EARLY STREET LIGHT SYSTEMS

Part Five

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Lamp Color, Perception and Visibility It is important to consider the color temperature produced by the equipment one plans to use to retrofit vintage lamps. For traffic safety, lamps that produce light in color ranges similar to mercury vapor, induction and LED systems tend to result in improved driver reaction to signals and brake lights. The reason for this effect is the contrast between cooler street lamps and signal lamps. Thus lamps producing cooler colors are less likely to wash out red and amber indications from other vehicles and traffic control devices. However for security lighting, lamps having color temperatures in the range of traditional incandescent to "daylight" produce the best color rendering which in turn provide more efficient human observation and identification of illuminated objects. It is therefore worthwile to determine which kind of light source best suits your particular intended use before spending money on retrofit hardware for vintage lamps.   Visibility Studies and Reports Driver Response to Peripheral Moving Targets Under Mesopic Light Levels Mesopic Street Lighting Demonstration and Evaluation - Final Report RPI Lighting Research Center Visibility, Performance and Perception (Kenneth Siderius) Strategic Road Lighting Opportunities for New Zealand If anyone wishes to recommend additional studies and reports that could benefit those making decisions regarding best use of lighting technologies, please Email me.   Epilogue The development of street lights in the United States over the past 130-plus years has produced an incredible journey that is still moving forward. With the exception of carbon arc lamps, a number of these old street lights, some perhaps 100 years old, are still in service. With improved retrofit technology and new autotransformers that can operate modern low energy consuming lamps on ancient series circuits, perhaps some of these historic lamps will be saved from the scrap yards for future generations to see. There is a great deal of money being spent in historic districts to acquire classic looking street lamps. I offer the suggestion that those existing lamps having the appropriate "look" be evaluated for retrofitting rather than replacement. Certainly there is a need for modern, state-of-the-art roadway lighting and the new innovations being brought forward. But let's not forget some of the tried and true designs that the taxpayers and utility rate payers have already paid for and that can be modernized in order to be more efficient.

Vanishing Circuits Across the country there are still a few vintage lighting circuits still in service. Most appear to be located where service is provided underground and replacing old series circuits with 110 volt or 220 volt service would be incredibly costly. Others have just remained either because local citizens wished to preserve a particular look or because there wasn't funding to make upgrades. Improved retrofit technology may preserve a few of these relics of the past. The rest will likely find their way to the scrap yards in our dash to replace and discard what we deem to be obsolete.

A series incandescent lamp still in service in LA. A series lamp (right) among the new in LA

Regulator & oil switch. (Photo control on opposite side.) An old bishop's crook still in service in Pasadena

To see more vintage street lights and designs, please visit: Old Time Survivors Street Light Patents, 1800-Present Street Lights, A. C. Walker

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