elevation Model (DEM) in a public map. No doubt the ACT Suburban Land Agency has this data, but it is not a part of the Development Application for Stage 3 (Whitlam Stage 2 Development Application 201936061, 10 September 2019). I would presume that gradient analysis of bike paths are not mandated in the development application process (worth noting).
Figure 9 shows how the Active Travel Network in Whitlam fits together. Local Community Routes follow the streets for the most part, in some case adjacent to a Local On-road Route. Yellow is equestrian routes that, at the best have recreational value. The red line winding its way through Whitlam is also a recreational route. Blue lines are the Main Community Route. There are two Main Community Routes, running north-south on both sides of Whitlam. The Main Community Route on the east side runs along John Gorton Drive.