The completion of this project marks the creation of just the second single point urban interchange (SPUI) in all of Ohio. The first was at the interchange of I-270 and Sawmill Road, also in Columbus.
This project, part of a $280 million transportation system upgrade design, helps improve traffic flow along the east side of the Columbus outerbelt. ms consultants supplied comprehensive design for the reconstruction of State Route 161 and Sunbury Road.
SPUIs are used to minimize space needed for an interchange, in addition to simplifying traffic signal operations at crossroad ramp terminals. According to Project Manager Thomas Hibbard, P.E., this type of interchange “improves the traffic flow by combining two ramp intersections along the crossing street to one intersection that is either over or under the freeway.” The provision of a single-ramp terminal on the crossroad results in only one traffic signal being required to serve the entire interchange.
The outcome? A higher level of efficiency on the crossroad and opportunities to coordinate traffic signals along the crossroad improve. “It also has the advantage of needing less right-of-way than other possible solutions,” says Hibbard. Less right-of way drives the cost of property acquisition and business relocation down, along with required approval procedures.
SPUI interchanges also provide increased capacity but are capable of being constructed within the footprint of most standard diamond interchanges. This may be why they are seen as a more viable option in some regions. Hibbard notes, “These types of interchanges are being considered more often in Ohio, especially in urban areas where there are traditional diamond interchanges that are congested.”
This project included hydraulic analyses of existing SR 161 bridges over Big Walnut Creek. Those bridges were replaced with roadway and interchange improvements, including ramp bridges to enter and exit from SR 161. ms consultants conducted pre- and post-project analyses to ensure that the final design would not increase flood elevations or significantly change the stream channel velocities.
Environmental assessments were also conducted for the project, including ambient noise monitoring and noise impact studies for over 240 adjacent residences. ms used the Federal Highway Administration’s Traffic Noise Model to conduct noise mitigation analysis and barrier design at 12 separate locations in the project area.