摘要: |
Roadway lighting is provided on selected highways to improve the visibility of the nighttime environment. Roadway lighting is typically warranted on the basis of the daily traffic volume. However, in the earlymorning hours, the traffic volumes may be so low as to diminish the need for roadway lighting. At present, the lighting infrastructure in place on Texas Department of Transportation (TxDOT) highways is not well suited to being dimmed. As a result, turning off roadway lighting during early morning hours is the only option. This concept is known as a lighting curfew for purposes of this research project. The lighting curfew section of the TxDOT 2003 Illumination Manual does not provide specific guidelines or criteria for implementing lighting curfews. Although lighting curfews are of interest around the country, no state has developed guidelines for lighting curfews, nor are there national guidelines at this time. The most significant potential benefits of lighting curfews include reduced power consumption and reduced light pollution. This project focused upon developing guidelines for implementing lighting curfews on urban freeways, which have the potential to impact TxDOTs ability to manage its lighting infrastructure in an advantageous manner. The guidelines developed through this project identify threshold criteria under which freeway main lane lighting can be turned off. The guidelines also identify conditions or exceptions under which lighting curfews should be suspended, modified, canceled, or not used at all (such as periods of inclement weather or during a major late-night event). |