Newsletter #25 - 9 March 2017
In this week’s issue, we float an idea, we sink some myths, salvage some good data, and warn of a gathering storm. Fixing Hill Street was never going to be plain sailing.
Auckland Transport released the results of the Elizabeth Street trial. They gave this presentation: http://bit.ly/2mJALFH.
We spent a lot of time trying to make sense of the selected data. We know the capacity of Sandspit Road (400 vehicles per hour), Whitaker Road, and the Hill Street intersection (~3000 vph). The number of left-turning traffic into Sandspit Road dropped by 851 vehicles a day and left-turning traffic into Whitaker Road increased by 1400 vehicles a day.
The trial wasn’t just the installation of a few bollards. Extra sensors further from the intersection allowed better sequencing of the traffic light phases. As a result, longer green light phases for left turns from Sandspit Road allowed 32% (or 1032) more vehicles and State Highway 1 southbound traffic increased by 17% (911).
The trial generated discussion and highlighted the need to deal with the confluence of Sandspit and Matakana Road traffic. Auckland Transport identifies the intersection as a “high risk motorway off ramp” (http://bit.ly/2jzCQ6o).
If some bollards can be trialled, other ideas can also be trialled. At this week’s Snells Beach Residents and Ratepayers Association’s monthly meeting, several members made some great suggestions. In a nutshell, realigning the kerb between the corner of Sandspit Road and Millstream Place and introducing a ‘merge like a zip’ signage for Sandspit and Matakana Road traffic would allow more Sandspit Road traffic through the intersection.
Considering that the Kowhai Park is being upgraded, we thought that pedestrian crossings could be synchronised with certain green light phases. Here is what we came up with:
It’s a bit of a squeeze, but by moving the pedestrian crossings to the lights, we removed the Sandspit Road footpath to fit three lanes southbound. It’s a start. It will work with the bigger picture, such as our Pill design (http://www.fixhillstreetnow.org/discussion).
What do you reckon?
The responses to Winston Peters’ Parliamentary written questions have been insightful. While the SH16/Muriwai Rd Roundabout produces benefits five times its cost of $5.6 million (http://bit.ly/2nhcK5A), the Matakana Link has benefits of only half of its $42 million cost (http://bit.ly/2m5rDrb). The answer even gets its BCR wrong. It should be 0.5, not 2.0.
What the means is that money would have been better spent on a major upgrade of the Hill Street intersection. The NZTA took the benefits of fixing Hill Street and reallocated it to other projects (http://bit.ly/2lGyRWs).
The most fascinating information provided by the NZTA was its revised data and projections since the Board of Inquiry hearing for the Puhoi to Warkworth Road of National Significance. Since then, actual data has been able to be compared with projections. The Auckland Unitary Plan and roading projects has changed traffic patterns and growth.
We’ve put together this table. (You can download the picture and enlarge it.)
First, you’ll notice how NZTA’s traffic growth projections for the Puhoi to Warkworth motorway have inexplicably swelled by 50% within 18 months of getting resource consent, significantly increasing congestion at Hill Street. Even after the motorway, Matakana Link, and Western Collector is built, traffic at the Hill Street intersection is 18% higher than it was in 2016. If they have not built the Mansel Drive stage 2 by 2026, the increase is 24%. Using our figures, there is a 77% increase.
Look at the growth in traffic of Matakana Road, even with the completion of the Matakana Link. How can NZTA say that traffic volumes on Sandspit Road will double from 9,000 to 18,000 between now and 2026 when, according to the Elizabeth Street trial, Sandspit Road already operates at capacity for most of the time between 7am-6pm Weekdays and 9am-6pm Weekends?
We all know the intersection is intolerable. The conclusion is that the situation is only going to get worse and that it will be less disruptive to build final solution now than later.