Section 1
ROUNDABOUTS SELECTED
FOR THREE INTERSECTIONS IN SECTION 1

As a part of the analysis that was completed for Section 1, traffic and safety data was analyzed to help the Project Team select roundabouts as the preferred intersection treatments for three locations.

The Project Team studied the performance of three intersection types: stop-controlled, signalized and roundabout. Based upon comparative data, it was determined that the most beneficial proposed intersection treatment for all three intersections was a roundabout. The intersections were analyzed using forecasted traffic volumes for the year 2022 (when Section 1 construction is anticipated to be completed) and 2042 to accommodate anticipated future growth in the region. The predicted traffic volumes showed that traffic signals would be warranted, but would require installation of additional turning lanes at all three intersections, potentially causing greater property impacts. Roundabouts will minimize the footprint of the intersections and reduce property impacts. All three roundabouts will be designed to accommodate interstate trucks. The roundabout options provided the best level of service and the least amount of delays through the intersections. Additionally, the roundabouts will all be designed with entrance speeds of 25 mph to address a public concern for increasing speeds in the corridor. Based upon the safety analysis utilizing the American Association of State Highway Transportation Officials' Highway Safety Manual (HSM), roundabouts provide a reduction in predicted future fatal and injury crashes compared to signalized and stop-controlled intersections at these locations. Based upon the safety improvements, the roundabouts provide a greater benefit to cost ratio compared to the other intersection types.

Route 981/Route 819 Intersection
The proposed roundabout at the intersection of Route 981 and Route 819 will consist of four approaches to the intersection and a channelized right turn at the Route 981 southbound approach, to the west of the existing railroad pier. A roundabout will improve operation of traffic and safety at this intersection. The roundabout provides the least amount of delay and the greatest level of service compared to signalized or stop-controlled intersection options. Based on the methodology from the HSM, there would be 71% fewer predicted total crashes at a roundabout than a signalized intersection and more than four times fewer predicted total crashes compared to a stop-controlled intersection at this location.

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Route 981/Route 2007 Intersection (Hecla Road)

The proposed roundabout at Route 981 and Route 2007 will consist of four approaches to the intersection. The intersection will be realigned slightly to minimize impacts to adjacent properties and to better maintain traffic at this intersection during construction. A roundabout will improve operation of traffic and safety at this location. The roundabout provides a delay and level of service similar to a signalized intersection and significantly lesser delays and greater level of service than a stop-controlled intersection. Based on the methodology from the HSM, there would be 63% fewer predicted total crashes at a roundabout than a signalized intersection and more than three times fewer predicted total crashes compared to a stop-controlled intersection at this location.

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Route 981/Route 2021/Route 2027 Intersection (Norvelt Intersection)

The proposed roundabout at Route 981 and Route 2021/2027 will consist of five approaches to the intersection and consolidate the primary movements at the current triangle intersection configuration into a single intersection. The primary intersection will be shifted slightly to the northwest to minimize impacts to businesses and to better maintain traffic through these intersections during construction. A roundabout will improve operation of traffic and safety at this intersection. The roundabout provides a delay and level of service similar to a signalized intersection and significantly lesser delays and greater level of service than a stop-controlled intersection. Based on the methodology from the HSM, there would be 43% fewer predicted total crashes at a roundabout than a signalized intersection and more than three times fewer predicted total crashes compared to a stop-controlled intersection at this location.
FHWA PennDOT