<p> Engineering practitioners using microsimulation tools to models traffic impacts, have limited guidelines from municipalities regarding how drivers behave. In the Midwest of the United States, drivers may behave similarly on certain types of roads. The objective of this study was to see whether there are significant differences in travel time and delays when using different drivers&rsquo; behavior input on VISSIM. </p><p> To conduct this study, the researcher studied two locations that had traffic simulation models already available. The first study site was a section of MO-364, which is in the northwest of Saint Louis area, and the second study site was along US-76 in Branson, Missouri. MO-364 and I-270 have posted speed limit of 60 mph. The researcher collected free-flow speed data from both sites and put the inputs-desired speed distributions- into VISSIM for MO-364 model. The software gave outputs for travel time, delays on the links and delays on delays on the nodes. The researcher did the same procedure for US-76 model for US-76 corridor and Northwest University Rd. </p><p> To see whether there were any differences in travel time and delays by choosing different drivers&rsquo; behavior, the researcher collected free flow speed in all the roads and put it into VISSIM to see the outcomes of 1) Travel time, 2) Delay on the links, and 3) Delay on the intersections. In order to analyze the results, paired two sample t-test was used through Microsoft Excel. </p><p> The results showed that there are significant differences in travel time and delay on the links that have little congestion during the study period. However, in the roads that have more congestion, statistical analysis proved that based on paired two sample t-test with 95 percent confidence interval, the differences are significant in those features. The only feature that remained the same in any condition was delay on the nodes (intersections). This result means that for simulation studies focused on measuring intersection delay, driver speed behavior can be applied from other locations within the region and need-not be collected at the specific study site.</p><p>

<p> Traffic simulation has become an invaluable part of the traffic engineering toolbox. However, the majority of driver models are designed to recreate traffic performance based on interactions among vehicles. In keeping with this pursuit, most are fundamentally built to avoid collisions. This limits the applicability of using these models for addressing safety concerns, especially those regarding pedestrian safety performance. However, by explicitly including some of the sources of human error, these limitations can, in theory, be overcome. While much work has been done toward including these <i>human factors</i> in simulation platforms, one key aspect of human behavior has been largely ignored: driver distraction. </p><p> This work presents a novel approach to inclusion of driver distraction in a microsimulation or agent-based model. Distributions of distraction events and inter-distraction periods are derived from eye-glance data collected during naturalistic driving studies. The developed model of distraction is implemented &ndash; along with perception errors, visual obstructions, and driver reaction times &ndash; in a simulated mid-block pedestrian crossing. </p><p> The results of this simulation demonstrate that excluding any of these human factors from the implemented driver model significantly alters conflict rates observed in the simulation. This finding suggests that inclusion of human factors is important in any microsimulation platforms used to analyze pedestrian safety performance.</p><p>

<p> Heavy commercial vehicles account for a large percentage of vehicles operating on public roadways, and an even larger percentage of vehicle miles traveled. The pneumatic braking system which heavy vehicles are equipped with, is often found to be deficient by law enforcement and investigators during roadside inspections or following a collision. Deficient pneumatic braking systems increase the distance necessary for a fully laden heavy vehicle to slow or stop. The stopping distance of a heavy vehicle, even when the braking system is fully functional, is significantly longer than that of a passenger vehicle. Slow deceleration rates and long stopping distance can, and do, result in collisions. The licensed commercial driver of a heavy vehicle is federally mandated to complete pre-trip inspections. These pre-trip inspections, and inspections completed by maintenance personal during the servicing of the vehicle, are often inadequate and may fail to identify burgeoning problems within the vehicle&rsquo;s braking system. Current technology in heavy vehicle braking systems lessens the burden on the driver to constantly maintain the braking system, but does not eliminate the need for regular inspections, and maintenance if needed. Even with current technology, it remains common to find the adjustment of the braking system components on over-the-road heavy vehicles beyond safe limits during roadside inspections. </p><p> This project presents an overview of the mechanical function of the modern S-cam pneumatic braking system commonly found on heavy vehicles in the United States. The areas of failures and potential deficiencies within S-cam pneumatic brakes is explored and discussed. Additionally, several different pneumatic braking performance analysis methods are presented, which can be used to determine the maximum deceleration rate and speed of a heavy vehicle with a fully operational braking system, and when the braking system is compromised. Examples of each analysis method are included in appendices to this paper. </p><p> This project presents research examining the potential use of an ultrasonic sensor to, in real-time, measure and relay the adjustment of a heavy vehicle&rsquo;s brakes to the operator of the vehicle. In this way the operator of the vehicle will be alerted when the adjustment limit of a brake on their vehicle or trailer(s) is reached. Additionally, an alternative design for the studied sensor, which would fulfill the same purpose, is presented in detail.</p><p>

<p> Pedestrians are the most vulnerable road users. The risks to pedestrians crossing at uncontrolled locations are much higher than at signalized intersections. There has been an increasing trend in pedestrian deaths during the past decade. Specifically, pedestrian fatality as the percent of total fatalities indicates an increasing trend in a ten-year period from 2005 to 2014. Several research projects funded by both federal and state transportation agencies have attempted to identify effective strategies for improving pedestrian safety within their jurisdictions. However, very little research was conducted on pedestrian safety at uncontrolled locations in Illinois. The objectives of this study were to identify the best practices of approving pedestrian crossings and pedestrian treatments at uncontrolled locations and to develop guidelines to be used by the Illinois Department of Transportation (IDOT) and local agencies. To achieve the research goal, comprehensive literature review of related studies and existing guidelines, analysis of Illinois pedestrian-crash data from 2010 to 2014, and a field review of selected high-crash corridors (HCC) in Illinois were conducted. The field review identified several common issues associated with the high-pedestrian-crash-prone roads, e.g., speeding, poor lighting, noncompliance with posted signage, inadequate or missing signage, lack of conspicuity. Several geometric features were also proven to be related to pedestrian crashes; for instance, long crossing distances, insufficient sight distance, inappropriate placement of bus stops and parking were also proved to affect pedestrian safety. Based on the research findings, best practices for implementing various pedestrian treatments were identified and recommendations were made for the pedestrian treatments at uncontrolled locations, with a comprehensive discussion of uncontrolled pedestrian crossing warrants, five categories of pedestrian treatments, selection of appropriate at grade and separate grade treatments, and other safety considerations. The target audiences for the final guide book are transportation professionals, highway designers, traffic engineers, law enforcement officers, and safety specialists who may be involved in efforts to reduce pedestrian crashes at uncontrolled locations. </p><p>

<p> There are miniscule amounts of intersections in roadway networks, but is always a concern of safety. Many different countermeasures have been adopted to maintain safety at intersection. Previous studies have shown that Restricted crossing U-turn (RCUT) intersection implementation contributes to improving intersection safety by reducing the number of left turn and right angle crashes. RCUT intersection helps the minor road traffic to navigate safely through the intersection at heavy traffic major road. MUTCD has included RCUT as one of the cost-effective counter measure for intersection. In this study, three years before and three years after crash data, along with their original crash reports, were studied on ten different facilities in Louisiana to evaluate the safety effectiveness of RCUT installation.</p><p> Two different safety analysis statistical method&mdash;Improved Predictive method and Empirical Bayes method&mdash;were used to conduct analysis, which concluded that RCUT are success in reducing the total crashes at intersections. They are effectively addressing the targeted crashes Left Turn crashes decreased by 61%, Right angle decreased by 65%, Rear end decreased by 33%. The estimated CMF for RCUT intersection is 0.69 (for intersection only) and 0.86(for U-turn to U-turn, whole segment) based on improved prediction method. Whereas, Empirical Bayes method calculated the CMF for intersection as 0 .80, which implies that RCUT installation, on average, can reduce crashes by 20% at intersection. </p><p>

The purpose of this research is to provide insight into the effectiveness of certain real time dispatching control actions on service reliability for transfer from a high frequency bus route to a low frequency bus route. A model of the operation of 2 connected bus routes was built based on data from real bus routes operated by OC Transpo in Ottawa, and a simulation program was designed and developed. This simulation program was used to conduct experiments to compare different control actions to improve transfer effectiveness, to test the impacts of the bus threshold on passenger waiting time and to evaluate the AVL detector location. We defined an objective function---cost/benefit function, to measure the system performance of the above cases. This objective function considered 2 important factors: number of passengers relevant to transfer and waiting time relevant to control. The research and simulation experiments suggested that real time monitoring technologies can improve the transit bus transferring significantly without preplanned timed transfer. The detector location is determined by feeder line headway primarily and the connecting bus holding threshold secondarily. Without considering the hard requirements from outside system, the bus holding threshold should not be greater than the feeder line headway.

The critical criterion for evaluating a bus control strategy is how well it can improve the reliability of bus service. For high-frequency urban bus service, the service reliability is more a function of bus regularity than schedule adherence. Previous research has shown that headway control strategy is more appropriate for improving bus service with high service frequencies than the traditional schedule control strategy. A customer survey has been undertaken to determine what is the largest headway, i.e., the time between the departure of two successive buses at stops of a given route, such that headway control strategy is still reasonable for bus control. Based on the results of our survey, the research of this thesis is focused on headway control when it is believed to be suitable. Regularity of a given route for a given period of the day can be controlled through real-time actions aimed at maintaining adherence to the planned headway. While holding policies have been shown to be very effective in keeping the headway constant, they usually suffer from an inability to adjust quickly to the changing conditions along the route, such as buses breaking down, or not pulling out from the garage. In this thesis, we propose an improved holding policy--"flexible scheduling" as a means for the buses along the route to auto-regulate themselves based on real-time data obtained through the Automatic Vehicle Location Control (AVLC) system, a technology that allows the controller to know the relative position of buses along the route. The idea of flexible scheduling will be discussed in detail. Experimentation of this policy will be conducted on a simulation model. Results will be reported and analysed. A user interface which provides easy access to both the simulation model and a control module is also developed to provide a better working environment to the users of these models. Finally, conclusions and avenues for future research will be discussed.

Abstract not available.

This thesis aims to address three research topics in intelligent transportation systems which include multi-intersection traffic light control based on stochastic flow models with delays and blocking, optimization of mobility-on-demand systems using event-driven receding horizon control and the optimal control of lane change maneuvers in highways for connected and automated vehicles. First, for the traffic light control work, we extend Stochastic Flow Models (SFMs), used for a large class of discrete event and hybrid systems, by including the delays which typically arise in flow movements, as well as blocking effects due to space constraints. We apply this framework to the multi-intersection traffic light control problem by including transit delays for vehicles moving from one intersection to the next and possible blocking between two intersections. Using Infinitesimal Perturbation Analysis (IPA) for this SFM with delays and possible blocking, we derive new on-line gradient estimates of several congestion cost metrics with respect to the controllable green and red cycle lengths. The IPA estimators are used to iteratively adjust light cycle lengths to improve performance and, in conjunction with a standard gradient-based algorithm, to obtain optimal values which adapt to changing traffic conditions. The second problem relates to developing an event-driven Receding Horizon Control (RHC) scheme for a Mobility-on-Demand System (MoDS) in a transportation network where vehicles may be shared to pick up and drop off passengers so as to minimize a weighted sum of passenger waiting and traveling times. Viewed as a discrete event system, the event-driven nature of the controller significantly reduces the complexity of the vehicle assignment problem, thus enabling its real-time implementation. Finally, optimal control policies are derived for a Connected Automated Vehicle (CAV) cooperating with neighboring CAVs in order to implement a lane change maneuver consisting of a longitudinal phase where the CAV properly positions itself relative to the cooperating neighbors and a lateral phase where it safely changes lanes. For the first phase, the maneuver time subject to safety constraints and subsequently the associated energy consumption of all cooperating vehicles in this maneuver are optimized. For the second phase, time and energy are jointly optimized based on three different solution methods including a real-time approach based on Control Barrier Functions (CBFs). Structural properties of the optimal policies which simplify the solution derivations are provided in the case of the longitudinal maneuver, leading to analytical optimal control expressions. The solutions, when they exist, are guaranteed to satisfy safety constraints for all vehicles involved in the maneuver.

Real-time information plays an important role in travelers’ routing choices in an uncertain network by enabling online adaptation to revealed traffic conditions. The quality of the information affects its effectiveness. Usually there are some limitations in the information provided to the travelers, spatially, temporally or both. In this thesis, three variants of an optimal adaptive routing problem with partial online information problem are introduced: global information with time lag, global pre-trip information and radio information on a subset of links without time lag. A generic description of online information is provided. An algorithm is designed for the optimal routing problem in stochastic time-dependent networks with partial online information and specializations required for each of the three variants are given. A test example is conducted and computationally verifies the non-negative value of information. The work in this thesis is potentially of interest to traveler information systems evaluation and design.