Interpretation ID: nht94-7.16

DATE: March 29, 1994

FROM: John Womack -- Acting Chief Counsel, NHTSA

TO: Tom Delapp -- Executive Coach Builders, Inc. (Springfield, MO)

TITLE: None

ATTACHMT: Attached to undated letter from Tom Delapp to Chief Council, NHTSA (OCC 8868)

TEXT:

This responds to your letter requesting an interpretation of Federal Motor Vehicle Safety Standard (FMVSS) No. 206, "Door locks and door retention components," as it pertains to the locking mechanism of a so-called "5th" door installed on your limousines. I apologize for the delay in responding. We conclude that the locking mechanism on the 5th door is not prohibited by Standard 206.

Based on your letter and a conversation with David Elias of my office, I understand that you have replaced the extra panel on the right side of a 1993 Lincoln Town Car based limousine with a passenger door (i.e., the 5th door). The door consists completely of the original equipment manufacturer's materials and hinges. The 5th door is a supplementary door, and does not replace or effect in any way the two side rear doors with which your vehicles are normally equipped.

When the 5th door is closed, its locking mechanism engages automatically, and the door cannot be opened from the inside or the outside. A solenoid locking mechanism that unlocks the 5th door is located inside the vehicle in a "privacy panel" behind the driver's seat. For the driver to unlock the 5th door, the car must be stopped and the driver must then get out of the car and reach through a window into the area behind the driver's seat. The locking mechanism cannot be reached by the driver while seated in the driver's seat, and cannot be reached by the passengers in the rear seats. The 5th door cannot be accidentally opened; unless the locking mechanism has been actively disengaged, the door remains locked. Disengaging the locking mechanism for the 5th door allows the driver to open the door from the outside, although passengers could push the door open from the inside, as well.

There are two pertinent requirements of FMVSS No. 206 to your situation. First, S4.1.3 (Door Locks) states that:

Each door shall be equipped with a locking mechanism with an operating means in the interior of the vehicle.

In two prior letters, to Mr. Charles Murphy on May 10, 1974, and to Mr. Gary Hackett on April 11, 1988, the agency interpreted S4.1.3 to mean that the locking mechanism must also be OPERABLE from within the vehicle.

The first question to be addressed is whether the 5th door meets the requirement of S4.1.3. We believe the answer is yes, the door is equipped with a locking mechanism with an operating means in the interior of the vehicle that is operable from within the vehicle. The operating means for the locking mechanism is in the interior of the vehicle in that the locking mechanism engages automatically when the 5th door is closed. While the means to

disengage the operating mechanism is not accessible to occupants in the vehicle, Standard 206 does not require the locking mechanism to be capable of being disengaged by an occupant. This is because the purpose of the standard is to minimize the chance that occupants of the vehicle will be ejected in a collision. Thus, the thrust of the standard is to ensure that occupants are retained within the vehicle, such as by requiring doors to have door locks that occupants are capable of locking.

The second pertinent requirement is S4.1.3.2 (Side Rear Door Locks), which states that:

... when the locking mechanism is engaged both the outside and inside door handles or other latch release controls shall be inoperative.

The 5th door appears to comply with S4.1.3.2, in that it cannot be opened from the outside or inside when the locking mechanism is engaged.

In a letter to Ms. C.D. Black, dated April 10, 1987, the agency interpreted a question on child safety locks that is relevant to your situation. The child safety lock operated as a "secondary locking system" that, when activated, rendered the inside rear door handle incapable of opening the door. (It had no effect on the outside door handle.) As we stated in that letter, our conclusion was that Standard 206 permitted the child safety lock because the standard prohibits only secondary locking systems that interfere with the ENGAGEMENT, but not with the DISENGAGEMENT, of the primary locking system. In that letter, we wrote:

The answer to your question about the child locking systems is dependent on whether the systems interfere with an aspect of performance required by Standard No. 206. We have determined that the answer is no, because the requirements of... S4.1.3.2 are written in terms of what must occur when the primary system is engaged and impose no requirements regarding the effects of disengaging the system. Thus, the aspect of performance required by S4.1.3 for the interior operating means for the door locks is that it be capable only of ENGAGING the required door locking mechanisms. The aspect of performance required by S4.1.3.2 for door locks on the rear doors is that the inside and outside door handles be inoperative when the locking mechanism is ENGAGED. Since we have determined that... S4.1.3.2 do(es) not address the effects of disengaging the required door locks--i.e., S4.1.3.2 does not require that the inside rear door handles be operative (capable of releasing the door latch) when the required locking system is disengaged--a child locking system may be provided on a vehicle if it does not negate the capability of the door lock plunger (the operating means) to engage the door locks.

I hope this information has been helpful. If you have any further questions, feel free to contact Mr. Elias at the above address or by phone at (202)366- 2992.