Interpretation ID: 17056niv.df
Patrick M. Raher, Esq.
Hogan & Hartson
555 Thirteenth St., N.W.
Washington, DC 20004-1109
Dear Mr. Raher:
This responds to your letter on behalf of your client, Sachs Automotive of America (Sachs), concerning how NHTSA would test vehicles equipped with Sachs's "Nivomat" vehicle leveling system to Federal Motor Vehicle Safety Standard No. 214, "Side Impact Protection." I apologize for the delay in responding.
You explain that Sachs's Nivomat leveling system is-
a compact, fully enclosed suspension unit that takes the place of a conventional shock absorber and assures a level ride to manufacturer specifications, even when the vehicle is fully loaded. . . . [T]he Nivomat senses the vehicle's load condition and levels the vehicle to the manufacturer's specification shortly after the vehicle is loaded and driven for a short distance (at most, 3 miles). . . .
The Nivomat is activated by relative motion between the vehicle's body and axle. Thus, as you state, the vehicle has to be driven (or otherwise bounced to achieve the relative motion between body and axle) to activate the Nivomat, to level the vehicle and to maintain the level height. The Nivomat is designed to maintain the manufacturer's ride height specification for the duration of the trip. When the vehicle is stationary for 4 hours, it will begin to lose its leveled condition. The Nivomat would be activated again when the vehicle is driven for a distance not exceeding 3 miles.
With regard to Standard 214 compliance testing, you believe that NHTSA should test vehicles equipped with Nivomat at "optimal vehicle attitude," i.e., with the Nivomat activated. You state that while testing at optimal vehicle attitude may not be required by the standard, you believe that NHTSA should test at this attitude because that "would ensure that the test vehicle is most reflective of real world situations in conformance with established NHTSA policy."
In asking about Standard 214, you note that NHTSA has previously issued an interpretation which you believe supports your position that vehicles should be tested at the optimal vehicle attitude. In an October 2, 1990, letter to Mr. Kadoya of Mazda, NHTSA discussed the issue of how compliance is determined in situations where a standard does not specify a particular test condition. The letter addressed Mazda's questions about how NHTSA would test vehicles equipped with an active suspension system that adjusts vehicles to variable heights.(1) At issue were standards that do not specify a suspension height that is to be used during compliance tests. NHTSA stated on page two of the letter:
In cases where a standard does not specify a particular test condition, we believe there are several relevant factors to consider in interpreting the standard. First, in the absence of a specification of a particular test condition, we believe there is a presumption that the requirements need to be met regardless of such test condition, since the standard does not include any language which specifically limits applicability of its requirements to such test condition. For example, where a standard does not specify suspension height, its requirements may need to be met at all heights to which the suspension can be adjusted. Before reaching such a conclusion, however, we also consider the language of the standard as a whole and its purposes. Even if a standard is silent as to a particular test condition, the language of the standard or its purposes may indicate limitations on such test condition. Finally, in situations where a limitation on a particular test condition may appear to be appropriate, we also must consider whether the limitation is sufficiently clear, both with respect to justification and specificity, to be appropriate for interpretation. For example, in a situation where it may appear to be reasonable to limit a particular test condition but it is not obvious what particular limitation should be adopted, it would be inappropriate to select a particular limitation by interpretation. Instead, such a decision should be reached in rulemaking.
You believe that the purpose of Standard 214 is to protect occupants during side impact collisions, which occur during operation of the vehicle. You also believe that during vehicle operation, the Nivomat system levels the vehicle to the manufacturer's specified optimal operational height. You therefore conclude that vehicle equipped with the Nivomat should be tested with the Nivomat activated to reflect real world situations. You ask (1) whether NHTSA agrees with this position, and (2) for the purposes of compliance testing to the requirements of Standard 214, whether your suggested means of maintaining the optimal vehicle attitude would be satisfactory to NHTSA.
Standard 214 specifies requirements for protection of occupants in side impact crashes. The standard requires each vehicle to protect its occupants in a full scale dynamic crash test. Even though the test vehicle is at rest, the test procedure simulates a crash of a vehicle which is traveling at 30 miles per hour (mph) into the side of the test vehicle traveling at 15 mph. There also is a static test that requires doors to resist a piston pressing a rigid steel cylinder inward against the door. While the standard specifies a number of test conditions for these tests, it does not specify vehicle operational height.(2)
The Mazda letter addressed frontal, side and other impacts, to the extent these are incorporated into Standards 204, 208, 212, 219 and 301. NHTSA concluded that the frontal test requirements of these standards need to be met only at the suspension heights that can occur at the speed used in the crash test (generally speeds up to 30 mph), even though the requirements have relevance at higher and lower speeds. The letter also determined that Standard 208's lateral moving barrier crash test requirements must be met at all suspension heights that can occur with the vehicle operational, i.e., at all vehicle heights that can occur during vehicle operation, regardless of speed. This is because Standard 208 specifies that the lateral moving barrier test is conducted with the vehicle at rest. Thus, the standard's evaluation of this aspect of safety performance is not limited to how vehicles perform at certain limited speeds (e.g., speeds up to 30 mph). For basically the same reason, NHTSA also concluded that Standard 301's side and rear moving barrier crash tests would have to be met at all suspension heights that can occur with the vehicle operational.
With respect to your inquiry and Standard 214, applying the language of the standard and the principles and conclusions of the Mazda letter leads us to conclude that crash testing of vehicles equipped with the Nivomat would be performed with the vehicle at all suspension heights that can occur with the vehicle traveling at a 15 mph vehicle speed. In issuing the dynamic side impact requirements of Standard 214, the agency decided to limit the standard's evaluation of occupant crash protection in side impacts to how vehicles perform in impacts between a vehicle traveling 15 mph (the test vehicle) and a striking vehicle traveling 30 mph. A vehicle equipped with the Nivomat could attain a speed of 15 mph before traveling the distance that is needed to activate the Nivomat, and could become involved in a side impact crash before activation of the Nivomat. Thus, while we agree that a vehicle could be tested to Standard 214 with the Nivomat activated, we also conclude that NHTSA should not exclude testing of the vehicle without activating the Nivomat. Testing a vehicle both prior to and after activation best ensures that the vehicle would provide the requisite level of safety protection at all ride heights that can occur with the vehicle operational.(3) Thus, manufacturers must assure that the vehicle complies with the standard under both conditions; i.e., when the Nivomat is activated and when it is not.
Your second question relates to testing a vehicle with the Nivomat system in the activated mode.(4) You suggest a means that NHTSA could take "to ensure that the Nivomat system's leveling action is taken into account during compliance testing."
You state on pp. 2-3 of your letter:
Specifically, the test facility would measure the test vehicle's attitude as follows. Pursuant to FMVSS 214, S6.2, the test facility would measure the test vehicle's attitude in the "as delivered" condition precisely as set forth in the standard. When measuring the test vehicle in the "fully loaded" condition, the test facility would add the appropriate ballast, and then bounce the vehicle up and down on both the front and back ends of the vehicle for several minutes. This bouncing will simulate the action of driving the vehicle on the road and activate the Nivomat system. Once bouncing is completed on both sides, the test facility would immediately measure the test vehicle's attitude. Once these test vehicle attitude parameters are obtained, the test facility may make appropriate adjustments prior to conducting the actual test.
For the dynamic test, FMVSS 214 requires the test vehicle attitude to be at or between the measurements mentioned above. If, due to time delays, the test vehicle is not at the appropriate attitude, the test facility is able to use standard, available means to adjust the test vehicle attitude. For example, the test facility may use after-market spacers placed between coils in the suspension springs as a means to easily maintain the measured attitude.
We understand you to be asking how a test vehicle can be adjusted (raised) to reflect the condition of the vehicle with the Nivomat in the activated mode. NHTSA typically does not specify in an interpretation a particular means for testing a vehicle when that means is not set forth in the standard. We stated in the Mazda letter, however, that the basic principle that should be followed in selecting a means for maintaining suspension height is that it should not result in different test results than would occur if testing could be conducted with suspension height being maintained as it would happen in the real world. NHTSA also stated, "For a crash test, it is important that a vehicle not be altered in any way that would change the vehicle's crash performance relevant to the aspect of performance being tested." We believe that the use of spacers could be a suitable way of maintaining the height of a vehicle to replicate an activated Nivomat system. Bouncing the vehicle to activate the Nivomat (and to measure the fully loaded condition) could be acceptable, if the bouncing action would not affect the vehicle being tested or the test devices (e.g., the side impact dummies) that were installed in the vehicle for the dynamic test. NHTSA may or may not use these suggested means in its compliance testing. The suitability of these means would have to be determined in the context of an actual compliance test, for the particular vehicle being tested.
I hope this information is helpful. Please contact Deirdre Fujita of my staff if you have other questions.
Sincerely,
Frank Seales, Jr.
Chief Counsel
d.7/24/98
ref:214
1. Mazda's vehicle had an active suspension system that was operational only when the vehicle's engine was operating. At vehicle speeds in excess of approximately 35 mph, the suspension height would be lowered a certain amount from the nominal or design position for vehicle operation. If the vehicle were not used for several days, the height may be lowered from the nominal or design position even more than the height attained at 35 mph. The suspension height would return to the nominal or design position for vehicle operation after such an extended period of inoperation almost immediately after starting the vehicle's engine.
2. As you indicate in your letter, the standard does specify that the vehicle attitude during the test must be at or between the "as delivered" and the "fully loaded" attitude (S6.2). Attitude is the vehicle position as measured from the ground to a reference point above each of the four wheels. Thus, attitude is a measure of vehicle position with respect to the ground and is a combination of both height and angle.
3. Further, it is unclear whether the Nivomat would be activated if the driver were alone in the vehicle.
4. Please note that, as stated in the previous paragraph, we could test a Nivomat-equipped vehicle with the Nivomat not activated, as well as with it activated.