Gowanus Expressway Final Design Phases V and VI Traffic and Environmental Assessment Services

SIMCO provided detailed traffic engineering and environmental assessment services in connection with the Gowanus Expressway Viaduct Rehabilitation Project.

• Comprehensive traffic analyses were performed to evaluate the potential traffic impacts of travel lane closures on the mainline and the resulting traffic diversions during the emergency median repair and deck replacement contracts following SEQR standards. In addition, the traffic impacts of vehicle diversion onto local streets were assessed for the various entrance and exit ramp closures required during the interim repair contracts following CEQR standards. A user cost analysis was also performed to quantify the incentive-disincentive clause to be included in the $700 million construction contracts.
• SIMCO also participated in the completion of environmental assessment for the proposed Park-Ride facilities at two candidate sites (i.e., Arthur Kill and South Shore, in Staten Island). Technical work tasks included traffic impact studies, ecology review, wetlands delineation and accident analysis. Potential wetland impacts at the sites were identified in compliance with US Army Corps of Engineers (USACOE) and NYS Department of Environmental Conservation (NYSDEC) criteria. Results of the technical analyses were incorporated into the NYSDOT Design Report.

The potential carpool and express bus users at these sites were expected to reduce vehicle travel demand on the Gowanus Expressway Corridor. The CORSIM traffic simulation model was used to quantify the operational merits of the newly signalized intersection and its impacts on existing bus movements from the Arthur Kill Bus Depot.

Additionally, as part of interagency coordination between NYSDOT and NYCT, SIMCO also completed a detailed traffic assessment of the Arthur Kill Bus Depot to determine the feasibility for installing two new traffic control signals at the intersections of Richmond Avenue at Wainwright Avenue and the proposed Bus Depot Exit Driveway at the Korean War Veterans Memorial Parkway.

All work was done in accordance with CEQR and SEQR standards.  SIMCO also performed extensive mainline traffic flow simulations using CORSIM, VISSIM and SYNCHRO models to evaluate the multi-stage construction sequence schemes implemented to maintain acceptable traffic service levels during the weekday and weekend construction periods.