6(09)-6 (E) – Late Merge Symbols for PCMSs — RI DOT

FHWA's Response Letter Conditionally Approving the Request to Experiment

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MUTCD Team Contacts

U.S. Department of Transportation
Federal Highway Administration

1200 New Jersey Avenue, SE.
Washington, D.C. 20590

November 17, 2010

In Reply Refer To: HOTO-1

Mr. Michael P. Lewis
Director
Rhode Island DOT
Two Capitol Hill
Providence, RI 02903-1124

Dear Mr. Lewis:

Thank you for your of March 12 letter transmitting a request to experiment (RTE) with the use of symbolic messages, rather than standard word legend messages, when using portable changeable message signs (PCMSs) to inform road users about temporary lane closures in temporary traffic control (TTC) zones in the State of Rhode Island.

We have had numerous discussions with your staff about the design of your experiment and the proposed methods for evaluating the effectiveness of the symbolic messages on the PCMSs. We appreciate your staff's efforts in developing the experimental work plan and the evaluation criteria. We understand that the University of Rhode Island will conduct the evaluation for your agency.

We received an e-mail message dated September 16 from Ms. Jill Silva of your staff, which included hand-drawn sketches of the set-up for PCMSs that display word legends and for PCMSs that display symbols.

We reviewed your March 12 request and the supplemental materials transmitted via e-mail on September 16. Your request to experiment is approved subject to the DOT's agreement to comply with the following two conditions:

In order to make a direct comparison of the relative effectiveness of the two types of PCMS messages, the same number of PCMSs and message phases should be used for each set-up. Therefore, in the word legend set-up at the PCMS location that is approximately 2,000 feet upstream from the arrow board, a two-phase message needs to be shown. We suggest that the two alternating phases say "MERGE AHEAD" and "USE BOTH LANES." Also, in the word legend set-up, the PCMS located on the right-hand shoulder approximately 500 feet upstream from the arrow board needs to be replaced by a static W4-2 sign, which would match the signing on the symbol set-up.
In the word legend set-up, the digital board located on the left-hand shoulder approximately 500 feet upstream from the arrow board should display a two-phase message ("MERGE HERE" and "TAKE YOUR TURN").

Please indicate your agreement with the above stated conditions via an e-mail to Mr. Ken Wood of this office at ken.wood@dot.gov.

We look forward to receiving your semiannual progress reports and your final evaluation report at the end of the study period.

For recordkeeping purposes, we have assigned the following official experiment number and title: "6(09)-6 (E) – Late Merge Symbols for PCMSs — RI DOT." Please refer to this number in any future correspondence regarding this experiment.

Thank you for your interest in improving the capacity and safety of merging maneuvers in temporary lane closures in TTC zones. Please contact Mr. Ken Wood at ken.wood@dot.gov if you have any further questions concerning this matter.

Sincerely yours,

Original signed by:

Mark R. Kehrli
Director, Office of Transportation Operations