When the New Jersey Department of Transportation (NJDOT) tasked Dewberry with eliminating the Route 30/130 Collingswood Circle in the boroughs of Collingswood and Woodlynne, the state's objective was clear: remove a circa-1920s traffic circle along one of New Jersey's oldest transportation corridors and improve safety and traffic operations.
Once an innovative approach to intersection design, the circle had become obsolete as development and associated traffic volume had increased through the decades. Yet the problems with the intersection were much more complex than simply the constant vehicle congestion. The corridor also experienced chronic flooding, causing even more traffic problems and plaguing the surrounding commercial and residential neighborhoods.
In addition, NJDOT sought assistance with a comprehensive approach to environmental remediation in the area. The agency had identified ten properties within the corridor as environmentally sensitive Areas of Concern (AOCs), with soil or groundwater contamination from past or current land use, such as petroleum service stations. The corridor also contained concentrations of naturally occurring arsenic at levels that exceeded the New Jersey Department of Environmental Protection's Soil Cleanup Criteria.
From Eyesore to Gateway
With a multidiscipline team at work to address the many challenges presented with this circle elimination project, we were able to resolve problems that had frustrated local residents for years. A new traffic signal and efficient ramp network now serve the very tight corridor. Detention basins, four 60-inch pipes constructed atop a crushed stone bedding layer, and other special drainage features have eliminated the flooding issues.
A new pedestrian bridge with an attractive brick veneer is a highlight of the improvements, creating a pedestrian and bike-friendly crossing. Other context-sensitive design features include stamped concrete sidewalks and ornamental lighting. Once viewed as an eyesore, the improved area now serves as a gateway to Collingswood.
The Unseen Benefit
Though less visible within the finished upgrades, the environmental remediation work is clearly an exceptional part of this successful project. Remedial measures included the proper closure and removal of 19 underground storage tanks, the excavation and off-site disposal of nearly 161,000 tons of contaminated soil, installation of a soil-bentonite slurry wall to inhibit the migration of Light Non-Aqueous Phase Liquids from a nearby source area, and installation of cement groundwater baffles within and adjacent to parcels with identified groundwater contamination.
Our team is now involved in the construction of the next phase of transportation improvements along this corridor, which will benefit another stretch of Route 30/130 in Collingswood and Pennsauken. We look forward to exploring more opportunities to work with NJDOT to resolve as many challenges as possible and improve the quality of life for New Jersey residents in the area.