A new state audit of how Caltrans has handled the replacement of portions of the San Francisco-Oakland Bay Bridge points the finger of blame squarely back at the state agency itself.

State Auditor Elaine Howle concludes that total cost estimates on all seismic retrofit bridge projects (statewide) have increased $3.2 billion since April 2001.

A full $930 million of that cost overrun is due to efforts for the so-called “signature design” of the Bay Bridge’s eastern span.

You’ll remember that last week, the Schwarzenegger administration moved to scrap that design, and replace it with a simple– and some would say less visually exciting– design, which they say will lessen the cost of the project.

You can read the auditor’s new report for yourself on her website, and my colleague at KQED, Erika Kelly, will be reporting on this later today and tomorrow morning on The California Report.

Some highlights of the new audit:

* Caltrans did not have a risk management plan for the Bay Bridge project, and had no way to adequately track problems when they arose

* Caltrans failed to keep both the Legislature and federal highway officials apprised of the financial problems with the Bay Bridge project, even when the auditor says they “should have known that the program was over budget.”