bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of Damage Mechanism of Reinforced Concrete Pavement Joint Sealant
Authors: Herabat Pannapa , Kerdput Nuttapol
Published: May 2018

Highway agencies in Thailand select reinforced concrete pavement for highways that have to carry a high traffic volume because of the pavement's durability and ability to support heavy loads with less deformation. Joint sealant is a structural component that interconnects the pavement slabs. Limited information on the joint sealant is available in Thailand. This research proposes to analyze the damage mechanism of the joint sealant by application of the finite element method under the local environment in which it is subjected to different load patterns, temperature, and time periods. Three-dimensional finite element analysis of the joint sealant and its fatigue property are presented in this paper. Displacement of slab edge surface on both sides of the rigid pavement expansion joint by traffic loading and curling effect can cause stress and strain in the joint sealant. This study conducts an experiment to obtain the fatigue property of the joint sealant subjected to the cyclic movement induced by traffic loads and the curling effect in the rigid pavement slabs. Results of sealant behavior analysis under different configurations and damage analysis of joint sealant under fatigue loading are presented in regard to the stress–strain relation and percentage of joint sealant damage with respect to its service life. Case studies are selected to illustrate how an agency could mechanistically determine maintenance frequency of joint resealing.
Components of Congestion
Authors: Kwon Jaimyoung , Mauch Michael , Varaiya Pravin
Published: May 2018

A method is presented to divide the total congestion delay in a freeway section into six components: the delay caused by incidents, special events, lane closures, and adverse weather; the potential reduction in delay at bottlenecks that ideal ramp metering can achieve; and the remaining delay, caused mainly by excess demand. The fully automated method involves two steps. First, the components of nonrecurrent congestion are estimated by statistical regression. Second, the method locates all bottlenecks and estimates the potential reduction in delay that ideal ramp metering can achieve. The method can be applied to any site with minimum calibration. It requires data about traffic volume and speed; the time and location of incidents, special events, and lane closures; and adverse weather. Applied to a 45-mi section of I-880 in the San Francisco Bay Area in California, the method reveals that incidents, special events, rain, potential reduction by ideal ramp metering, and excess demand respectively account for 13.3%, 4.5%, 1.6%, 33.2%, and 47.4%, respectively, of the total daily delay. The delay distribution of the various components is different between the morning and evening peak periods and between the two freeway directions. Quantifying the components of congestion at individual freeway sites is essential for developing effective congestion mitigation strategies.
FAST Miles
Authors: DeCorla-Souza Patrick
Published: May 2018

In America's large and severely congested metropolitan areas, carpools and express bus service could attract many more riders if buses and carpools could operate between residential areas and job centers on free-flowing highways that provided premium service opportunities. FAST Miles attempts to eliminate recurring congestion on limited-access highway systems by using a possibly more publicly acceptable form of road pricing, along with an integrated multimodal strategy to encourage shifts of solo-driving commuters to alternative modes. Every motorist would get a share of free peak period use of FAST highway facilities, “already paid for” through his or her taxes, through a limited number of FAST Miles credits. FAST Miles could be self-financing and generate a surplus that could be used for expansion of transportation capacity. It could also introduce new possibilities for public–private partnerships for the efficient and effective provision of metropolitan transportation services, including expansion of transportation infrastructure and operation of the priced highway system, the express bus system, and passenger access and distribution services at transit transfer stations. This paper provides estimates of the benefits and financial feasibility of a FAST Miles strategy.
Low-Temperature Thermal Cracking of Asphalt Binder by Asphalt Binder Cracking Device
Authors: Kim Sang-Soo , Wysong Zachary D. , Kovach Jonathan
Published: May 2018

An asphalt binder cracking device (ABCD) is proposed to determine the low-temperature cracking potential of an asphalt binder. ABCD is a simple test method; the operating principle is based on the differential thermal contraction between the metal ABCD ring and an asphalt binder placed outside the ring. As the temperature is lowered, the test binder shrinks more rapidly than the ABCD ring placed inside; this results in the development of thermal stresses. When the developed thermal stress exceeds the strength of the binder, the binder specimen cracks. Strain gauges installed inside the ABCD ring detect the fracture, and the temperature is recorded as the ABCD cracking temperature. With a number of modified and unmodified binders, ABCD repeatability was studied. On the basis of this study, the ABCD and its test procedures were modified to produce repeatable results. In laboratory tests of unmodified and polymer-modified asphalts, ABCD showed a strong correlation with thermal stress restrained specimen test results. Also, ABCD cracking temperatures of the binders used in the well-known Elk County, Pennsylvania, test road correlates well with the cracking index of the test pavements.
Characterization of Aggregate Resistance to Degradation in Stone Matrix Asphalt Mixtures
Authors: Gatchalian Dennis , Masad Eyad , Chowdhury Arif , Little Dallas
Published: May 2018

Stone matrix asphalt (SMA) mixtures rely on stone-on-stone contacts among particles to resist applied forces and permanent deformation. Aggregates in SMA should resist degradation (fracture and abrasion) under high stresses at the contact points. This study uses conventional as well as advanced imaging techniques to evaluate aggregate characteristics and the resistance of aggregates to degradation. Aggregates from different sources and aggregate types with various shape characteristics were used in this study. The micro-Deval test was used to measure aggregate resistance to abrasion. The aggregate imaging system was used to examine the changes in aggregate characteristics caused by abrasion forces in the micro-Deval. The resistance of aggregates to degradation in the SMA was evaluated through the analysis of aggregate gradation before and after compaction with conventional mechanical sieve analysis and nondestructive X-ray computed tomography. The findings of this study led to the development of an approach for evaluating aggregate resistance to degradation in SMA. This approach measures aggregate degradation in regard to abrasion, breakage, and loss of texture.
National Port Planning
Authors: Knatz Geraldine
Published: May 2018

A systemwide analysis of the capacity of U.S. ports is needed to ensure that the United States can handle forecast volumes of trade. Long resisted by the port industry, such an analysis should be viewed from a capacity deficit rather than a capacity surplus perspective. Port capacity should be examined from different temporal perspectives—the short-term capability to respond to an interruption in the supply chain and the ultimate capacity to handle the nation's long-range trade forecast. This information is vital in understanding the elasticities in the port system to recover quickly from a natural disaster or terrorist event and to ensure that the necessary infrastructure is in place to support long-term growth projections. Environmental and infrastructure constraints in the Ports of Long Beach and Los Angeles, California, might prevent the nation's largest port complex from developing needed facilities in time to accommodate trade forecasts. This paper addresses the implications of port growth for the Ports of Long Beach and Los Angeles and how decisions made to address cargo growth there can have national repercussions. Only through national port planning can the systemwide implications of locally based decisions be understood.
Impact of Temporary Seaport Closures on Freight Supply Chain Costs
Authors: Lewis Brian M. , Erera Alan L. , White Chelsea C.
Published: May 2018

A decision model designed to help stakeholders quantify the productivity impacts of temporary closures of a container seaport on global supply chains is presented. Such closures have many potential causes, including natural disasters, labor disruptions and shortages, and security-related disruptions. Temporary closures result in highly variable product delivery lead times and thus increase supply chain inventory management costs. The decision model is a Markov decision process that determines an optimal inventory management policy and its resultant long-run average cost for a firm operating a supply chain that uses a seaport subject to unexpected closure. Since short port closures typically lead to ships waiting to off-load containers, a simple deterministic queuing approach is used to model port freight processing dynamics. The results of a numerical study indicate that the expected length of a seaport closure more negatively affects supply chain productivity than the probability of closure, for example, causing increases in expected supply chain inventory holding and penalty costs of up to 136%. Furthermore, supply chain firms that do not properly account for port closures during inventory planning can expect significant inventory holding and penalty cost increases, which in some cases eliminate positive operating income. The results indicate the importance of contingency planning and disruption management for all stakeholders, including private firms and public agencies. In addition, results of the study point to the economic importance of investment to increase the processing capabilities of highly utilized seaports immediately following a port closure, when resultant congestion is at its worst levels.
Dynamic Continuous Network Design Problem
Authors: Karoonsoontawong Ampol , Waller S. Travis
Published: May 2018

A linear bilevel programming model and two analytical solution methods (the Kth-best algorithm and mixed integer programming reformulation) for the continuous network design problem are presented on the basis of the multiorigin, single-destination, user-optimal dynamic traffic assignment (UO DTA) problem. From the test problem, it is shown that the bilevel formulation is more desirable than the two known single-level models based respectively on system-optimal and UO DTA. For the multiorigin, multidestination, larger-size problem, three metaheuristics that can produce solutions beyond local optimality are employed: simulated annealing (SA), genetic algorithm (GA), and random search (RS). These metaheuristics share the same functional evaluation: a simulation-based UO DTA that propagates traffic according to Daganzo's cell transmission model. From computational results, GA outperforms the others for all three test problems in terms of solution quality, convergence speed, and processor time, whereas SA and RS appear nondominated. It is also shown that the appropriate set of algorithm parameters is network-specific and should be recalibrated for each network to achieve the best results.
Real-Time Traffic Volatility Forecasting in Urban Arterial Networks
Authors: Tsekeris Theodore , Stathopoulos Antony
Published: May 2018

A methodology is presented for forecasting traffic volatility in urban arterial networks with real-time traffic flow information. This methodology provides a generalization of the standard modeling approach, in which both the mean, modeled by an autoregressive moving average process, and the variance, modeled by an autoregressive conditional heteroscedastic process, are time-varying. The statistical analysis and forecasting performance of the proposed model are investigated with real-time traffic detector data from a real urban arterial network. The results indicate the potential of the proposed model to improve the accuracy of predicted traffic volatility across different lengths of forecasting horizon in comparison with the standard generalized autoregressive conditional heteroscedastic methodology.
Estimation of Traffic Dynamics Models with Machine-Learning Methods
Authors: Antoniou Constantinos , Koutsopoulos Haris N.
Published: May 2018

Speed–density relationships are a classic way of modeling stationary traffic relationships. Besides offering valuable insight into traffic stream flows, such relationships are widely used in dynamic traffic assignment (DTA) systems. In this research, an alternative paradigm for traffic dynamics models, appropriate for traffic simulation models and based on machine-learning approaches such as k-means clustering, k-nearest-neighborhood classification, and locally weighted regression is proposed. Although these models may not provide as much insight into traffic flow theory as speed–density relationships do, they allow for easy incorporation of additional information to speed estimation and hence may be more appropriate for use in DTA models, especially simulation-based models. This paper (with data from a network in Irvine, California) demonstrates that such machine-learning methods can considerably improve the accuracy of speed estimation.
Impact of Differences in Driver-Desired Speed on Steady-State Traffic Stream Behavior
Authors: Farzaneh Mohamadreza , Rakha Hesham
Published: May 2018

This paper analyzes steady-state behavior of car-following models within state-of-the-practice commercial traffic simulation software. Car-following models are classified on the basis of their uncongested regime steady-state behavior into two categories. Apart from the INTEGRATION software that uses the Van Aerde car-following model, the research demonstrates that all state-of-the-practice traffic simulation software assumes a constant desired speed that is insensitive to the flow level within the uncongested regime. The paper then quantifies the effect of speed variability, as a common approach to model driver differences with respect to desired speed, on steady-state traffic stream behavior. The paper not only demonstrates that speed variability has a significant impact on the speed at capacity but also develops procedures for calibrating the steady-state relationship while accounting for the effects of speed variability. Finally, the effectiveness and validity of the proposed procedure are demonstrated with an example.
Modeling and Simulation of Unconventional Traffic Circles
Authors: Bartin Bekir , Ozbay Kaan , Yanmaz-Tuzel Ozlem , List George
Published: May 2018

Microscopic simulation tools have been gaining popularity among traffic engineers. Enhanced input–output capabilities of these simulation tools allow engineers to model and to simulate complex transportation networks and to gather results relatively quickly. However, extensive validation and calibration efforts are required to verify the credibility of the results of these simulation models. This paper deals with the development of credible and valid simulation models of two unconventional traffic circles in New Jersey, namely, the Collingwood and Brooklawn Circles. These two circles are modeled in PARAMICS simulation software. Model development and the validation and calibration steps are presented in detail. PARAMICS is one of the few off-the-shelf simulation software packages that can model unconventional traffic circles. However, the default capabilities of PARAMICS are not sufficient to model statistically valid simulation models of these two unconventional circles. Use of the application programming interface (API) feature of PARAMICS is required to develop realistic models that can accurately represent drivers’ facility-specific behaviors. A gap acceptance–rejection binary probit model based on the analysis of field data was developed and implemented with PARAMICS API. The differences between the simulation results of the API enhanced model and the default PARAMICS model are presented to demonstrate the importance of extending the existing default models and the careful validation and calibration using real-world data. Finally, the sensitivity analyses of the developed simulation models are presented.
Trip Generation Rates for Large Elevators
Authors: Tolliver Denver , Dybing Alan , Mitra Subhro
Published: May 2018

Large grain elevators are major sources of truck traffic in many areas. Shuttle trains, a recent railroad innovation, have further concentrated truck deliveries at larger elevators. These facilities—which have not been analyzed in previous trip generation studies—pose issues such as large truck access and pavement design. In this paper, elevator trip generation equations are estimated from detailed facility, land use, and highway traffic data in North Dakota. A trip attraction equation is used to explain the effects of elevator storage capacity and side track capacity on elevator throughput. Elevators are classified on the basis of track capacity as shuttle train, unit train, and multicar. Shuttle-train elevators typically consign 110-car trains, while unit-train elevators consign 50- to 100-car trains. The analysis shows that large shuttle-train elevators may generate 35,000 to 40,000 loaded and empty truck trips per year. A large unit-train elevator may generate 20,000 annual trips. The trucks are usually a mixture of combination five-axle and single-unit trucks. On average, each truck generates 1.04 equivalent single-axle loads on flexible pavements. Thus, a large facility may generate much of the traffic load experienced by pavements in the area. Moreover, truck deliveries to elevators exhibit seasonal variation. Approximately 15% of the annual volume is delivered during the peak month. Thus, a large shuttle facility may generate 225 trucks per day during the peak harvest month.
Resilient Modulus Estimation System for Fine-Grained Soils
Authors: Han Yuh-Puu , Petry Thomas M. , Richardson David N.
Published: May 2018

A software tool was developed to estimate the resilient modulus of finegrained subgrade soils. The subgrade resilient modulus is a key factor for use in mechanistic–empirical pavement design methods. However, for routine design use, the test method is too expensive and difficult to perform. Resilient modulus estimation software was developed with expert system approaches. Information entered by the user is first examined for reasonableness and accuracy. Then, data searching processes are initiated, and more than 30 estimation models can be invoked, depending on the availability of input data. All results were evaluated on the basis of certainty rules, such as how well data meet limitations existing during the model's original development environment. The user is given four alternate methods on which to base the choice of a resilient modulus that is most appropriate for the site: one based on certainty rules and three based on statistical methods.
Comparative Design Case Studies of Pavement Performance on Expansive Soils
Authors: Hong Gyeong Taek , Aubeny Charles P. , Bulut Rifat , Lytton Robert L.
Published: May 2018

Vertical movements calculated with the new design method for six case study cross sections in three different climatic zones in Texas were compared with the swelling movement predicted by the potential vertical rise (PVR) method, which has been used by the Texas Department of Transportation. Vertical movements included both swelling and shrinking. A review of assumptions that underlie the PVR method shows that two assumptions are unrealistic because they are not based on sound analytical principle and the three others cannot be supported by subsequent findings on actual Texas pavements or on soils of the United States. Pavement treatments were selected to provide acceptable predicted performance at high levels of reliability, and the vertical movements were calculated both at the edges of pavements and beneath the outer wheelpaths. The case studies were based on a variety of traffic levels, site conditions, and sample testing. The pavement treatments included lime-stabilized and cement-stabilized layers, removal and replacement with inert layers, and vertical and horizontal moisture barriers. The results of the case studies showed that the PVR method overpredicts the swelling movement that can be expected with the new method and does not predict shrinkage movement, which is important because that is an indicator of future longitudinal shrinkage cracking along the pavement edge.
Investigations of Environmental and Traffic Impacts on Mechanistic–Empirical Pavement Design GuidePredictions
Authors: Zaghloul Sameh , Ayed Amr , Halim Amir Abd El , Vitillo Nicholas , Sauber Robert
Published: May 2018

The Mechanistic–Empirical Pavement Design Guide (MEPDG) represents a major improvement on its predecessors, particularly in its comprehensive coverage of environmental impact on pavement performance. Another improvement is the approach introduced to assess and accumulate damage created by traffic. A major strength of the MEPDG is the consideration given to the interaction between environmental, material, and traffic parameters, rather than consideration of only the parameters themselves. The process through which these interactions are considered sounds very comprehensive; however, is it practical? The Enhanced Integrated Climatic Model (EICM) is a core component of the MEPDG; it controls the material properties used in the analysis to a great extent. As a result, EICM predictions have a significant impact on MEPDG-accumulated damage and therefore on predicted service life. In a previous study, an effort was made to validate EICM predictions with field-measured temperature and moisture profiles outside the MEPDG. However, this effort was not successful. Therefore, the potential impacts of the accuracy of EICM predictions on MEPDG-predicted damage and hence on expected pavement service life were investigated. Eight weather stations closest to New Jersey's Long-Term Pavement Performance Specific Pavement Study 5 site were analyzed. In addition, to address the interaction between environment and traffic in the MEPDG, analyses were run with two traffic input levels: first with Level 3 traffic data and then with Level 1 traffic data.
Application of Genetic Neural Networks to Real-Time Intersection Accident Detection Using Acoustic Signals
Authors: Zhang Yunlong , Xie Yuanchang
Published: May 2018

A genetic neural network (GNN) classification method using acoustic signals is proposed for real-time accident detection at intersections. Backpropagation neural networks (BPNNs) have been widely used in pattern classification. They have fast computation speeds that are desirable for real-time detection systems. However, they tend to converge to local optimums, which consequently affects classification accuracy. The proposed GNN uses a genetic algorithm to improve the global searching ability of BPNNs. GNN performance (i.e., detection rate, false alarm rate, and detection time) is compared with that of a widely used probabilistic neural network (PNN). Test results indicate that the GNN performs comparably to a PNN but with much less computation time. Results of the GNN transferability analysis indicate that the GNN method also is robust and can be successfully applied to intersection accident detection with training data from different sources. Computationally inexpensive and highly accurate, the new GNN is thus suitable for real-time application.
Effect of Red Light Cameras on Accident Risk at Intersections
Authors: Huang Helai , Chin Hoong Chor , Heng Alan Heng Hock
Published: May 2018

One major cause of accidents at signalized intersections is vehicles running red lights. To discourage red light running (RLR), a number of authorities have installed red light camera (RLC) systems on the approaches to these signalized intersections. There have been indications from several studies that RLCs have been effective in curbing RLR; this leads to potential reduction in right-angle collisions. However, there are also concerns over a possible increase in rear-end collisions. This paper investigates the effect of RLCs on accident risks at signalized intersections for both right-angle collisions and rear-end collisions. A binary logit model was preliminarily developed to examine how the stopping–crossing decision of drivers at the onset of amber is affected by geometric, traffic, and situational variables. Results showed that the presence of RLCs is one of the five significant factors affecting a driver's decision to cross at the onset of amber. A multinomial logit model further confirmed that RLCs are effective in reducing RLR frequency. Further analysis on the fitted models revealed that while the presence of RLCs is effective in reducing risk of right-angle collisions, it has a mixed effect on the risk of rear-end collisions. Whether the RLC reduces or increases the possibility of rear-end collisions depends on the speed of the trailing vehicle and the headway between vehicles.
Safety-Conscious Planning in Practice
Authors: Goldman Lois M. , Herbel Susan , Suhrbier John , Davies Gary , Papayannoulis Vassillos
Published: May 2018

In response to U.S. Department of Transportation (USDOT) guidance, and acting at a regional level, the North Jersey Transportation Planning Authority, Inc. (NJTPA), initiated the Development of Regional Safety Priorities study to identify transportation safety needs and solutions in the 13-county NJTPA region. The study was a proactive, multimodal effort to elevate safety considerations to a high priority at all levels of decision making. The project's goal was to develop specific, targeted metropolitan planning organization (MPO) actions to reduce the frequency and severity of crashes. The study incorporated principles of Safety Conscious Planning, a USDOT initiative. Safety Conscious Planning is a planning process model that considers multimodal, comprehensive safety issues at all phases of MPO processes. It includes data analysis, interdisciplinary professional perspectives, and public input. The NJTPA study had three elements: a data-driven, collaborative assessment of priority multimodal safety needs throughout the region; recommended applications of engineering, enforcement, and educational countermeasures; and development of project concepts for advancement through the MPO planning process. Active, meaningful interagency and public input was integral in all these steps. The Development of Regional Safety Priorities study does not represent a one-time effort, but is a first step toward improving how considerations of safety are integrated throughout development of transportation plans, programs, and projects. Since the study's conclusion in spring 2005, recommended improvements at three locations developed through this effort have been funded for construction, and several more are under consideration for funding in the near future.
Houston, Texas, Metropolitan Traffic Safety Planning Program
Authors: Levine Ned
Published: May 2018

The metropolitan traffic safety planning program of the Houston–Galveston Area Council in Texas monitors safety in the eight-county region, identifies hazardous locations, and supports other safety efforts. With a spatial crash information system, safety analysis is conducted of counties, cities, roadways, and hot spots. Particular attention is paid to crashes involving fatalities, injuries, speeding, red light running, teenagers, driving under the influence, pedestrians, bicyclists, trucks, and railroad trains. Much of the effort involves distributing information about safety to local governments and to the public at large. In collaboration with local governments and with the Texas Department of Transportation, engineering analysis is conducted of specific safety hot spots to recommend measures to mitigate crashes. Partnerships are created to widen the scope of safety efforts in the region. In addition, major crash hot spots have been identified and are included in the long-range transportation plan. Finally, a Regional Safety Council has been established to allow a policy forum for integrating the various safety efforts of transportation, medical, law enforcement, industry, nonprofit, and other organizations. An annual safety summit is being planned, as are safety training courses for local governments.
Evaluation of Hamburg Wheel-Tracking Device Test with Laboratory and Field Performance Data
Authors: Lu Qing , Harvey John T.
Published: May 2018

The Hamburg wheel-tracking device (HWTD) test has been gaining acceptance by some state highway agencies. Although a few studies showed that test results from this device have the potential to evaluate the moisture sensitivity of asphalt mixes, the correlation between the test results and field performance has not been widely studied and well established. The capability of the device to predict field performance therefore has not been sufficiently validated. The study presented evaluates the effectiveness of the HWTD test in determining the moisture sensitivity of asphalt mixes and in predicting field performance by using both laboratory test data and field performance data. It was found that the current test procedure may give false positive and false negative results. Binder properties have a significant effect on the test results. The correlation between the test results and field performance was unsatisfactory. Recommendations for potential improvement of the test are provided.
Simple Method for Predicting Laboratory and Field Permeability of Hot-Mix Asphalt
Authors: Masad Eyad , Al-Omari Aslam , Lytton Robert
Published: May 2018

The infiltration of water in asphalt pavements promotes moisture damage, primarily by damaging the binder cohesive bond and the adhesive bond between aggregates and binder. The first step in addressing the problems caused by the presence of water within pavement systems is quantifying the permeability of hot-mix asphalt (HMA) mixes. A simple equation for predicting the permeability of HMA has been developed. This equation includes parameters that quantify percentage air voids, aggregate gradation, and asphalt binder content. Pavement engineers can use this formula to design asphalt mixes that exhibit acceptable levels of permeability. A comprehensive database of materials and laboratory and field permeability measurements was used to calibrate the equation. Consequently, the ability of the equation to predict the permeability of field cores that were not used in the calibration process was verified. Included is an example illustrating the usefulness of the equation in estimating the permeability distribution in asphalt pavements by using mix properties.
Dissipated Energy Approach to Study Hot-Mix Asphalt Healing in Fatigue
Authors: Carpenter Samuel H. , Shen Shihui
Published: May 2018

The healing phenomenon has been noted by pavement engineers for years, but its relation to hot-mix asphalt (HMA) fatigue behavior is still far from clear. This study conducted an analysis of healing and HMA fatigue behavior by introducing a specifically designed fatigue-healing test. These results help explain the differences in fatigue behavior at normal and low strain levels. An approach using the ratio of dissipated energy change, which is based on energy concepts, is used in this study. The results show that healing does exist, and its effect on fatigue life can be indicated by an energy recovery per second of rest period. The effect of healing is more prominent at low strain levels or in very long rest periods. At low strain conditions, the dominance of healing compared with the very low external load damage, considering the energy equilibrium, can result in full damage recovery. This full recovery of energy explains the existence of a fatigue endurance limit, below which HMA materials tend to have extraordinarily long fatigue lives that, as is shown, can be related to healing. The testing conducted clearly shows why polymer modification may extend the fatigue life in the field even though laboratory testing may show minimal differences compared with the neat binder test results.
Bus Rapid Transit in New York City
Authors: McNamara Ian G. , Zimmerman Samuel L. , Orosz Theodore , Levinson Herbert S. , Sampson David
Published: May 2018

Selecting corridors for implementing bus rapid transit (BRT) projects in most communities is relatively straightforward; however, in cities such as New York, this is far more complicated because of the large numbers of corridors with many characteristics compatible with BRT provision. This paper describes the framework developed to evaluate and screen corridors in New York City for five demonstration BRT projects. A mechanism was identified to reduce the number of candidate corridors from 80 to 36 at an early stage. An evaluation framework building on the previous work and detailed field observations further refined the list from 36 corridors to 15. The evaluation included two key considerations: the potential benefits of BRT implementation in a given corridor and the potential ease of implementation of BRT in that corridor. The study team defined a series of measures to reflect these key considerations (four measures for each). The relative ranking of the 36 corridors showed how each corridor performed with respect to these measures. The results of the evaluation yielded the 15 corridors that moved to the conceptual development phase of the study. This paper describes the steps taken in reducing the universe of candidate corridors for BRT implementation and provides a sequential, transparent, and cost-effective approach to the issue of corridor identification that can be applied in any urban area.
Bi-Level Mathematical Programming Model for Locating Bus Stops and Optimizing Frequencies
Authors: dell'Olio Luigi , Moura Jose Luis , Ibeas Angel
Published: May 2018

This paper proposes a model for locating bus stops and optimizing bus frequencies in congested local public transport networks. The analysis addresses the issue of reducing the overall costs of operating a transport system, including costs associated with provision of services and bus stop construction, using a bi-level mathematical programming method. The upper level defines the overall cost of the system, which must be kept to a minimum taking into account operational restrictions, and the lower level defines a behavioral model for system users. The suggested model mixes optimization and simulation and allows supply and demand to be linked; this ensures consistency between equilibrium flows and bus frequencies and between equilibrium flows and the distances between bus stops calculated at each iteration of the algorithm.
Simulation Model for Estimating Bus Dwell Time by Simultaneously considering Numbers of Disembarking and Boarding Passengers
Authors: Li Min-Tang , Zhao Fang , Chow Lee-Fang , Zhang Haitao , Li Shi-Chiang
Published: May 2018

Dwell time at a bus stop is one of the major components of bus travel time, and it is highly correlated with numbers of boarding and alighting passengers. With more resources from federal, state, and local governments currently being devoted to improving public transit services, transit ridership rates are expected to increase. Consequently, dwell time needs to be modeled in terms of ridership to allow accurate estimations of bus travel time. Typically, passengers can board a bus only through the front door but can choose to exit the vehicle through either the front or rear door. To estimate dwell time accurately, this study used data collected from Florida's Broward County Transit system to develop a binary door choice model predicting the proportion of alighting passengers who will use the front or rear door to disembark from the bus. Because the model explicitly considered passengers disembarking through the front and rear doors as well as passengers boarding through the front door, it was more effective in quantifying transit dwell time than the existing simulation algorithms available in CORSIM and VISSIM.
Minimizing Transfer Times in Public Transit Network with Genetic Algorithm
Authors: Cevallos Fabian , Zhao Fang
Published: May 2018

This paper presents a systemwide approach based on a genetic algorithm for the optimization of bus transit system transfer times. The algorithm attempts to find the best feasible solution for the transfer time optimization problem by shifting existing timetables. It makes use of existing scheduled timetables and ridership data at all transfer locations and takes into consideration the randomness of bus arrivals. The complexity of the problem is mainly due to the use of a large set of binary and discrete variables. The combinatorial nature of the problem results in a significant computational burden, and thus it is difficult to solve with classical methods. Scheduling data from Broward County Transit, Florida, were used to calculate total transfer times for the existing and proposed systems. Results showed that the algorithm produced significant transfer time savings.
Comparative Analysis of Global Positioning System–Based and Travel Survey–Based Data
Authors: Bricka Stacey , Bhat Chandra R.
Published: May 2018

This paper examines the driver demographics, driver travel characteristics, and driver adherence to survey protocol considerations that affect the likelihood of underreporting in a household travel survey. The research considers both the likelihood of vehicle driver trip underreporting and the level of vehicle driver trip underreporting by using a joint binary choice-ordered response discrete model. The empirical analysis uses the Global Positioning System–equipped sample of households from the 2004 Kansas City (Kansas and Missouri) Household Travel Survey which also provided travel diary information. The empirical results provide important insights about underreporting tendencies in household travel surveys. In particular, adults younger than 30 years of age; men; individuals with less than a high school education; unemployed individuals; individuals working in clerical and manufacturing professions; workers employed at residential land uses; individuals who make many trips, travel long distances, and trip chain; and respondents who fail to use a travel diary to log their travel before telephone retrieval of their patterns are associated with more underreporting. The underlying factors that influence whether an individual underreports are different from the factors that affect the level of underreporting.
Competition between Egress Transport Modes
Authors: Molin Eric J. E. , VonkNoordegraaf Diana M. , Mol Fieke , Timmermans Harry J. P.
Published: May 2018

This paper describes the results of a stated choice experiment that was conducted to understand better the substitution and synergy effects among various options for egress transport modes. The stated choice experiment that was designed varies the availability of alternative transport modes and makes it possible to identify which modes compete for the same market share. The survey consisted of 996 respondents in the Netherlands. The results show evidence of substitution effects of high-frequency public transport services on other transport modes, especially on train taxi and public transport bicycle, and evidence of synergy effects between low-frequency public transport services, especially taxi and walking. Taxi and train taxi show substitution effects on car-based transport modes and synergy effects on most other modes. The three bicycle alternatives do not exhibit any significant availability effects; this implies that they appear to have their own market.
Usage Analysis of First-Generation Intelligent Transportation Systems Data Archive
Authors: Smith Brian L. , Venkatanarayana Ramkumar
Published: May 2018

ADMS Virginia is an archived data management system (ADMS) established to provide access to archived intelligent transportation systems data for use in numerous offline applications. The development team of ADMS Virginia faced the challenge—with limited experience—of developing an information technology-based system, that effectively anticipates uses of the system and users of the system. The team attempted to address this challenge, faced by many information technology professionals in the field of transportation, by using a spiral software development methodology and incorporating significant stakeholder input. This paper presents a usage analysis of ADMS Virginia. This analysis highlights key lessons learned that are of use to those developing ADMSs specifically and new transportation information technology systems in general. Key lessons learned include the following: ( a) do not overspecialize early in a system's life, ( b) anticipate a wide range of users, and ( c) spiral development creates the risk of establishing system usage patterns prematurely.
Integration of Geographic Information System for Transportation with Real-Time Traffic Simulation System
Authors: Zhou Mu , Korhonen Ari , Malmi Lauri , Kosonen Iisakki , Luttinen Tapio
Published: May 2018

Real-time traffic information applications (RTIA) collect real-time traffic data from a wide variety of detectors. The problem with these applications is that they are complex and hard to maintain because of the large number of distributed detectors involved. However, it is well recognized that traffic simulation systems have the ability to improve the efficiency of traffic analysis, prediction, and control. This paper presents an application framework that integrates a real-time traffic simulation system with RTIA. Within this framework, a geographic information system for transportation (GIS-T) architecture, combined with a temporal–spatial database, provides a flexible way to present the real-time traffic information for road users. Several critical system components are introduced as well, including a real-time dynamic traffic data exchange model. The real-time simulation system, a static traffic model in GIS-T, and a Java-based application architecture are also briefly discussed.
AGORA-C Map-Based Location Referencing
Authors: Wevers Kees , Hendriks Teun
Published: May 2018

This paper describes the AGORA-C method for map-based on-the-fly location referencing. Unlike the traffic message channel, location referencing based on precoding locations and location tables, the code is created when needed from a map database in the sending system, transmitted in a message, decoded with the map database in the receiving system, and then discarded. The presented method is a follow-up of earlier work in the AGORA project to improve code size and hit rate. The method now consists of a core profile for traffic information and hazard warning applications and an optional extended profile for destination locations that may not be present in the receiving map database. Extensive tests demonstrated a hit rate of about 98% and an average code size not larger than 34 bytes, which is well below the generally agreed number of 50 bytes for maximum acceptable average code size. The method is adopted for the Transport Protocol Expert Group automotive protocol, which is under development.
Determining Colors for Traffic Control Devices at Transponder-Controlled Tollbooth Lanes with a Sign Simulator
Authors: Golembiewski Gary A. , Katz Bryan J. , Knoblauch Richard L. , Rousseau Gabriel K.
Published: May 2018

The number of toll roads is increasing in the United States, and drivers face signing practices that vary greatly across jurisdictions. In addition to the increase in toll roads, there is an increase in the use of electronic toll collection (ETC) transponders. The present study was undertaken to develop standard signing practices—specifically for background color, legend color, underlay color (i.e., the background color for the pictographs), and pictograph—for ETC-supported toll road signs. The study reviewed selected ETC toll road signs in the United States to help select candidate elements and options to be used in a laboratory experiment. On the basis of that review, 120 signs depicted on 35-mm slides were developed with a standard sign-design software package. The signs were presented to 60 participants (equally divided by sex and age group) in the recently updated Turner–Fairbank Highway Research Center's sign simulator. The signs were shown to participants starting at a simulated distance of approximately 1,125 ft (343 m), and then the image was zoomed toward the participants at a constant speed controlled by the laboratory's computer. Each participant's detection distance, guidance legibility distance, and pictograph legibility distance were recorded. The results showed that, overall, green as a background color obtained the longest guidance information legibility distance. Also, fonts that provided the highest contrast to the background color (such as white on black) were the most effective for legibility. Underlay colors that showed the highest contrast to the pictographs were the most effective and included all of the lighter colors tested (white, yellow, and blue).
Pavement Marking Photometric Performance and Visibility under Dry, Wet, and Rainy Conditions
Authors: Burns David M. , Hodson Neil , Haunschild Dale , May Dave
Published: May 2018

Pavement markings are a fundamental component of the roadway safety infrastructure. They play an especially important role at night, when there are fewer visual cues for the driver. Although progress is being made in pavement marking management practices, advances in materials are still needed to fulfill driver needs for nighttime visibility and guidance under all weather conditions, especially wet and rainy conditions. This study was conducted to investigate the relationship between the photometric properties of pavement markings and their visual performance under dry, wet, and rainy conditions. For this pilot study four levels of material performance were created by a systematic reduction of the retroreflective efficiency of a single wet retroreflective tape construction. The nighttime visibility of the pavement marking materials was evaluated under dry, wet (just after rainfall), and rainy conditions. Eight 4-in. skip lines were viewed on the road in a standard 10-ft skip line and 30-ft gap pattern. The dependent measures were the number of skips visible, the subjective rating of the skip line relative to its adequacy for driver guidance, and average skip line luminance as a function of distance. Under rain conditions of 0.5 in./h, a material with an retroflected luminance in the rain ( RL-rain) of 30 mcd/m2/lux (per ASTM E2176-01) was found to provide an inadequate preview time and was rated as providing unacceptable visibility. A good correlation ( R2 = 0.94) was obtained for the instrumental measurement of RL and the number of skips seen. The luminance data suggest that an average pavement marking luminance greater than ∼0.5 cd/m2 is required for a skip line to be visible to the driver at night.