Ask Phoebe: Traffic flow info and what it's all about

The images used in the traffic cameras are deliberately low resolution to protect privacy. Photo / Jason Oxenham

I feel the NZTA could provide much better information to the public regarding traffic flow. Its website (and, specifically, the traffic cams) have not been updated in years. They are low resolution and next to useless for judging whether traffic is heavy but moving or stopped. Also temporary signage is often wrong. I often drive from Whangarei to Auckland on a Sunday evening, enough times to know that the sign in Wellsford saying "Heavy traffic, take SH16" is usually wrong and I always ignore it. Are there any plans to upgrade the IT communication and provide better real-time information? Joseph Davy, Auckland.

Sarah Azam, media spokeswoman for the Transport Agency, had the following response: "The Transport Agency is constantly looking at ways of improving customer journeys and providing them with predictable journey times through the best real-time travel information. This year TA launched its upgraded website, designed to make it easier to navigate. Social media streams including twitter (@NZTAAkl) and Facebook have become a very popular and reliable way of receiving updated travel information. So too has signing up for the OnTheMove service (www.onthemove.govt.nz), a fully customisable service which provides information prior to a journey.

The images used in the traffic cameras are deliberately low resolution to protect privacy.

The Visual Messaging Boards about the likes of SH16 are about giving motorists the information to make informed decisions and give them alternative routes if it suits them. This also helps to split the traffic and assists with easing congestion."

I was wondering if you could tell us why more and more traffic lights are being installed all over Auckland, when there is proof that traffic islands ensure a far better flow of traffic. Aidan Crabtree, Titirangi.

I'm assuming you mean roundabouts. Here is an explanation from Auckland Transport in July.

"When deciding on the type of control for a given intersection we look at:

•The traffic volumes (or a forecast of traffic volumes).
•The types of user (ie, how many pedestrians or cyclists are we expecting to cross the intersection, is it next to a primary school or in a town centre etc?).
•Whether we need to assign a higher level of priority to certain movements or a certain class of user.

Roundabouts and traffic signals have their own sets of pros and cons.

Roundabouts are cheaper to run, are usually more efficient at quieter times of the day and there are generally fewer serious crashes. But it can be difficult to provide a safe environment for pedestrians or cyclists. At busy times traffic can experience significant delays where approaches carry differing volumes.

Signals are often selected to incorporate protected pedestrian crossings, to assign priority during busy periods to main road movements and in some cases, you can accommodate higher traffic volumes in a smaller footprint (ie, minimising land purchases).