May 15, 2012
“SLOW THEN GO” TRAFFIC CONTROL DEVICE
By: Mark Randall, Research Fellow
You asked if any states have adopted new signage, such as a “slow then go” sign, to replace the stop sign.
No states have adopted “slow then go” traffic control devices. All traffic control devices must substantially conform to the national standards specified by the Federal Highway Administration (FHWA) in the Manual on Uniform Traffic Control Devices (MUTCD). States must conform at a minimum to the standard statements included in the national MUTCD. While states may be more restrictive in their traffic control devices than the national MUTCD, they cannot omit or change national MUTCD mandatory conditions. Presumably, “slow then go” signs would not meet these standards.
SLOW THEN GO
States have not adopted a “slow then go” sign to replace the stop sign because all states must substantially conform to the national standards specified in the FHWA's MUTCD. The MUTCD specifies the standards by which traffic signs, road surface markings, and signals are designed, installed, and used. These specifications include the shapes, colors, and fonts used in road markings and signs.
In the U.S., all traffic control devices must generally conform to these standards. The manual is used by state and local agencies as well as private construction firms to ensure that the traffic control devices they use conform to the national standards. While some state agencies have developed their own sets of standards, including their own MUTCDs, these must substantially conform to the federal MUTCD.
Federal regulations state that “substantial conformance” means that the state MUTCD or supplement must conform at a minimum to the standard statements included in the national MUTCD and that “the guidance statements contained in the national MUTCD shall also be in the State Manual or supplement unless the reason for not including it is satisfactorily explained based on engineering judgment, specific conflicting state law, or a documented engineering study” (23 C.F.R. § 655.603(b)).
State MUTCDs can be more restrictive in their traffic control devices than the national MUTCD. This means that a state can (1) make a national MUTCD mandatory instead of optional, (2) allow only one of several national MUTCD optional designs for a particular device, or (3) prohibit the use of a particular optional device. State MUTCDs cannot, however, omit or change national MUTCD mandatory conditions. The FHWA reviews each state MUTCD and makes determinations as to substantial conformance.
FHWA may grant exceptions in cases where a state MUTCD or supplement cannot conform to standards in the national MUTCD because of (1) requirements in a specific state law in effect before January 16, 2007 and (2) the nonconformance does not create a safety concern.
For more information, see the FHWA's frequently asked questions about the MUTCD: http://mutcd.fhwa.dot.gov/knowledge/faqs/faq_general.htm#q2