1,720,964 research outputs found
Implementation of a V2I Highway Safety System and Connected Vehicle Testbed
No full textTo better prepare for the Connected Vehicle (CV) roadway, RSI has established a CV testbed along a highly crashed section of I-94, building on the Minnesota Traffic Observatory’s existing field lab infrastructure. This real- world testbed was designed to implement and evaluate the next generation of vehicle-based freeway safety applications. The priority of this project was to establish the backbone of the sensor communication network and data collection system along the testbed length.Hourdos, John; Parikh, Gordon; Dirks, Peter; Lehrke, Derek. (2019). Implementation of a V2I Highway Safety System and Connected Vehicle Testbed. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/202580
A Tool for Designing MnPASS Access Spacing
Full text linkDynamically priced High Occupancy Toll (HOT) lanes have been recently added to the traffic operations arsenal in an attempt to preserve infrastructure investment in the future by maintaining a control on demand. This study focuses on the operational and design features of HOT lanes. HOT lanes’ mobility and safety are contingent on the design of zones (“gates”) that drivers use to merge in or out of the facility. Existing methodologies for the design of access zones are limited to engineering judgment or studies that take into consideration undersized amount of observations. This project capitalized on the results of an earlier project that performed an assessment of safety and mobility on the HOT facilities in Minnesota highlighted the issues involved in either designs. The product of this project, the MnPASS Access Design application, provides a tool for traffic managers and planners to examine the conditions within an existing or prospective corridor and the distribution of shockwave lengths which are expected. From the distribution of shockwave lengths, decisions can be made regarding access restriction on the HOT lane to ensure that drivers do not attempt to make lane changes at locations prone to dangerous conditions. This tool provides support for the managers and planners by aggregating the entire behavior of the HOT lane within the corridor into a framework for simplified consideration.Zitzow, Stephen; Parikh, Gordon; Hourdos, John. (2018). A Tool for Designing MnPASS Access Spacing. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/197460
I-94 Connected Vehicles Testbed Operations and Maintenance
No full textIn March 2017, the Connected Vehicle Testbed along I-94 went live. The original project was sponsored by the Roadway Safety Institute and built on the Minnesota Traffic Observatory's (MTO) existing field lab, also utilizing certain Minnesota Department of Transportation (MnDOT) infrastructure. The testbed originally consisted of seven stations, rooftop and roadside, capable of transmitting radar and video data collected from the roadway back to a database at the MTO for analysis, emulating what a future connected vehicle (CV) roadway will look like. This project funded maintenance and upgrades to the system, as well as movement of some stations due to construction on I-94. In addition, better visualization tools for reading the database were developed. The CV testbed is state-of-the-art, fully functional, and uniquely situated to attract freeway safety-oriented vehicle to infrastructure (V2I) and vehicle to vehicle (V2V) safety application development, implementation, and evaluation projects going forward.Duhn, Melissa; Parikh, Gordon; Hourdos, John. (2019). I-94 Connected Vehicles Testbed Operations and Maintenance. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/203633
Evaluation of Safety and Mobility of Two-Lane Roundabouts
Full text linkWhen looking at measures of fatal and severe-injury crashes, roundabouts have demonstrated improved safety performance compared to traditional signalized intersections. Despite this, when it comes to less severe crashes, multilane roundabouts fail to provide a similar benefit. Previous research into this topic has identified behaviors that are associated with crashes in two-lane roundabouts, with yielding violations and turn violations generally being the largest contributors to crashes. This study sought to build on that work by expanding the data collection effort to include more sites and relate the frequency of individual behaviors to specific design features. Ultimately, four roundabouts were chosen for data collection and analysis, with two of them being full 2x2 roundabouts and the other two half-2x2. These locations were University Dr. S and 5th Ave. S in St. Cloud (half-2x2), 185th St. W and Kenwood Trail in Lakeville (full-2x2), and TH-22 and Adams St. (half-2x2) and TH-22 and Madison Ave. in Mankato (full-2x2). In the last two, changes in traffic control were implemented to reduce failure-to-yield crashes, and the study compared the driver behavior before and after the interventions. In general, the collective results show that the problems observed in the earlier site are present in all of the other sites with scale variations prompted by geometric and traffic control design elements. For example, in the St. Cloud roundabout, an increased rate of right-from-inner-lane turn violations were observed, which can be attributed to the sharper deflection angles present. Additionally, from the aforementioned roundabout as well as the one in Lakeville, it was concluded that turn violation rates are affected on the single or multilane geometry of the links approaching the roundabout. Single-lane roads result in fewer left-from-outer-lane violations. Overhead lane designation signs result in reduced turn violations similar to the earlier studies’ interventions in the approach lane markings. Unfortunately, apart from confirming the trend, no successful design or intervention was discovered regarding yield violationsHourdos, John; Parikh, Gordon. (2017). Evaluation of Safety and Mobility of Two-Lane Roundabouts. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/190714
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 the Smart Work Zone Speed Notification System
Full text linkThe Smart Work Zone Speed Notification (SWZSN) system aims to alleviate congestion, queuing, and rear end crashes in work zones by informing drivers of the speed of the downstream segment using a type of portable Intelligent Lane Control System (ILCS), Portable Changeable Message Signs (PCMS). The hypothesis was that drivers, knowing the speed up to 1 mile downstream, will slow down early or at least be alert and perform smoother decelerations. Video of the SWZSN was analyzed over two years of operation by the Minnesota Traffic Observatory. Overall, the system resulted in beneficial reductions of selected decelerations by the drivers. In situations where the messages communicated to the drivers were consistent and accurate, reductions of more than 30% in the selected deceleration rates were observed. Unfortunately, there were several cases where counterproductive or misleading messages were communicated to the drivers, prompting relative increases to the selected deceleration rates. The most important observation, stemming from both positive and negative influences, was that the speed notification system was noticed by drivers and resulted in a statistically significant influence on driving behavior, unlike other driver alert systems.Hourdos, John; Parikh, Gordon; Dirks, Peter; Lehrke, Derek; Lukashin, Pavel. (2019). Evaluation of the Smart Work Zone Speed Notification System. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/206588
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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