Column No.8 Safety and Nemoto - (6) "Trunk Release handles for Cars"
(Oct. 27, 2000))
Written by; Y. Murayama
Technical Advisor
Nemoto & Co., Ltd., Tokyo
During a three-week period between July and August 1998, eleven children died of heatstroke and suffocation in three separate incidents when they accidentally locked themselves in the trunk of a car.
The NHTSA (National Highway Traffic Safety Administration) took a serious view on these sad events, and convened an independent panel of experts to start investigation on this safety problem.
The Expert Panel met three times in Washington D.C. in January, March and May, 1999, and finally announced a series of recommendations to the NHTSA. Finally the NHTSA published a Notice of Proposed Rulemaking to require that all new vehicle trunks to be equipped with a release latch inside the compartment starting in January 1, 2001. This was added to the FMVSS (Federal Motor Vehicle Safety Standard) as a new standard No. 401 that came in force as from October 20, 2000.*1
This new standard requires:
- Each passenger car with a trunk compartment must have an automatic or manual release mechanism inside the trunk compartment that unlatches the trunk lid.
- Each manual release mechanism installed pursuant to the above 1. must include a feature like lighting or phosphorescence, that allows the release mechanism to be easily seen inside the closed trunk.
- Each automatic release mechanism installed pursuant to the above 1. must unlatch the trunk lid within 5 minutes of when the lid is closed with a person inside the trunk compartment.
- Actuation of each release mechanism required by the above 1. must completely release the trunk lid from all latching positions of the trunk lid latch, notwithstanding the requirements of any other standards.
Thus, as of September 01, 2001, it becomes compulsory that all new passenger cars with trunks must be equipped with a release latch inside the trunk compartment.
All American car manufacturers started investigation and development work for adequate trunk release mechanisms.
Mr. Michael Stando of Ford Motor Company developed a cable-operated mechanism with a T-shaped handle in a size to fit the hands of children 3 - 5 years old. This was based on a child psychologist's advice that the most natural response for children 18 months to 4 years old to an object that interests them is to grasp the object and pull it towards themselves,
Then Ford human factors specialists tested the recognition of this handle design on 27 children between the ages of three to five. They found out that 18 of the 27 children achieved the handle recognition. This handle was made of polypropylene containing a phosphorescent "Glow-in-the-dark" pigment, so it needed no electrical power. The handle was quick charging - it needed only 10 seconds of the garage's light to glow visibly inside the closed trunk - and operated with a pull motion.
According to the Report of Dr. C.Wood *2, psychologist, who helped the development work of General Motor Corp., GM engineers also worked with a child psychologist to design a handle that children could figure out easily on their own. The handle was big enough so that small children could use an entire hand to operate it, and it was not so brightly illuminated that children would fear it because many are taught not to touch something that appears hot.
After testing nine different types of escape mechanisms on more than 100 children, the team found most children could figure out how to escape the trunk with a simple lever-type door handle. However, the smallest children still had difficulty sometimes, leading GM to add a mechanism on the trunk latch that prevents it from being closed unless manually adjusted.
As the new standard will also be applied to Japanese cars sold in the States and Canada on and after September 01, 2001, Japanese manufactures also evaluated various designs. All of them have selected our long afterglow phosphorescent pigment "LumiNovaR", and started full-scale production of glow-in the-dark trunk release handles.
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| Photos. Glow-in-the-dark trunk release handles |
The above photos show a trunk release handle made by Toyota Motor Corp. This is an injection-molded plastic handle containing LumiNovaR pigment, and its phosphorescent properties are as follows. Two different illumination and climate conditions are assumed to closely approximate real life situations: inside a garage and outdoors. To approximate a trunk lid that is opened in a dimly lit and moderately warm garage interior, the excitation conditions are set at 70 lux for 30 seconds at room temperature, and for outdoors, at 1,000 lux for 30 seconds under 80 °C. Afterglow measurement for the latter case is done also under 80 °C (because decay of the afterglow luminance at 80 °C is faster than at room temperature). The luminance decay constant *3 (1.1 at room temperature) is increased to 1.6 at 80 °C, but the time to decay down to 0.3 mcd/m3 (100 times the human perception to level) is still over 2 hours in the both conditions. Trunk release handles containing LumiNovaR pigment thus have proven their effectiveness.
Table: Afterglow properties of handles containing LumiNovaR.
Excitation with
D65 light source |
Afterglow luminance (mcd/m 2) |
| 10min |
20min |
30min |
40min |
50min |
60min |
70lx, 30sec
23±2°C |
8.0 |
3.9 |
2.5 |
1.8 |
1.4 |
1.1 |
1000lx, 30sec
23±2°C |
64.4 |
27.7 |
16.5 |
11.2 |
8.4 |
6.4 |
1000lx, 30sec
80±2°C |
24.5 |
8.4 |
4.1 |
2.7 |
1.7 |
1.3 |
| Remarks; Measured at the same temperature as at excitation |
While it is our sincere hope that such a situation never arises, we are pleased to protect children safety with LumiNovaR.
Remarks:
*1 Federal Register Vol.65,No.204, Oct.20,2000
*2 GM Trunk Entrapment Press Conference, Dec.16,1998
| *3 Luminance decay constant: Formula I = I0t-n |
. |
t = Time
I0 = Initial brightness
n = Decay constant
I = Brightness at a time point (t) after removal of excitation source |
Copyright 2000,2001 by Nemoto & Co.,Ltd , Yoshihiko Murayama, Hiro Yamamoto.
