If you haven’t noticed it, it’s working.
In October, the Alaska Department of Transportation and Public Facilities installed a new traffic management system to reduce jams in the Mendenhall Valley. This summer, that system is coming to downtown Juneau as well.
“We have a couple new things popping up,” said David Epstein, regional traffic and safety engineer for DOT’s Southcoast region.
In October, DOT finished work on a million-dollar system of radar traffic detectors, monitoring cameras and a sophisticated software program that ties them together. The goal is to make driving easier at rush hour.
“What our observation has been (in the past seven months) is that it has made a substantial difference in the Valley,” Epstein said.
Traditionally, traffic lights have operated on timers or have been operated by in-ground sensors that detect cars above them. The light can then stay green (or switch) to let those cars proceed if no cars are waiting on the cross-street.
The problem: Those sensors are expensive to maintain. If something breaks, the traffic lane has to be torn up.
A few years ago, DOT tried a camera-based system as an alternative. It didn’t work, Epstein said. The cameras couldn’t cope with reflections from icy and wet streets, even with the manufacturer coming up to maintain it.
“We’re not going to have that problem with radar,” Epstein said.
The new system has been used across the country already, but it is relatively new in Alaska, Epstein said. Networking the signals helps only in places where traffic lights are close together — and Alaska doesn’t have many of those places.
In the Valley, the system is easy to overlook: White panels hang from the traffic-signal crossbars at the McNugget intersection and others nearby. Above, pan-and-tilt cameras watch.
The panels are also visible at the Salmon Creek traffic light, but the Valley intersections have a special feature: software networks them together, allowing the signals to adjust themselves to demand between 7 a.m. and 7 p.m. on weekdays.
“The system responds to traffic volume,” Epstein said.
Monitoring cameras allow DOT engineers to monitor how well the system is working.
“We don’t store, we don’t take pictures, we don’t take still shots, we’re expressly prohibited from doing that,” he said. The cameras just stream a live video to allow realtime adjustments.
This summer, DOT will renovate Egan Drive between the Douglas bridge and Main Street. As part of that effort, the traffic lights at the bridge, Whittier Street and Main Street will get the same treatment as the Valley intersections.
When that project is finished, drivers can expect to hit green lights more often, and traffic will flow more smoothly from place to place.
“Really, it’s a fantastic system,” Epstein said.
Contact reporter James Brooks at james.k.brooks@juneauempire.com or call 419-7732.
