Vasco Road

As originally constructed, Vasco Road was unprepared to meet the demands of high-volume traffic. Blind curves, narrow lanes, steep hills and inadequate shoulders all contributed to the increasing number of accidents. Some of these issues remained even after the relocation and reconstruction of much of the road. Many of these accidents were fatal, head-on collisions. A 2004 engineering study reported that there had been 254 collisions between June 1996 through August 2003.[6]

The engineering firm that performed the safety report considered the feasibility of installing a concrete barrier down the center median. This proposal was rejected because of the high cost, as well as objections by some county agencies about lack of adequate access to emergencies. As an alternative, the engineers recommended that Contra Costa County install "rumble strips" from Walnut Boulevard to the Alameda county line. These are roughened strips of asphalt placed down the center line and the sides of each lane, intended to alert drivers when they stray off the road or into the oncoming traffic lane. This alternative was implemented by the county, along with adding "Do Not Pass" and "Passing Lane Ahead" signs at appropriate places.[6]

In August 2006, former Governor Arnold Schwarzenegger signed SB 3 into law, establishing a "double fine" section on Vasco Road from Walnut Boulevard in Brentwood to Interstate 580 in Livermore. The law doubled the fines for "unlawful passing and overtaking, excessive speed, reckless driving, drunken driving and other serious moving violations" until Jan. 1, 2010.[7] However, road signs declaring the double fine zone were still up as of June 2016.

Contra Costa County began a project in 2010 to install a median barrier along a one-mile stretch of the road. This also required widening the roadway and a bridge, building retaining walls, and extending a passing lane.[8]