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 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 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 Overhead Guide Sign Visibility Factors written by Anthony C. Stein and published by . This book was released on 1989 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: The project discussed in this report concerned the night use of overhead guide signs, including button and reflectorized copy and all practical combinations of reflectorized and opaque backgrounds. This project was a follow up effort to the literature review by Gordon. Gordon's review found areas requiring further investigation, including the comparison of nonilluminated nonretroreflectorized signs with both illuminated nonretroreflectorized and retroreflectorized signs.
Download or read book Minimum Retroreflectivity Levels for Overhead Guide Signs and Street name Signs written by Paul John Carlson and published by . This book was released on 2003 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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 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 Implementation Strategies for Sign Retroreflectivity Standards written by Kent L. Black and published by Transportation Research Board. This book was released on 1992 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Transportation Research Record written by and published by . This book was released on 2003 with total page 644 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book OPTIMAL AND REPLACEMENT LUMINANCES OF TRAFFIC SIGNS A REVIEW OF APPLIED LEGIBILITY RESEARCH written by Michael Sivak, Paul L. Olson and published by . This book was released on 1983 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Minimum Retroreflectivity Levels for Blue and Brown Traffic Signs written by Andrew J. Holick and published by . This book was released on 2008 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Special Report Highway Research Board written by National Research Council (U.S.). Highway Research Board and published by . This book was released on with total page 728 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Minimal Luminance Requirement for Official Highway Signs Final Report written by Douglas J. Mace and published by . This book was released on 1986 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:
