Advance Planning Studies


An Advance Planning Study (APS) is a required component in a Project Study Report (PSR) which documents the scope and cost of structure work in a project. An APS shows basic structure layout details and a cost estimate for each structure in a project. APSs must be made for all structure work, which includes bridges, culverts, tunnels, retaining walls, pumping plants, structure modifications, and any non-standard or special design structures.


Four APSs were prepared for the Railroad Canyon Road Interchange Improvement project. They are listed as follows:

    1. Railroad CFI APS

    Continuous Flow Interchange (CFI) APS for new retaining walls with tiebacks along Railroad

    2. Railroad DDI APS

    Diverging Diamond Interchange (DDI) for retaining walls along Railroad

    3. Railroad SPUI APS

    Single Point Urban Interchange (SPUI) for new bridges over Railroad

    4. San Jacinto SPUI APS

    Single Point Urban Interchange (SPUI) for new ramp bridges over the San Jacinto River