It is recognised that roundabouts improve traffic safety, says John Williamson. They reduce the speed environment and provide a calming effect while improving overall traffic flow. Photo / NZME
It is recognised that roundabouts improve traffic safety, says John Williamson. They reduce the speed environment and provide a calming effect while improving overall traffic flow. Photo / NZME
ON THE ROAD
Roundabouts are all the rage. In recent months the Government has announced new roundabouts at Puketona and Kawakawa at a cost of $21 million as well as an additional $23m to further develop the Loop Rd roundabout already under construction.
When you add in the recently started, Waipapa roundabout, there'saround $70m being spent on upgrading high risk intersections on Northland's state highways.
This is good news for the long term improved safety of our state highways where most of our fatal crashes occur. However, with construction under way for two years yet, there will be little short term respite for peak hour drivers into Whangārei.
It is well recognised that roundabouts improve traffic safety. They reduce the speed environment and provide a calming effect while improving overall traffic flow.
Researchers at Kansas State University found that average delays were 65 per cent less at roundabouts than at signalised intersections. Vehicle crashes are relatively low speed and red light running is eliminated.
One study suggested that roundabouts reduce all crashes by 30 per cent, with a decline in injury crashes by 65 per cent and a decline in the most severe injury crashes by 82 per cent.
Motorists sometimes look through cyclists while watching for other vehicles, creating the risk of SMIDSY (Sorry mate I didn't see you) collisions, like this one at the Walton St roundabout in 2016.
Roundabouts provide environmental benefits by reducing vehicle stops which mean less vehicle idling, fewer air emissions and reduced fuel consumption.
Roundabouts though are expensive to construct, they require a lot of land compared to intersections and they are very difficult for pedestrians and cyclists. As well, there is a quite different context between major state highway roundabouts and smaller urban intersections.
In this role of writing a regular column, I am often contacted by people wanting to describe a roading situation which they believe should be different. I had two such engagements relating to urban intersections and roundabouts in the past week.
The first driver was continually frustrated by the congestion in the morning as a result of the relatively new traffic lights at Hospital Rd. "It should have been a roundabout," he said. "There's enough room."
This issue questions the merits of signalised intersections versus roundabouts in urban areas and that distinction is less clear cut than with state highways.
The Hospital Rd lights were installed to ensure residents, employees, visitors and patients were able to get some priority of exit to the state highway, particularly at peak times.
It is debatable whether there is enough room for a roundabout, and even though there might be a five to 10 minute delay at peak times, the traffic lights do what they were installed for.
The second issue was raised by a senior e-bike rider who had tried to safely negotiate the five finger roundabout in Walton St. Now he will go out of his way to avoid it!
Cyclists and pedestrians have a demonstrably harder time with roundabouts. Research suggests that on large urban roundabouts, cyclists have a 10-15 times higher injury rate than motorists.
There is a tendency for motorists to look through cyclists while watching for other vehicles, creating the risk of SMIDSY (Sorry mate I didn't see you) collisions.
So, as urban environments become more pedestrian and cyclist friendly, the preference is for urban planners to replace roundabouts with traffic signals - and this creates a quite different traffic environment.
For many drivers signalised intersections are a law unto themselves. The red light is always longer than it should be and the traffic light phasing never seems to allow for the variations of heavier or lighter volumes of traffic throughout the day.
The reality is that the SCATS (Sydney co-ordinated adopted traffic system) has the potential to co-ordinate the phasing of a whole series of traffic lights, to allow a relatively even flow at all times of the day, throughout the network.
Sometimes though, the length of the cycle causes frustration, and drivers take on the system such that red light running creates the risk of T-bone crashes and pedestrian fatalities.
Traffic engineers know that traffic lights and roundabouts each have their place. It's just that all us other experts often disagree with them.
• John Williamson is chairman of Roadsafe Northland and Northland Road Safety Trust, a former national councillor for NZ Automobile Association and former Whangārei District Council member.
