The Highway Safety, Traffic Reduction, Air Quality, and Port Security Bond Act of 2006, approved by the voters as Proposition 1B on November 7, 2006, included an authorization of $1 billion to be available to the Department of Transportation, upon appropriation in the annual Budget Bill by the Legislature, for safety, operational enhancements, rehabilitation, or capacity improvements necessary to improve the State Route 99 Corridor in the San Joaquin and Sacramento Valleys.