The SAE lighting committee meeting, held last week, was in fact not a meeting of that group. It’s because SAE management, in recognition of the extreme workload and productivity of those who busy themselves with SAE lighting documents, have elevated the committee to the higher “system group” level. So, it was a meeting of the SAE Lighting Systems Group. This new recognition and structural promotion can be said to reflect the awakening American interest in vehicular lighting.
Front position lamps/Parking lamps
A great deal of discussion was packed into the three-day meeting docket. Several highlights are worth mentioning. The first is a document title change at once both trivial and substantial. The title of SAE J222 has been changed to “Front Position Lamps (Parking Lamps)”. This is admittedly just a change of a few words, but it constitutes adoption of international UN terminology—a sign of dawning acknowledgement of global automotive realities. Worldwide, most countries’ vehicle regulations are either fully or closely in line with UN (“ECE”) Regulations. The North American “island” of unique regulations carries on growing smaller as plateaued sales in the region are dwarfed by burgeoning sales in developing—and ECE-aligned—regions like China, India, and Brazil. It can legitimately be asked how much longer different regulations that don’t generate discernibly better safety results will be economically justifiable in the North American market.
Moreover, the terminology change takes a large step towards resolving an old and vexing name game: For many years, front position lamps have been called “parking lamps” in America. Except for the allowance of amber or white light, and some minor photometric details, the American “parking lamp” is functionally and specifically more or less identical to the UN front position light.
But there’s also a UN function called the “parking lamp”, totally different to front position lamps. The UN “parking lamp” is intended to mark the street side of a vehicle parked near but out of the traffic stream after dark, so it does not get struck by passing traffic. Conversations involving the phrase “parking lamp” have long been fraught with perils of misunderstanding because of this dual application of the term. Now that the SAE standard has prioritised international terminology for this function, the confusion should begin to wane.
It’ll take quite a while, though; SAE standards do not have the force of law, and US FMVSS 108 (which does have the force of law) is not automatically or periodically amended to refer to updated SAE documents. So the American regulations will likely continue to refer to “parking lamps” for quite some time. For that reason, the old “Parking Lamps” term remains in the title of SAE J222, though in deprecated and parenthetical form. Perhaps eventually American regulators will realise it would be helpful and consequence-free to adopt the international name (at least)—meanwhile, European and international vehicle lighting regulators can work toward seeing that the mandatory American side marker retro-reflector does a better, more dependable job of marking parked cars than the (European) “Parking Lamp”, and without its power consumption or necessity for the driver to switch it on.
Identification lamps
Another interesting discussion at the SAE Lighting Working Group meeting concerned identification lamps. These, basically unknown outside America, are a group of three marker lights, separated by about 180 mm, centred at the front and rear of vehicles more than 2,032 mm wide—at the top, usually, of truck cabs and trailer bodies. This is one of the oldest required lighting functions to be found in North American rules—long before there was a NHTSA or a legal framework in which to regulate vehicle lights, identification lamps were known as “ICC lights”. This was a reference to the Interstate Commerce Commission, which regulated commerce and transport among the US states. Identification lamps are, by very long tradition, red at the rear and amber at the front. It has long been lamented that a truck driver’s eyes are greatly separated from the truck’s headlamps, making it difficult for them to effectively illuminate retro-reflective overhead road signs for the driver. The observation angle is far larger than that of the passenger car driver, so even though the same amount of light shines on the signs from truck headlamps as from car headlamps, the truck driver can’t see the signs as well.
So why not have white front identification lamps, with their photometric distribution modified to provide a wide fan of not-very-intense light to wash the overhead signs at the correct angle for the driver to see them, but without downward stray light to cause glare for other drivers (or self-dazzle in bad weather)? The idea was broached and not rejected out of hand, which is at least a start.
Yellow turn signal
Also in colour-convention news, there is an effort under way to remove red as an optional colour for rear turn signals in the SAE standards applicable to light and heavy vehicles and trailers. There is broad general agreement in principle that yellow turn signals are better than the red ones still allowed by American regulations, but industry is reluctant to give up the option for red because of another American regulation: the one requiring a minimum of 50 cm 2 lit lens area for each stop lamp and each rear turn signal on a vehicle less than 2,032 mm wide—the figure for wider vehicles is 75 cm 2 . Such a requirement doesn’t exist outside America, and often forces automakers to put red turn signals on their American-market models because there’s not enough room in the rear lamp package for two separate lamps adequately large to meet the requirement. Watch DVN for more discussion of this matter next week. In any event, a task force has been formed to look at how to modernise and optimise the stop and turn signal lamp technical specifications.
