ACHD Marks Four Decades of Service
ACHD eyes 'smarter signals,' better black ice detection and other advances for Ada county's transportation future

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.
Traffic Management Center
“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 fighAnti-icingt 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 crews.

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 rebuild.

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 stchipsealingate 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.”