Imperial Highway over North Fork Coyote Creek Bridge Barrier Replacement Project

The Imperial Highway over North Fork Coyote Creek Bridge is a two-span steel girder bridge constructed in 1960. It measures 129 feet in length, 91 feet in width, and carries three lanes of traffic in each direction with a raised median. The bridge is jurisdictionally shared between Los Angeles County and the City of Santa Fe Springs. This project, which represents a collaborative effort between two agencies, included safety enhancements, pedestrian access improvements, and sustainable design features. Vehicular Safety Enhancements Imperial Highway has a posted speed limit of 45 miles per hour and an average daily traffic (ADT) of 48,000 vehicles at the bridge. The bridge was built in 1960 to the standards of that time, however, the metal hand railing along the edges of the bridge were not adequate to resist the current AASHTO recommended vehicular impact loading. As part of the project development process, a review of the reported traffic collisions that took place near the bridge within the previous 5 years was conducted. A total of seven collisions were identified within 500 feet of the bridge. One resulted in a fatality and the remaining six resulted in property damage. Although no collisions had been documented on the bridge, the close proximity of numerous collisions coupled with barrier railing that did not meet the current standards, posed a safety risk that needed to be addressed. To mitigate the safety risk, the metal hand railings on the bridge were replaced with Caltrans Type 26-modified concrete barrier railing, meeting AASHTO standards. Pedestrian Access Improvements Prior to the project, no sidewalk existed along the north side of the bridge. As a result, pedestrians traveling on that side of the roadway were forced to either cross Imperial Highway to access the sidewalk on the south side of the bridge or to unsafely step down onto the roadway to cross the bridge. The installation of new barrier railing on the bridge presented an opportunity for Public Works to improve the pedestrian access at this location. After performing a structural evaluation it was decided to widen the bridge to accommodate a new sidewalk on the north side of the bridge. This involved the construction of a new concrete edge beam and steel framing system to support the new sidewalk and barrier railing. Additionally, a 4-foot tall steel picket railing was installed on top of the barrier rails to provide safety benefits for pedestrians and bicyclists and an Americans with Disabilities Act (ADA) compliant curb ramp was constructed on the south side of the bridge at the intersection of Marquardt Avenue and Imperial Highway. Sustainable (Energy-Efficient) Design Features Due to the proposed addition of sidewalk, an existing Caltrans Type 17 traffic signal supported along the north edge of the bridge needed to be relocated. A concrete pilaster was constructed on top of the existing bridge pier wall to provide support for a new Caltrans Type 28 traffic signal. The latest technology for lighting was included in the project with the incorporation of energy efficient LED lights for the traffic signals. This project has improved the quality of the local roadway system within Los Angeles County. It has enhanced safety and increased mobility for pedestrians.