Traffic signals that spot large groups of vehicles and tweak a road’s
signals to speed the traffic glut through will soon debut in Ada County.
The implementation of adaptive or “smarter signals” is one of a number of
innovations the Ada County Highway District is currently pursuing as it
moves into its fifth decade of service. Other ongoing initiatives include an
on-pavement weather detection system to guide Winter Street Service crews
and a program to diagnose failing pavement for maintenance.
“We want to better calibrate ACHD’s efforts to provide the right service at
the right time for the biggest benefit,” said Bruce Wong, ACHD director.
“Using technology and building on our past successes, we can provide what
people need – and at a lower cost.”
An example would be adaptive signal technology, the next-generation of
signal timing software and hardware that ACHD hopes to acquire this year and
deploy in 2013. Such “smart signals” constantly monitor traffic flow along
major roads and adjust the amount of green time to best serve the demand.
The technology differs from the existing signal timing in that it will
deviate from pre-set timing programs – calibrated for the usual traffic
volumes known to occur on specific days and times – and make adjustments to
better move large groups of vehicles.
This could be especially useful after special events or on a Friday at
mid-afternoon before a holiday weekend, said Terry Little, ACHD’s traffic
manager, adding that the technology can reduce delay by 10 percent.
“Adaptive systems recognize the traffic flow and have wide flexibility to
make continuous adjustments,” Little said. “It’s a refinement over the
standard timing system, which is set for the normal conditions and does not
have great flexibility to respond to variations.”
Although the technology has been around for 30 years overseas, it has only
now progressed to the point of working well with ACHD’s existing signal
controllers and traffic detectors, Little said. Some cities in the Pacific
Northwest that adopted adaptive systems years ago experienced problems and
had to ramp back their efforts, he said.
ACHD’s initial move to adaptive signalization is estimated to cost $600,000.
New technology is also helping ACHD target the application of deicer, sand
and salt to figh
slippery pavement this winter. New weather monitoring stations and software
measure pavement-level temperature and the presence of ice and water,
allowing ACHD to know where and when to roll its Winter Street Service
The system, which cost $125,000, was put into service this winter and is
being used and refined this month.
“With this late winter, we wondered if we were ever going to be able to try
it,” said Paul Daigle, deputy director of maintenance. “But we’re happy with
the system’s performance and hope to expand it as we move forward.”
ACHD may be able to save up to $200,000 annually by responding with the
right treatment for specific areas within the county and conserve manpower
and materials, Daigle said.
Similarly, ACHD hopes its new pavement management system will do a better
job of targeting when pavement receives a crack seal, a chipseal or a
Faced with an ever-expanding system of 2,200 miles of local roads, the
District needs to become more selective in how it approaches maintenance of
the asphalt, Daigle said. The answer has been the Street Saver system that
will track the condition of the roads and indentify stretches in need of
attention, he said.
“We want to be more efficient and apply the best treatment at the proper
time,” Daigle said.
Since the mid-1990s, the District has relied on chipsealing to keep most
roads in a good st
of repair, applying the rock-and-oil treatment to more than 200 miles each
summer. While this approach has ensured that ACHD’s roads are in a good
shape, the one-size-fits-all aspect provided too much attention to some
streets and too little to other problem spots. Some roads have been
chipsealed multiple times and the gutter pans and manholes are lower than
the street, which means the road will eventually have to be ground down.
In the future, chipseals will be largely reserved for arterial roads that
get the highest traffic loads and most wear. Crack repairs, light surface
treatments and spot excavations and repairs will be performed elsewhere on
an as-needed basis as indicated by the system, Daigle said. This more
focused approach may save up to $2 million previously devoted to
chipsealing, which can be applied to other needed maintenance activities.
“We can continue to keep our roads in great shape by targeting the needed
treatment,” he said. “Instead of overkill, we’re going to do what is
required, saving tax dollars.”