Evaluation Of Dynamic Speed Display Signs Dsds
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Evaluation Of Dynamic Speed Display Signs Dsds
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Author : Elisabeth R. Rose
language : en
Publisher:
Release Date : 2003
Evaluation Of Dynamic Speed Display Signs Dsds written by Elisabeth R. Rose and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2003 with Roads categories.
Dynamic speed display signs (DSDS), devices that detect and display a vehicle's current speed back to the driver, have been shown to have a significant speed-reducing effect in temporary applications such as work zones or neighborhood speed watch programs. In this report, researchers examined the effectiveness of DSDS installed permanently in several locations that were experiencing speed-related problems. Seven sites were evaluated, including a school speed zone, two transition speed zones in advance of a school speed zone, two sharp horizontal curves and two approaches to signalized intersections on high-speed roadways. Data were collected before the DSDS were installed, about one week after installation to determine initial effects of the signs upon vehicle speeds, and again about four months after installation to determine how well the initial speed reductions were maintained. Researchers analyzed average speeds, 85th percentile speeds, percent of the sample exceeding the speed limit and standard deviations of the samples. Also, least square regression analyses between the speed of a vehicle upstream of the DSDS and that vehicle's speed measured again at the DSDS were performed to determine whether the sign affected higher speed vehicles more than lower speed vehicles. Overall, average speeds were reduced by 9 miles per hour at the school speed zone. Elsewhere, the effect of the DSDS was less dramatic, with average speeds reduced by 5 mph or less, depending on the location tested. As expected, the influence of a DSDS was found to differ depending on how fast a motorist approached the DSDS. Those motorists traveling faster than the posted speed did appear to reduce their speed more significantly in response to the DSDS than did motorists traveling at or below the posted speed limit. The results of this project suggest that DSDS can be effective at reducing speeds in permanent applications if appropriate site conditions apply.
Evaluation Of Dynamic Speed Display Signs Dsds
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Author : Edward Roderick Rose
language : en
Publisher:
Release Date : 2003
Evaluation Of Dynamic Speed Display Signs Dsds written by Edward Roderick Rose and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2003 with Speed limits categories.
Overall, average speeds were reduced by 9 miles per hour at the school speed zone. Elsewhere, the effect of the DSDS was less dramatic, with average speeds reduced by 5 mph or less, depending on the location tested. As expected, the influence of a DSDS was found to differ depending on how fast a motorist approached the DSDS. Those motorists traveling faster than the posted speed did appear to reduce their speed more significantly in response to the DSDS than did motorists traveling at or below the posted speed limit. The results of this project suggest that DSDS can be effective at reducing speeds in permanent applications if appropriate site conditions apply.
Evaluating The Effectiveness Of Dynamic Speed Display Signs
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Author : Mansoureh Jeihani Koohbanani
language : en
Publisher:
Release Date : 2012
Evaluating The Effectiveness Of Dynamic Speed Display Signs written by Mansoureh Jeihani Koohbanani and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with Variable message signs categories.
This study investigates the impact of dynamic speed display signs (DSDSs) on drivers' speed-related behavior. A survey questionnaire regarding attitudes and reactions to DSDSs on different road classes was distributed to Maryland drivers of different ages and socioeconomic backgrounds. In addition, the research team collected vehicle speed data upstream and downstream of the DSDS location on different corridors. The data was collected with a portable Trax Flex High Speed Counter, which records vehicles' length, speed, and number of axles as they pass over the device's tubes on the road. The speed data was collected on three roads with different speed limits: 25 mph, 35 mph, and 45 mph. Conventional statistical analysis, Bayesian network, and planned behavior theory were applied to assess the DSDS' effectiveness with reducing speed. To investigate the shortterm and long-term effects of the DSDS, the research team collected the data in different periods (few days to few months) after the installation. Furthermore, the effective distance for the DSDS was investigated. Two different sizes of the DSDS were used to find the impact of size on drivers' compliance.
Texas State Publications
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Author : Texas State Publications Depository Program
language : en
Publisher:
Release Date : 2004
Texas State Publications written by Texas State Publications Depository Program and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2004 with State government publications categories.
Offset Right Turn Lanes For Improved Intersection Sight Distance
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Author : Karen S. Schurr
language : en
Publisher:
Release Date : 2010
Offset Right Turn Lanes For Improved Intersection Sight Distance written by Karen S. Schurr and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with Right-turn lanes categories.
Effectiveness Of Dynamic Speed Display Signs Dsds In Permanent Applications
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Author : Gerald L. Ullman
language : en
Publisher:
Release Date : 2004
Effectiveness Of Dynamic Speed Display Signs Dsds In Permanent Applications written by Gerald L. Ullman and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2004 with Roads categories.
Acronyms Initialisms Abbreviations Dictionary
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Author :
language : en
Publisher: Gale Cengage
Release Date : 2001-05
Acronyms Initialisms Abbreviations Dictionary written by and has been published by Gale Cengage this book supported file pdf, txt, epub, kindle and other format this book has been release on 2001-05 with Language Arts & Disciplines categories.
Each volume separately titled: v. 1, Acronyms, initialisms & abbreviations dictionary; v. 2, New acronyms, initialisms & abbreviations (formerly issued independently as New acronyms and initialisms); v. 3, Reverse acronyms, initialisms & abbreviations dictionary (formerly issued independently as Reverse acronyms and initialisms dictionary).
Evaluating Dynamic Road User Feedback Systems And The Calibration Of Video Tracking Data Collection Systems
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Author : Philip Morse
language : en
Publisher:
Release Date : 2019
Evaluating Dynamic Road User Feedback Systems And The Calibration Of Video Tracking Data Collection Systems written by Philip Morse and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019 with categories.
"As technology within the transportation industry develops, road users are presented with increasingly complex information. Measuring the impacts of driver feedback devices is a constant challenge for researchers and road network authorities alike. The objective of this thesis is to examine dynamic road user feedback systems and expand on automatic video-based data collection methods for evaluating these systems using new computer vision technology. This is accomplished through three different studies. First, a systematic literature review on variable message signs (VMS) is undertaken. Topics explored include a review of variable message sign study methodologies, legibility factors, operational factors and measures of effectiveness. Second, a dynamic speed display sign (DSDS), which uses many parameters measured in the first study, is evaluated in a before and after study on a low-speed arterial (30 km/h) with low traffic volumes with excessive speeding problems. Video-based data collection is used to obtain vehicle speeds. Improvements of 9.5 km/h (19.2%) for speed and 60% and 45% for fatality risks of vehicle-pedestrian and vehicle-cyclist collisions are measured. Thirdly, to improve from manual annotation to automatic, the transferability of video tracking optimization between camera views for traffic data collection is evaluated. Ideal parameters are obtained through use of a genetic algorithm with a MOTA fitness function. Optimized parameters were found to transfer well under clear condition, with performance results that ranged from 88% to 98% of their maximum. However, the winter, low-visibility video, needed an entirely different set of requiring much higher computation time." --
Evaluation Of Dynamic Speed Feedback Signs On Curves
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Author : Shauna L. Hallmark
language : en
Publisher:
Release Date : 2015
Evaluation Of Dynamic Speed Feedback Signs On Curves written by Shauna L. Hallmark and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with Automobiles categories.
Lane departure crashes are a significant safety concern. The majority of lane departure crashes occur on rural two-lane roadways, with a disproportionate number of these crashes on horizontal curves. Curve-related crashes involve a number of roadway and driver causative factors. A primary driver factor is speeding. Dynamic speed feedback sign (DSFS) systems are one method to reduce vehicle speeds and, consequently, crashes on curves. These systems show promise but they have not been fully evaluated on curves. The Center for Transportation Research and Education at Iowa State University conducted a national demonstration project to evaluate the effectiveness of two different DSFSs in reducing speed and crashes on curves at 22 total sites on rural two-lane roadways in seven States. The goal is to provide traffic safety engineers and other professionals with additional tools to manage speeds and crashes on rural horizontal curves more effectively. Data were collected before and at 1, 12, and 24 months after installation of the DSFS. On average, most sites had decreases in mean speeds, with decreases up to 10.9 miles per hour (mph) noted for both the point of curvature (PC) and center of curve (CC). Most sites experienced changes in 85th percentile speed of 3 mph or more at the PC, with the majority of sites having a decrease of 2 mph at the CC. The numbers of vehicles traveling 5, 10, 15, or 20 mph over the posted or advisory speed limit were also compared. Large reductions in the number of vehicles traveling over the posted or advisory speed occurred for all of the after periods at the PC and CC, indicating that the signs were effective in reducing high-end speeds, as well as average and 85th percentile speeds. A before-and-after crash analysis was also conducted, and crash modification factors (CMF) were developed. CMFs ranged from 0.93 to 0.95 depending on the crash type and direction of the crash.
Evaluation Of Dynamic Speed Feedback Signs On Freeway Interchange Ramps
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Author : Md Shakir Mahmud
language : en
Publisher:
Release Date : 2022
Evaluation Of Dynamic Speed Feedback Signs On Freeway Interchange Ramps written by Md Shakir Mahmud and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022 with Electronic dissertations categories.
Dynamic speed feedback signs (DSFS) are promising countermeasure to reduce curve speeds and subsequent lane departures at freeway interchange ramps, although their use in such contexts has been limited. Consequently, the impact of DSFS on driver performance at interchange ramps has remained unproven. To that end, research was performed to determine the effect of DSFS installed at freeway interchange ramps on measures of driver behavior, particularly vehicular speeds approaching and entering the ramp curve. To accomplish this objective, a series of field evaluations were conducted at six freeway interchange ramps possessing significant horizontal curvature. Several factors were tested during these evaluations, including: DSFS messaging strategy, positioning of the DSFS with respect to the start of the curve and side of the ramp, physical characteristics of the DSFS, radar detection range, interchange type, and temporal effects. Speed data were collected using one of these three techniques selected based on the site characteristics and types of data desired: 1) a series of high-definition video cameras, 2) handheld LIDAR, and 3) a speed-trailer. Several measures of effectiveness including speed at different locations, speed of drivers at different speed percentiles, and initial braking location were analyzed using appropriate regression techniques. Considering all phases of the field evaluation, it was concluded that DSFS are an effective countermeasure for reducing the speeds of vehicles approaching and entering horizontal curves on freeway exit ramps. The most critical aspect influencing the effectiveness of the DSFS as a speed reduction countermeasure was the longitudinal positioning of the sign relative to the ramp curve. Overall, the presence of a DSFS positioned near the start of the curve resulted in curve entry speeds that were, on average, 1.5 mph to 5.3 mph lower than without a DSFS present at the site. When the DSFS was present near the start of the curve, the lowest curve entry speeds were observed for cases where the feedback message activated when vehicles were within 250 to 400 ft of the start of the curve. Regarding DSFS lateral position, both the right-side-mounted and forward-mounted (i.e., ramp gore area) installations resulted in similar curve entry speeds. Furthermore, there were no discernable differences in curve entry speeds between 15-inch and 18-inch display panels, nor were speeds impacted by the inclusion of an advisory speed panel. In terms of feedback message, the most effective strategy was to display the measured speed alternating with a SLOW DOWN message. The effects on driver behavior associated with the DSFS were consistent between system interchanges and service interchanges, and across all vehicle types. The DSFS was equally effective irrespective of the mainline speed limit or ramp advisory speed. However, more pronounced speed reduction effects were observed for faster drivers (i.e., those within the highest quantiles) compared to the slower or average drivers. Furthermore, there was no evidence of temporal changes in driver behavior during the initial 14 months of operation of the permanent DSFS installation evaluated here. Finally, message activation did not show any significant effect on the speeds of mainline (i.e., non-exiting) vehicles. These findings were subsequently utilized towards the development of guidelines and recommendations for future use of DSFS at freeway interchange ramps.