The purpose of this report is to outline some of the facts associated with automotive brake lamps so that a well-informed decision may be taken as to whether or not they are suitable for inclusion in a multiplex system.
For background data, driver reaction time is defined and quantified at around 700 ms, with individuals tested falling in the range 280 ms-2 s.
The rate at which a hard-wired brake lamp bulb increases its luminance is then examined; this is found to depend largely upon the impedance of the wiring that connects the bulb to the battery. A minimum level of intensity that the bulb must reach is decided upon (297 lm), and it is found that the hard-wired bulb takes between 105 ms (Rline=250 mΩ) and 135 ms (Rline=500 mΩ) to reach this level.
A similar experiment carried out using the bulb driven by a multiplex system found it now took between 108 and 120 ms to reach the same level.
The conclusion is that for the system tested there can be no justification for not multiplexing the brake lamp circuit on the grounds of system latency.
Switch-On Delays in Multiplexed Automotive Brake Lamps
1988-07-01
5 pages
Article (Journal)
Electronic Resource
English
Switch-on delays in multiplexed automotive brake lamps
Automotive engineering | 1988
|European Patent Office | 2016
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