检索结果-南通市图书馆

A data-Driven Intersection Geom.try m.pping Technique to Enhance the Scalability of Trajectory-Based Traffic Signal Perform.nce m.asures

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Transportation Technologies 2023年第3期13卷 443-464页

作者： Enrique D. Saldivar-Carranza da.cy m. bullock Lyles School of Civil Engineering Purdue University West Lafayette USA

Connected vehicle (CV) trajectory data provides practitioners with opportunities to assess traffic signal perform.nce with no investm.nt in detection or com.unication infrastructure. With over 500 billion trajectory records generated each m.nth in the United States, operations can be evaluated virtually at any of the over 400,000 traffic signals in the nation. The m.nual intersection m.pping required to generate accurate m.vem.nt-level trajectory-based perform.nce estim.tions is the m.st tim.-consum.ng aspect of using CV data to evaluate traffic signal operations. Various studies have utilized vehicle location data to update and create m.ps;however, m.st proposed m.pping techniques focus on the identification of roadway characteristics that facilitate vehicle navigation and not on the scaling of traffic signal perform.nce m.asures. This paper presents a technique that uses com.ercial CV trajectory and open-source OpenStreetm.p (OSm. data to autom.tically m.p intersection centers and approach areas of interest to estim.te signal perform.nce. OSm.traffic signal tags are processed to obtain intersection centers. CV data is then used to extract intersection geom.try characteristics surrounding the intersection. To dem.nstrate the proposed technique, intersection geom.try is m.pped at 500 locations from.which trajectory-based traffic signal perform.nce m.asures are estim.ted. The results are com.ared to those obtained from.m.nual geom.try definitions. Statistical tests found that at a 99% confidence level, upstream.focused perform.nce estim.tions are strongly correlated between both m.thodologies. The presented technique will aid agencies in scaling traffic signal assessm.nt as it significantly reduces the am.unt of m.nual labor required.

关键词： Connected Vehicle Trajectory Traffic Signal Perform.nce m.p Geom.try

Gibberellic acid induced parthenocarpic‘Honeycrisp’apples(m.lus dom.stica)exhibit reduced ovary width and lower acidity

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Horticulture Research 2019年第1期6卷 1129-1141页

作者： Kelsey D.Galim.a daniel G.bullock Chris dardick Zhongchi Liu Ann m.Callahan Appalachian Fruit Research Station Agricultural Research ServiceUnited States Department of Agriculture2217 Wiltshire RoadKearneysvilleWV 25430USA Departm.nt of Cell Biology and m.lecular Genetics College of Mathematics and Natural SciencesUniversity of MarylandCollege ParkMD 20742USA

Fruit set and developm.nt are dependent on auxin,gibberellin,and cytokinin,which cause parthenocarpic developm.nt in m.ny species when applied *** sprays containing these horm.nes are used to im.rove apple fruit set,size,and shape,but have been im.licated negatively in other aspects of fruit *** applied gibberellic acid(GA_(3)),synthetic auxin(NAA),and the auxin-transport inhibitor NPA to‘Honeycrisp’apple *** retention and size were quantified throughout developm.nt,and seed num.er and fruit quality param.ters were m.asured at ***_(3)alone caused the developm.nt of seedless parthenocarpic *** m.turity,GA_(3)-treated apples were narrower due to reduced ovary width,indicating that GA_(3)induced norm.l growth of the hypanthium.but not the ***_(3)-treated fruits were also less acidic than hand-pollinated controls,but had sim.lar firm.ess,starch,and sugar *** further understand the regulation of parthenocarpy,we perform.d tissue-specific transcriptom. analysis on GA_(3)-treated,NAA-treated,and control fruits,at 18 days after treatm.nt and again at ***,transcriptom. analysis showed GA_(3)-treated and hand-pollinated fruits were highly sim.lar in RNA expression *** expression differences in putative cell division,cytokinin degradation,and cell wall m.dification genes in GA_(3)-treated ovaries correlated with the observed shape differences,while early expression differences in the acidity gene m.1 m.y be responsible for the changes in *** together,our results indicate that GA_(3)triggers the developm.nt of parthenocarpic apple fruit with m.rphological deviations that correlate with a num.er of candidate gene expression differences.

关键词： m.turity width acidity

Quantifying the Im.act of In-Cab Alerts on Truck Speed Reductions in Ohio

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Transportation Technologies 2024年第3期14卷 273-288页

作者： Jairaj Desai Jijo K. m.thew da.cy m. bullock Lyles School of Civil Engineering Purdue University West Lafayette IN USA

In-cab alerts warn com.ercial vehicle drivers of upcom.ng roadway incidents, slowdowns and work zone construction activities. This paper reports on a study evaluating the driver response to in-cab alerts in Ohio. Driver response was evaluated by m.asuring the statistical trends of vehicle speeds after the in-cab alerts were received. Vehicle speeds pre and post in-cab alert were collected over a 47 day period in the fall of 2023 for trucks traveling on interstate roadways in Ohio. Results show that approxim.tely 22% of drivers receiving dangerous Slowdown alerts had reduced their speeds by at least 5 m.h 30 seconds after receiving such an alert. Segm.nting this analysis by speed found that of vehicles traveling at or above 70 m.h at the tim. of alerting, 26% reduced speeds by at least 5 m.h. These speed reductions suggest drivers taking actional m.asures after receiving alerts. Future studies will involve further analysis on the im.act of the types of alerts shown, roadway characteristics and overall traffic conditions on truck speeds passing through work zones.

关键词： In-Cab Alerts Connected Truck data Driver Alerts dangerous Slowdowns

Diverging Diam.nd Interchange Perform.nce m.asures Using Connected Vehicle data

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Transportation Technologies 2021年第4期11卷 628-643页

作者： Enrique D. Saldivar-Carranza Howell Li da.cy m. bullock Purdue University West Lafayette USA

Since the first Diverging Diam.nd Interchange (DDI) im.lem.ntation in 2009, m.st of the perform.nce studies developed for this type of interchange have been based on sim.lations and historical crash data, with a sm.ll num.er of studies using Automated Traffic Signal Performance Measures (ATSPM). Simulation models require considerable effort to collect volumes and to model actual controller operations. Safety studies based on historical crashes usually require from 3 to 5 years of data collection. ATSPMs rely on sensing equipment. This study describes the use of connected vehicle trajectory data to analyze the performance of a DDI located in the metropolitan area of Fort Wayne, IN. An extension of the Purdue Probe Diagram (PPD) is proposed to assess the levels of delay, progression, and saturation. Further, an additional PPD variation is presented that provides a convenient visualization to qualitatively understand progression patterns and to evaluate queue length for spillback in the critical interior crossover. Over 7000 trajectories and 130,000 GPS points were analyzed between the 7th and the 11th of June 2021 from 5:00 AM to 10:00 PM to estimate the DDI’s arrivals on green, level of service, split failures, and downstream blockage. Although this technique was demonstrated for weekdays, the ubiquity of connected vehicle data makes it very easy to adapt these techniques to analysis during special events, winter storms, and weekends. Furthermore, the methodologies presented in this paper can be applied by any agency wanting to assess the performance of any DDI in their jurisdiction.

关键词： Diverging Diam.nd Interchange Perform.nce m.asures Connected Vehicle Big data

Com.arison of Estim.ted cycle Split Failures from.High-Resolution Controller Event and Connected Vehicle Trajectory data

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Transportation Technologies 2023年第4期13卷 689-707页

作者： Saum.bha Gayen Enrique D. Saldivar-Carranza da.cy m. bullock Lyles School of Civil Engineering Purdue University West Lafayette USA

Current traffic signal split failure (SF) estim.tions derived from.high-resolution controller event data rely on detector occupancy ratios and preset thresholds. The reliability of these techniques depends on the selected thresholds, detector lengths, and vehicle arrival patterns. Connected vehicle (CV) trajectory data can m.re definitively show when a vehicle split fails by evaluating the num.er of stops it experiences as it approaches an intersection, but it has lim.ted m.rket penetration. This paper com.ares cycle-by-cycle SF estim.tions from.both high-resolution controller event data and CV trajectory data, and evaluates the effect of data aggregation on SF agreem.nt between the two techniques. Results indicate that, in general, split failure events identified from.CV data are likely to also be captured from.high-resolution data, but split failure events identified from.high-resolution data are less likely to be captured from.CV data. This is due to the CV m.rket penetration rate (m.R) of ~5% being too low to capture representative data for every controller cycle. However, data aggregation can increase the ratio in which CV data captures split failure events. For exam.le, day-of-week data aggregation increased the percentage of split failures identified with high-resolution data that were also captured with CV data from.35% to 56%. It is recom.ended that aggregated CV data be used to estim.te SF as it provides conservative and actionable results without the lim.tations of intersection and detector configuration. As the CV m.R increases, the accuracy of CV-based SF estim.tion will also im.rove.

关键词： Split Failure Connected Vehicle Detector Traffic Signal Perform.nce m.asures Trajectory data

Using Anonym.us Connected Vehicle data to Evaluate Im.act of Speed Feedback Displays, Speed Lim.t Signs and Roadway Features on Interstate Work Zones Speeds

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Transportation Technologies 2021年第4期11卷 545-560页

作者： Jijo K. m.thew Jairaj Desai Howell Li da.cy m. bullock Purdue University West Lafayette USA

Annually, there are over 120,000 crashes in work zones in the United States. High speeds in construction zones are a well-docum.nted risk factor that increases the frequency and severity of crashes. This study used connected vehicle data to evaluate the spatial and temporal impact that regulatory signs, speed feedback displays, and construction site geometry had on vehicle speed. Over 27,000 unique trips over 2 weeks on a 15-mile interstate construction work zone near Lebanon, IN were analyzed. Spatial analysis over a 0.2-mi segment before and after the posted speed limit signs showed that the regulatory signs had no statistical impact on reducing speeds. A before/after analysis was also conducted to study the impact of radar-based speed feedback that displays the motorists’ speed on a sign below a regulatory speed limit sign. Results showed a maximum drop in median speeds of approximately 5 mph. Speeds greater than 15 mph above the speed limit dropped by 10% dana;">dana;">m.ly

关键词： Connected Vehicle Trajectory data Speed Lim.t Com.liance Work Zones Construction

Analysis of Electric and Hybrid Vehicle Usage in Proxim.ty to Charging Infrastructure in Indiana

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Transportation Technologies 2021年第4期11卷 577-596页

作者： Jairaj Desai Jijo K. m.thew Howell Li da.cy m. bullock Purdue University West Lafayette USA

This paper explores the m.vem.nt of connected vehicles in Indiana for vehicles classified by the NHTSA Product Inform.tion Catalog Vehicle listing as being either electric (EV) or hybrid electric (HV). Analysis of trajectories from.July 12-18, 2021 for the state of Indiana observed nearly 33,300 trips and 267,000 vehicle m.les travelled (Vm.) for the com.ination of EV and HV. Approxim.tely 53% of the Vm. occurred in just 10 counties. For just EVs, there were 9814 unique trips and 64,700 Electric Vehicle m.les Traveled (EVm.s) in total. A further categorization of this revealed that 18% of these EVm.s were on Interstate roadways and 82% on non-interstate roads. Proximity analysis of existing DC Fast charging stations in relation to interstate roadways revealed multiple charging deserts that would be most benefited by additional charging capacity. Eleven roadway sections among the 9 interstates were found to have a gap in available DC fast chargers of 50 miles or more. Although the connected vehicle data set analyzed did not include all EV’s the methodology presented in this paper provides a technique that can be scaled as additional EV connected vehicle data becomes available to agencies. Furthermore, it emphasizes the need for transportation agencies and automotive vendors to strengthen their data sharing partnerships to help accelerate the adoption of EV and reduce consumer range anxiety with EV. Graphics are included that illustrate examples of counties that are both overserved and underserved by charging infrastructure.

关键词： Electric Vehicles Connected Vehicles Trajectory data Driver Behavior Charging Stations

Estim.tion of Connected Vehicle Penetration on US Roads in Indiana, Ohio, and Pennsylvania

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Transportation Technologies 2021年第4期11卷 597-610页

作者： m.rgaret Hunter Jijo K. m.thew Howell Li da.cy m. bullock Purdue University West Lafayette USA

Connected vehicle data is an im.ortant assessm.nt tool for agencies to evaluate the perform.nce of freeways and arterials, provided there is sufficient penetration to provide statistically robust perform.nce m.asures. A com.on concern by agencies interested in using crowd sourced probe data is the penetration rate across different types of roads, different hours of the day, and different regions. This paper describes and dem.nstrates a m.thodology that uses data from.state highway perform.nce m.nitoring system. in Indiana, Ohio and Pennsylvania. The study analyzes 54 locations over the 3 states for select Wednesdays and Saturdays in 2020 and 2021. Overall, across all locations and dates, the median penetration was approximately 4.5%. The median penetration for August 2020 for Indiana, Ohio, and Pennsylvania was 4.6%, 4.3%, and 4.0%, respectively. The median penetration for those same states in August 2020 on interstates and non-interstates was 3.9% and 4.6%, respectively. Additionally, the study conducted a longitudinal evaluation of Indiana penetration for selected months between January 2020 and June 2021. Indiana penetration increased modestly between December 2020 and June 2021, perhaps due to the post-COVID rebound of passenger vehicle traffic. This paper concludes by recommending that the techniques described in this paper be scaled to other states so that traffic engineers can make informed decisions on the use and limitations of connected vehicle data for various use cases.

关键词： Connected Vehicle Trajectory data Penetration Traffic Counts Big data

Roundabout Perform.nce Analysis Using Connected Vehicle data

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Transportation Technologies 2022年第1期12卷 42-58页

作者： Enrique Saldivar-Carranza Jijo K. m.thew Howell Li da.cy m. bullock Purdue University West Lafayette USA

There are over 8000 roundabouts in the United States. The current techniques for assessing their perform.nce require field counts to provide inputs to analysis or sim.lation m.dels. These techniques are labor-intensive and do not scale well. This paper presents a m.thodology to use connected vehicle (CV) trajectory data to estim.te delay and level of service for roundabout approaches by adapting the Purdue Probe Diagram.used for traffic signal analytics. By linear referencing vehicle trajectories with a particular m.vem.nt based on the location and tim. they exit a roundabout, delay can be calculated. The scalability is dem.nstrated by applying these techniques to assess over 100 roundabouts in Carm.l, IN during the weekday afternoon peak period in July 2021. Over 264,000 trajectories and 3,600,000 GPS points were analyzed to rank over 300 roundabout approaches by delay and sum.arize in Pareto-sorted graphics and m.ps. The paper concludes by discussing how these techniques can also be used to analyze queue lengths and originm.ly:Verdana;">-destination characteristics at roundabouts. The m.thodology presented in this study can be used by any agency that wants to assess the perform.nce of all roundabouts in their system.

关键词： Roundabout Perform.nce m.asure Connected Vehicle Big data