Harry W. Hanson, Esq.
Waller, Leonard, Chambers, and Hanson
Suite 206 Peoples National Bank Building
P.O. Box 469
Washington, Indiana 47501-0469

Dear Mr. Hanson:

This responds to your letter on behalf of Cornelius Manufacturing, Inc., a company that produces a flatbed trailer that can be converted to a dovetail configuration. We apologize for the delay in responding. You wrote asking whether this particular trailer design was excluded from the National Highway Traffic Safety Administration's (NHTSA's) rear impact protection (underride guard) regulations. As explained below, these vehicles are not excluded.

Federal Motor Vehicle Safety Standard No. 224, Rear impact protection, requires most trailers and semitrailers weighing over 10,000 pounds to be fitted at the rear with an underride guard. These regulations were issued to prevent the many fatalities that have resulted from crashes in which a passenger vehicle striking the rear end of a trailer or semitrailer penetrates so far underneath that the rear end of the heavy vehicle enters the passenger compartment.

Certain trailers are excluded from these requirements. You appear to be asking whether your vehicle is an excluded "low chassis vehicle." This is defined in section S4 of Standard No. 224 as a vehicle "having a chassis that extends behind the rearmost point of the rearmost tires and a lower rear surface that meets the configuration requirements of S5.1.1 through S5.1.3 of this section." S5.1.2 contains a requirement that the bottom edge must be no more than 560 mm (about 22 inches) from the ground.

The flatbed vehicle that Cornelius Manufacturing produces has a variable ground clearance. You note in the product literature that the lower rear surface of the vehicle is 16.5 inches when the dovetail is in the down position, and 28.75 inches when the vehicle is configured as a flatbed. The product literature refers to this vehicle as a "flatbed with the adjustable dovetail (optional)." We understand from this, from the illustrations showing it being used in the flatbed configuration, and from your statement that it is "quite possible that . . . it might never be in compliance," that it can be operated on the road in its flatbed configuration. In the flatbed configuration, the 28.75 inch bed height is over six inches too high to be considered low chassis, and would not provide adequate rear impact protection. In this configuration, these vehicles do not meet the definition of a low chassis vehicle, nor do they meet the definition of any other excluded category.

A vehicle would have to meet the definition of the excluded category in every position in which it can be operated on the road in order to be excluded. Since in the flatbed mode the vehicle would not meet the definition of any excluded vehicle type, and is capable of transport in that mode, it would not qualify for any exclusion. The vehicle would have to be equipped with an underride guard meeting the requirements of 49 CFR 571.223 in order to be certified.

Section S6.2(a) of Standard No. 223 allows the manufacturer to designate whether the agency should test for compliance on a rigid test fixture or on a trailer. On a rigid test fixture, the question of bed height is not an issue. However, if testing on the trailer there is a question of in which configurations, in the range of flatbed to dovetail, NHTSA will test the guard. Standard No. 223 does not specify in which configuration (flatbed, dovetail, or in between) the agency should test for compliance if there is a choice. When a standard does not specify a particular test condition, we begin with a presumption that the requirements must be met in every test condition in which the vehicle can be operated. See, for example, NHTSA's October 2, 1990 letter to Mr. S. Kadoya of Mazda. It is not practical to specify every possible test condition in Standard No. 223 because of the wide variety of trailer configurations. Changeable configurations like Cornelius Manufacturing's trailers are a good illustration of the difficulty.

Starting from this presumption, we look to the language of the standard and its purposes for guidance to decide whether some limitation on the test condition should be implied. The language excluding low chassis trailers from the standard's requirements is one indication that the trailer should not be subject to the requirements in the dovetail configuration. No language would imply a limitation as to configurations that would not qualify for an exclusion. As to the purposes, with the trailer configured in the flatbed mode with its rear end at a height above 560 mm, a colliding vehicle would likely underride the trailer. This safety concern is one that the agency considered extensively in the January 24, 1996 final rule (see 61 FR 2016-18), and it is this kind of situation the regulation was intended to prevent. However, in the dovetail configuration and at rear bed heights of 22 inches or less the vehicle would be excluded if it were fixed in that position, and the bed of the vehicle would probably prevent a colliding vehicle from underriding it.

In this case, we find an implied limitation on the test condition based on the standard's language and purposes. Therefore, NHTSA could test a vehicle with an adjustable rear end for compliance with the rule in all non-excluded configurations in which it can be operated on the highway. In the case of the Cornelius Manufacturing flatbed, this means NHTSA could test whenever the rear bed is positioned between a height between 22 inches and the flatbed height of 28.75 inches. At lower heights the guard would not have to be present for the vehicle to comply.

We cannot provide a specific opinions on how your trailer might be redesigned to accommodate a guard. We note, however, that manufacturers of tilt bed trailers have told us that they have found engineering solutions that would meet the requirements of the standard without compromising the function of their vehicles. Some of them are using guard designs that deploy when in the flatbed configuration and automatically retract when in the tilted configuration. Perhaps some of these solutions may also work for you. However, we emphasize that NHTSA is not responsible for vehicle design.

The agency would consider a petition for temporary exemption from Standard No. 224. Under one of our regulations (49 CFR Part 555), vehicle manufacturers may apply for a temporary exemption from the Federal motor vehicle safety standards. Under Sec. 555.6(a), a manufacturer whose yearly production is not more than 10,000 units may ask for an exemption of up to three years on the basis that compliance would cause it substantial economic hardship and that it has attempted in good faith to comply with the standard from which it has asked to be excused. We have enclosed a copy of Part 555 for your information. We have also enclosed a copy of our regulations relating to the protection of confidential business information. Most of the trailer manufacturers submitting petitions for temporary exemption have requested that their financial information remain confidential.

Please note Part 555 requires the agency to publish a notice in the Federal Register seeking public comment on each exemption petition before a decision can be made on such a request, and then publish a second notice either granting or denying the petition. This process normally takes three to four months from the date of submittal. NHTSA would try to handle a request from Cornelius Manufacturing expeditiously.

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.

John Womack
Acting Chief Counsel
Enclosures: 49 CFR Part 512

cc: Congressman John N. Hostettler
Senator Richard G. Lugar