ACHD's Road Wizard Sunday, August 12, 2018

When roads are new, manhole covers are flush with the surrounding surface. In many cases, concrete rings, or "collars", are poured around manholes to provide a strong, supportive transition to the asphalt.

But even manholes with collars can settle over time, especially when they are directly in the wheel path of vehicles. Metal rings on manholes can also flatten out, and chip seal applications may raise the road surface around manholes, giving them pothole-type qualities.

Drivers don't have to always bump and bear it, however. ACHD consistently works on problem areas by removing the concrete collars, and then pouring fresh, level concrete. Unfortunately, this also comes at a cost of around $1,000 per manhole.

No good deed goes "uncongested", right? The new roundabout sends a more random stream of traffic down Hill Road, which is different than how traffic approached from the old signalized intersection. In the past, traffic coming from the signal tended to flow in clusters, which offered better opportunities for drivers turning onto Hill.

But at least some of the trouble is being caused by an entirely different intersection. The big State Street/Veterans Memorial Parkway/36th Street rebuild has changed traffic patterns in the area, and some drivers are using Hill as an alternative east/west route.

This level of congestion isn't necessarily standard for Cherry at Linder. Utility work being done prior to the widening of Franklin Road has closed the section between Black Cat and McDermott roads, and Ustick Road widening work is underway. Drivers are using Cherry as an alternate route.

Improving and maintaining State as the primary east/west route means that the number of people using Hill may decrease in the future. It's best to see how that all works out before seriously considering a new traffic signal at 28th/Hill.

While nearly all signalized intersections in the downtown Boise traffic grid are coordinated, 16th and Hays is not.

To ensure optimal traffic flow, it's important to allow two turning movements to happen at the same time - drivers turning right onto southbound 16th from Hays and drivers turning left onto southbound 16th from Hays. This has to be carefully planned so pedestrian crosswalk times are not impacted.

As a result, there isn't much wiggle room for a longer left-turn light, and the signal can't easily be coordinated with other signals, including 15th. Even if the left-turn light at 16th was green for a bit longer, it would still work independently, so the benefit would be minimal.