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Author: H. Gene Hawkins Publisher: ISBN: Category : Reflective materials Languages : en Pages : 19
Book Description
Sign retroreflectivity is an important characteristic of traffic signs, and it is a critical factor in defining the effectiveness of signs in a nighttime environment. This synthesis summarizes previous research on various aspects of sign sheeting retroreflectivity in nine areas: basic retroreflectivity science; retroreflectivity materials, specifications, and measurement; sign performance; sign degradation, minimum retroreflectivity; field measurement of sign retroreflectivity; economic benefits; fluorescent materials; and safety. The synthesis of previous research serves as the basis for recommendations for selecting sign sheeting based on sheeting grade and roadway environment.
Author: H. Gene Hawkins Publisher: ISBN: Category : Reflective materials Languages : en Pages : 19
Book Description
Sign retroreflectivity is an important characteristic of traffic signs, and it is a critical factor in defining the effectiveness of signs in a nighttime environment. This synthesis summarizes previous research on various aspects of sign sheeting retroreflectivity in nine areas: basic retroreflectivity science; retroreflectivity materials, specifications, and measurement; sign performance; sign degradation, minimum retroreflectivity; field measurement of sign retroreflectivity; economic benefits; fluorescent materials; and safety. The synthesis of previous research serves as the basis for recommendations for selecting sign sheeting based on sheeting grade and roadway environment.
Author: Susan C. Paulus Publisher: ISBN: Category : Languages : en Pages :
Book Description
In this thesis, the author developed a retroreflective sheeting selection technique for traffic signs. Previous research was used to determine the luminance needed by drivers (demand luminance). The author used roadways scenarios to determine the amount of luminance the retroreflective sheeting on a sign would produce (supply luminance). A spreadsheet was developed to determine the performance of different retroreflective sheeting types by comparing the demand and supply luminance for specific roadway scenarios. Using the results of previous studies, three demand luminance levels were created: replacement, adequate, and desirable. The replacement level represents the level of luminance when a sign needs to be replaced and is 2.5 cd/m2. The adequate level is the recommended amount of luminance when installing new traffic signs and is 10 cd/m2. The desirable level is the approximate level when additional luminance has diminishing returns and is 30 cd/m2. Supply luminance on a specific traffic sign was determined by evaluating roadway geometries, sign placement, retroreflective sheeting type and vehicle data. The author reviewed roadway geometries in Texas to estimate typical number of lanes, shoulder widths and horizontal curvature in the US. Sign placement from the MUTCD determined the typical lateral placements, sign heights, and sign twists. Vehicle data included vehicle dimensions and headlamp type. Both the supply and demand luminance were determined for a specific viewing distance for a given scenario. The viewing distance is the distance a driver needs to read or recognize a sign to respond properly. In addition, the type of sign, alphanumeric or symbol, determined how this distance was calculated. The author developed four sign groups to calculate the distance required to read and respond to a traffic sign, including 1) Stop required, 2) Reduction in speed required, 3) Read the message provided, and 4) Change of lane required. For symbol signs, the minimum required visibility distance (MRVD) was determined for the sign group and for text signs, the viewing distance at a legibility index (LI) of 30 ft/in was found. At these distances, the author calculated the supply luminance and then compared it to the demand luminance levels to determine the performance level. The author developed the Retroreflective Sheeting Selection Spreadsheet (RSSS) to allow others to use the methodology presented in this thesis. RSSS allows users to input the roadway data, vehicle data, and sign data. RSSS takes this information and looks up the supply luminance for the scenario. RSSS then compares the supply luminance to the demand luminance levels and outputs the retroreflective sheeting performance level for the scenario.
Author: Paul John Carlson Publisher: ISBN: Category : Reflectance Languages : en Pages : 106
Book Description
This report includes an updated set of recommended MR levels for traffic signs based on recent developments in vehicle headlamps, vehicle types/sizes, nighttime driver needs, and newer sheeting materials. The updated MR levels are also based on more robust computer modeling of retroreflective sheeting performance.
Author: Kent L. Black Publisher: ISBN: Category : Reflective materials Languages : en Pages : 120
Book Description
The ability to predict coefficient of retroreflection (RA) values for inservice traffic signs is critical for the Federal Highway Administration's (FHWA) Sign Management System (SMS). Within the SMS, tools for predicting inservice retroreflective performance of traffic signs and for determining the motorist's visual needs are required. The research which focuses on the motorist's needs in terms of traffic sign luminance, legibility distance, conspicuity, etc., is on-going by others. The project reported on here evaluated the effects of climatological and geographic variables on sign sheeting deterioration. A national data collection effort was undertaken. Data samples from 6,275 traffic signs were collected across the country.
Author: Eugene R. Russell Publisher: ISBN: Category : Highway engineering Languages : en Pages : 194
Book Description
The main objective of this study was to determine the best, cost-effective policy, consistent with safety, for sign sheeting material to be used on signs and construction work zone traffic control devices on State highways in Kansas. The investigation consisted of reviewing literature, contacting knowledgeable traffic engineers and research, conducting a survey of selected States' practice, conducting a life-cycle cost analysis, and reviewing a previous reflective sheeting study conducted for the Kansas Department of Transportation (Bellomo-McGee Inc., 1988).
Author: Jonathan M. Re Publisher: Transportation Research Board ISBN: 0309223601 Category : Business & Economics Languages : en Pages : 54
Book Description
TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 431: Practices to Manage Traffic Sign Retroreflectivity includes examples of practices that illustrate how different types of transportation agencies might meet federal retroreflectivity requirements for traffic signs.
Author: Juan M. Morales Publisher: ISBN: Category : Reflectors (Safety devices) Languages : en Pages : 32
Book Description
This study determined the performance of STOP signs based on their retroreflective properties. Thirty-five 30-inch STOP signs, including engineering grade and high intensity, were measured in the laboratory to determine their retroreflective properties. A subset of ten signs was taken to the field to determine how far they could be recognized by paid subjects. Mathematical relationships between the various retroreflective properties and recognition distance were developed. The overall specific intensity per unit area (SIA) was found to be a good measure for estimating the recognition distance of STOP signs.
Author: H. Gene Hawkins
Author: H. Gene Hawkins
Author: Susan C. Paulus
Author: Paul John Carlson
Author: Kent L. Black
Author: Eugene R. Russell
Author: Kent L. Black
Author: Stephen F. Shober
Author: British Standards Institute Staff
Author: Jonathan M. Re
Author: Juan M. Morales