As part of the “Restoring the George” improvement program, the Palisades Interstate Parkway Helix – a key set of three bridges carrying approximately 7 million vehicles annually onto the George Washington Bridge – was targeted for a full replacement to preserve mobility, enhance safety and modernize infrastructure in one of the busiest corridors in the Northeast. STV was selected by the Port Authority of New York and New Jersey to prepare the final design for this $80 million highway/bridge replacement program.
What challenges did STV address?
The project posed significant logistical and structural challenges. With heavy vehicular volumes crossing the GWB and constrained site conditions in a dense urban setting, maintaining traffic operations on I-95, Route 9 and the existing Helix during construction was crucial. STV developed an innovative phasing and traffic control strategy, deploying a temporary ramp structure while the new Helix was being built. When unexpected underground utilities were discovered during construction, STV’s design team rapidly revised the ramp elements to minimize disruption.
What solutions did STV deliver?
STV provided comprehensive structural and civil engineering for the new Helix bridges and associated roadways, including foundations, drainage and stormwater systems, and demolition of the existing ramps. The team also delivered electrical and mechanical engineering for fire protection, standpipes and utility systems. Key design innovations included the temporary ramp strategy to maintain traffic flow and utility conflict resolution via re-profiling the ramp alignment with minimal impact to surrounding structures and traffic.
How does this project improve the community and region?
By replacing deteriorating bridges and ensuring uninterrupted access to the George Washington Bridge – the busiest bridge in the U.S. – the project enhances safety, reliability and regional mobility for motorists, freight carriers and commuters alike. The work supports economic vitality by safeguarding a significant transport link, reduces maintenance risks and improves resilience in a dense corridor.
Key stats and accolades
- Final design for three new Helix bridges plus all associated roadways, foundations, drainage, mechanical and electrical systems
- Maintained traffic operations across I-95, Route 9 and the George Washington Bridge corridor during construction
- Recognized with the Grand Honor Award in the Engineering Excellence Awards from the American Council of Engineering Companies New Jersey Chapter (ACEC NJ) – the event’s highest honor
