Assembly Bill (AB) 43, signed into law in 2021 and effective in 2024, allows local jurisdictions more flexibility in setting local speed limits. Traditionally, speed limits are set through engineering and traffic surveys (E&TS) based on the 85th percentile speed. AB 43 allows for local municipalities to reduce speed limits in eligible school zones, areas that generate high concentrations of bicyclists or pedestrians, business corridors, and designated safety corridors.
Marin County has received funding for design and construction of reduced speed school zones and is currently in the process of identifying safety corridors throughout our unincorporated roadways. Marin County will begin implementing AB 43 speed limit reductions in 2026.