Download or read book Using Microsimulation to Estimate the Impact of Transportation Improvements and Operational Policy Changes on Travel Time Reliability written by Reza Golshan Khavas and published by . This book was released on 2017 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt: Traditionally, traffic engineers have designed roadway networks and operational strategies to manage congestion and minimize delays during the peak demand period for some “average” or “typical” day. However, increasingly, there is concern about not only the average traffic conditions along a route (during some period of the day), but also about the variability of the required time to traverse the route. Travel times vary as a function of the departure time according to relatively predictable changes in the traffic demands (i.e. travel times are longer during the peak commuting periods than during off peak periods). However, the time to complete the same trip at the same departure time also varies from day to day. The variability of travel time, and the associated additional costs, has introduced another performance measure in transportation engineering called travel time reliability (TTR). Travel time reliability has gained significant attention among the transportation researchers and practitioners recently. In this research, we aimed to implement traffic microsimulation models in order to model travel time reliability and finally to incorporate it into the alternative comparison. The contribution areas of this research are explained briefly in the following paragraphs. Previous work that has examined the impact of weather on the characteristics of the speed-flow-density relationship has defined the weather conditions a priori and then attempted to determine the macroscopic traffic stream characteristics for these categories. However, for the purposes of modeling travel time reliability, it is necessary to only capture those weather conditions for which the associated macroscopic characteristics are statistically different. In this research we develop a technique to distinguish distinct weather categories through an innovative method. Also, the process of determining macroscopic traffic stream characteristics requires the calibration of a macroscopic speed-flow-density model to field data. In employing this approach, we observed that the errors associated with the estimated parameters are impacted by the number and distribution of the observation points that used to calibrate the model. Therefore, we developed models to estimate the corresponding errors of the estimated traffic parameters and found that for most practical applications, the estimation of the jam density is most sensitive to the distribution of the calibration data. As a result, we suggested some specific conditions for which the jam density value should be assumed a priori rather than calibrated on the basis of the available field data. We additionally wanted to be able to model specific weather categories. We knew the traffic flow parameters of those weather conditions from the field data and we wanted the same traffic characteristics to be simulated in the traffic microsimulation model. Therefore, we proposed and evaluated a method to map the traffic flow characteristics to the TMM input parameters. The model developed in this research is not only applicable to simulate different weather categories, but also can be used to simulate any traffic condition -within the acceptable range of the model- when the traffic flow parameters are known. Furthermore, we aimed to monetize travel time (un)reliability. To do this we have adopted the unreliability cost in terms of the costs of arriving early or arriving late. This approach has been widely used to quantify the costs of unreliability of public transport system; however, for road transport, this construct requires that we know the scheduled travel time which, from the user's perspective is the anticipated travel. We carried out a stated preference survey to estimate the anticipated travel time based on the travel time distribution. On the basis of the survey responses, we proposed two models in which travelers ignore unusually long travel times when determining their anticipated travel time. Finally, we incorporated all of these findings to create an approach to quantify the cost of travel time (un)reliability using traffic microsimulation tools. We demonstrate this approach to evaluate two road improvement alternatives. We used the traffic simulation model VISSIM to compare these two alternatives based on the travel time cost and travel time reliability cost together.

Download or read book Methods to Analyze and Predict Interstate Travel Time Reliability written by Xiaoxiao Zhang and published by . This book was released on 2021 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Moving Ahead for Progress in the 21st Century Act (MAP-21) defined requirements for system reliability performance measures. Under MAP-21, state departments of transportation are responsible for reporting travel time reliability and for setting targets and showing progress toward those targets. In order to know how to improve travel time reliability and what to expect from investments in transportation infrastructure, these agencies need a better understanding of the factors that affect travel time reliability and methods to predict future travel time reliability. The purpose of this study was to quantify the factors influencing travel time reliability and investigate how to account for these factors in setting reliability targets and communicating progress. To achieve these objectives, this study developed models to estimate quantiles (the 50th, 80th, and 90th) of travel time distributions to quantify the effects of travel time reliability impact factors and predict select reliability measures. First, linear quantile mixed models (LQMMs) were built using both data maintained by the Virginia Department of Transportation (VDOT) and crowdsourced event data. Model results using the crowdsourced data were unstable and difficult to interpret because of data quality issues such as unbalanced spatial density, duplicate reporting, and inconsistent event classification because of individual observer bias. The results using VDOT-maintained data were more reliable and interpretable. Those models showed that frequencies of non-recurrent events, such as incidents and weather, were correlated with higher travel time percentiles. The LQMM was compared with the trend line approach, a common prediction method used in practice, and the results showed that LQMMs significantly improved the accuracy of predictions over the trend line approach based on mean absolute percent error. Generalized random forest (GRF) models were also tested as an alternative prediction method. GRF models improved the prediction accuracy over LQMMs for the 50th and 80th percentiles, but the accuracy was slightly worse for the 90th percentile. In addition, the GRF models could also reflect the impact of variables that were removed from LQMMs because of insignificance, such as the presence of safety service patrols. Before-after studies were conducted to illustrate the application of LQMMs and GRF models. LQMMs captured the changes in the 90th percentile travel times better, and GRF models captured the changes of level of travel time reliability better in most cases. GRF models were more sensitive to the reliability changes caused by non-recurrent events, such as incidents or work zones, and could reflect the impact of variables that were removed from LQMMs because of insignificance. The study recommends that VDOT use the GRF model for predicting travel time reliability on interstate highways. In addition, further research is recommended to extend the GRF models to meet the requirements of MAP-21 federal target setting.

Download or read book Using Travel Time Measures to Estimate Mobility and Reliability in Urban Areas written by Timothy J. Lomax and published by . This book was released on 2002 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: There are several keys to developing and applying mobility measures that are technically useful and generally understandable. Travel time measures are relatively easy to comprehend, but they have not always been used because of data concerns, mandated reporting practices and other issues. Travel time and speed measures can serve many different uses, communicate to many different audiences and enhance the ability of project analysis techniques to determine the most appropriate set of policies, programs and projects for a situation. The overriding conclusion from any investigation of mobility and reliability measures is that there is a range of uses and audiences. No single measure will satisfy all the needs, and no single measure can identify all aspects of mobility or reliability - there is no "silver bullet" measure. The problems are complex and in many cases require more than one measure, more than a single data source and more than one analysis procedure. Mobility and reliability performance measures, when combined in a process to uncover the goals and objectives the public has for transportation systems, can provide a framework to analyze how well the land use and transportation systems serve the needs of travelers and businesses

Download or read book Data Collection and Modeling Requirements for Assessing Transportation Impacts of Micro scale Design written by Travel Model Improvement Program (U.S.) and published by . This book was released on 2000 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Predicting Air Quality Effects of Traffic flow Improvements written by Richard Gerhard Dowling and published by Transportation Research Board. This book was released on 2005 with total page 241 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Toward Smart Mobility by Enhancing Travel time Reliability written by Avinash Sankarasetty and published by . This book was released on 2018 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: Here is my abstract – Smart mobility is an essential element in building smart cities. To realize connected and automated smart mobility as a service, the capability to efficiently estimate the travel-time reliability measures responding to various operating conditions is of critical importance. My research topic mostly focuses on a travel-time reliability estimation system, which is applied to determine the effects of the operational changes on the travel-time reliability. The application results to the metro freeway net work in Minnesota indicate the substantial improvements in travel-time reliability after the changes were introduced, indicating the possibility of modeling the causal relation ship between reliability and specific operational strategies.

Download or read book The Benefits and Costs of Highway and Transit Investments written by and published by DIANE Publishing. This book was released on 2005-09 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Integrating Business Processes to Improve Travel Time Reliability written by and published by Transportation Research Board. This book was released on 2011 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Addresses various ways that transportation agencies can reengineer their day-to-day business practices to enhance traffic operations, address nonrecurring traffic congestion, and improve the reliability of travel times delivered to roadway system users"--Foreword.

Download or read book Economic Analysis Primer written by and published by . This book was released on 2003 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: This primer provides a foundation for understanding the role of economic analysis in highway decision making. It is oriented toward state and local officials who have responsibility for assuring that limited resources get targeted to their best uses and who must publicly account for their decisions. Economic analysis is presented as an integral component of a comprehensive infrastructure management methodology that takes a long-term view of infrastructure performance and cost. The primer encompasses a full range of economic issues, including economic fundamentals, life-cycle cost analysis, benefit-cost analysis, forecasting traffic for benefit calculations, risk analysis and economic impact analysis.

Download or read book Analytical Procedures for Determining the Impacts of Reliability Mitigation Strategies written by and published by Transportation Research Board. This book was released on 2013 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Reliability of transport, especially the ability to reach a destination within a certain amount of time, is a regular concern of travelers and shippers. The definition of reliability used in this research is how travel time varies over time. The variability can apply to the travel times observed over a road segment during a specific time slice (e.g., 3 to 6 p.m.) over a fairly long period of time, say a year. The variability can also pertain to the travel times of repeated trips made by a person or a truck between a given origin and destination. Agencies are increasingly aware of the issue of reliability, although the transportation industry as a whole as yet lacks a firm understanding of the causes and solutions to failures of reliability. As the agenda for the SHRP 2 research on travel time reliability took shape, it became clear a fundamental study was required to be able to talk about travel time reliability in a meaningful way"--Foreword.

Download or read book Evaluating Alternative Operations Strategies to Improve Travel Time Reliability written by and published by . This book was released on 2013 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: The research included an effort to determine the economic value of improvements in travel time reliability by applying options theory from the financial sector. This method is predicated on determining the certainty equivalent of the variability of speed. This innovative approach, briefly summarized in the body of the report and described in an appendix, deserves further exploration despite the lack of consensus from experts about its validity. A prominent part of the report presents a forecast of the year 2030 under alternative assumptions that may influence travel time reliability. The researchers set out three alternative outcomes--optimistic, mediocre, and pessimistic--regarding climate change, economics, and demographics. In addition, they examined a range of technological developments that might affect reliability. To paint a picture of the future, they prepared a concept of operations for the year 2030.

Download or read book Cost effective Performance Measures for Travel Time Delay Variation and Reliability written by National Cooperative Highway Research Program and published by Transportation Research Board. This book was released on 2008 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: TRB¿s National Cooperative Highway Research Program (NCHRP) Report 618: Cost-Effective Performance Measures for Travel Time Delay, Variation, and Reliability explores a framework and methods to predict, measure, and report travel time, delay, and reliability from a customer-oriented perspective.

Download or read book Urban Transportation Abstracts written by and published by . This book was released on 1983 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Transportation Statistics and Microsimulation written by Clifford Spiegelman and published by CRC Press. This book was released on 2016-04-19 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: By discussing statistical concepts in the context of transportation planning and operations, Transportation Statistics and Microsimulation provides the necessary background for making informed transportation-related decisions. It explains the why behind standard methods and uses real-world transportation examples and problems to illustrate key conc

Download or read book New Frontiers in Microsimulation Modelling written by Ann Harding and published by Routledge. This book was released on 2017-10-19 with total page 607 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past fifteen years, microsimulation models have become firmly established as vital tools for analysis of the distributional impact of changes in governmental programmes. Across Europe, the US, Canada and Australia, microsimulation models are used extensively to assess who are the winners and losers from proposed policy reforms; this is now expanding into new frontiers, both geographically and in terms of policy areas. With contributions from more than 60 international experts, this volume offers a comprehensive introduction to the state of microsimulation internationally, illustrating a wide range of new applications and approaches. It will be of relevance to government policy makers, social policy planners, economists and those concerned with predicting the impact of public policy change and to academics in a variety of disciplines, especially social and public policy, human geography, development studies and economics.

Download or read book Prediction of Interstate Travel Time Reliability Phase II written by Mo Zhao and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accurate prediction of travel time reliability measures would help state departments of transportation set performance targets and communicate the progress toward meeting those targets as required by the Moving Ahead for Progress in the 21st Century Act (MAP-21). In a recent Virginia Transportation Research Council study, Methods to Analyze and Predict Interstate Travel Time Reliability, researchers developed and tested statistical and machine learning models to analyze and predict travel time reliability on interstate highways. The generalized random forest (GRF) model showed promise in terms of data processing (no need for pre-clustering of travel times) and the relative accuracy of the results and was recommended for further evaluation by the study’s technical review panel. The current study directly adapted the previously developed GRF models to meet the requirements of MAP-21 federal target setting. In particular, the GRF approach developed using the INRIX Traffic Message Channel network for weekday peak period traffic by the prior study was successfully (1) adapted to the federally required National Performance Management Research Dataset (NPMRDS) network, and (2) expanded to cover the weekday midday and weekend daytime periods. The technical review panel was also interested in practical steps to implement the predictive models. To that end, suggested procedures for applying the new GRF models—including relevant model inputs and data preparation steps—are documented in this report. Direct application of the GRF models trained with INRIX data (2017-2018) to predict travel time reliability measures in 2009 on the NPMRDS network highlighted the need for developing new GRF models targeted to the NPMRDS network, especially when the 90th percentile travel time was predicted. Whereas the INRIX models showed mean absolute percentage errors of 37% and 51% for freeway and interchange segments, respectively, for the PM peak hours, the new GRF models (trained with 2017-2018 NPMRDS data) had relatively smaller mean absolute percentage errors of 34% for freeway segments and 38% for interchange segments depending on how work zones were characterized and how data were aggregated. Because operational improvements are often evaluated on the basis of how they improve reliability, especially on how the 90th percentile travel time is affected, the new GRF models are relevant for planning operational investments. In addition, because many of these improvements affect interchanges, the remedy of the new GRF models is essential for evaluating weaving strategies or traveler information systems that could be implemented at these locations.

Download or read book Urban Mobility Report 2004 written by David Schrank and published by DIANE Publishing. This book was released on 2008-10 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Congestion continues to grow in America¿s urban areas. This report presents details on the 2004 trends, findings and what can be done to address the growing transportation problems. Trend data from 1982 to 2002 for 85 urban areas provides both a local view and a national perspective on the growth and extent of traffic congestion. The 2004 Report provides clear evidence that the time for improvements has arrived. Communicating the congestion levels and the need for improvements is a goal of this report. The decisions about which, and how much, improvement to fund will be made at the local level according to a variety of goals, but there are some broad conclusions that can be drawn from this database. Tables.