Mr. James O. Webb
Chief Engineer
Converto Mfg. Co., Inc.
P.O. Box 287
Cambridge City, Indiana 47327

Dear Mr. Webb:

This responds to your letter pointing out some difficulties you anticipate in complying with the National Highway Traffic Safety Administration=s (NHTSA) recent rear impact protection (underride guard) regulations. Your company manufactures Aroll off@ hoist equipment, both trailer and truck mounted, that is used to pick up, put down, and dump the long rectangular dumpsters often used to collect trash and construction debris. The short answer to your question is that your straight-body vehicles are excluded from the requirements, while the trailers are not.

Your equipment basically consists of frame rails that lay on the back of the truck or trailer and are hinged at the rear of the trailer. To load a dumpster, the front end of the frame rails are raised by hydraulic pistons to a 45 to 50 degree angle, until the rear end of the rails touches the ground behind the vehicle. Once at this angle, a hoist cable pulls the dumpster up the rails onto the back of the vehicle, after which the pistons are collapsed to return the dumpster to a horizontal orientation. The opposite sequence is used to lower the dumpster. Based on the product literature you enclosed, it appears that your factory mounts this equipment on new truck and trailer chassis prior to first sale. You state that it would be impractical, if not impossible, to mount underride guards on these vehicles, presumably because the guard would be mounted on the rails and would prevent them from being fully raised.

Federal Motor Vehicle Safety Standard (FMVSS) No. 224, Rear impact protection, requires most trailers and semitrailers weighing over 10,000 pounds to be fitted at the rear with a rear impact (underride) guard meeting the requirements of FMVSS No. 223, Rear impact guards (49 CFR 571.223 and 571.224, published on January 24, 1996 at 61 FR 2004). Two excluded categories of vehicles that are relevant for the purposes of this letter are single unit trucks and special purpose vehicles.

With regard to the Outside Rail Roll-off Tilt Frame Hoist installed on a truck, the vehicle is excluded. Note that the regulation applies only to trailers and semitrailers. Because these vehicles are single unit (i.e., unarticulated) trucks, FMVSS No. 224 does not apply to them.

A special purpose vehicle is defined in S4 of FMVSS No. 224 as being Aa trailer or semitrailer having work- performing equipment . . . that, while the vehicle is in transit, resides in or moves through the area that could be occupied by the horizontal member of the rear underride guard . . . (emphasis added).@ Your Semi- trailer Roll-off Tilt Frame Hoist is not excluded, because it does not meet the definition of a special purpose vehicle. Although NHTSA considers the rails to be work performing equipment that, as the frame is tilted, passes through the area where the horizontal member of the underride guard would be located, they do not do so while the vehicle is in transit.

NHTSA addressed the issue of roll off hoist trailers in the final rule. The National Solid Wastes Management Association (NSWMA), a trade group that we believe represents many of your customers, requested special consideration for roll-off hoist vehicles. However, NSWMA=s main objection was requiring guards on the containers themselves, which is not your concern. NSWMA stated in their comment that:

[t]he most common type of roll-off tilt frame used is the >outside rail= design . . . In these cases the rear underride [guard] required by [23 CFR] 393.86 will contact the ground at a frame tilt angle of approximate [sic] 40 degrees. Since this causes instability if the ground is uneven, a number of manufacturers have resorted to a retractable underride [guard] design, where a strut attached to the rear chassis frame will cause the underride [guard] to move forward and out of the interference area as the frame is tilted.

NHTSA assumed by this comment that a design solution had been found to address the problem of the guard hitting the ground. Therefore, NHTSA believed it was only necessary to respond to NSWMA that guards were not required on the container, only the trailer that carries it. We suggest that you contact NSWMA to explore the possibility of using the retractable guard design that it discussed.

If you believe your trailers should be excluded from Standard No. 224, you may submit a petition for rulemaking (see 49 CFR Part 552, which I have enclosed for your convenience) requesting that NHTSA amend the standard. If you have any further questions, please feel free to contact Paul Atelsek of my staff at this address or by telephone at (202) 366-2992.


Samuel J. Dubbin Chief Counsel

1 Enclosure: Part 552 ref:224 d:5/16/96