Grove City, located just outside of Columbus, Ohio, has grown significantly in both territory and population over the past decade and continues to expand. The most established portions of Grove City are located west of I-71, a north-south freeway corridor that bifurcates the city. City administrators engaged in a planning process during the 1990s to establish a blueprint for growth they anticipated to occur east of I-71. The vision for Buckeye Parkway as a key north-south arterial route in the area arose from that planning process.
Buckeye Parkway was designed and constructed in sections as various land areas were annexed to the city and developed. Development occurred earlier at the northern and southern extremities of the 5-mile-long corridor and proceeded inward until the final midsection was constructed. The importance of Buckeye Parkway as a traffic-carrying arterial met head-on with quality-of-life issues in adjacent neighborhoods at the point where the northern and southern sections of roadway were connected.
Once considered a farming community, Grove City has increased in population from 19,661 in 1990 to 33,483 in 2007, according to the Mid Ohio Regional Planning Commission (MORPC). Mixed-use developments are budding, such as Parkway Centre, a regional commercial center that encompasses more than 1 million sq ft of retail space. In addition to commercial development, residential subdivisions are being built all around the city, as well as new schools, parks, a YMCA and a golf course. Scheduled to open in January 2008, Norfolk Southern’s 248-acre Rickenbacker Intermodal Terminal, located near Grove City, has created tremendous commercial and residential growth in preparation for the over $15 billion in revenue it is expected to produce.
Grove City is now one of Ohio’s fastest-growing cities and recently underwent major infrastructural changes to make way for growing traffic needs attributed to major economic development in the area. Comprehensive thoroughfare planning for eastern Grove City called for the creation of Buckeye Parkway, a new north-south arterial roadway built to divert traffic away from overcrowded Hoover Road and support growth associated with new residential and commercial development such as Parkway Centre in the surrounding area.
Commercial vs. residential
The design of Buckeye Parkway faced two opposing requirements: accommodation of high traffic volumes and maintaining the neighborhood feel of a road that meanders through both existing and planned residential neighborhoods. These competing needs were on the forefront as design concepts were developed for the corridor. The northern section of Buckeye Parkway provides easy access to the adjacent interstate system and a rapidly growing commercial environment, while the southern terminus is completely immersed within residential communities. As a result, the majority of the corridor serves as a transitional thread between these two starkly different zones.
Overall concepts established by the community thoroughfare plan conducted in 1996 laid the foundation for the Buckeye Parkway corridor and established the minimum number of travel lanes required to provide adequate capacity throughout the roadway system. The southern end of the corridor consists of two lanes, while the northern end has five or more lanes.
Designed in phases and tied to surrounding development, the southern section of the corridor was the first to be established in conjunction with expanding residential communities. The northern section of Buckeye Parkway followed, sparked by robust commercial development. The remaining transitional thread proved to be the most challenging element, because it needed to provide functionality in harmony with both environments.
A motivating force behind completion of the transitional thread was the Pinnacle Club Golf Course Community. This Lanny Wadkins-signature-design golf course and accompanying 1,064 residential lots required completion of the Buckeye Parkway Corridor and addition of Pinnacle Club Drive. This two-lane facility (Pinnacle Club Drive) connects Buckeye Parkway to State Rte. 104 through residential neighborhoods and serves as an east-west collector roadway. Planners for the intersection of Buckeye Parkway and Pinnacle Club Drive quickly recognized it as the focal point of both the neighborhoods and traffic flow in the area.
At a circle-roads
Grove City was faced with the challenge of designing an intersection that would carry significant traffic and also be consistent with the quality and scale of adjacent neighborhoods. The intersection needed to accommodate pedestrians on the Pinnacle Club development’s 2 miles of asphalt leisure trail, which connects to an already-extensive bike path and pedestrian network throughout the city. Speed control and traffic safety were paramount considerations in balancing neighborhood quality of life and the needs of commuters at this location.
Grove City officials, in cooperation with private developers, commissioned engineering consultant Evans, Mechwart, Hambleton & Tilton Inc. (EMH&T) to find a solution that served the disparate needs of various constituencies. The resulting design of a modern roundabout offered the unique ability to accommodate large traffic volumes, promote lower operating speeds and provide a neighborhood-friendly environment. The city administration was bold to embrace the innovative concept; when the roundabout at Buckeye Parkway and Pinnacle Club Drive was designed, it was only the second of its kind in central Ohio.
The benefits of a modern roundabout include:
- Slower vehicle speeds (under 30 mph): Drivers have more time to judge and react to other cars and pedestrians, reducing the severity of crashes and keeping pedestrians safer;
- Efficient traffic flow: Flow is increased 30-50% compared with an all-way-stop-controlled or signalized intersection;
- Lives saved: There are 75% fewer conflict points than in a conventional four-way intersection, so fatalities, injuries and pedestrian crashes are reduced drastically;
- Reduction in pollution and fuel use: It improves traffic flow for intersections that handle a high number of left turns;
- Money saved: Savings are estimated at an average of $5,000 per year in electricity and maintenance costs; and
- Community benefits: The modern roundabout has traffic-calming effects and is aesthetically pleasing.
Balancing competing needs for intersection capacity, safety, pedestrians, right-of-way and truck movements through the intersection are examples of a few opposing design elements that were accommodated when preparing engineering plans for the Buckeye Parkway and Pinnacle Club Drive intersection. It was critical that the geometry of the planned roundabout accommodate anticipated truck traffic through the corridor, while defining restrictive travel paths necessary to command desired operating speeds. Additionally, this intersection must be able to accommodate the traffic volumes forecast by comprehensive land use and regional planning efforts to use the facility throughout its design lifetime.
Implementation of a modern roundabout proved to be a key element for satisfying the need to accommodate vehicular traffic-volume demands and reduce speeds consistent with a pedestrian-friendly residential atmosphere. The geometry required to produce a safe low-speed intersection as necessitated with roundabout design has desirable traffic-calming side effects that extend beyond the conventional intersection influence area. Roadway geometry was designed to gradually reduce vehicular travel speeds prior to entering the intersection.
Speed by design
The west leg of the intersection had to connect to, and was constrained by, an existing residential neighborhood with a narrow street and limited right-of-way. The arterial component of the Buckeye Parkway corridor called for two travel lanes in each direction and a large landscaped boulevard separating opposing directions. In order to accommodate all of these competing needs, the roundabout went through a multistaged, iterative design process systematically reaching the optimum geometry for the given constraints.
The results produced a roundabout with an inscribed circle diameter of 210 ft, a circulating travel width of 30 ft, two travel lanes for the north-south arterial and a single travel lane for the east-west Pinnacle Club Drive roadway. Each leg of the intersection was designed to be curvilinearly tangential to the circulating roadway, while providing enough approach deflection to slow-approaching vehicular traffic.
Splitter islands used to deflect approaching traffic also double as pedestrian refuge islands allowing pedestrians to cross only one direction of traffic at any given time. Slow operating speeds, coupled with staged pedestrian crossings, created the desired pedestrian atmosphere.
The geometry of the roundabout intersection can only go so far when it comes to alerting drivers to the upcoming intersection and the need to reduce speed. Landscaping played a critical role with respect to enhancing both traffic operations and the visual appearance of the corridor and intersection for drivers and pedestrians alike. Vertical landscape features within the central island are intended to create a natural sight obstruction alerting motorists to the upcoming roundabout intersection.
The Buckeye Parkway/Pinnacle Club Drive roundabout contains decorative stone walls and small trees within the central island. Decorative stone walls also were strategically placed on each of the four corners to provide the appropriate intersection sight distance. In an effort to help control approach speeds, these walls were precisely located to furnish appropriate sight distance, but not allow additional unobstructed views of adjacent legs of the intersection. By limiting sight distance to the desired amount, and creating a visual impediment within the central island, a subtle announcement of the intersection was made and a level of speed control was achieved.
Circular definitions
This project had both a roundabout and a traffic circle. Pinnacle Club Drive, the east-west connector roadway connecting Buckeye Parkway to S.R. 104, was originally slated to traverse a large stand of trees. Efforts to save this stand of trees led to development of a traffic circle intersection. The proposed traffic circle had an inside diameter of over 260 ft and a single-lane circulating roadway width of 20 ft encompassing the stand of trees.
During the design process, many questions arose concerning the differences between a traffic circle and a modern roundabout. There are many differences between them but two of the major design distinctions are:
- Traffic circles are often stop-sign controlled, whereas roundabouts typically require yield on entry; and
- Traffic circles do not slow approaching vehicles with roadway alignment deflection as required for proper roundabout design.
The traffic-circle design of Pinnacle Club Drive was appropriate for the lower-volume, low-speed traffic on the neighborhood streets leading into it, and related well to the tree preservation area. The roundabout was the preferred design solution on Buckeye Parkway where traffic volumes and operating speeds are higher and more sophisticated intersection control was required.
As commercial and residential development in Grove City continues to grow, the now-completed Buckeye Parkway helps alleviate the strain on overcrowded parallel routes, while providing a transition between a heavy-retail-commercial environment to the north and a residential-pedestrian-orientated environment to the south. The use of a modern roundabout was a key factor in facilitating this transitional aspect. Though the entire Buckeye Parkway has only been opened a short time, Grove City has been very impressed with the safety record of the roundabout.
“When the roundabout first opened, it was certainly different for citizens to experience,” explained Grove City Police Chief Dennis Deskins. “Overall, the roundabout has been quite successful in maintaining traffic flow in the area with very few traffic incidents.”
The decorative features, including wide medians, street lighting and landscaping throughout the corridor, tie the multifaceted street project together, creating a calm, peaceful driving experience.
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