Mr. Thomas Betzer
Global Engineering Manager
46941 Liberty Drive
Wixom, MI 48393
Dear Mr. Betzer:
This responds to your email asking whether a certain theft deterring double-lock function will meet the requirements of Federal Motor Vehicle Safety Standard (FMVSS) No. 206, Door Locks and Door Retention Components, as amended by a February 6, 2007 final rule. As discussed below, our answer is no.
You did not describe the double-lock system in detail, but we assume for the purposes of this letter that the system has features described in the agencys April 10, 1987 letter to Karl-Heinz Ziwica of BMW (copy enclosed). With that system, the driver locks the doors with a key. If the key is rotated to a certain point and removed, the vehicles burglar alarm is armed and the doors are double locked, such that after the plungers move downward, the outside handle, the inside handle, and the locking plunger cannot be used to unlock a door. When double locked, the doors can only be unlocked using a key in a front door lock. In your letter, you stated that the double-lock function disables the interior unlocking mechanisms to prevent car theft by reaching into the vehicle to open a locked door.
The February 6, 2007 final rule amended and updated requirements and test procedures of FMVSS No. 206, and harmonized with the worlds first global technical regulation (GTR) for motor vehicles (72 FR 5385). (The effective date of the final rule is September 1, 2009; there are pending petitions for reconsideration of the final rule. Docket No. NHTSA-2006-23882.) The amended door locks requirements of the current standard are located in paragraphs S4.3 (door locks), S4.3.1 (rear side doors), and S4.3.2 (back doors) of the amended standard, as follows:
S4.3 Door Locks. Each door shall be equipped with at least one locking device which, when engaged, shall prevent operation of the exterior door handle or other exterior latch release control and which has an operating means and a lock release/engagement device located within the interior of the vehicle.
S4.3.1 Rear side doors. Each rear side door shall be equipped with at least one locking device which has a lock release/engagement device located within the interior of the vehicle and readily accessible to the driver of the vehicle or an occupant seated adjacent to the door, and which, when engaged, prevents operation of the interior door handle or other interior latch release control and requires separate actions to unlock the door and operate the interior door handle or other interior latch release control.
S4.3.2 Back doors. Each back door equipped with an interior door handle or other interior latch release control, shall be equipped with at least one locking device that meets the requirements of S4.3.1.
These provisions changed some requirements of current FMVSS No. 206. The new S4.3 specifies that each door have an operating means and lock release/engagement device located within the interior of the vehicle, whereas current FMVSS No. 206 door locks requirements only specify that the door locking mechanism have an operating means in the interior of the vehicle. The current requirements read as follows:
S4.1.3 Door Locks. Each door shall be equipped with a locking mechanism with an operating means in the interior of the vehicle.
S188.8.131.52 Side Front Door Locks. When the locking mechanism is engaged, the outside door handle or other outside latch release control shall be inoperative.
S184.108.40.206 Side Rear Door Locks. In passenger cars and multipurpose passenger vehicles, when the locking mechanism is engaged both the outside and inside door handles or other latch release controls shall be inoperative.
With regard to these existing requirements which the 2007 final rule changed, NHTSA had interpreted current S4.1.3, S220.127.116.11 and S18.104.22.168 to permit a double-lock system such as the one you describe (April 10, 1987 letter to Kark-Heinz Ziwica of BMW). In the BMW letter, we explained that the permissibility of the system was dependent on whether the system interfered with an aspect of performance required by FMVSS No. 206. We interpreted the requirement for an interior operating means for the door locks to require only an operating means to engage the required door locking mechanisms, and not an operating means to disengage the locking mechanism. Therefore, NHTSA concluded that FMVSS No. 206 did not prohibit an additional locking device that negated the capability of the inside operating means for the door locks to disengage the locks, provided that the device does not interfere with the engagement of the required door locking system.
Those FMVSS No. 206 requirements changed under the new door locks requirements set forth in the February 2007 final rule. Under the amended standard, each door will require an operating means and a lock release/engagement device (a device that both releases and engages the locking mechanism) located within the interior of the vehicle (new S4.3). A secondary locking device that negates the capability of the inside operating system for the door locks to disengage the locks will not meet the requirement in S4.3 that each door have a lock release device within the interior of the vehicle.
NHTSAs intent to mandate locking devices with interior means to both release and engage the lock was made clear in the preambles to the February 6, 2007 GTR final rule and to the preceding December 15, 2004 notice of proposed rulemaking. In the preambles, the agency said that it sought to require interior door locks to be capable of being unlocked from the interior of the vehicle by means of a lock release device that has an operating means and a lock release/engagement device located in the interior of the vehicle. See 72 FR at 5394-5395; 69 FR 75020, 75027. Thus, the agency at S4.3 and S4.3.1 adopted requirements for a lock release/engagement device located within the interior of the vehicle.
After reviewing the preambles of the GTR rulemaking and the regulatory text of current and amended FMVSS No. 206, we have determined that a double-lock system such as that described in the BMW letter will no longer be permitted under the standard because it interferes with the interior lock release device of the door. Since neither the inside nor the outside door handle can open the door, it is presumed that the lock is engaged and that the interior lock release device was unable to unlock the door.
Child Safety Locks
Conversely, we interpret the amended FMVSS No. 206 to continue to permit child safety locks that only disable the interior latch release (door handle) of rear side doors. When such a child safety lock is engaged on a rear side door, the interior lock release/engagement device can continue to engage and release the door lock. In addition, when the door lock is released, the door can be opened by operating the exterior door handle even when the child safety lock is engaged.
If you have any further questions, please do not hesitate to contact Sarah Alves of my staff at (202) 366-2992.
Stephen P. Wood
Acting Chief Counsel
 We note that with your system, electronic unlocking via a key fob can also deactivate the double-lock function.