Posted by Clint Dixon [74.206.62.210] on Sunday, February 01, 2015 at 11:08:16 :
Not to be splitting hairs too far past their ends, but the vintage cab lights in the excellent photo that Fred Coldwell graciously provided in the post below are not technically "marker lights."
Shown mounted to the cab roof on Fred's truck is a combination of "Clearance Lamps" and "Identification Lights." The three clustered together and centralized above the windshield are known as identification lights. In the attached image is shown another variant known as an "identification light bar (or strip)" which is more commonly found mounted at the back of a truck and facing rearward but was also popular, up into the 1950's found mounted above the windshield and facing forward.
The two lights shown in Fred's image mounted towards the outer front corners of the cab roof are known as "clearance lamps." These can sometimes also be found mounted to the rear outer corners of the cab.
The intent of clearance lamps was to alert other drivers traveling on the roadway, either approaching from the front or from the rear, of the extreme width (and height) of the vehicle that they were approaching.
In 1946, clearance lamps were generally required to be displayed on any bus or truck of 80 inches or more in width. Thus, they were somewhat uncommon on Power-Wagons having mainly appeared on trucks wearing wider or taller beds and/or other attached commercial equipment larger the stock express bed.
"Side Marker Lamps" were those mounted to the sides of a vehicle - one near the front and one near the rear (on each side). These alerted vehicles approaching via intersections from the side of the overall length of the vehicle displaying the side marker lamps.
"Identification Lights" were intended as an additional means to alert approaching traffic that the vehicle was a truck or commercial vehicle.
Each state had its own unique regulations outlining the requirements as to what vehicles were to display the above mentioned lamps, under what conditions they were to be displayed, distances they were to be visible to approaching traffic, and to the color of light emission required. For instance, in 1946, the Illinois requirement for clearance, marker, and identification lamps/lights covered vehicles pulling or carrying freight and vehicles carrying more than seven persons - the length of which together with any trailer or trailers in tow thereof, was more than 25 feet, and the width was more than 80 inches. The identification lights on the front had to be green in color and visible for 500 feet, during the period one hour after sunset to sunrise. The rear identification lights had to be red in color and otherwise meet the same requirements. Both of these identification light "sets" could be substituted with reflectors (conforming to the same requirements) if the vehicle was fitted with acetylene headlights rather than electric. For the year of 1946, Illinois did not require ANY clearance or side marker lamps.
I am sure the laws have changed many times since then.
I have found that when searching for vintage accessory lights for our vehicles, it is helpful to search using the correct terminology. I currently have a vintage identification light strip with red glass lenses mounted under the rear of the flatbed on my '51 B3PW which is right at 80-inches wide. I also have a vintage identification light strip with green glass lenses that I have yet to mount to the front center of the cab roof. Currently I am looking for ideas on old brackets that may have been used that would mount under the windshield wiper bezels while not effect the function of the wipers themselves and not require holes to be drilled in the sheetmetal.
Junior
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