Auckland motorists are burning billions of extra litres of fuel as they crawl along in stop-start traffic on the region's choked roads.
Results from a New Zealand Automobile Association test show cars can use four times as much fuel on congested roads as when traffic is flowing freely.
When a
car is at a standstill, stopping and starting or moving slowly in heavy traffic, it uses 24.4 litres of fuel for every 100km driven. Put the same car in free-flowing traffic, travelling at 50km/h or more, and consumption drops to 6.4 litres per 100km.
AA spokesman Greg Hunting said the results were a shock and pointed to the need for a more intensive study. Before the end of the year the association will run another test, using a wider range of vehicles in more controlled conditions.
Mr Hunting said the experiment used a modern two-door car fitted with a computer that measured kilometres driven per litre of fuel consumed. The monitored journey was between Albert St, in downtown Auckland, and St Heliers. Results were recorded over three days in the morning and evening traffic peaks.
The journeys typically involved about 20 minutes of stop-start driving in heavy traffic and 15 minutes on the freer-flowing Tamaki Dr at speeds around 50km/h.
"The same results came in every time - driving in congested traffic used four times as much fuel, which was a lot more than we would have expected," he said. "And many Aucklanders sit in congestion for a lot longer than 20 minutes, especially with that bottleneck coming into the city at Spaghetti Junction."
The AA believes these results underline the need for maximising potential public transport and completing the roading network, especially the Avondale extension, Western ring route, Manukau crossing and an eastern corridor.
"If the roads flow, you use less petrol and save money, the trip is a lot faster and atmospheric pollution is reduced," Mr Hunting said.
The study results came as no surprise to drivers at Auckland trucking firm Swanson Transport. A company spokesman said an idling truck used about the same fuel as one travelling at 70km/h.
"It costs us and many other operators a huge amount of money each week sitting in congested Auckland traffic. That's why we want the roading network completed."
The National Road Carriers Association estimated the productivity of its Auckland members was 66 per cent down because they could not travel through the region at an optimum speed of 55km/h. The average truck speed is 33km/h.
But Auckland City Council's transport policy manager Stuart Knarston said congestion was a price people paid for living and working in a successful international city.
Mr Knarston said while the council aimed to reduce congestion with a package supporting public transport and roading initiatives, peak hour problems could be expected.
"So our goal is not for cars to travel at 80km/h in the city."
"Travel demand management" with a strong focus on getting people on to buses or trains was as important as supporting completion of major roading links, he said.
But Mr Hunting said the reality was most Aucklanders drove their cars so his organisation has taken heart from the election campaign, where the major parties saw resolving congestion as a priority.
"We will be looking to whoever is in Government to keep their promise and accelerate roading solutions."
- HERALD ON SUNDAY
Auckland motorists are burning billions of extra litres of fuel as they crawl along in stop-start traffic on the region's choked roads.
Results from a New Zealand Automobile Association test show cars can use four times as much fuel on congested roads as when traffic is flowing freely.
When a
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