Our Projects

  • Create a safe, driver & pedestrian-friendly solution to a hazardous intersection on Chester Road (SR 0320)
  • Complex five-leg intersection
  • Provide access to Swarthmore College south campus & Town Center West
  • Immediately south of the SEPTA rail overpass
  • Primary access to the SEPTA rail station & downtown businesses
  • Lack of pedestrian connectivity between Swarthmore College, business district & town center
  • Public perception
Our Solutions
  • Municipal & PennDOT Traffic impact studies
  • Trip generation & pedestrian studies
  • Data collection & traffic analysis
  • Municipal, PennDOT, SEPTA coordination
  • Expert witness testimony
  • Conceptual roadway improvement plans, including a roundabout
  • Midblock pedestrian crossing evaluation & design
  • Extensive public engagement

Swarthmore Roundy

Mid AtlanticHighways, Streets & StructuresTraffic & ParkingTransitWalking & Biking
Swarthmore College | Swarthmore Borough, Delware County, PA
  • Swarthmore Roundy by McMahon Associates
  • Swarthmore Roundy by McMahon Associates
  • Swarthmore Roundy by McMahon Associates
  • Swarthmore Roundy by McMahon Associates
  • Swarthmore Roundy by McMahon Associates
  • Swarthmore Roundy by McMahon Associates
  • Swarthmore Roundy by McMahon Associates
  • Swarthmore Roundy by McMahon Associates
  • Swarthmore Roundy by McMahon Associates
  • Swarthmore Roundy by McMahon Associates
  • Swarthmore Roundy by McMahon Associates
  • Swarthmore Roundy by McMahon Associates
  • Swarthmore Roundy by McMahon Associates


This video has been featured on the PennDOT roundabout page on their website. See HERE

McMahon Associates, Inc. was engaged by Swarthmore College to resolve a complicated and dangerous intersection on Chester Road (SR 0320) in connection with their Swarthmore Town Center West development concept, opposite Rutgers Avenue and Swarthmore Borough’s central business district. The existing intersection was a unique five-leg, unsignalized expanse which was dangerous and confusing for drivers and completely prohibited pedestrian crossing of its 140-foot width. This essentially divided the campus from the businesses in the downtown area.

As part of the project, McMahon designed and oversaw the construction of a single-lane roundabout at the intersection of Chester Road with Rutgers Avenue, Station Square East and West, and relocated Fieldhouse Lane, which now serves as access to the College’s south campus, and provides a key multimodal connection between campus and Swarthmore Borough’s commercial business district and town center. PennDOT granted final design approval in August 2014. Construction began in September 2014, and the roundabout was opened to traffic on July 11, 2015.

The Chester Road project required the incorporation of a “Complete Streets” transportation solution, extensive community outreach with Swarthmore College and Swarthmore Borough, and included many unique design, permitting and construction challenges that were overcome during the many phases of the project.


The Chester Road (SR 0320) Swarthmore Roundabout Project was part of a larger initiative that Swarthmore College had to develop a mixed-use building at the south entrance of the campus. This development includes the construction of an inn, restaurant, and retail space for a campus and community bookstore, located in Swarthmore, PA within the Swarthmore College campus along the west side of Chester Road. Chester Road had served as a barrier between the College campus and the business district and town center within the Borough, which needed to be resolved as part of the Town Center West project.

Chester Road passes under the Southeastern Pennsylvania Transportation Authority (SEPTA) Media/Elwyn Regional Rail, then rises and intersects Rutgers Avenue at grade. Also at grade and parallel to Chester Road is Station Square East and West, providing one-way circulation for access to commercial businesses, the SEPTA train station pick-up/drop-off area and parking, and access to Swarthmore College’s south campus via Fieldhouse Lane. This five-leg, unsignalized intersection configuration resulted in side street delay, and the intersection configuration prohibited pedestrians from crossing Chester Road and from Swarthmore College on the west side to Swarthmore Borough’s commercial district on the east side, due to the long crossing widths, high vehicle speeds and lack of pedestrian facilities.

McMahon Associates was engaged by the College after a recommendation from Swarthmore Borough, a long-standing client of the firm. McMahon’s engineers analyzed the intersection and prepared a series of options to solve the intricacies of the intersection. As these options were reviewed it quickly emerged that a roundabout was the best option for the location given the intersection’s size and traffic analysis indicated that traffic volumes were ideal for this configuration.


While McMahon brought a wealth of experience to the project design and execution, the firm also brought their expertise in local community outreach to help the College and Borough engage with local citizens during the planning and construction of the project. This was important because roundabouts are generally new to the state of Pennsylvania, especially to the Philadelphia metropolitan area where Swarthmore is located. Many citizens had seen them used in other places, but they were skeptical of its effectiveness for their location. Extensive public outreach and education were required to build acceptance of the project’s design.

A project specific brochure was prepared to educate the community on navigating the roundabout as a motorist, a pedestrian, and a bicyclist. It also included information on how large trucks will navigate through the roundabout utilizing the truck apron, and how motorists should react to emergency vehicles entering the intersection. The brochure provided the College and the Borough with an educational tool that could be provided electronically and in hard-copy form to business owners, residents, and commuters traveling through the area.

Several public outreach meetings were conducted throughout the project approval process. The local community was generally unfamiliar with modern roundabouts, and therefore, several meetings were specifically focused on the roundabout traffic operations and design. In order to properly model all of the unique elements at this location, McMahon completed Vissim microsimulation to provide detailed traffic modeling, with consideration for the interaction between all modes of travel. The Vissim model included the operations of vehicles traveling through the roundabout, as well as the operational effects from the nearby SEPTA bus stops along Chester Road (SR 0320), the SEPTA rail arrivals and departures along Station Square, and pedestrian crossings of each leg of the roundabout.

Swarthmore College wanted to go one step further to demonstrate the positive influence the Town Center West and roundabout would have in the community, creating that stronger bond between the College campus and the Swarthmore business district and residents, while maintaining traffic flow through the key intersection. The Vissim traffic modeling, the roundabout design which was completed in AutoCAD Civil 3D, and architectural renderings and building elevations were combined by McMahon within a third-party graphics software package in order to generate a three-dimensional, real-world, moving visualization upon completion of the project. The resulting videos provided the combined traffic operational and visual context needed to relay the post-construction conditions to the community at-large.


In addition to the challenges of building support for the project, maintenance and protection of traffic (MPT) during construction was of paramount importance. This is specifically challenging for roundabouts, generally due to their size and geometry. This was a major concern for the Borough, College and local citizens. Detailed construction staging plans were developed in order to maintain vehicular traffic along Chester Road (SR 0320) and at the busy intersection, while balancing the needs of pedestrians through the area to the College, SEPTA bus stops, SEPTA Media/Elwyn Regional Rail Station, and the Borough’s commercial business district.

During preliminary and final design, preconstruction coordination meetings were set up with McMahon, PennDOT, Swarthmore Borough, the College and their preconstruction consultant, W.S. Cumby, to review the design and develop construction staging and MPT details. This collaborative partnership proved invaluable, as W.S. Cumby was ultimately selected to be the general contractor for the construction of both the Town Center West development and the roundabout, with Brubacher Excavating, Inc. priming the roadway work. Five construction stages were developed in order to minimize phasing and provide large sections of the roundabout to be constructed during each stage. Pedestrian detours were established to reduce exposure to potential construction hazards, while providing access to the College, SEPTA bus stops and rail station, and the Borough’s business district. Limited, short-term truck and vehicle detours were implemented to reduce intersection conflicts in order to build constrained sections of the roundabout. At the end of May, a “College Commencement” phase was developed to clean up the work zone and limit construction activity during the College’s graduation ceremonies. The following summarizes the work completed in each of the five construction stages:

Stage 1A: Install storm water drainage facilities under short-term flagging operations during night time hours.
Stage 1B/C: Shift SR 0320 traffic east. Construct southbound side of SR 0320 and Station Square West and Fieldhouse Lane approaches.
Stage 2A/B: Separate/split northbound and southbound SR 0320 traffic. Construct center section of SR 0320 approaches.
Stage 3A: Shift SR 0320 traffic west. Construct northbound side of SR 0320 and Station Square East approach.
Stage 3B: Detour Rutgers Avenue. Construct Rutgers Avenue approach.
Stage 4/5: Separate/split northbound and southbound SR 0320 traffic. Construct SR 0320 splitter islands and central island. Install final asphalt overlay under short-term flagging operations during night time hours. Install final pavement marking and signs under short-term flagging operations during daytime hours.

Communication and coordination throughout construction was key. W.S. Cumby’s head foreman, Robert Long, was in constant contact with McMahon, PennDOT and Swarthmore Borough Police to implement new MPT staging geometry and make minor field adjustments, as necessary. Mr. Long is a friendly, personable man, which were essential characteristics for a head foreman working at a busy intersection with high pedestrian activity. Only one minor vehicle accident (fender bender) was reported, due to driver error (illegal turning movement), during the entire 10 month construction schedule.

PennDOT granted final approval and issued a Highway Occupancy Permit for the roundabout in August 2014. Roundabout construction began in September 2014, and the roundabout opened to traffic on July 11, 2015. The 10-month construction schedule included approximately 3 months of winter shutdown. Final landscaping has been installed at the intersection, and the Swarthmore Town Center West development was completed and opened in May 2016.


The Swarthmore Roundy (as the local citizens now call it), has been in use now for more than a year and the College, Borough and McMahon continue to solicit feedback on how it has worked for local traffic and pedestrians, including a post-construction survey.
The surveys and editorial contributions in the local newspaper, The Swarthmorean, have shown overwhelming support for the project, such as:
• “I like it and I’m glad it’s here!”
• “I think the roundabout is great and was a wonderful decision.”
• “Seems much safer that it was before”
• “I love the Swarthmore Roundy!”

In fact, all of the major participants including the College, Borough, Mayor, Fire and Police representatives, SEPTA and local citizens recently consented to being included in the video at the top of the page to celebrate the success of the project. Make sure you check it out!