Hello all, I'm happy to have found this forum and I hope one or more of you can help me. I am a relatively new TAI and Reconstructionist.
Only 3 months after obtaining this position in my Dept., I was called out to a head-on, Double Fatal. This crash left absolutely no markings on the roadway and both vehicles were just a few feet from the area of impact. A witness (driver following veh 2) says they were traveling about 40 mph (the exact speed limit) and he states he never saw any headlights prior to the impact. I want to conduct an analysis on the headlights of veh 1 (2006 Lexus RX330H) but the only lamps that weren't destroyed on impact are HID lamps. I've searched and searched for anyone with experience examining these lamps with no result. Anyone have any ideas?
HID or gas discharge lamps obviously do not have the traditional filament which gets examined. So far haven't read anywhere that suggests how they can be exmained with any reliability to say whether they were or weren't in use at the time of an impact
I agree with you on that. No documented process or procedure is immediately available on the internet. I should have mentioned that I found, within the bulb itself, some white oxidation consistent with similar presentation in a filament bulb. I was able to extract a filament bulb from the front passenger (non-impact) side of the vehicle that was intact with no hot shock or cold shock evident. I attempted to contact the manufacture (Philips) of the bulb to gain some insight from them with very limited success. Here are the best pics of the bulbs I pulled of the Lexus that I could manage.
The absence of distortion does not neccesarily lead to a negative conclusion. That is to say, that the absence of distortion is not proof or suggestion that the bulb was not illuminated at the time of the impact.
The oxidation that you found may have been present whether the lamp had been illuminated or not. Can't see all the image and filament so limited as to what one can say. The main coil of the fialment on the face of it appears to be in a limted ditortion condition.
This is a late reply, but you might consider the fact that the Lexus was equipped with electroluminescent gauges, which are always illuminated. They will be lit even if the headlamps are turned off. The lit gauges suggest to the driver that the headlights are on, when they are not.
Many of these vehicles have automatic headlamps, but also feature a solid-state on-off-auto switch, so the headlamps may be turned off and left off without resetting to "auto" when the ignition is cycled.
Did you look at the tale lights. Were they disformed. If they are you can tell that the lights were switched on. Then measure if you have current on the cables in the front. It would have been strange if both headlight were broken. The driver would have noticed it. Did you also try to get a dealer diagnostic readout. In the dtc history you can see if the lights were broken or if they went broken in the accident. In a lot of cases the dealer readout gives a milage if the mil licht cam on. In the netherlands we can use this as evidence. If you have more quistins I will here from you.
