Extensive Traffic Study Leads to Roadway Improvements
Cedar Falls has experienced a steady population and commercial growth over the past three decades. Along with that growth comes the correlating issue of heavier traffic and more congested roadways. In Cedar Falls, one of these pain points is along the Greenhill Road corridor. Greenhill Road is a four-lane, undivided arterial that serves as a main east/west thoroughfare along the southern edge of Cedar Falls. In addition to new commercial development in the area, one other factor that has led to the increased traffic volumes is the continued expansion of the Pinnacle Prairie development to the south of Greenhill Road.
Snyder & Associates was contracted by the city to perform a traffic study on the 2.7-mile section of Greenhill Road, from the intersection with Hudson Road in the west to the Cedar Heights Drive intersection in the east. This comprehensive study encompassed eleven public intersections that currently consist of a mix of signalized and two-way STOP controlled (TWSC) intersections.
Signalized Intersections vs. Roundabouts and Multimodal Considerations
The goal of the study was to provide the city with short- and long-term plans for upgrades and improvements to the Greenhill Road corridor. The study’s challenges included:
- Determining functional lane needs and intersection improvements.
- Forecasting traffic demand changes due to new and anticipated development.
- Analyzing pedestrian/bicycle needs and “Complete Streets” considerations.
- Potential conversion of traditional signalized intersections to roundabouts
This study was accomplished through data collection, a safety performance review, and current and forecasted traffic volumes and intersection operations. A life cycle cost analysis was also performed to compare the alternatives for a traffic signal or roundabout at the intersections requiring traffic control beyond TWSC. In addition, three public feedback sessions were held to allow interested citizens the opportunity to express opinions regarding the corridor plan.
The immediate, short-term recommendations offered to the city were to update vehicle and pedestrian clearance timings at signals, fill in the sidewalk gaps along the south side of Greenhill Road and improve signage and pavement markings at several intersection approach locations.
For long-term consideration, it was recommended to add signals at two current TWSC intersections and to widen roadways for turn lanes at four of the intersections. Also, it was recommended to convert five signalized intersections to roundabouts, with immediate priority being given to the Cedar Heights Drive and South Main Street intersections. After being approved by the city council, these two roundabout conversions are slated to begin construction in 2020 and 2021, respectively. While upfront costs will be higher than traditional signalized intersections, our firm’s study determined the roundabout conversions will result in considerable cost savings over the lifespan of the project, as well as improved safety, efficiency, and traffic flow.