The amount of yellow warning time at California intersections would drop along with speed limits under a bill being considered by the state legislature. The Senate Transportation Committee will hold a hearing Tuesday on Assembly Bill 529, a proposal that re-writes the state’s speed trap law so that cities would be able to round down all speed limits after conducting a traffic study. The measure passed the full Assembly by a 77 to 0 vote on May 19.
California has a strict rule prohibiting the use of radar guns on roads where the speed limit has not been established according to the 85th percentile speed of traffic. Engineering studies have shown that using this means of setting the limit at the prevailing speed of free-flowing traffic provides for maximum safety. Municipalities dislike this requirement because it limits their ability to set lower speed limits and rely instead on heavy police enforcement.
Under current law, jurisdictions must set the speed limit at 35 MPH if the study shows traffic is moving at, for example, 34 MPH. The limit must be rounded to the nearest 5 MPH increment. A locality can only reduce the limit to 30 MPH if it can document a specific safety hazard that is not readily apparent to drivers. The proposed legislation would allow municipalities to lower that speed limit to 30 MPH without any justification needed by rounding down 5 MPH. The rounding change will be made in California’s manual on uniform traffic control devices, which also establishes the minimum duration of yellow timing based upon the posted speed limit.
A city that lowers its 35 MPH speed limits to 30 MPH may also legally shorten its yellow times from 3.6 seconds to 3.2 seconds. While this 0.4 second difference may seem minor, it would generate a significant amount of additional revenue from red light camera tickets that run between $450 to $505 each. The Texas Transportation Institute concluded in 2004 that yellows shorter by a second than the ITE recommended amount generated a 110 percent jump in citations (view report). The vast majority of those extra violations happened within the first 0.25 seconds (see chart).
If passed by the committee Tuesday and adopted by the state Senate, the bill would go to Governor Jerry Brown (D) for his signature. A copy of the legislation is available in a PDF file at the source link below.