Download or read book Characteristics and Needs for Overhead Guide Sign Illumination from Vehicular Headlamps written by Eugene Russell and published by . This book was released on 1999 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: A team of Kansas State University researchers was given a contract to determine the minimum luminance requirements for overhead guide signs and to determine if the illuminance from vehicle headlamps on highways was sufficient to provide drivers with this required minimum luminance. This report covers a literature review to determine the minimum luminance value needed, an overview of the equipment developed for field studies of vehicle headlamp illuminance, results of a small laboratory study to determine minimum luminance of highway guide signs, and the results of field studies to determine illuminance values from a sample of the fleet of vehicles on highways, and the results of a study of illuminance values obtained from the headlamps of 50 known vehicles of varying ages and types.
Download or read book Headlamp Illumination Provided to Sign Positions by Passenger Vehicles written by Susan T. Chrysler and published by . This book was released on 2003 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: Traffic sign visibility at night is largely determined by sign luminance. Sign luminance, in turn, is determined by viewing geometry, retroreflective characteristics of the sign material, and headlamp illumination. Computer modeling of sign luminance has advanced to allow sign luminance to be predicted based on data sets of retroreflective material performance and headlamp luminous intensity matrices. This research project sought to assess the amount and variability of illumination provided to sign positions by a sample of Texas vehicles. The Texas Transportation Institute measured vehicle dimensions and headlamp illuminance at prespecified points representing typical sign locations. Data collection included 25 passenger cars and 21 light trucks and vans. Vehicles were measured without aiming, but after cleaning the headlamps. Each lamp was measured independently and total illuminance at sign locations was calculated. The project found that the vehicle dimensions specified in computer models encompassed the vehicles measured. The illumination values obtained were also in the range of those provided by the composite lamps in the existing computer models. Theoretical sign luminance values for different types of retroreflective sheeting were calculated using the median illumination values from the vehicles measured. The project confirms the validity of using computer models to predict sign luminance. It also confirmed current TxDOT retroreflective sheeting policy. It is recommended that TxDOT consistently aim the headlamps of vehicles used to perform nighttime sign inspections to assure consistency of sign appearance.
Download or read book Public Roads written by and published by . This book was released on 2000 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book IESNA Recommended Practice for Roadway Sign Lighting written by and published by . This book was released on 2001 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Study of Luminance Values of Overhead Guide Signs written by and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Federal Highway Administration (FHWA) is concerned that too little illuminance from the present fleet of vehicles on US highways is getting to overhead guide sign locations. If this is true, overhead guide sign luminance, a function of the sign sheeting and the external illuminance, may not be high enough for the sign to be read. A team of KansasState University researchers was given a contract to determine in the laboratory, minimum luminance requirements for overhead guide signs and to determine if the illuminance from vehicle headlights on highways was sufficient to provide drivers with this required minimum luminance. This paper covers the components and operation of a computerized headlight measurement system (HMS) that was developed to record illuminance values at an overpass location. The system was designed to automatically measure and record upligh from vehicle headlights as a function of various vertical angles and distances from an overhead guide sign location. Headlight illuminance readings from a sample of over 1,000 vehicles, identified as to make/type/year and headlight type through their license plates, were taken at seven points over the highway. The paper discusses the design and operation of the system, the results of the illuminance readings broken down by vehicle/headlight type, and the safetyimplications of these results. For the covering abstract of this conference see IRRD number 872978.
Download or read book A Review of KDOT Overhead Guide Sign Lighting Policy written by Aditya Gund and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Before year 2012 the US States must implement and continue using an assessment or management method to maintain traffic signs' retro-reflectivity at or above the minimum levels adopted by FHWA. Overhead guide signs are a particular problem because past research has shown that with available sheeting types, external illumination may still be necessary. Newer sheeting types and more energy efficient and cost-effective lighting systems are currently available. Over the next several years there is potential for savings of tens of thousands of dollars if the states don't have to use external illumination for their overhead guide signs, or, if more energy efficient, low cost lighting systems are used when necessary. A detailed literature review was conducted on minimum retro-reflectivity values for overhead guide signs, the legibility distance under reduced sign luminance and the lighting systems available for external illumination. There is no agreement found in the previous research studies as to what is the optimum or minimum luminance of the guide signs. In addition, a survey was sent to all state DOTs. This survey was focused on finding states' policies regarding the use of sheeting type and external illumination requirement, and methods and lighting systems for maintaining minimum values for overhead guide sign luminance. The total response rate was 56% (28 out of 50 state DOTs responded). Out of 28 respondents 19 said that they have usage policy for the type of sheeting material used for overhead guide signs and 18 of them provided details about their policy. An equipment to control the illumination levels from vehicle headlamps was built and pilot tests were conducted in the laboratory. A pulse-with-modulation dimming circuit designed around the Atmel ARM-based microcontroller board and power MOSFETs was used to control the brightness of the headlights for the high- and low-beams. Field tests were conducted in the later stages during nighttime to evaluate three different types of sheeting materials using 10 human subjects from age group 18-34. The materials DG3 and Type IV were found to perform better than Type I material for nighttime visibility but they were not significantly different from each other.
Download or read book Night Visibility of Overhead Guide Signs written by Donald A. Gordon and published by . This book was released on 1985 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: Considers adequacy of proposed guidelines which will eliminate illumination and the use of reflective sign backgrounds in highway guide signs.
Download or read book Roadway Lighting Design Guide written by American Association of State Highway and Transportation Officials and published by AASHTO. This book was released on 2005 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: This guide replaces the 1984 publication entitled An Informational Guide for Roadway Lighting. It has been revised and brought up to date to reflect current practices in roadway lighting. The guide provides a general overview of lighting systems from the point of view of the transportation departments and recommends minimum levels of quality. The guide incorporates the illuminance and luminance design methods, but does not include the small target visibility (STV) method.
Download or read book Guidelines for Nighttime Visibility of Overhead Signs written by Paul John Carlson and published by . This book was released on 2016 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chapter 1. Introduction -- chapter 2. Background -- chapter 3. Closed-course study -- chapter 4. Open-Road study -- chapter 5. Research findings -- References -- appendix A. Incremental effects of light sources and sign sheeting on legend luminance for overhead guide signs -- appendix B. Assessment of background complexity using digital images of roadway scenes by image processing -- appendix C. Open-road study details -- appendix D. Guidelines for Nighttime overhead sign visibility.
Download or read book Transportation Research Record written by and published by . This book was released on 2004 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Roadside Design Guide written by American Association of State Highway and Transportation Officials. Task Force for Roadside Safety and published by . This book was released on 1989 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Guidelines for Nighttime Visibility of Overhead Signs written by Paul John Carlson and published by . This book was released on 2016 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chapter 1. Introduction -- chapter 2. Background -- chapter 3. Closed-course study -- chapter 4. Open-Road study -- chapter 5. Research findings -- References -- appendix A. Incremental effects of light sources and sign sheeting on legend luminance for overhead guide signs -- appendix B. Assessment of background complexity using digital images of roadway scenes by image processing -- appendix C. Open-road study details -- appendix D. Guidelines for Nighttime overhead sign visibility.
Download or read book Proceedings of the Conference written by Hans-Joachim Schmidt-Clausen and published by Herbert Utz Verlag. This book was released on 1999 with total page 516 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on 2000 with total page 648 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation of Alternative Lighting Systems for Guide Sign Illumination written by Jonathan Everett Upchurch and published by . This book was released on 1986 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study objective was to identify a lighting system which has a lower power cost and reduced maintenance requirements and which provides adequately for motorists' needs in terms of legibility and illumination level. Twenty-five candidate lighting systems were identified through a review of technical data and specifications for lamps and fixtures by an independent lighting expert. Photometric tests and computer analyses of sign illumination levels reduced the number of candidates to ten alternative systems which were then field tested. Each alternative lighting system was tested for 10 to 14 months. Sign luminance was measured with a telephotometer. Power consumption was monitored. Maintenance requirements and lamp life were noted. A human factors study determined legibility distance and rated viewing comfort, lighting uniformity, and color rendition. An economic analysis was performed which considered the initial cost of acquiring and installing the lighting systems and annual costs for electric power, washing, relamping, and ballast replacement. A lighting system using the high pressure sodium light source was recommended. Compared to the existing commonly used fluorescent system, it uses one-third as much electric power and has about one-third of the annual owning and operating cost. The recommended system has a satisfactory illumination level and provides the best legibility distance of the ten systems tested.
Download or read book FHWA Nationally Coordinated Program of Highway Research Development and Technology Annual Progress Report Fiscal Year 1992 written by and published by . This book was released on 1992 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of Headlight System Performance Criteria written by Douglas J. Mace and published by . This book was released on 1993 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt:
