Evaluating Safety and Operational Effectiveness of Truck Climbing Lanes Along Interstate 80 in Wyoming PDF Download

Author: Muhammad Tahmidul Haq
Publisher:
ISBN: 9780438100312
Category : Climbing lanes
Languages : en
Pages : 131

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Book Description
Roadway safety is of a primary concern for all stakeholders in the transportation industry, as well as the general public. A major use of the highway system is the movement of goods, and the trucking industry keeps on contributing fundamentally to the nation’s economy. Over the recent years, the United States has encountered steady development in the amount of freight transported by truck because of globalization, trade growth, and improvements in logistics and supply chain management. In 2012, 4 million tons of freight in United States were transported by trucks, which accounted for 68.5 percent of the total freight weight. This percentage is expected to continue to grow in the next ten years. Although these improvements have prompted financial development, there has been a sharp increase in the extent of cargo/truck movement going along key routes that has caused significant interactions between trucks and other vehicles. In 2016, over 4,300 people died in large truck related crashes in the United States. The number of motor vehicle fatalities increased by 1,976 in 2016 compared to 2015, which was about 5.6% increase. Among these motor vehicle occupants killed in traffic crashes, approximately 21% were due to truck-related crashes. The approximate average cost of a large-truck related crash was more than $91,000. Wyoming is also encountering an extensive increase in truck movement along Interstate 80 (I-80). The increased interactions between trucks and other vehicles have raised many operational and safety concerns along I-80. According to Wyoming Department of Transportation (WYDOT) annual crash report, 65% of fatal truck crash (medium and heavy truck) occurred on interstate highways of Wyoming in 2016, and 54% of these fatal crashes were observed on I-80 in Wyoming. On the other hand, the presence of heavy truck traffic degrades the operational performance of roadway system. According to the Highway Capacity Manual (HCM), passenger cars can negotiate upgrades of 4% to 5% without a noticeable loss in speeds maintained on level roadways. However, the performance of trucks is greatly affected by vertical grades. Trucks start losing their speeds at freeway grades of about 1%. Trucks generally decrease speed by more than 7% on upgrades as compared to their operation on level terrains. The reduction in truck speeds depends on the rate and length of grades, as summarized by the HCM. This causes a lot of friction between passenger cars and trucks on upgrades, with a noticeable difference in speeds. Also, because of the high truck percentage, it is very common for trucks to use the left lane, which causes a queue buildup behind them and leading to deteriorated traffic conditions. This study investigated the impacts of truck traffic on selected upgrades of freeway segments along I-80 in Wyoming and climbing lanes were considered as one of the potential mitigation strategies to enhance operational efficiency and safety. Cross-sectional analysis was adopted to evaluate the safety effectiveness of climbing lanes. Data were collected from different sources and Wyoming-specific Safety Performance Functions (SPFs) were developed using crash data from 2008 to 2016 for different severity levels and crash types. All the segments were selected from I-80 in Wyoming with climbing lanes as treatment sites, and segments with similar geometrical characteristics without climbing lanes as comparison sites. The Negative Binomial (NB) and Zero-Inflated Negative Binomial (ZINB) model were used to develop Wyoming-specific SPFs for I-80 as they were found to fit better for the crash data. The Crash Modification Factors (CMFs) for climbing lanes were found effective in reducing different severity levels and crash types. For operational analysis, a ten-mile eastbound segment along I-80 (MP 313 – MP 323) was chosen, and the traffic volume and roadway geometry associated with this segment were collected to evaluate the climbing lane efficiency for this specific segment. A combination of VISUM and VISSIM was applied to develop microsimulation model for both current and future (the year 2027 and 2037) traffic conditions at selected segment of I-80 corridor. It was found that the installation of climbing lanes has the potential to improve operational performances (average delay, total delay, total travel time, average speed) for a 10 and 20-year planning horizon.

Author: Muhammad Tahmidul Haq
Publisher:
ISBN:
Category : Climbing lanes
Languages : en
Pages :

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Book Description
I-80 in Wyoming is characterized by heavy truck traffic, with an average of 47 percent of heavy trucks in the traffic flow. This research analyzes the impacts of truck traffic along I-80 in Wyoming, as well as mitigation strategies to minimize negative impacts, through analyses of safety and operational implications that result from the interactions between trucks and other vehicles. Various traffic, geometrical, and weather characteristics were found significant to increase truck-related crashes, whereas the presence of climbing lanes was found to have potential safety and operational benefits. The analysis of occupant injury severity in passenger car-truck collisions shows that car drivers are more responsible than truck drivers contributing more severe injuries. The disaggregate modeling approach shows significant differences in both the combination and the magnitude of the impact of variables that justify the importance of examining the injury severity of truck-involved crashes broken down by vehicle types, truck configurations, and driving actions. The crash rate analysis shows a higher tire failure rate for trucks compared to the total tire failure rate considering equal vehicle miles traveled as exposure. Benefit-cost analysis for climbing lane installations indicates that the installation of climbing lanes has a significant potential to improve traffic performances for a 20-year planning horizon, with aggregated benefits significantly outperforming the corresponding costs. Findings from this study are expected to help the Wyoming Department of Transportation and policymakers take necessary actions in reducing truck-related crashes and improve the overall operational performance by targeting appropriate strategies and proper resource allocation.

Author: Arash Khoda Bakhshi
Publisher:
ISBN:
Category : Interstate 80
Languages : en
Pages : 342

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Book Description
Traffic crashes impose a significant socio-economic cost on societies. According to the World Health Organization (WHO), 1.2 million people die every year, and more than 50 million people are injured due to fatal and non-fatal crashes globally. Safety concerns are more serious on rural corridors that play crucial roles in freight movement, such as Interstate 80 (I-80) in the State of Wyoming. Being affected by Wyoming’s adverse weather conditions, high altitude, challenging geometric characteristics, and critical traffic composition, there has been a notable crash and critical crash rate on 402-miles of this major freight corridor in Wyoming. To alleviate these safety concerns, the United States Department of Transportation Federal Highway Administration (USDOT FHWA) selected the Wyoming Department of Transportation (WYDOT) to deploy a Connected Vehicle (CV) Pilot Program along I-80 in Wyoming (WYDOT CV Pilot). The WYDOT CV Pilot focuses on the needs of the commercial vehicle operator and will develop CV applications to support a flexible range of services under Vehicular Ad-hoc Network (VANET), including roadside alerts, parking notifications, and dynamic travel guidance. In this regard, evaluation of the safety impacts of the CV Pilot is central to the USDOT’s strategic goals. The literature pointed out that the Market Penetration Rate (MPR) of CVs should be large enough to ensure safety and operational benefits of CVs. However, at early stages of the WYDOT CV Pilot, CVs will be contributing to a small fraction of the entire traffic stream, challenging traditional safety performance evaluation methodologies to assess the effectiveness of the CV technology. With these concerns, a comprehensive Analysis, Modeling, and Simulation (AMS) framework in addition to reliable baseline Analyses are required to scrutinize the safety performance of CVs under various MPR. These requirements have been fulfilled in this research through the use of advanced statistical modeling, Machine Learning, Deep Learning, data mining techniques, data visualization, and taking practical advantages of simulation- and driving simulator-based analyses. In the developed baseline and under the concept of Real-Time Risk Assessment (RTRA), significant real-time traffic-related variables contributing to crash and critical crash occurrences on the 402-miles I-80 in Wyoming during CV pre-deployment were identified. Using advanced statistical modeling and data visualization tools provided by Machine Learning techniques, the causal effect of these significant factors on the crash/ critical crash probabilities were explored. These causations are expected to be affected due to CV technology under notable MPRs in the future. Accordingly, the conducted baseline will be used as a benchmark against explored crash causations during CV post-deployment to grasp how this technology alleviates or changes the causality patterns, revealing the WYDOT CV Pilot safety performance. Furthermore, based on the preprocessed real-time traffic observation from the RTRA, the research calibrated and validated a reliable AMS framework to assess the safety effectiveness of the WYDOT CV Pilot that mainly goes around level-0 and level-1 of automated driving systems. At these levels, drivers are in charge of the execution of steering, acceleration/deceleration, and monitoring of the driving environment; thus, the human factor contributing to more than 90% of traffic crashes is still in that safety loop. Having said that, the AMS framework primarily aims to show how various CV applications, designed under WYDOT CV Pilot, would alter CV drivers’ behavior under traffic critical safety events and measure the effect of this alteration on I-80 traffic safety performance. Accordingly, drivers' behavioral alterations due to CV notification were quantified under the concept of with/without analysis and in a series of comprehensive high-fidelity driving simulator experiments conducted at the University of Wyoming Driving Simulator Lab (WyoSafeSim). These quantifications were analyzed separately and were conflated with traffic microsimulation modeling to reveal the safety effects of CV technology on the I-80 traffic stream under varying CV MPRs. This dissertation's findings and insights would be of interest to the WYDOT, the USDOT FHWA, and practitioners in the safety domain. The provided crowd-sourced real-time traffic dataset in the conducted baseline would help the WYDOT in understanding the current safety performance of I-80, identifying black-spot points in high-risk I-80 segments, and developing proactive countermeasures and interventions for Active Traffic Management (ATM) to alleviate the risk of traffic crashes on this major freight corridor. The data-driven crowdsourcing procedure performed on the AMS framework would shed some light on realizing the impact of CV technology on enhancing drivers’ situational awareness and minimizing the rate of motor vehicle crashes, which is not limited to I-80 in Wyoming. The integration of a high-fidelity driving simulator with traffic microsimulation modeling, as a two-pronged approach applied in the AMS framework, would show a fruitful pathway for the safety performance assessment of other CV pilots deployed by the FHWA with small CV MPRs at early deployment stages. Besides, beyond the main scope of assessing CV applications designed for WYDOT CV Pilot, the developed AMS framework could be utilized to evaluate the safety effect of other CV applications, such as the application of CV Variable Speed Limit (VSL) on lengthy rural corridors for the sake of spatiotemporal speed harmonization. The developed Road Weather Connected Vehicle Applications AMS framework was further extended by incorporating driver behavior and performance in adverse weather conditions utilizing a comprehensive Naturalistic Driving Study (NDS) dataset from the second Strategic Highway Research Program (SHRP2). The developed AMS framework could be helpful for a wide array of safety and operations of the next generation active traffic management.

Author: Sadia Sharmin
Publisher:
ISBN: 9780438564725
Category : Roads
Languages : en
Pages : 116

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The complexity of traffic movements at signalized intersections is of a significant interest to transportation professionals due to a disproportional high amount of conflicts and crashes involving turning vehicles followed by through vehicles. Moreover, the wide variability in geometric and operational characteristics at signalized intersections may exacerbate this complexity. Intersection-related fatalities in Wyoming exhibited a sharp increase after 2012. Fatality rate in Wyoming exceeded the national rate by 12 percent in 2014 and 2015. In 2015, Wyoming’s urban intersections crashes constituted 50% of total urban crashes while that the proportion at the national level in the US was 32%. These issues could be addressed through successful engineering approaches which necessitate reliable methods to estimate intersection safety. Currently, Safety Performance Functions (SPFs) are used as the main tool to estimate traffic safety of different roadway elements including intersections. The Highway Safety Manual (HSM), published by the American Association of State Highway and Transportation Officials (AASHTO) in 2010 provides SPFs for intersections. The unique nature and distinct attributes of Wyoming also necessitates developing its own jurisdiction-specific SPFs. SPFs are needed to identify potential candidate locations for safety improvements and for implementation of various safety countermeasures. Therefore, the research in this thesis focuses on calibrating SPFs for four-leg signalized intersections in Wyoming. The thesis also utilizes advanced statistical techniques to address various issues in crash data at intersections. Crash data at four-leg signalized intersections were structured as pooled data averaged across time and panel data with respect to time. The key issues addressed in this study include: i) addressing overdispersion characteristics of crash data, ii) considering unobserved random effects of the intersections due to their heterogeneity, and iii) allowing the effects of the confounding factors on intersection crash trends over time. This study examined the effects of geometry, weather, traffic and driver characteristics on crash frequencies incorporating time trends and taking longer time frames into consideration. Standard crash models using longer time frames and aggregated data do not consider time-varying effects on crash frequency, and can introduce error due to unobserved heterogeneity. This study analyzed the findings among traditional Negative Binomial (NB) model (using pooled and panel data) which account for the overdispersion of data, Random Effect Negative Binomial (RENB) model using panel data that consider unobserved random effects of the sites due to their heterogeneity and Generalized Estimating Equation (GEE) with Negative Binomial (NB) distribution. RENB model outperformed NB models by comparing the Akaike Information Criterion (AIC) values and hence, RENB models were chosen to explain the effects of the confounding factors on the crash counts. A marginal model approach which is different from the random effect approach was attempted through applying GEE to the panel data. “Time” was included as an explanatory variable with linear and quadratic effects to investigate the crash trends across time. The interactions of variables with “time” were considered to determine the effect of fixed variables over time. GEE was also fitted using variables without incorporating “time”, however, GEE accounting for “time” performed better. Model assessment was performed using the quasi-likelihood information criterion (QIC). This method also showed that the GEE model with autoregression structure had the best model performance. Installing left-turn lanes at signalized intersections physically separates left-turning vehicles, hence can reduce the number of conflicts by removing slow or decelerating vehicles from through traffic resulting in safer operations. The safety effectiveness of left-turn lanes at four-leg signalized intersections was estimated with these approaches along with predicting and describing the confounding factors. The aforementioned objectives were attained by developing SPFs using 174 four-leg signalized intersections crash data of Wyoming from the years 2005 through 2014. Wyoming specific data, including traffic, weather and driver characteristics, were incorporated into the models along with site-specific geometric characteristics. The results of this study highlighted the advantages of predicting crash frequencies by crash type and severity. To examine the impact of weather on intersections crashes, three sets of SPFs were calibrated; winter, summer, and all year. The cross-sectional panel data analysis for evaluating the safety effectiveness of adding left-turn lanes at four-leg signalized intersections indicated a reduction of Fatal+Injury (F+I) and angle crashes by 21.6% and 30.8%, respectively. The calibrated models for the winter indicated a reduction of 19.4% and 38.8% for the aforementioned crashes, respectively for adding left-turn lanes. For the summer, crash reduction for these crashes for the same treatment were found 71% and 69%, respectively.

Author: Md. Hamidur Rahman
Publisher:
ISBN: 9781369761856
Category : Roads
Languages : en
Pages : 176

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Book Description
To achieve better traffic management, transportation agencies implement a variety of traffic safety countermeasures in their roadway system. Regulatory headlight sign is a countermeasure which can be implemented on roadway sections with challenging geometrical characteristics to require drivers to turn on their headlights manually. Several studies showed that Daytime Running Lights (DRL) technology reduces certain types of multi-vehicle daytime crashes. Elvik (1996) conducted a meta-analysis using previous 17 studies that estimated safety effectiveness of DRL and concluded that DRL technology reduces certain types of daytime multi-vehicle crashes (head-on and opposite sideswipe crashes) by 10- to-15%. It is recognized that the overall safety effectiveness of DRL for different road users is still up for debate. Assuming that instructions given on a headlight sign will be observed and obeyed by motor vehicle drivers, these signs may help in increasing vehicle conspicuity and detectability. Headlights may help drivers maintaining appropriate lane position and proper gap with ambient traffic and hence improve safety. This study evaluated the safety efficacy of regulatory headlight signs by calibrating Crash Modification Factors (CMFs) on rural two-way two-lane mountainous roadway sections in Wyoming using various case-control, and observational before-after studies. Research related to the Crash Modification Factor estimation of regulatory headlight signs is hard to come by. The Federal Highway Administration (FHWA) launched an online site named “Crash Modification Factor Clearing House” in a bid to compile CMFs reported by various researchers in the transportation field. The Highway Safety Manual (HSM 2010) also provides CMF values for a number of countermeasures. The HSM also provides detailed steps on how to calibrate quality CMFs. The CMF for regulatory headlight 6zsign does not exist in the FHWA CMF Clearinghouse and the Highway Safety Manual suggesting scarcity of research on this countermeasure. This study will augment the understanding of the role of regulatory headlight signs on two-way two-lane mountainous roadway sections. There are seven regulatory headlight sign sections in Wyoming’s two-way two-lane roadway system. Daytime Running Light can be enforced in two forms; as a mandatory technological feature equipped in vehicles that turn on headlights with the start of the ignition, or as a behavioral measure that requires drivers to turn on headlights of their vehicles manually wherever they enter such regulatory headlight sign sections on a roadway. The main focus of this study was the manual headlight operation with taking into consideration the market penetration of the automatic DRL technology as well as drivers’ compliance with the headlight sign countermeasure. Three methods were attempted to achieve the goal of this research. In the case-control method, simple odds and odds ratios were utilized to quantify how strongly the presence of DRL is associated with the existence of headlight signs for crashes in two-way two-lane highways. Cross-sectional data for crash frequency and factors affecting crash frequency of a segment from both headlights sign sections and reference sections were also used in a cross-sectional design. In the before-after with EB study, only three sections; WY220 MP 88-102, WY59 MP 76-101, and WY28 MP 24.408-68.219 were used in a 3-year before and 2-year after study due to data limitation. Wyoming-specific simple Safety Performance Functions (SPFs) and full SPFs were used to estimate safety effectiveness of regulatory headlight signs for different crash types. Odds ratio determined from case-control analysis for total crash type indicates no significant effect of the presence of DRL equipped vehicles on the roadway sections with or without regulatory headlight signs. Similar conclusion was obtained for target crashes, i.e., head- on and opposite sideswipe crashes. It should be noted that both findings were not statistically significant. Results from the cross-sectional study show that Crash Modification Factor of regulatory headlight sign is less than 1 in all crash types considered except target crash type indicating safety benefit with the maximum value of 1.20 observed in target crash type and the minimum value of 0.5233 observed in fatal plus injury crash type, respectively. None of the results are statistically significant at 95% confidence level. Results from the before-after with EB study using both simple SPF and full SPF show that installing regulatory headlight sign on rural two-way two-lane mountainous roadway sections results in unreasonable safety effectiveness for total, target, and fatal plus injury crash types. Both results are over-estimating the safety effects of headlight signs and cannot be accepted from an engineering perspective. There might be several reasons behind this high safety estimate including some other unobserved treatments that were not considered in the analysis. Moreover, the limited number of treated sites could be another reason; only three sites were utilized in the study.

Author:
Publisher:
ISBN:
Category : Freight and freightage
Languages : en
Pages : 58

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Author:
Publisher:
ISBN:
Category : Transportation
Languages : en
Pages : 320

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Author: American Association of State Highway and Transportation Officials. Task Force for Roadside Safety
Publisher:
ISBN:
Category : Roads
Languages : en
Pages : 560

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Author: Douglas W. Harwood
Publisher: Transportation Research Board
ISBN: 0309099277
Category : Automobile driving
Languages : en
Pages : 95

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At head of title: National Cooperative Highway Research Program.

Author: Ronald D. Tabler
Publisher: Strategic Highway Research Program (Shrp)
ISBN:
Category : Science
Languages : en
Pages : 396

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