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18 December 2009
Motorists could save millions in lost time and fuel costs
without the need to invest in new road works, according to a series
of trials conducted by leading infrastructure consultancy firm
GHD.
The Auckland Regional Transport Authority (ARTA) and the
Auckland Traffic Management Unit have begun working with the firm
to create a regional route optimisation programme for Auckland.
“Route optimisation, which is the more efficient coordination of
a corridor of traffic signals, can significantly cut travel time,
and reduce stop-starts and idling time,” said Blair Monk, who
manages the GHD intelligent transport systems group in New
Zealand.
GHD has ascertained that full route optimisation throughout the
Auckland region would result in overall savings of $50 million per
year. Traffic congestion in the region is estimated to cost the
local and national economy more than $700 million a year.
The route optimisation trials carried out by GHD transport
systems professionals Blair Monk and Tim Booth found that better
coordination of traffic signals could reduce fuel consumption by at
least 10 percent and cut travel time by more than 13 percent for
city road users.
One trial, carried out (on behalf of the Energy Efficiency and
Conservation Authority (EECA)) on five adjacent intersections in
Auckland, was estimated to have saved road users a total of 63,453
hours and more than 214,660 litres of fuel over one year. The trial
showed potential savings of more than $1 million annually with
optimisation of those intersections.
The optimisation of another key arterial consisting of nine
intersections resulted in reduced peak-hour delays by approximately
a third. Optimisation of further arterial routes is achieving
similar results.
“Approximately 10 routes have already been optimised due to
local councils recognising the benefits of the technique to reduce
congestion on key arterials,” Mr Monk said. “However, the programme
that is being developed is designed to provide a coordinated
approach across Auckland to tackle the most severe congestion
first. In addition, as traffic patterns change over time, every
site will be revisited every three years, maintaining the most
efficient coordination of traffic lights.”
Mr Monk said the ideal timeframe for route optimisation in
Auckland would be five years, with a spend of $10.5 million over
that time, and an ongoing spend of $1 million per year to maintain
optimisation beyond that.
“Route optimisation has an effect on vehicle fuel consumption,
CO2 emissions and safety, and our work shows that it can
contribute positively to economic development, accessibility and
mobility without major infrastructure works, and at a greatly
reduced cost.”
But it is not just reducing congestion that is of interest. GHD
has also been achieving other objectives through route
optimisation, including improving the safety of pedestrians and
cyclists and promoting public transport use. For example, signals
can be configured to reduce the amount of traffic through a town
centre by encouraging an alternative route, or to give pedestrians
priority over cars by making crossing times more frequent. In one
city, where a new cycle lane was disrupting traffic on a key
arterial route, route optimisation helped improve safety and
eliminate the traffic delays that had been caused by the cycle
lane.
Route optimisation can also be used to give priority to public
transport – without delaying other traffic. An innovative solution
gave priority to buses, but only when they were running late,
improving travel times for all road users.
Mr Monk said governments were beginning to see the economic and
environmental benefits of investing in route optimisation, but he
said ongoing funding for route optimisation needed to be identified
to reduce traffic congestion and energy use in the transport
sector. He said more funds should be allocated to route
optimisation programmes. “This is another way to meet ongoing
demand, and a realistic alternative to continuing to physically
build capacity. Why not improve the performance of the roads we
already have?”
He said that under a supercity model, the process would be
simplified, with a single budget for transport-related expenditure
throughout the Auckland region.