The Interstate 78 Toll Bridge carries Interstate 78 between Williams Township, Pennsylvania, and Phillipsburg, New Jersey over the Delaware River. Opened on November 21, 1989, it is operated by the Delaware River Joint Toll Bridge Commission and is one of the newest bridges across the Delaware River. The span has an overall length of 1,222 feet (372 m) and is a twin four girder span. There is only one toll plaza for the bridge; this is for traffic heading west into Pennsylvania. It has four conventional lanes and two Express E-Z Pass lanes. Just after the toll plaza is the Pennsylvania Welcome Center.
The Robinson team provided Low-altitude Mapping Photography (LAMP) services and Photogrammetric Base Mapping at a scale of 1”=30’ with one-foot contour interval. Photogrammetric Mapping from LAMP was utilized in order to reduce the overall cost of the base mapping effort.
LAMP is a helicopter based camera system. It utilizes a Wild RC-30 precision aerial mapping camera with Forward Motion Compensation (FMC) and stabilized in the three axes using a gyroscopic mount. The combination of the slower forward speed of the helicopter and the use of FMC allows for unparalleled clarity in the photographic image. The improved image clarity allows for ground control points to be observed much more closely than with conventionally flown photography. This allows the control network to be held to a much greater accuracy. The use of LAMP allows areas that are prone to dense traffic to be accurately mapped with minimal impact on traffic flow and more safely by reducing field personnel’s exposure to hazardous situations. RAS utilized LAMP at a nominal scale of 1”= 100’. The photography was taken at an altitude of 600 feet above the mean terrain. This allows for survey grade accuracies to be achieved through photogrammetric mapping.