Evaluation Of The New Virginia Department Of Highways And Transportation Skid Testing Trailer
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Evaluation Of The New Virginia Department Of Highways And Transportation Skid Testing Trailer
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Author : Stephen N. Runkle
language : en
Publisher:
Release Date : 1975
Evaluation Of The New Virginia Department Of Highways And Transportation Skid Testing Trailer written by Stephen N. Runkle and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1975 with Pavements categories.
The purpose of this study was to evaluate the new skid trailer obtained by the Virginia Department of Highways & Transportation and to determine how the survey skid testing program should be conducted in light of the findings. Specifically, those things considered about the new trailer were: (1) testing precision; (2) operational error, defined as unexplained day-to-day variation; (3) the speed-skid number relationships obtained for some customary surface types used in Virginia; and (4) the relationship of the new skid trailer to the Research Council's skid trailer and stopping distance car. Based on the findings of the study several recommendations were made, including the following: (1) Normal survey testing should be done at 40 mph (64 km/h). (2) Corrections to skid numbers obtained at speeds other than the intended test speed should be based on a slope of -.55. (3) Control site testing should be included as a normal part of survey skid testing, and skid test results should be adjusted based on control site test results. (4) Survey skid test data collected with the trailer should be reported in terms of predicted stopping distance car skid numbers based on regression results obtained in this study. (5) The relationships between the three testing devices should be verified at least annually. (6) The testing rate in the survey program should be five tests per lane mile. (7) At sites having borderline skid resistance, additional testing should be run with the trailer before taking action or verifying the results with stopping distance car tests when the standard deviation of the trailer results exceeds 2.25.
Virginia Department Of Highways And Transportation Skid Testing Equipment Correlation Results 1974 1975 And 1978
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Author : Stephen N. Runkle
language : en
Publisher:
Release Date : 1978
Virginia Department Of Highways And Transportation Skid Testing Equipment Correlation Results 1974 1975 And 1978 written by Stephen N. Runkle and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1978 with Pavements categories.
The purpose of this study was to modify, as required, the previously established relationships between the VHTRC skid trailer, the VHTRC stopping distance car, and the first VDHT skid trailer, and to develop appropriate relationships with the above three devices for the second, recently acquired VDHT trailer. Regression equations indicating the relationships between the trailers are given below. In general these equations indicate that 1. the relationships remain the same with changes in test speed, and from year to year; and 2. the relationships are essentially one to one, i.e., the slopes generally are not significantly different from 1.0 with some difference in average results as follows. VDHT Trailer #1 : VDHT Trailer #2 + 2.5 SN VDHT Trailer #1 VHTRC Trailer 3.0 SN VDHT Trailer #2 VHTRC Trailer- 7.0 SN As expected, the SN values obtained with the trailers were less than the SDN values obtained with the car at the same initial test speed and the relationships differ with test speed. However, it is important to note that for these relationships the slopes generally do differ significantly from 1.0; i.e., the difference in measured values between the car and trailers is not constant from low to high levels of skid resistance, with the difference being larger on low skid resistance sites. Since most of the survey skid data have been controlled with the VDHT Trailer #1, it seems reasonable to standardize results in terms of this test unit. Thus, survey data collected with the newer VDHT Trailer #2 should be corrected either in terms of adding 2.5 SN or by using equation 4 in Table 3 of the report. However, it should be pointed out that no correction of this type would result in a conservative (i.e. lower) interpretation of survey SN data. Predictions of SDN values, or stopping distances, should be made based on equations 17-21, 25, or 30-34 from Table 2 of the report, depending on the test trailer used.
Virginia State Library Publications
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Author :
language : en
Publisher:
Release Date : 1976
Virginia State Library Publications written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1976 with categories.
Variations In Skid Resistance Over Time
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Author : Stephen N. Runkle
language : en
Publisher:
Release Date : 1980
Variations In Skid Resistance Over Time written by Stephen N. Runkle and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1980 with Pavements categories.
The purpose of this project was to quantify the magnitude of changes in skid resistance over time, to isolate the variables that seem most important with respect to the changes, and, to the degree possible, formulate a model for converting skid resistance values obtained under a given set of conditions to the values that would be measured under a different set of conditions. The Virginia Department of Highways and Transportation survey skid trailer, the Department's research trailer, the research stopping distance car, and the grease patch method of measuring surface texture were evaluated with respect to time-and weather-dependent changes in measured values. The grease patch method of measuring texture seems to have the same basic relationship to weather variables as does the Department's survey trailer, but the relationship is inconsistent among sites. Also, the use of this method is time consuming and, consequently, expensive. The research trailer experienced so many breakdowns that the researchers place little confidence in the results obtained with this testing device. For the stopping distance car it was found that the average standard deviation for all test speeds on the six sites tested was 3.26 skid numbers. For the Department's survey skid trailer it was found that adjustments could be made to measured values to predict values for times other than when the measurements were made, either by evaluating weather variables or using specified correction values for designated months.
Selected Library Acquisitions
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Author : United States. Department of Transportation
language : en
Publisher:
Release Date :
Selected Library Acquisitions written by United States. Department of Transportation and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on with categories.
Transportation Research Record
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Author :
language : en
Publisher:
Release Date : 1993
Transportation Research Record written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1993 with Air travel categories.
Nchrp Synthesis 401
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Author :
language : en
Publisher: Transportation Research Board
Release Date :
Nchrp Synthesis 401 written by and has been published by Transportation Research Board this book supported file pdf, txt, epub, kindle and other format this book has been release on with categories.
Bibliography On Motor Vehicle Traffic Safety
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Author : United States. National Bureau of Standards. Office of Vehicle Systems Research
language : en
Publisher:
Release Date : 1971
Bibliography On Motor Vehicle Traffic Safety written by United States. National Bureau of Standards. Office of Vehicle Systems Research and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1971 with Motor vehicles categories.
Nasa Sp 7500
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Author : United States. National Aeronautics and Space Administration
language : en
Publisher:
Release Date : 1982
Nasa Sp 7500 written by United States. National Aeronautics and Space Administration and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1982 with categories.
Virginia S Wet Accident Reduction Program
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Author : David Crenshaw Mahone
language : en
Publisher:
Release Date : 1995
Virginia S Wet Accident Reduction Program written by David Crenshaw Mahone and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1995 with Automobile driving in rain categories.