CO 21 (Powers Boulevard) & Research Parkway Interchange Design Study
About the Project:
A project team is designing and developing the Colorado Highway 21 (Powers Boulevard) and Research Parkway Interchange. The project is a phased approach, currently focused on Phase 2.
In response to growth in the northeast area of Colorado Springs along the Powers Boulevard Corridor, the Colorado Department of Transportation (CDOT) is constructing a new interchange at Powers Boulevard and Research Parkway. This project is part of an on-going CDOT effort to improve interchanges along the Powers Boulevard Corridor. Construction is anticipated to start summer 2021. The Colorado Department of Transportation (CDOT) completed the design of the Powers Boulevard and Research Parkway Interchange last fall.
Project Facts
- Location: From mile point (MP) 149 to MP 151, and on Research Parkway between Scarborough Drive and Cross Creek Drive
The project is in El Paso County on CO 21 between mile points 149 and 151, and on Research Parkway, between Scarborough Drive and Cross Creek Drive. CO 21 carries north/south traffic from the town of Fountain to northern Colorado Springs, while Research Parkway carries east/west traffic between commercial and residential developments.
The conceptual design of this interchange was approved in 1997 as part of the Powers Boulevard Extension North, Woodmen Road to I-25 Environmental Assessment. Due to growth in the area CDOT is advancing the planning and design. The planning and design process will be in compliance with National Environmental Policy Act (NEPA) during the Environmental Assessment re-evaluation.
The current configuration is an at-grade signalized intersection. Key issues at this intersection include excessive wait times for left turn movements, inadequate left turn lanes, multimodal movements and excessive congestion.
The project includes interchange design, increased capacity and simultaneously design of the Fairfax Pond (federal storm water discharge facility in the northwest quadrant of the project). This large flood control and water quality pond is current designed as a standalone city project. The recommended improvements will be constructed in phases as funding becomes available.
The project is intended to produce the following improvements:
- increased capacity – Interchange at Powers Boulevard and Research Parkway intersection
- improved safety
- higher level of service
- improved riding surface (smoother and stronger pavement)
- bridge replacement construction
- resurfacing, restoration, rehabilitation
- reconstruction
Background
In 1997, a project team approved design concepts for this interchange as part of the Powers Boulevard Extension North, Woodmen Road to I-25 Environmental Assessment. Currently, the intersection has a signal and is configured at-grade.
Alternative Selected
Based upon the Valued Engineering study (completed in summer 2018) the design alternative selected for this intersection is a Diverging Diamond Interchange (DDI), (similar to the Fillmore/I-25 Interchange). This DDI will have more distance between the signalized intersections as compared to Fillmore/I-25 Interchange.
HOW TO DRIVE A DDI:
Although DDIs can seem confusing in an aerial view, traveling through them is extremely efficient. Motorists simply follow the pavement markings, signage and traffic signals just like any other intersection.
A Diverging Diamond Interchange (DDI) is a type of diamond interchange in which the two directions of traffic on the non-freeway road (Research Parkway) cross to the opposite side on both sides of the bridge at the freeway (Powers Boulevard). It is unusual in that it requires traffic on Research Parkway to briefly drive on the opposite side of the road from what is customary. The crossover “X” sections can either be traffic-light intersections or one-side overpasses to travel above the opposite lanes without stopping, to allow nonstop traffic flow when relatively sparse traffic.
Advantages
- Two-phase signals with short cycle lengths, significantly reducing delay.
- Reduced horizontal curvature reduces the risk of off-road crashes.
- Increases the capacity of turning movements to and from the ramps.
- Potentially reduces the number of lanes on the crossroad, minimizing space consumption.
- Reduces the number of conflict points; thus, theoretically improving safety.
- Increases the capacity of an existing overpass or underpass, by removing the need for turn lanes. Costs significantly less than a normal interchange.
Powers Research Bridge
