Associate Professor and Division Chief
Experimental and Forensic Biomechanics
69115 Heidelberg, Germany
Dear Dr. Kallieris:
This responds to your FAX to Dr. Rolf Eppinger of NHTSA, requesting an interpretation of the requirements specified in Standard No. 212, Windshield Mounting. The answers to your two questions are provided below.
Standard No. 212 sets different windshield retention requirements for a vehicle depending on whether it is equipped with passive or manual restraints. S5.1 of the standard provides that vehicles equipped with passive restraints must retain not less than 50 percent of the windshield periphery after crash testing. S5.2 of the standard provides that vehicles that are not equipped with passive restraints must retain not less than 75 percent of the windshield periphery.
You stated that you have conducted 30 m.p.h. crash tests of motor vehicles with freshly adhered windshields. In the test vehicle, two Hybrid III dummies were placed in the front driver and passenger positions. Each dummy was restrained "by a three-point belt and air bag."
Your first question asked whether the vehicle is subject to the requirements of S5.1 for "vehicles equipped with passive restraints," or S5.2 for "vehicles not equipped with passive restraints." The answer to your question depends on whether the restraint system in the tested vehicle meets the definition of "passive restraint system" set forth in S4 of the standard. That term is defined as:
a system meeting the occupant crash protection requirements of S5. of Standard No. 208 by means that require no action by vehicle occupants.
Section S5 of Standard No. 208 sets occupant protection requirements that must be met in frontal, lateral and rollover crashes.
You did not provide much information about the vehicle in question. We assume it is a passenger car. Standard No. 208 (S4.1.4) requires the following of current production passenger cars:
(a) At each front outboard designated seating position, each vehicle must meet the standard's frontal crash protection requirements (S5.1) by means that require no action by vehicle occupants (e.g., by means of an air bag or automatic restraints);
(b) at the front center designated seating position and at each rear seating position, have a type 1 (lap) or type 2 (lap/shoulder) belt assembly that meet specified requirements; and
(c) either meet the lateral and rollover crash protection requirements of Standard No. 208 by means that require no action by vehicle occupants, or at each front outboard designated seating position, have a type 1 or type 2 belt assembly that meets the requirements of S5.1 with front test dummies restrained by the type 1 or type 2 assembly in addition to the means that require no action by the vehicle occupant.
We assume that the "three-point belt and air bag" to which you refer were installed in the front outboard seating positions pursuant to these occupant protection requirements of Standard No. 208. NHTSA's longstanding position is that a vehicle equipped with a type 2 belt assembly and an air bag in those seating positions is equipped with a "passive restraint system," and is thus subject to the requirement of S5.1 that 50 percent of the windshield periphery must be retained. (See, e.g., August 18, 1986 letter to Volvo, copy enclosed.) As discussed in the enclosed letter, one of the reasons the agency adopted the 50 percent retention requirement for passive restraint-equipped vehicles was because there could be contact between an air bag system and the windshield, and incidental contact between an air bag-restrained test dummy and the windshield.
The Standard No. 208 requirements listed above mean that a vehicle with passive restraints must meet the Standard No. 208 performance critera using only the passive restraints (air bag or automatic seat belt), and using both the passive and manual restraints. This would also be the case for Standard No. 212. The windshield retention would have to be at least 50 percent with the dummies restrained by only the passive restraint, and with the dummies restrained by both the passive and manual restraints. Therefore, your test (which appeared to have been conducted using both the air bag and the type 2 belt assembly) may not have been the worst case situation.
Your second question asked whether the windshield displacements described in S5.1 and S5.2 are measured dynamically (i.e., during the crash), or statically (i.e., after the crash). NHTSA determines the portion of the windshield periphery that is retained by the vehicle after the dynamic crash test specified in the standard.
I hope this information is helpful. If there are any further questions, please contact Dorothy Nakama of my staff at this address or at (202) 366-2992. Our FAX no. is (202) 366-3820.
Philip R. Recht Chief Counsel