Repeater Lamp Location and Safety

[glarus]

I am interested in adding a set of repeater lamps to my daily driver in the interest of safety. The car is a rather small subcompact and I fear the obliviousness of other drivers. Other than picking the most conspicuous of the colors offered (white), I have been considering adding other safety measures. The North American release of this car does not have repeater lamps installed. However, the same car in other markets includes repeater lamps either on the front fenders or on the side view mirrors depending upon the trim level.

I am indifferent to installing the repeater on the fender or the side mirrors. Does one location offer an advantage over another if visibility is my main concern? I am also unsure if there will be a significant difference in brightness between the two types as the fender repeater uses a 5W5 lamp and the side mirror version uses LEDs. I will be wiring these repeaters to flash in conjunction with the turn signals and not wire them to come on with the parking lights like I have seen some mouth breathers around here do.

I know that this is an obscure question, but any help would be appreciated.

 

[-Virgil-]

Research at the University of Michigan Transportation Research Institute not long ago showed that the sideview mirror location tends to provide better repeater conspicuity than the fender location (full report PDF here) , but — as usual — there are a lot of caveats to consider before deciding to retrofit the mirror-type repeater on your car based on this study.

The study was carried out, by necessity, using original-equipment installations to gather data. Some of these are quite good (the European and Japanese LED face-of-mirror-housing repeaters, the American bulb-type bottom-of-mirror-housing repeaters, and most amber-lens/clear-bulb fender repeaters mounted reasonably high). Some of them are quite poor (the American red or amber mirror-surface chevron, the Ford rear-edge-of-mirror-housing item, many amber-bulb/clear-lens fender repeaters, and many fender repeaters mounted too low to be visible to most adjacent drivers). So this shapes the data collected. When I discussed the study with the head researcher shortly after its release, he told me — not unexpectedly*— that in this as in most other aspects of lighting safety performance, a good implementation of an ordinary bulb-type fender-mounted repeater is better than a poor implementation of an LED mirror-mounted repeater. Also, mounting height is just one of several critical factors that influence the safety performance of side turn signals — higher is better, which is why good mirror-mounted repeaters are generally better than otherwise equally good fender-mounted repeaters. The "good" and "equally good" qualifiers are critical here; you don't mention what kind of car you're working with, nor what specific repeaters you're looking at, but there's a lot of toy trash on the market. Best to stick with original-equipment repeaters (not necessarily from your particular car model) or those made by reputable, major-name OE lighting suppliers.

Intensity is strongly positively correlated with safety performance (duh, the brighter the repeater, the better it works). And other good quality UMTRI research shows that with bulb-type turn signals, you get better safety performance from an amber lens/clear bulb combination rather than a clear lens/amber bulb. So, for example, the pre-2000-or-so Saab repeater that has an amber lens and a W5W colorless bulb is better than the 2000-up item with a colorless lens and WY5W amber bulb. Same with the clear and amber repeaters available on the various trim levels of MINI. Replace the W5W with a 2886x (85 lumens instead of 50), available only in colorless glass, and the amber-lens advantage grows much larger.

Not quite sure what you mean when you refer to the "most conspicuous of the colors offered (white)", but the repeaters must emit amber light. Not white nor any other color.

There are possibly beneficial locations for the repeater other than the mirror or the fender aft of the wheel, depending on what specific vehicle you're working on.

 

[270winchester]

this might sound noobish on my part, but what is a repeater lamp?

 

[PhotonWrangler]

this might sound noobish on my part, but what is a repeater lamp?

I haven't heard the term before either. I can guess what it is from the context though.

 

[glarus]

Thank you for taking the time to write out an informative and clear explanation Scheinwerferman! I especially appreciate the link to the University of Michigan study for further reading.

For clarification, the vehicle in question is the diminutive second generation Honda Fit and I was only considering the OEM repeaters used by Honda. Here are two pictures detailing the two possible repeater locations:

Based upon the information presented, it seems that the winner is the mirror mounted side repeater. The only real disadvantage that I can think of with the mirror mounted repeater is the lack of user serviceability. Though they are often stated as 'good for the life of the vehicle' I have seen enough CHMSLs with an LED or two burned out to consider that assertion false.

Not quite sure what you mean when you refer to the "most conspicuous of the colors offered (white)", but the repeaters must emit amber light. Not white nor any other color.

Sorry for being ambiguous there. I was referring to the conspicuity of different vehicle colors as presented in this study.

 

[-Virgil-]

Oh yeah, easy pick there; get the mirror repeaters. I wouldn't worry about longevity —*turn signal duty cycle is a great deal less (therefore effective service life a great deal longer) than brake lamp duty cycle.

 

[LukeA]

Mirrors are really pretty easy to get to. Just pop off the door's interior panel and only three or so bolts hold the thing on.

 

[irsa76]

Mirror mount repeaters for sure. I wish my wife's new Mitsubishi Colt had it's repeaters on the mirror. The only saving grace is they are "fairly" high up on the car. In contrast my Sprinter workvan has HUGE repeaters, with 21w globe!