Mr. Art Maison
2100 N. West By-Pass
Springfield, MO 66803
Dear Mr. Maison:
This replies to your letter of August 30, 1996, to Taylor Vinson of this Office, asking for an interpretation of the conspicuity requirements of Motor Vehicle Safety Standard No. 108.
You write that "the by-laws read that DOT-C is for the vehicles and trailers under 25,999 pounds require for that class. We would like to use these reflectors also for the DOT- C2, for the use on vehicles and trailers over 26,000 pounds."
We do not know the "by-law" to which you refer. Paragraph S5.7 of Standard No. 108 applies to all trailers of 80 or more inches overall width, and with a GVWR over 10,000 pounds. It does not distinguish between those over and under 26,000 pounds. Therefore, a trailer with a GVWR of 26,000 pounds must meet the same requirements of paragraph S5.7 as a trailer with a GVWR of 10,001 pounds.
We understand that you have discussed your problem with Pat Boyd, one of this agency's rulemaking engineers, and that your questions are: "What is the difference between DOT-C and DOT C-2" and "Does a reflex reflector have to be 2 inches wide, like reflective tape?"
Paragraph S5.7 permits a manufacturer to choose either reflex reflectors or reflective tape as the way to conform to the conspicuity requirements of Standard No. 108. "DOT-C" is the marking required for reflex reflectors, and is the reflector manufacturer's certification that the reflectors meet Standard No. 108 (Paragraph S184.108.40.206). "DOT- C2" is the marking required for reflective tape which has a width of not less than 50 mm (2 inches) and is the reflective tape manufacturer's certification that the tape meets Standard No. 108 (Paragraphs S220.127.116.11(d) and S18.104.22.168). Standard No. 108 does not require that reflex reflectors have a minimum width. Reflex reflectors are rated by the total light return per reflector, but reflective tape is rated by the light return per unit area. Standard No. 108 requires that one reflex reflector, meeting the DOT-C specification, have the same total light return as 100 mm of reflective tape meeting the DOT-C2 specification. We have seen reflex reflector bars 300 mm long certified to meet the DOT-C specification for each 100 mm segment. Standard No. 108 permits the use of these products even though they are only about 1 inch wide because they provide the same photometric performance as 300 mm of DOT -C2 reflective tape. I enclose a copy of the recent final rule which extended these requirements to truck tractors, and have circled language on p. 41357 which mentions this point.
I hope that this is responsive to your request. If you have any further questions, you may call Taylor Vinson at 202-366-5263.
Acting Chief Counsel