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FHWA's Interim Approvals Status in California

Section 1A.10 of the MUTCD contains a provision authorizing the Federal Highway Administration (FHWA) to issue Interim Approvals (IAs). Such approvals allow the interim use, pending official rulemaking, of a new traffic control device, a revision to the application or manner of use of an existing traffic control device, or a provision not specifically described in the MUTCD. IAs are considered by FHWA based on the results of successful experimentation, studies, or research, and an intention to place the new or revised device into a future rulemaking process for MUTCD revisions.  More information regarding IAs that have been issued by FHWA with links to the actual approval document and background information for each is available at the following web link:

Any agency in California can request and receive approval to use a device under the IA process directly from FHWA. However, until California Department of Transportation (Caltrans) and the California Traffic Control Device Committee (CTCDC) have reviewed and recommended approval of a particular IA, its use by any agency in California can constitute a violation of the California Vehicle Code (CVC) 21400 and 21401.  Also, if the agency installs the device under FHWA’s approval and later upon review by Caltrans and the CTCDC the particular device is not recommended for use in California, the agency will have to remove the device or potentially be in conflict with CVC 21400 and 21401.

To alleviate these concerns, Caltrans and the CTCDC have agreed to review each IA issued by FHWA at their earliest convenience for its application in California.  If the IA is recommended for use in California, then Caltrans will request FHWA’s approval for its use on a blanket basis statewide, eliminating the need for individual agencies to seek FHWA approval.  If the IA is not recommended for use in California, then Caltrans will publicize the status of the particular IA on this web site. 

Following is the status of Interim Approvals issued by FHWA in California:

No. Description Date Issued
Date Adopted
in CA
IA-1 Optional use of retroreflective borders on traffic signal backplates 2/6/04 12/7/06
IA-2 Optional use of wayside horn system (WHS) at highway-rail grade crossings 8/2/04 12/7/06
IA-4R REVISED Interim Approval for Use of Automated Flagger Assistance Devices (AFADs)
in Temporary Traffic Control Zones
1/28/05 5/9/06
IA-5 Interim Approval for Use of Clearview Font for Positive Contrast Legends on Guide Signs 9/2/04 12/7/06
IA-8 Interim Approval for Optional Use of RV Friendly Symbol Sign 9/6/05 12/7/06
IA-9 Interim Approval to Display More than Six Specific Service Logo Panels for a Type of Service 9/21/06 Incorportated in the CA MUTCD 2012
IA-10 Interim Approval for Optional Use of Flashing Yellow Arrow for Permissive Left Turns 3/20/06 11/3/08
IA-11 Optional Use of Rectangular Rapid Flashing Beacons 7/16/08 8/10/11
IA-12 Interim Approval for Optional Use of Traffic Signal Photo Enforced Signs 11/12/10 Continue to use SR56(CA) sign spec
IA-13 Interim Approval for Optional Use of an Alternative Electric Vehicle Charging General Service Symbol Sign 4/1/11 8/10/11
IA-14 Interim Approval for Optional Use of Green Colored Pavement for Bike Lanes 4/15/11 8/12/11
IA-15 Interim Approval for the Optional Use of an Alternative Design for the U.S. Bicycle Route (M1-9) Sign 6/1/12 10/27/12
IA-16 Interim Approval for the Optional Use of Bicycle Signal Faces 12/24/13 11/27/15