Surveying & Mapping

Emergency Surveys on Interstate 880 | Oakland, CA

Caltrans District 4


Geodetic Control
Terrestrial Control
Mobile Terrestrial Laser Scanning (MTLS)
Topographic Surveys
Point Cloud Processing
Feature Extraction

Failing Pavement on Busy San Francisco Bay Area Freeway

Failing pavement and ingress/egress issues along one of the busiest freeways in the San Francisco Bay area necessitated emergency repairs. Caltrans District 4 retained Psomas, who has the resources including the laser scanning equipment, to complete the design surveys for this quick-turnaround project.

The scope of the project involved I-880 from Oak Street south to High Street including all overcrossings, on-off ramps, acceleration/deceleration lanes and the Embarcadero East side street.

The Psomas team established new GPS geodetic control along the corridor to be used for the real-time operation of our GPS base stations during the mobile terrestrial laser scanning (MTLS) data acquisition. Since this corridor is one of the busiest in the Bay Area, the MTLS was performed from midnight to 5 am with the combined safety of a highway patrol vehicle to reduce risk to the traveling public. The point cloud processing and data extraction was completed, the fill-in topographic data was inserted and a DTM was created, from which cross sections were developed. The files were successfully delivered on schedule in CAiCE format.