RTE doesn’t need to think outside the box, we know there is no box!
The State of Alaska Department of Transportation and Public Facilities (DOT&PF) completed a Highway Safety Improvement Program (HSIP) project at the Danby Street and Wembley Avenue intersection (Danby-Wembley) in Fairbanks, Alaska. The Alaska DOT&PF has adopted a “Roundabout First” policy and give this project resounding praise to the tune of featuring RTE’s projects in their roundaobut informational video. The objective of this project was to upgrade the existing two-way stop controlled intersection with a modern roundabout in an effort to improve safety for all corridor and intersection users – especially for extreme OSOW truck traffic. During extensive truck trials in the field, large trucks with different configurations tested the roundabout design to make sure they can easily pass through RTE’s design layout. Mr. Ritchie creatively developed unique design treatments to allow a few excessibly long special permit OSOW trucks to traverse the roundabout backwards and through islands in order to maintain safety for all other road users. That’s not just thinking outside the box, but realizing there is no box!
TRUCKS STAY in lane
“This is the most complex roundabout project in the nation where only one designer could have actually pulled it off.” – FHWA
This state-of-the-art roundabout project consisting of five multi-lane roundabouts in an urban corridor included high traffic volumes (55k ADT), horizontal ROW and vertical grade constraints within the commercial business area, and requirements for STAA trucks to stay “in-lane” through each of the closely spaced multi-lane roundabouts. RTE is extremely proud of this design project as it validates the design flexibility of roundabouts. It not only converts five highly congested existing traffic signals to modern roundabouts for improved capacity and safety, but it also costs $10M less compared to other alternatives while preserving businesses.
We must keep our freight industry rolling and allow trucks to navigate through modern roundabouts safely without encroaching into adjacent travel lanes.
This is a multi-lane roundabout (MLR) interchange project with accompanying roundabouts on either side (4 MLRs total). The parallel roadway to the east of the interchange experienced high volumes to/from the freeway ramps with reversing flows in the peak hours. This required multi-lane approaches for nearly every leg of each roundabout (dual lefts, dual through lanes, and bypass lanes) to accommodate the business district to the east. In addition, the industrial district to the west (left) required OSOW trucks in excess of 200 feet long to traverse the roundabouts. This required special design techniques to accommodate such excessively long trucks.
The west roundabout has a gated truck only path through the center of the roundabout for OSOW trucks. RTE witnessed the construciton of this project in 2012 (Interstate 41 / CTH F (Scheurring Way) in Brown County, Wisconsin).
This is one of the projects inspired the USDOT and several state DOTs to have RTE develop the nationwide truck study completed in 2012 – Joint Roundabout Truck Study. This study not only proved how well trucks staying in lane can function for safety and capacity, but led to an instrumental change in roundabouts in the USA.