1,721,030 research outputs found
Evaluation of the Impact of Driver Behavior on Back of Queues Events in Work Zones Using the SHRP2 Naturalistic Driving Study Data
Full text linkThe SHRP2 Naturalistic Driving Study was used to evaluate the impact of various work zone and driver characteristics on back of queue safety critical events (crash, near-crash, or conflicts) The model included 43 SCE and 209 “normal” events which were used as controls. The traces included representing 209 unique drivers. A Mixed-Effects Logistic Regression model was developed with probability of a SCE as the response variable and driver and work zone characteristics as predictor variables. The final model indicated glances over 1 second away from the driving task and following closely increased risk of an SCE by 3.8 times and 2.9 times, respectively. Average speed was negatively correlated to crash risk. This is counterintuitive since in most cases, it is expected that higher speeds are related to back of queue crashes. However, most queues form under congested conditions. As a result, vehicles encountering a back of queue would be more likely to be traveling at lower speeds.This article is published as Hallmark, Shauna, Guillermo Basulto-Elias, Nicole Oneyear, and Omar Smadi. "Evaluation of the Impact of Driver Behavior on Back of Queues Events in Work Zones Using the SHRP2 Naturalistic Driving Study Data." Journal of Transportation Technologies 14, no. 2 (2024): 179-194. doi: https://doi.org/10.4236/jtts.2024.142011
Comparison of Different Transverse Rumble Strip Patterns at Rural Stop-Controlled Intersections in Minnesota
Full text linkTransverse rumble strips (TRS) provide a tactile and audible warning for drivers approaching an intersection and are used primarily to decrease crashes resulting from failure to yield. The objective of this study was to evaluate how TRS patterns affect behavior at rural stop-controlled intersections. A TRS design was selected based on the Minnesota (state in the midwestern U.S.) Department of Transportation’s current rumble strip depth/shape and panel locations. Four patterns representing variations of this design were developed and installed at rural intersections with stopping behavior concerns in St. Louis County, Minnesota. The patterns included two panels with six rumble strips each (two sites), two panels with 12 rumble strips each (two sites), three panels with six rumble strips each (one site), and three panels with 12 rumble strips each (two sites). Traffic volume, speed, and video data were collected 1 week before TRS installation and then 1 month and 9 months after installation. Evaluation metrics included average speed, percentage of vehicles traveling 45 mph or more upstream of the intersection, full/rolling stops, and late braking. Each pattern was assigned a qualitative score based on points assigned for each metric, and differences in metrics among the patterns were compared between the 1-month and 9-month-after periods. The three-panel/12-rumble strip pattern had the highest qualitative score (1.33). The second highest score was for the three-panel/six-rumble strip pattern (0.88). However, since this pattern was only installed at one site, this result should be interpreted with caution. The two-panel/12-rumble strip pattern had the lowest score (0.44).This is a manuscript of an article published as Hallmark, Shauna, Nicole Oneyear, David Veneziano, Hossein Naraghi, and Victor Lund. "Comparison of Different Transverse Rumble Strip Patterns at Rural Stop-Controlled Intersections in Minnesota." Transportation Research Record (2025): 03611981251320397. doi: https://doi.org/10.1177/03611981251320397
Applications of remote sensing data to highway access management
Full text linkThis research explored the applicability of remote sensing for access management using aerial photographs of different resolutions. The data elements extracted from imagery include driveway density, driveway land use, median type, intersection density, number of lanes and two-way left turn lanes. Based on the percentage of data elements identified, the most suitable resolution for data extraction was identified. The extracted data were used in crash prediction models, which were used to rate the road segments on a 1 to 5 scale. The rating was the basis for prioritizing road segments for access related improvements. Imagery was also used for qualitative assessment (i.e., prioritization of road segments by an observer trained to derive information on level of access control from imagery) of road segments on a 1 to 5 scale for access related improvements. The feasibility of this approach was tested by a comparison of the qualitative rating of road segments (given by different observers) to the actual rating of road segments (obtained from previous access related crash history). The advantages and disadvantages of both quantitative as well as qualitative methods to prioritize road segments for access related improvements were then discussed
Work-Zone Traffic Performance Measures
Full text linkThis project synthesized current work-zone performance measures into a toolbox that details the resources available and also provides current information and ideas on what other state agencies are doing to report performance to the public.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Evaluation of Sequential Dynamic Chevron Warning Systems on Rural Two-Lane Curves
Full text linkRoadway departure crashes are a significant safety concern. A majority of these crashes occur on rural two-lane roadways, with a disproportionate number occurring on horizontal curves. The average crash rate for horizontal curves is about three times that of other highway segments. Curve-related crashes involve a number of roadway and driver causative factors with speed being a preeminent factor. Implementing safety countermeasures on rural horizontal curves to address these crash types can improve the safety performance. Chevron alignment signs provide additional emphasis and guidance for drivers negotiating curves. To further emphasize the curve, some agencies have started using a Sequential Dynamic Chevron Warning System (SDCWS) which uses LED lights within each chevron sign to provide sequential lighted guidance through the curve.The research team evaluated eighteen rural horizontal curves where a SDCWS had been implemented on rural 2-lane curves. Reference sites with similar characteristics were selected and included in the study. Models were developed using an Empirical Bayes (EB) methodology for non-intersection (total) crashes and injury crashes. Additional countermeasures were present at some of the sites and were included in the model. Using these data, the study developed crash modification factors for SDCWS with a resulting Crash Modification Factor (CMF) of 0.34 for total crashes (non-intersection) and 0.49 for injury crashes.This is a manuscript of an article published as Hallmark, Shauna, Amrita Goswamy, Theresa Litteral, Neal Hawkins, Omar Smadi, and Skylar Knickerbocker. "Evaluation of sequential dynamic chevron warning systems on rural two-lane curves." Transportation research record 2674, no. 10 (2020): 648-657. doi: https://doi.org/10.1177/0361198120935872
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Modeling Merging Behavior at Lane Drops
Full text linkIn work-zone configurations where lane drops are present, merging of traffic at the taper presents an operational concern. In addition, as flow through the work zone is reduced, the relative traffic safety of the work zone is also reduced. Improving work-zone flow-through merge points depends on the behavior of individual drivers. By better understanding driver behavior, traffic control plans, work zone policies, and countermeasures can be better targeted to reinforce desirable lane closure merging behavior, leading to both improved safety and work-zone capacity. The researchers collected data for two work-zone scenarios that included lane drops with one scenario on the Interstate and the other on an urban arterial roadway. The researchers then modeled and calibrated these scenarios in VISSIM using real-world speeds, travel times, queue lengths, and merging behaviors (percentage of vehicles merging upstream and near the merge point). Once built and calibrated, the researchers modeled strategies for various countermeasures in the two work zones. The models were then used to test and evaluate how various merging strategies affect safety and operations at the merge areas in these two work zones.For the related 51-page full report, please see http://lib.dr.iastate.edu/intrans_reports/</p
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