2013 Session: 371

• Development of a Guide for Replacement of Roadway Lighting with New Lighting Technologies
  Abstract: The development of a simple guide for roadway lighting replacement approaches in New York State using new light source technologies to maintain visibility for safety, while reducing energy use, is described. Several roadway types were evaluated: parkways, residential streets and rural intersections. A review of published literature and a survey of transportation engineers in New York State were conducted. Based on this information as well as data on new light source technologies, recommendations for roadway lighting system replacement were developed. Analyses of the visual efficacy produced by different lighting systems under nighttime conditions, and the performance characteristics of light emitting diode and induction fluorescent lighting systems, resulted in recommendations for replacement of high pressure sodium (HPS) lighting systems. Several new light sources that produce “whiter” light than the incumbent HPS technology used on most roadways have been developed and significantly improved in the past decade. In combination with recent information about driver and pedestrian vision under nighttime conditions, these sources could result in energy savings for different roadway types, ranging from about 7% to 50%. Energy savings for isolated rural intersections could depend upon the level of pedestrian traffic expected.
  Authors: Bullough, John D.
  Authors: Bullough, John D.
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 371
  Paper Number: 13-2308
• Field and Software Evaluation of Illuminance from LED Luminaires for Roadway Applications
  Abstract: An evaluation of the illuminance from LED roadway luminaires was conducted using field measurements and lighting analysis software. Three sets of recently-developed LEDs and one set of HPS luminaires were installed in the field and repeated sets of data were collected for each set following IESNA LM-50-99 standard procedures. Field illuminance datasets were compared with expected performance of the luminaires based on AGi32 software using the photometry provided by the manufacturers. Results showed that illumination values from the field were at some points lower than those from software calculations, and these differences varied both in magnitude and location depending on the LED luminaire. Multiplicative factors to describe the differences were estimated and ranged from 0.96 (relatively small differences) to 0.57 (relatively large differences), with larger differences located at points near the light poles, and at middle and third points of the span. This suggests that quick checks can be performed by taking illuminance measurements at key points along the span to provide an approximation on the actual differences between field and software results for the whole grid. Discrepancies between software and field data may play a very important role in the use of the luminaires for a given road and pedestrian conflict classification, as the illuminance in the field may not reach minimum levels required by public agencies. An example using minimum requirements from the Illinois Department of Transportation is provided to illustrate this point. Full sets of repeated field data points following IESNA LM-50-99 are not commonly collected at new or upgraded installations, and moreover, using state-of-the-art luminaires, increasing the potential usefulness of the data and the comparisons included in this paper for practitioners and researchers alike.
  Authors: Medina, Juan C.; Avrenli, Kivanc A.; Benekohal, Rahim F.
  Authors: Medina, Juan C.; Avrenli, Kivanc A.; Benekohal, Rahim F.
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 371
  Paper Number: 13-3398
• Exploratory Evaluation of the Impact of Spectral Power Distributions on Driver Performance
  Abstract: The purpose of this project was to provide an initial investigation into the effects of different light source spectral distributions on detection and color recognition of roadway objects and pedestrians. This project included an investigation of both the light source spectrum from the overhead lighting spectrums as well as that from the vehicle headlamp. In order to investigate this, high-pressure sodium (HPS) and light emitting diode (LED) overhead lighting systems were considered, as well as headlamps filtered to resemble LED and the amber HPS sources. The detection and color recognition of pedestrians and wooden targets were evaluated by driver participants under controlled combinations of overhead and headlamp lighting using a similar protocol to studies that have already been performed at the Virginia Tech Transportation Institute.The main conclusions from this investigation indicate that: 1) There is not a significant difference between the spectrum of the vehicle headlamps selected in terms of the detection of pedestrians and targets located immediately alongside the roadway. 2) Overhead lighting is a significant factor in the detection and color recognition of pedestrian clothing, but results indicate it’s the intensity not necessarily the color of the lighting that makes it a significant factor. 3) Spectral components of overhead lighting and headlamp lighting may play a much more significant role in pedestrians located peripherally, rather than strictly along the roadway.
  Authors: Gibbons, Ronald B.; Meyer, Jason
  Authors: Gibbons, Ronald B.; Meyer, Jason
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 371
  Paper Number: 13-3803
• Analyzing Nighttime Visibility of In-Service Pavement Markings
  Abstract: Traditionally, retroreflectivity is used to quantify the visibility of traffic control devices, including pavement markings. However, retroreflectivity is a physical property of a material that is used as a surrogate for luminance. By itself, retroreflectivity is only limited in terms of describing the visibility of a pavement marking at night. One way to quantify the visibility of pavement markings at night is to assess the visibility level (VL) at the perspective of drivers’ visual demands. Based on the previous research on VL modeling, an extended VL model for pavement markings is introduced in the paper and used to determine the visibility of in-service pavement markings along lighted and unlighted highway sections in Anchorage, Alaska. We compare the measured pavement marking retroreflectivity with the FHWA proposed minimum required levels, and the calculated VL with the implied pavement marking visibility derived from the FHWA proposed minimum pavement marking retroreflectivity levels. The results indicate that areas with continuous roadway lighting appear to have more than adequate visibility despite having low retroreflectivity levels. The benefit of the roadway lighting was most evident when the pavement marking retroreflectivity was relatively low and at the longer distances tested (54 and 64 m).
  Authors: Ye, Fan; Carlson, Paul J.; Miles, Jeffrey David
  Authors: Ye, Fan; Carlson, Paul J.; Miles, Jeffrey David
  Year: 2013
  Document Type: Paper
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 371
  Paper Number: 13-4902
• Exploratory Evaluation of the Impact of Spectral Power Distributions on Driver Performance
  Authors: Meyer, Jason
  Authors: Meyer, Jason
  Year: 2013
  Document Type: Presentation
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 371
  Paper Number: 13-3803
• Field and Software Evaluation of Illuminance from LED Luminaires for Roadway Applications
  Authors: Medina, Juan
  Authors: Medina, Juan
  Year: 2013
  Document Type: Presentation
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 371
  Paper Number: 13-3398
• Development of a Guide for Replacement of Roadway Lighting with New Lighting Technologies
  Authors: Bullough, John
  Authors: Bullough, John
  Year: 2013
  Document Type: Presentation
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 371
  Paper Number: 13-2308
• Analyzing Nighttime Visibility of In-Service Pavement Markings
  Authors: Ye, Fan
  Authors: Ye, Fan
  Year: 2013
  Document Type: Presentation
  Subject: Design; Operations and Traffic Management; Safety and Human Factors
  Session: 371
  Paper Number: 13-4902