Intrepid High Mount Stop Lamp LEDs?

I'm not sure that LEDs will lose their benefits over incandescent bulbs. For example, LED traffic signals are usually easier to see, especially the arrows pointing every which way that my state likes to show the movements you can make at an intersection, instead of merely using them for protected turns.

However, green LEDs can be dazzling bright at night. I wish those $100,000 traffic signals could include a photo sensor to dim them at night. I've heard that they claim they don't/won't do this because of concerns of dimming too much in bad weather during the day. Fix the photo sensor sensitivity, I say.

Exactly such an arrangement is used with LED traffic lights in Europe and elsewhere in the world. As usual, North American regulators don't give a shit about glare.

Can't say I've ever heard this -- if anyone's used it, it's a lame excuse.

DS

Er...but it does. Go do an UMTRI search; a great deal of research has been done on it.

Aye caramba. Not this ignorant stupidity again. As I recall, that was your theory on center high mount brake lamps of any type, as well.

Hey, Dan, How 'bout a recommendation of a brand of 912 lamps for the Intrepid CHMSL? One or the other is always burnt out in mine. Maybe I'm buying el-cheapo stuff? Anyway, replacing 'em got old the first time.

--Geoff

There's no longer as much choice in the matter -- even the major brands are buying a lot of their stuff out of China, Korea, Taiwan, etc. Best advice I can give is to use a major brand (GE, Narva, Philips, Wagner, Sylvania) and check for country-of-origin information.

DS

I notice that GE (possibly other mfgrs.) list a variation of it with an "...LL" suffix indicating *L*ong *L*ife. Probably more mechanically robust filament (duh!) at the sacrifice of a little brightness and/or efficiency. Seems I remember seeing many replacement bulbs on the bulb rack at Advance A.P. in the LL flavor - don't recall if the 912 was one of 'em, but I think it was.

Bill Putney (to reply by e-mail, replace the last letter of the alphabet in my address with "x")

GE does not make or sell a 912LL bulb, nor does Philips. Don't believe Sylvania does, but they might. It's already considered a "long life" bulb with a 1000-hour rating.

No, you're confusing LL bulbs with HD bulbs. HD bulbs have greater mechanical robustness; LL bulbs just have longer life (with reduced efficacy).

DS

Hmmm - I see the 921LL (Concorde, 300M, LHS), but no 912LL (Intrepid).

OK - I just drove the 1/4 mile to the Advance store - what they have agrees with that list - they have the Sylvania 921LL and the 912 (no 921 and no 912LL). *BUT* I noticed that the two bulbs are physically interchangeable (same base, same bulb size) - probably different wattage and intensity. But if it's not too much of a brightness mismatch, you might try the 921LL to see if it last longer in the 'trep.

Bill Putney (to reply by e-mail, replace the last letter of the alphabet in my address with "x")

12 MSCP for the 912 21 MSCP for the 921.

Risk of socket and reflector melting by using 921s in place of 912s. I tried a similar swap on one of my Chrysler products, and wound up having to replace the CHMSL after a few months. Net savings from the longer-life bulb: Negative.

Isn't that the truth. I wonder why it doesn't bother them personally.

Not just anyone, US DOT (FHWA). They think that LED traffic lights controlled by photosensors may be too dim during bad weather. No doubt the European engineers that were the recipient of this letter were baffled by it.

They also noted that LED output will drop gradually, while incandescent bulbs will still produce 75-80% of initial output until they fail all at once. the second document gets fairly technical about lightingproperties).

No matter how much you try to obfuscate with your endless blather, you still can't get away from the fact that studies have been conducted and conclusions have been drawn. You're free to debate the conclusions on their scientific merits (as if!), but rest assured nobody with an ounce of sense is going to accept the idea that the studies are wrong just because you don't like what they say, or because they don't fit in with your oh-so-carefully crafted line of BS!

It sure sounds like you have a "don't confuse me with the facts" policy...are you sure your name ain't Lloyd?

--Geoff

In fairness, you and DS have previously cited "rigorous studies" to make light of OPs, yet when asked to cite same, have yet to respond.

As examples, take the Voevodsky Cyberlite/SFO taxi fleet and flashing brake light/aviation ACL threads. No feedback yet. TRB was in January.

Over to you, again.

- RWM

Actually, it is only Ted M. who has failed to give references to support his views. Presumably that is because there are no data to support his views. Me, I've given many references, each time this debate comes up. It's come up enough times and I've given the refs enough times that anyone may google for them or simply hit the UMTRI library online catalogue and the PAL symposium proceedings indices; I will not type them in again.

DS

No, google the Voevodsky Cyberlite/SFO taxi fleet and flashing brake light/aviation ACL threads. No feedback yet. TRB was in January.

Over to you, again.

- RWM

If you're going to google the wrong threads, there's not much I can do for you.

I haven't got a monopoly on the refs, y'know. They're readily available to everyone, including you. I grew tired of typing them in again and again and again, so I started pointing people in the right direction to find them themselves, and I've grown tired of that, too. Use the resources at your disposal to find my references and my reference sources, or find the refs on your own.

Nope. Over to you.

- RWM

Daniel Stern Light>

Daniel Stern Light>

On the aviation side of the TRB house, sequenced and random flashing strobes and landing lights (for pattern and low altitude use; helicopters especially, but Southwest uses them as well) have been used for years in anti-collision lighting (ACL) to good effect. Same for fixed ACL use (towers, etc.). Seems aviation adopted Voevodsky's theories for use against skyplane and groundplane lighting clutter.

- RWM

*shrug* OK, don't look 'em up, then. No skin off my nose.

DS

Here's one but it's pricy

http://autolum>