The Federal Highway Administration (FHWA) has approved a statewide blanket approval request by Caltrans regarding the use of Interim Approval (IA) 21– Rectangular Rapid-Flashing Beacons at Crosswalks. Caltrans and local agencies may now use Rectangular Rapid-Flashing Beacons per the conditions of the Interim Approval listed in IA-21.
Information on IA-21 can be found at www.dot.ca.gov/trafficops/camutcd/interim.html
FHWA has also posted a FAQ regarding IA-21 which can be accessed at https://mutcd.fhwa.dot.gov/resources/interim_approval/ia21/faq/index.htm