M7 Cycleway Saddle Survey Pictures

On 24 April 2010 a saddle survey was undertaken of the M7 Cycleway, north and south from Rooty Hill Station. The saddle survey was undertaken after photomap images at www.nearmap.com showed what appeared to be extensive surface cracking along much of its route.

When experienced at first hand, the surface was found to be reasonably smooth along most of the route. The pictures show that extensive use has had to be made of bitumen crack sealant, which is applied with a special wand. The aim of this is to prevent water seeping in through what are, initially, hairline cracks, leading inexorably to bigger cracks and the breakup of the surface. It's called crocodile cracking.

Away from the big engineered pieces, such as the Light Horse Interchange, the construction methods, standards, and conditions are reminiscent of the cycleways in Canberra. In some places the cycleway is very good to excellent. In others, they've simply laid asphalt down without much of a foundation and these are the places that are showing signs of breakup.

Of concern is that the cycleway was opened in 2005 and the surface has already required extensive remediation. The cracking suggests poor preparation of the underlying road bed and/or asphalt sheeting that was too thin or of low quality. This is especially the case given that in road construction terms, cyclists and pedestrians impose a negligible load on the surface, especially when compared with cars and trucks.

By way of comparison, the quality of the M7 Cycleway compares poorly to the Duck River Cycleway whose design and construction was undertaken by Roads and Traffic Authority.