Master Plan of Arterial Highways (MPAH)Overview
The MPAH was initially established in 1956 and is continuously updated to reflect changing development and traffic patterns. OCTA is responsible for administering the MPAH, including the review and approval of amendments requested by local agencies. The MPAH map documents and displays the current Plan in a visual format.
MPAH Zoomable Map:
Download Hi-Res Version (32MB).