TBUG asked them not to mark out Nelson Street, at least until we had been able to discuss it with them.
TRC has declined to respond, so far, at least.
Now we post new pictures of the Nelson Street roundabout, that uses the same design as we raised concerns about over at Drayton.
While standing at this roundabout, a number of vehicles, all cars, shot through the intersection at high speed, crossing into the bike lanes in order to get around the 8 metre concrete circle.
Nelson Street is a 60 kph speed zone, which is frequently exceeded by vehicles.
If one of the functions of a roundabout is to slow traffic, then this design is a failure.
As to the bike lanes going around the roundabout, this is what the Austroads people said in 1999:
Allott & Lomax reported that in an early attempt to provide for cyclists, a mandatory bicycle lane was marked around the periphery of the circulating roadway of a roundabout, giving cyclists priority access across approaches whilst other traffic had priority at the exits. A performance study indicated that cyclists felt that their trip was improved although crashes involving cyclists continued. It was also reported this treatment has been withdrawn in the absence of any detectable benefits for cyclists, due to the fact that cyclists are kept in the outer edge, 'the most hazardous area of the circulatory carriageway'
In 2011, Austroads warn designers of roundabouts:
A number of jurisdictions do not favour the provision of bicycle lanes on the approach to, and around the periphery of, roundabouts. Designers should clarify the policy of local jurisdictions before considering the application of cycle lanes at roundabouts. The matter is under review by the Austroads Road Design Review Panel and other key stakeholders including cycling organisations and road safety practicioners. Further advice will be issued in due course.