Mr. Ric Marzolf
VP of R&D
500 Bailey Avenue
New Hampton, IA 50659
Dear Mr. Marzolf:
This responds to your letter asking whether a new product TriMark is developing meets the requirements of Federal Motor Vehicle Safety Standard (FMVSS) No. 206, Door Locks and Door Retention Components. I apologize for the delay in responding. You ask whether the addition of two emergency release levers to the door latches on the rear and side doors of an emergency vehicle would meet certain provisions of a February 6, 2007 final rule amending FMVSS No. 206. As discussed below, our answer is yes.
As we understand your letter, the door system that TriMark is developing for side rear doors and back doors of emergency vehicles (ambulance and fire trucks) has door latches that, for purposes of this letter, we assume meet the requirements of FMVSS No. 206 as amended by the February 6, 2007 final rule. The locking system also has two single rotor latches with a primary and secondary position, with one latch located at the top of the door and the other at the bottom of the door. You explain that the top and bottom latches each contain a release lever, independent of the interior and exterior door handles, that protrudes through the door to the interior of the vehicle. You state that, in an emergency situation where some system binding occurs that does not allow the door to be opened via the interior or exterior handles, the levers can be actuated individually on the top latch and on the bottom latch to release and open the door. This function provides a direct emergency release for each latch.
The February 6, 2007, final rule added to and updated requirements and test procedures of FMVSS No. 206, and harmonized with the worlds first global technical regulation 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.)
To prevent inadvertent rear door openings, the amended standard specifies, among other requirements:
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 mechanism 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.
The amended requirements for rear side doors are similar to the current FMVSS No. 206 requirement for rear side doors (S184.108.40.206), which states:
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.
In your letter you state that your system requires separate actions to actuate each latch via their emergency release levers before the door can be opened. These release levers are about four feet apart. You believe that the door system feature should be permitted because two distinct operations are needed to open the door.
The door system you describe in your letter has an interior latch release control. As such, per new S4.3.1 and S4.3.2, when the door is locked, there must be separate actions to unlock the door and operate the interior latch release control.
Although NHTSA did not address which types of actions are permissible separate actions, the agency has stated that the door lock requirements for rear and back doors are in place to reduce inadvertent door openings due to impact upon or movement of the inside or outside door handle. 72 FR at 5395; 33 FR 6465 (April 27, 1968). Thus, the safety concern this requirement intends to mitigate is risk of ejection from a moving vehicle through inadvertent rear and back door openings. We believe that the separate actions should be separate, discrete actions on the part of the consumer (separate from an action associated with a normal driving maneuver) indicating a definitive decision, or intent, to unlock the door and egress the vehicle.
We believe that opening a side or rear door using the emergency release levers you describe in your letter does require separate actions: actuation of the top emergency lever, and actuation of the bottom emergency lever. As we understand your letter, because the two emergency release levers are four feet apart and must be actuated independently before the door is opened, the relevant safety concern (ejection risk via inadvertent door openings) is reduced with the door system you describe. In part, this is because the emergency release levers cannot be reached simultaneously by a seated occupant.
Since the door requires separate actions to operate the latch release and open the door, NHTSA believes that the emergency door lock system described in your letter meets the amended side rear door lock requirement that a rear side door lock require[ ] separate actions to unlock the door and operate the interior door handle or other interior latch release control in S4.3.1 of FMVSS No. 206.
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