bluuebunny/crossref_metadata_2025 huggingface dataset:
Integration of Fleet Assignment and Aircraft Routing
Authors: Li Yihua , Wang Xiubin
Published: May 2018

Fleet assignment and aircraft routing are two sequential steps in airline capacity planning. The fleet assignment model allots the scheduled flights covered by a type of aircraft on the basis of aircraft availability, and the aircraft routing model generates a route for each particular aircraft to ensure that the path-specific requirements for maintenance and connection times are satisfied. Although it is known that the sequential method is not able to minimize the overall cost, no results have been reported on the integration of the two steps. Here these two steps are completed simultaneously. A path-based integrated model is presented and tested on real data. A heuristic is proposed to solve the formulation. The numerical test indicates that a significant cost saving can be achieved and that the heuristic shows encouraging promise in solving large-scale real-world problems.
Assessment and Rehabilitation of Foreign Object Damage Potential on Airfield Shoulder and Blast Pavements
Authors: Keegan Katherine , Murrell Scott D. , Zummo Guy , Rada Gonzalo
Published: May 2018

Foreign object damage (FOD) is a term used by the aviation industry to describe damage caused by any object that can be ingested by an aircraft engine or flight control mechanism. FOD is estimated to cost the global aerospace industry up to $4 billion annually. Deteriorated pavements are one source of FOD and fall into two categories: runway, taxiway, and apron pavements that aircraft traverse and shoulders and other infield pavements that are not traversed but are subjected to jet blast. Widely recognized procedures for the assessment of pavements traveled on by aircraft are well documented. However, procedures for the assessment of FOD potential for shoulder and blast pavements at commercial airports are not widely recognized. In an effort to manage shoulder and blast pavements proactively and eliminate pavement-related FOD incidents, the Port Authority of New York and New Jersey undertook to assess the current condition of these pavements, rehabilitate and repair areas with unacceptable FOD potential, and initiate periodic inspections on these pavements to facilitate the implementation of an effective pavement maintenance and rehabilitation program. To achieve this goal, a dual project- and network-level inspection approach was implemented. The project-level objective was to identify immediate repairs needed to address unacceptable FOD potential. The network-level objective was to assess the current condition and initiate a proactive inspection regime to assist in maintaining these pavements. The approaches to assessment and rehabilitation are detailed and steps to implement a pavement management system for these pavements are discussed.
Modeling the Proximate Covariance Property of Air Travel Itineraries along the Time-of-Day Dimension
Authors: Coldren Gregory M. , Koppelman Frank S.
Published: May 2018

The estimation of advanced air travel itinerary share models formulated to capture interitinerary competition dynamics along the time-of-day dimension is reported. These models predict airline ridership at the itinerary level and aid carriers in long- and intermediate-term decision making. Previous estimations by the authors indicated increased competition among air travel itineraries within broad time periods. In this study, a more realistic time-of-day competition dynamic is modeled with the ordered generalized extreme value (OGEV) model and hybrid OGEV models. The hybrid OGEV models incorporate the traditional OGEV model structure with other GEV components such as the nested logit (NL) and weighted NL model structures. These hybrid OGEV models measure interitinerary competition along the carrier or level-of-service dimensions along with the time-of-day dimension. The estimated OGEV models have the property of proximate covariance in which itineraries that are closer to each other by departure time exhibit greater covariance and therefore greater substitution or competition with each other than with itineraries that are more separated in time. Independent variables for all of the models measure itinerary service characteristics such as level of service, connection quality, carrier attributes, aircraft type, and departure time. Finally, all models estimated in this study offer insights into air traveler behavior, with the advanced models outperforming the more basic specifications with regard to statistical tests and behavioral interpretations.
Monitoring and Predicting Freeway Travel Time Reliability
Authors: van Lint J. W. C. , van Zuylen H. J.
Published: May 2018

Generally, the day-to-day variability of route travel times on, for example, freeway corridors is considered closely related to the reliability of a road network. The more that travel times on route r are dispersed in a particular time-of-day (TOD) and day-of-week (DOW) period, the more unreliable travel times on route r are conceived to be. In the literature, many different aspects of the day-to-day travel time distribution have been proposed as indicators of reliability. Mean and variance do not provide much insight because those metrics tend to obscure important aspects of the distribution under specific circumstances. It is argued that both skew and width of this distribution are relevant indicators for unreliability; therefore, two reliability metrics are proposed. These metrics are based on three characteristic percentiles: the 10th, 50th, and 90th percentile for a given route and TOD-DOW period. High values of either metric indicate high travel time unreliability. However, the weight of each metric on travel time reliability may be application- or context-specific. The practical value of these particular metrics is that they can be used to construct so-called reliability maps, which not only visualize the unreliability of travel times for a given DOW-TOD period but also help identify DOW-TOD periods in which congestion will likely set in (or dissolve). That means identification of the uncertainty of start, end, and, hence, length of morning and afternoon peak hours. Combined with a long-term travel time prediction model, the metrics can be used to predict travel time (un)reliability. Finally, the metrics may be used in discrete choice models as explanatory variables for driver uncertainty.
Comparison of Trip Determination Methods in Household Travel Surveys Enhanced by a Global Positioning System
Authors: Forrest Timothy L. , Pearson David F.
Published: May 2018

Improvements in vehicular tracking with Global Positioning Systems (GPSs) have fostered new analysis methods in transportation planning. Emerging geographical information systems have helped in developing new techniques in the collection and analysis of data specifically for travel demand forecasting. In 2002, more than 150 households in Laredo, Texas, participated in a GPS-enhanced household travel survey. Trip diary data were collected by means of a computer-assisted telephone interview (CATI), and GPS trip data were collected from survey participants’ vehicles. For trip purpose, a comparison of the two data sets yielded significant results. It was found that the number of trips in the GPS data was much greater than the number reported in the CATI data. Despite that, almost all home-based work (HBW) trips found in the GPS data were also found in the CATI data. That result differs sharply from the other trip purposes: home-based nonwork (HBNW) and non-home-based (NHB); for these two trip purposes, less than half the trips found in the GPS data were found in the CATI data. That result indicates the potential for serious deficiencies in the CATI process for collecting certain types of trips in the region of study. In additional, household size and household income were found to be significant factors affecting the reporting accuracy in the CATI data. Despite that, the CATI method of household trip data retrieval is still considered to be an effective and valuable tool.
Reality-Based Approach to Stated Preference Surveys
Authors: Chu Xuehao
Published: May 2018

This paper defines a reality-based approach to soliciting stated preference data. It is related to existing preference methods in regard to both a common conceptual framework and recent trends in the literature. The reality-based approach is compared with the standard approach in both general characteristics and design procedures. Its expectations-based validity is illustrated with an application to pedestrian street-crossing behavior in the Tampa Bay area of Florida. The approach combines the realism of revealed-preference surveys and the flexibility of standard stated preference surveys. It adds to the toolbox of travel behavior research.
Experience Implementing a User Service for Archived Intelligent Transportation Systems Data
Authors: Bertini Robert L. , Hansen Steve , Byrd Andrew , Yin Thareth
Published: May 2018

In cooperation with the Oregon Department of Transportation (ODOT) and other regional partners, the Portland regional intelligent transportation systems (ITSs) data archive was recently inaugurated via a direct fiber-optic connection between ODOT and Portland State University (PSU). In July 2004, the Portland Regional Transportation Archive Listing was activated; it received 20-s data from the 436 inductive loop detectors composing the Portland area's advanced traffic management system. PSU is designated as the region's official data archiving entity, consistent with the ITS architecture being developed. This paper discusses the steps taken for successful implementation of the Portland region's functional ITS data archive and plans for development and expansion. Included is a discussion of the archive structure, data storage, data processing, and user interface. An experiment involving Metro, the Portland region's metropolitan planning organization, demonstrates that archived loop detector data can be used to improve travel demand forecasts for the Portland region. The data archive will expand to include transit data, freeway incident data, city traffic signal data, and truck weigh-in-motion data.
Guide Signing for Two-Lane Exits with an Option Lane
Authors: Upchurch Jonathan , Fisher Donald L. , Waraich Bhupinder
Published: May 2018

In recent years U.S. freeways have seen an increase in the number of exit ramps that feature a two-lane exit with an option lane. This is a situation in which motorists in the rightmost lane of the freeway must exit, and those in the adjacent lane may either exit or continue on the mainline. Communicating information to the motorist about this type of exit is exceptionally difficult. Ideally, a sign should convey the following: ( a) If you stay in the right lane, you will be forced to exit. ( b) If you wish to exit, you may do so from either the right lane or the adjacent lane. ( c) If you are in the adjacent lane and wish to continue on the mainline, you need not change lanes. Making all of these discrete concepts obvious in a simple sign is challenging, and there is no standard sign design for this situation in FHWA's Manual on Uniform Traffic Control Devices for Streets and Highways (MUTCD). As a result, at least eight different sign designs are being used throughout the United States. This paper presents the results of an NCHRP human factors study conducted to identify the best design for a guide sign for this type of exit. Four candidate sign designs were evaluated with 96 test subjects in a driving simulator. Measures of effectiveness included the number of missed exits and the number of unnecessary lane changes. On the basis of the study results, one of the four designs is recommended for inclusion in the MUTCD.
Effects of Adding Dual-Logo Panels to Specific Service Signs
Authors: Hawkins H. Gene , Rose Elisabeth R.
Published: May 2018

Currently, FHWA's Manual on Uniform Traffic Control Devices for Streets and Highways allows only one business logo to be placed on a logo panel. Dual-logo panels were proposed by business owners as a solution to the complaint that single locations operating two or more business brands are ignored and unduly restricted to limited highway signing. Business owners are concerned that separate logos do not convey to the public that two brands are available at the same location; they believe that dual logos provide a means of linking services that are combined under the same roof. However, the use of dual logos raises concerns related to category placement, dual-logo recognition and legibility, and information overload. This research effort addressed several of these issues through the use of a timed survey in which subjects were asked to indicate whether various business logos were present in a series of photographs that included both single- and dual-logo panels. The objective was to gain some understanding of whether the use of dual logos would reduce the effectiveness of the logo signs. The results of the survey indicate that dual logos have lower recognition levels at shorter response times, but that, in general, the difference in recognition levels between single and dual logos decreases as both exposure time and driver familiarity with the business increases. The research results did not indicate a need to prohibit the use of dual-logo panels.
Closed-Form, Six-Slab, Thick-Plate Solution for Analysis of Edge Slab of Concrete Pavement
Authors: Wei Liu , Fwa T. F.
Published: May 2018

The development and application of a theoretical closed-form solution of a six-slab, thick-plate model for the structural design and analysis of an edge slab in jointed concrete pavement subjected to vertical loads are described. The jointed concrete pavement system is idealized as a six-slab system resting on a Winkler foundation. The six slabs are arranged in two rows with three slabs in each row. The loaded slab of interest is represented by a middle slab with five surrounding slabs to consider the effects of jointed pavement system. Fundamental equations of the proposed model were derived from thick-plate theory. Solutions of the fundamental equations were obtained by superposition of the solutions of appropriate elemental slabs. The validity of the proposed solutions was checked against finite element solutions. The six-slab model was applied to analyze the critical stresses and deflections of an edge slab under the following three loading conditions: interior, edge, and corner loadings. Comparisons of the computed critical stresses and deflections were made with Westergaard's solutions. Westergaard's solutions were found to overestimate the maximum bending stresses and deflections for large slabs but to tend to underestimate these pavement responses for small slabs. The likelihood of underestimation by Westergaard's solutions also increased as the load transfer efficiency of pavement joints fell.
Tests of a Family of Trip Table Refinements for Long-Range, Quick-Response Travel Forecasting
Authors: Horowitz Alan J.
Published: May 2018

This paper addresses the problem of using traffic counts to ascertain zonal trip generation characteristics when performing quick-response travel forecasts. A family of origin–destination (O-D) trip table estimation methods containing three unexplored members (biproportional, uniproportional, and dynamic biproportional) is proposed to solve this problem. The family is tested on static planning networks for Tallahassee, Florida; Northfield, Minnesota; and Fredericton, New Brunswick, Canada. Results indicate that travel forecasting models can be made to match ground counts better by a simple factoring of origins, destinations, or both. The three methods that directly solve for origin or destination factors have computational and statistical advantages over full-matrix O-D trip table estimation procedures, and the results are qualitatively and quantitatively interpretable.
Evaluation of Optimization Methods for Estimating Mixed Logit Models
Authors: Bastin Fabian , Cirillo Cinzia , Hess Stephane
Published: May 2018

The performances of different simulation-based estimation techniques for mixed logit modeling are evaluated. A quasi–Monte Carlo method (modified Latin hypercube sampling) is compared with a Monte Carlo algorithm with dynamic accuracy. The classic Broyden–Fletcher–Goldfarb–Shanno (BFGS) optimization algorithm line-search approach and trust region methods, which have proved to be extremely powerful in nonlinear programming, are also compared. Numerical tests are performed on two real data sets: stated preference data for parking type collected in the United Kingdom, and revealed preference data for mode choice collected as part of a German travel diary survey. Several criteria are used to evaluate the approximation quality of the log likelihood function and the accuracy of the results and the associated estimation runtime. Results suggest that the trust region approach outperforms the BFGS approach and that Monte Carlo methods remain competitive with quasi–Monte Carlo methods in high-dimensional problems, especially when an adaptive optimization algorithm is used.
Market-Based Framework for Forecasting Parking Cost in Traditional and Microsimulation Modeling Applications
Authors: Erhardt Gregory D. , Kurth David L. , Sabina Erik E. , Myung Smith
Published: May 2018

Parking cost is an important variable in determining mode choice, yet it receives little attention in most travel forecasting models. This paper presents a framework for modeling parking supply and cost that has three advantages over most parking cost models: a market-based approach is used to equilibrate parking demand with parking supply; actual parking costs paid by groups of travelers rather than average parking costs are estimated for each transportation analysis zone; and estimates are made from longitudinal data. This framework has been applied successfully in a traditional four-step travel model and is being used in practice. It also provides additional opportunities for application in a segmented manner or in concert with a microsimulation modeling approach. Mode choice results based on aggregate and segmented applications of the framework are substantially different. Improved forecasting of parking costs should be an important consideration in any new model development. In recent years, substantial efforts have been focused on household interactions and activity modeling. Although the understanding of travel behavior has improved substantially, the improved techniques still depend on good input data for credible forecasts.
Florida Activity Mobility Simulator
Authors: Pendyala Ram M. , Kitamura Ryuichi , Kikuchi Akira , Yamamoto Toshiyuki , Fujii Satoshi
Published: May 2018

The development of modeling systems for activity-based travel demand ushers in a new era in transportation demand forecasting and planning. A comprehensive multimodal activity-based system for forecasting travel demand was developed for implementation in Florida and resulted in the Florida Activity Mobility Simulator (FAMOS). Two main modules compose the FAMOS microsimulation model system for modeling activity–travel patterns of individuals: the Household Attributes Generation System and the Prism-Constrained Activity–Travel Simulator. FAMOS was developed and estimated with household activity and travel data collected in southeast Florida in 2000. Results of the model development effort are promising and demonstrate the applicability of activity-based model systems in travel demand forecasting. An overview of the model system, a description of its features and capabilities, and preliminary validation results are provided.
Multijurisdictional Safety Evaluation of Red Light Cameras
Authors: Persaud Bhagwant , Council Forrest M. , Lyon Craig , Eccles Kimberly , Griffith Mike
Published: May 2018

The use of red light camera (RLC) systems has risen dramatically in the United States in recent years. The size of the problem, the promise shown by RLC systems in other countries, and the paucity of definitive U.S. studies have motivated a multijurisdictional U.S. study. The fundamental objective of this study, which was sponsored by FHWA, was to determine the effectiveness of the RLC systems in reducing crashes at monitored intersections as well as jurisdictionwide. Phase I involved the development of a detailed experimental design that included collection of background information, establishment of study goals, selection of potential study jurisdictions, and specification of statistical methodology. In Phase 2, an empirical Bayes before-and-after study used data from seven jurisdictions across the United States, with a total of 132 treatment sites. Effects detected were consistent in direction with those found in many previous studies—a decrease in right-angle crashes and an increase in rear-end crashes—although both effects are somewhat lower than those reported in many sources. The extent to which the increase in rear-end crashes negates the benefits for right-angle crashes is unclear and points to the need for an examination of the economic cost of crashes, which is the subject of a companion paper, to aggregate the effects on rear-end, right-angle, and other crash costs. That second paper seeks to isolate all factors that would favor the installation of RLC systems by using the aggregate economic benefit as the outcome variable. There were weak indications of a spillover effect, which point to a need for a more definitive, perhaps prospective, study of this issue.
Integrated Planning for School and Community
Authors: Tsai Jeff , Miller Mike
Published: May 2018

The Operations Research/Education Laboratory (OR/Ed. lab) at the Institute for Transportation Research and Education, North Carolina State University, has a long history of providing school systems with data-driven solutions for school population forecasting, school attendance studies, and determination of new school locations. These planning processes, known as Integrated Planning for School and Community (IPSAC), provide school districts with mathematically optimal solutions that minimize transportation distance. The OR/Ed. lab works closely with school districts in politically and emotionally charged environments involving school locations and attendance district changes. The success of IPSAC lies in its approach to enumerate school planning needs and school population growth impression through the use of data. Furthermore, through the operations research optimization techniques, favorable solutions are achieved to satisfy the constraints, needs, and policies of the school district. Recent national studies in active school travel have reported that distance to school and built environment have a significant influence on how children travel to school. These research findings prompted the OR/Ed. lab to investigate ways to enhance IPSAC so that school districts may obtain solutions to include multimode school transportation as one of their considerations. This paper describes the IPSAC process, challenges faced by school districts, and areas in which the integration between school planning and transportation planning deserve explorations.
Methodology to Establish Hurricane Evacuation Zones
Authors: Wilmot Chester G. , Meduri Nandagopal
Published: May 2018

A review of practice in hurricane evacuation modeling reveals that the criteria determining the delineation of hurricane evacuation zones have not been clearly defined. In addition, there is no recommended procedure with which to establish hurricane evacuation zones once criteria have been accepted. A set of criteria has been adopted in this paper to design a procedure that mechanically establishes a recommended set of hurricane evacuation zones for an area. The procedure, which is based on a geographic information systems platform, is described, and its use is demonstrated for establishing hurricane evacuation zones for the northern part of the New Orleans, Louisiana, metropolitan area on the north shore of Lake Pontchartrain. The procedure can be applied to any area, and although it is specifically directed at identifying evacuation zones for hurricanes, it could be used for any emergency in which flooding is the major hazard, or it could be adapted to other emergency situations for which evacuation is an appropriate response.
Does Separating Trucks from Other Traffic Improve Overall Safety?
Authors: Lord Dominique , Middleton Dan , Whitacre Jeffrey
Published: May 2018

Decision makers have long speculated that building separate roads for trucks and passenger cars, or at least separating these into their own lanes, would accomplish two major objectives: (a) roadways would be made safer for passenger cars and (b) roadways designed specifically for a select class of vehicles rather than for all vehicles might represent overall savings in construction costs. This paper addresses the first objective. Recent studies on the evaluation of safety effects of truck traffic levels on general freeway facilities have not provided a clear understanding of how they affect the number of crashes. In some cases, studies have been contradictory. In addition, no studies have specifically compared passenger car–only with mixed-traffic freeway facilities. The research on which this paper is based aimed to assess whether more homogeneous flows of traffic by vehicle type are safer than the current mixed-flow scenario. An exploratory analysis of crash data was conducted on selected freeway sections of the New Jersey Turnpike for 2002. These sections operate as a dual–dual freeway facility: divided inner and outer lanes. At these locations, the inner lanes have the special characteristic of being for passenger cars only (homogeneous traffic). The selected sections, therefore, offer a very good opportunity to compare the crash experience between passenger car–only and mixed-traffic rural freeway facilities. The results of the study show that outer lanes experience more crashes, both when raw numbers are used and when exposure is included in the analysis. It was shown that truck-related crashes contribute significantly to the total number of crashes on the outer lanes. In fact, trucks are overinvolved in crashes given the exposure on these sections. Although the outcome of this study suggests that separating truck traffic from passenger cars for freeway facilities improves safety, further work is needed to understand the contributing factors leading to truck-related crashes in the outer lanes.
Motorcycle Helmet use and Trends before and after Florida's Helmet Law Change in 2000
Authors: Turner Patricia A. , Hagelin Christopher
Published: May 2018

The Center for Urban Transportation Research at the University of South Florida conducted this study for the Florida Department of Transportation to analyze motorcycling trends in Florida before and after the July 2000 change to the motorcycle helmet law. The change permits motorcyclists 21 years of age and older to ride without a helmet if they carry at least $10,000 in insurance to cover medical costs incurred as a result of a crash. This paper discusses study findings on motorcycle trends before and after the Florida change related to observed and reported motorcycle helmet use, number and severity of motorcycle crashes, and number and severity of injuries sustained in motorcycle crashes. Additionally, national and Florida data related to vehicle miles of travel (VMT), registrations, crashes, injuries, fatalities, and helmet use are presented, and recommendations for future motorcycle research are made. Findings show that Florida's observed helmet use rate declined from 99.5% in 1998 to 52.7% in 2002. Sport bike riders were among those most likely to be helmeted, whereas lack of helmet use typically was associated with riders on cruiser-style motorcycles. Declines in observed helmet use rates in Florida are comparable to declines in other states with recently amended universal helmet laws. Helmet use among crash-involved motorcycle operators continues to decline even among younger riders required by law to wear helmets. Crash rates and injury rates per registered motorcycle and per motorcycle VMT declined following the helmet law change, with the exception of fatal crash rates.
Using Simulation to Test Traffic Incident Management Strategies
Authors: Wirtz John J. , Schofer Joseph L. , Schulz David F.
Published: May 2018

This study tested a dynamic traffic assignment model as a tool for preplanning strategies for managing major freeway incidents. Incidents of various scales and durations were modeled in the northern Chicago, Illinois, highway network, and the impacts of incidents and response actions were measured in lane mile hours of highway links at Level of Service F and spread of congestion to alternate routes around the incident. It was found that the best response action to a given incident scenario was not necessarily intuitive and that implementing the wrong response could worsen congestion on the directly impacted freeway and its surrounding highway network. The simulation model showed that a full closure of the freeway caused congestion to spread to alternate parallel routes around the simulated incident. An event of this scale constitutes a major disruption that may warrant handing off traffic control authority from first responders to a corridor or regional traffic management center. Major arterials accessible from the impacted freeway sometimes need increased capacity to provide access to less congested parallel alternate routes during incidents. The simulation model showed that congestion increases with delayed response, underscoring the benefits of preplanning to speed the implementation of effective incident response actions. Regression analysis using data generated by the simulation demonstrates that incident scale and duration are statistically significant predictors of lane mile hours of congestion in the zone near the incident and on the expressway.
Optimizing Location and Relocation of Response Units in Guarding Critical Facilities
Authors: Sathe Aamod , Miller-Hooks Elise
Published: May 2018

The ability to locate military units or equipment, police forces, and first responders optimally and to relocate idle units quickly in response to changing conditions is crucial to a country's ability to guard its critical facilities. Such facilities include vital components of the transportation infrastructure, government and monumental buildings, locations of large gatherings, emergency operations centers, and public and private utilities and communications facilities. In this paper, the problem of making optimal location and relocation decisions for a fixed fleet of response units in a transportation network, where travel conditions are uncertain, is addressed. A mixed integer linear program with multiple objectives (maximize secondary coverage and minimize cost) is presented. Because exact solution of such problems may require considerable computational effort, a metaheuristic based on the principles of genetic algorithms is proposed. The heuristic seeks the set of Pareto-optimal location and relocation decisions for each network state. All facilities of concern must be covered by at least one response unit. If the state of the network changes so that coverage is lost (e.g., travel times increase or a response unit is no longer available), one or more of the response units must be relocated. These relocation decisions are also addressed.
Enhancement of Automatic Incident Detection Algorithms for Singapore's Central Expressway
Authors: Mak Chin Long , Fan H. S. L.
Published: May 2018

Timely detection of accidents, vehicle breakdowns, and events that obstruct normal traffic flow is critical to successful implementation of an incident management system in combating traffic congestion along expressways. The purpose of this study is to enhance the performance of existing expressway automatic incident detection algorithms in detecting lane-blocking incidents. In this study, a video-based vehicle detector system was used along the Central Expressway (CTE) in Singapore to collect 160 incidents. Two main tasks were carried out with the CTE incident database to investigate factors that influence incident detection performance and to investigate the use of these findings to enhance existing CTE-calibrated incident detection algorithms. Results indicated that the inclusion of preincident traffic flow or occupancy conditions and the use of traffic speed together with occupancy in an algorithm would yield enhanced detection performance. Of the algorithms studied, the dual variable algorithm, which uses traffic speed and occupancy, can consistently give the best detection performance. From an efficiency perspective, there were no significant changes in time lag in the detection of an incident. A comparative evaluation suggested that the occupancy-based algorithms were generally more effective than the flow-based algorithms in detecting incidents.
Online Consistency Checking and Origin–Destination Demand Updating
Authors: Zhou Xuesong , Mahmassani Hani S.
Published: May 2018

To maintain an internally consistent representation with actual traffic conditions, this paper presents an origin–destination (O-D) demand consistency-checking and updating model for online dynamic traffic assignment operation. Both predictive and reactive approaches are proposed to minimize the deviations between simulated states and real-world observations and O-D demand adjustment magnitude. The two objectives are combined into a weighted linear quadratic function to construct a guaranteed overdetermined optimization problem. Alternative recursive solution algorithms are presented to design an efficient feedback controller that regulates the demand input for the real-time dynamic traffic assignment simulator. The proposed model is tested with field data from the Irvine test bed network.
Study on Optimal Frequency Design Problem for Multimodal Network Using Probit-Based User Equilibrium Assignment
Authors: Uchida Kenetsu , Sumalee Agachai , Watling David , Connors Richard
Published: May 2018

In this paper, a probit-based multimodal transport assignment model is developed. Three transport modes (railway system, bus system, and automobiles) and their interactions are considered. The walking time to a bus stop or a station also plays an important role in multimodal networks. Thus, walking to a bus stop or to a railway station is included in the model. The factors affecting travelers’ route choices considered in this model include actual travel times, discomfort effects on transit systems, expected waiting times, fares, and constants specific to transport modes. A route in the model may be composed of different modes. The paper also deals with the optimal transit frequency design problem. The frequency design problem is formulated as an implicit program in which the objective function of total disutility in the multimodal network is minimized with respect to frequencies of transit lines. The flows on a multimodal network follow a probit-based stochastic user equilibrium assignment. A numerical example is presented.
Using Custom Transportation Data Collection Software with Handheld Computers for Education, Research, and Practice
Authors: Bertini Robert L. , Monsere Christopher M. , Byrd Andrew , Rose Michael , El-Seoud Tarek Abou
Published: May 2018

In an effort to facilitate data collection for research, give students firsthand experience collecting data for course projects, and generate interest in the transportation field through outreach, the Intelligent Transportation Systems Laboratory of Portland State University, Oregon, has developed custom data collection software for handheld computers using the Palm OS platform. The software is designed to export the collected data to desktop computers in common file formats suitable for analysis in spreadsheet and geographic information systems applications. Data collection problems addressed include recording position over time, recording geographic location of features, and performing cumulative vehicle or pedestrian counts.
Transportation Skills Needed by Private-Sector and Public-Sector Organizations
Authors: Humphrey Thomas F.
Published: May 2018

The University of Rhode Island requested an assessment of the potential demand for developing new academic programs in the areas of transportation and logistics. Although the research focused on Rhode Island public- and private-sector organizations, it was concluded that the results have broader applications for the academic community. The research was accomplished by interviewing a total of 24 key executives in four large private companies and five large public-sector organizations. The questions focused on “skills required to do your job.” The interviews resulted in the following conclusions: ( a) a distinct difference must be made between education needs, training needs, and outreach needs; ( b) concerning public agency needs, responses tracked closely to the several national studies that have taken place over the past several years; ( c) private-sector organizations view logistics and supply chain management as critical to their bottom line; ( d) there appears to be a common interest among interviewees for universities to establish more outreach programs; ( e) private-sector companies all expressed possible interest in targeted logistics and supply chain management programs (certificate programs or individual courses could be of interest, either as traditional classroom or Internet-based); ( f) definite interest existed among public agencies to establish courses and distance-learning–based certificate programs in “transportation policy and management” (the author's label); and ( g) there were a surprising number of common needs.
Hedonic Analysis of Impacts of Traffic Volumes on Property Values
Authors: Kawamura Kazuya , Mahajan Shruti
Published: May 2018

This research attempts to quantify the cumulative impacts of vehicle traffic, both passenger cars and trucks, by using the hedonic price analysis of the relationship between property values and the traffic along selected arterial corridors in Chicago, Illinois. The traffic characteristics are derived from the traffic counts data obtained from the City of Chicago and include average daily traffic, maximum daily peak, and nighttime volumes, calculated separately for trucks and for total traffic. Autoregressive models, with assessed property value as the dependent variable and traffic characteristics along with other determinants of property value as the independent variables, are constructed. The models include a spatial-lag term to control for the spatial autocorrelation and are estimated using the two-stage least squares. The regression results from the final models suggest that although the characteristics for total traffic have modest but statistically significant impact on property values, the traffic characteristics for trucks are statistically insignificant. Also, the strong evidence of spatial dependence in the data set underscores the importance of paying close attention to the model specification and controlling the autocorrelation in the hedonic price analysis.
Distributional Consequences of Gasoline Taxation in the United Kingdom
Authors: Santos Georgina , Catchesides Tom
Published: May 2018

This paper assesses the regressive effects of gasoline taxation in the United Kingdom. When all households are considered, middle-income households suffer most of the burden. When only car-owning households are considered, gasoline taxation is strongly regressive. Low-income households that own a car are more severely affected than high-income households because they spend a larger proportion of their income on motoring. This conclusion is similar to that of previous studies on the topic.
Can a Sustainable Transportation System be Developed for San Antonio, Texas?
Authors: Barker William G.
Published: May 2018

This paper makes the case that the current urban transportation system in San Antonio, Texas, is far from sustainable. Implications of that status are presented. After a review of the measures that are recommended to move a region toward sustainability, a comparison is made between current programs and plans, expert recommendations, and input from local citizens. The paper closes with recommendations for improving the planning process.
Linking Asset Management to Strategic Planning Processes
Authors: Pagano Anthony M. , McNeil Sue , Ogard Elizabeth
Published: May 2018

The research described in this paper assembles a set of tools on the basis of experiences and best practices in a diverse set of states for linking strategic goals to resource allocation and implementation decisions using aspects of asset management. A survey of practices in each of the state DOTs explored documents and synthesized both strategic planning processes and asset management. With input from an expert advisory panel, five states were the subjects of detailed analysis: Florida, Maryland, Michigan, Montana, and Pennsylvania. Each of the states was visited by a project team that spent 2 days on-site. Information on the strategic planning and asset management process was obtained through personal interviews with DOT officials and the acquisition of materials describing these processes. Based on detailed documentation of the practices in each of these states, a synthesis of best practices of the linkage between asset management and strategic planning was developed. The resulting model process does not represent any particular state, but incorporates elements from all five states. This synthesis can provide useful guidance to states interested in augmenting their existing processes.
Effectiveness of Programs for Work Site Trip Reduction
Authors: Hendricks Sara J.
Published: May 2018

The purpose of this research was to investigate other explanations for the success of work site trip reduction programs besides the combinations of incentives offered by organizations to their employees. Specifically, the study examined the organizational culture of individual work sites as manifested by the effect of the employee transportation coordinators (ETC) on their work site trip reduction programs. A case study methodology adapted from the social sciences was used. Investigators attempted to disprove a null hypothesis stated as the effectiveness of work site trip reduction programs does not depend on organizational culture. Research results appear to indicate that the null hypothesis is true sometimes. This study found evidence that management support and an effective ETC are not necessary for a successful work site trip reduction program if the work site is located in an area with access to high-quality public transportation and employs lower-income staff who must choose transportation cost savings over time savings and convenience. However, management support and an effective ETC are necessary for a successful work site trip reduction program if the work site is not located in an area with access to high-quality public transportation. The goals of the study were to provide guidance to employers in ETC selection, help ETCs implement their trip reduction programs more effectively, and help transportation demand management (TDM) professionals target those work sites identified as most likely to respond positively to TDM programs.
Investment Analysis Using the Constraint Multiobjective Programming Method
Authors: Chowdhury Mashrur , Tan Paulin
Published: May 2018

Transportation infrastructure decisions that optimize available resources and provide maximum benefits are of tremendous potential advantage to the transportation professional. Decision makers attempt to reach their goals with well-timed and cost-effective decisions that invest limited available resources according to future needs. Thus, it becomes increasingly important for them to use objective tools to make the proper investment choices. This paper presents a multiobjective analysis that uses a set of objectives and constraints to aid investment decisions. Multiobjective decision analysis gives planners technical tools to solve a decision problem with multiple objectives. The effects of each objective might then be evaluated according to selected measures of effectiveness (MOEs). The MOEs derived from these objectives might include a resulting reduction in environmental impacts, a level of improved access to cultural facilities, or a level of comfort with the given alternatives. With complex transportation planning problems, no single option may be considered the best by all measures. Economic, safety, ecological, social, and operational measures may produce varied results. Multiobjective programming does not provide a single solution or alternative, but rather provides a set of best alternatives from all available options. This paper presents a constraint multiobjective programming method for use in analyzing major investment decisions. A case study based on the Ohio River Bridge Project demonstrates the application of the multiobjective analysis tool.
Analysis of Freeway Traffic Incident Conditions by Using Second-Order Spatiotemporal Traffic Performance Measures
Authors: Ishak Sherif , Alecsandru Ciprian
Published: May 2018

The characteristics of preincident, postincident, and nonincident traffic conditions on freeways are investigated. The characteristics are defined by second-order statistical measures derived from spatiotemporal speed contour maps. Four performance measures are used to quantify properties such as smoothness, homogeneity, and randomness in traffic conditions in a manner similar to texture characterization of digital images. With real-world incident and traffic data sets, statistical analysis was conducted to seek distinctive characteristics of three groups of traffic operating conditions: preincident, postincident, and nonincident. The study results showed that the spatiotemporal characteristics of each of the three groups were not discernible. Although the distributions of performance measures within each group are statistically different, no consistent pattern was detected to imply that certain characteristics could increase the likelihood of incidents or identify precursory conditions to incidents.
Use of Performance Measurement System Data to Diagnose Freeway Bottleneck Locations Empirically in Orange County, California
Authors: Bertini Robert L. , Myton Aaron M.
Published: May 2018

To improve freeway modeling and operations, it is important to understand how traffic conditions evolve in both time and space. The widespread availability of freeway sensor data makes detailed operational analysis possible in ways that were not available in the past. This study, inspired by several other studies of a 6-mi segment of Interstate 405 in Orange County, California, describes the evolution of traffic conditions over one morning peak period by using inductive loop detector data, including vehicle count and lane occupancy measured at 30-s intervals. With cumulative curves of vehicle count and occupancy, transformed in ways that enhanced their resolution, 10 bottleneck activations were identified in time and space over one morning peak period. At bottleneck activation, queue propagation was observed in generally predictable ways. Bottleneck outflows were carefully measured only while the bottlenecks were active, that is, while queued conditions persisted upstream and unqueued (freely flowing) conditions prevailed downstream. When bottlenecks were activated immediately following freely flowing conditions, outflow reductions were observed at queue formation. These reductions were consistent with those in previous studies. The study was limited in that only one day's data were analyzed and ramp data were not available on the day analyzed. Future research will include further analysis of the same site by using more recent data now that ramp counts are available in the California Performance Measurement System database. Understanding the mechanisms that lead to bottleneck activation is a critical step toward improving the understanding of how freeways function and is necessary for addressing operational issues. This clear understanding provides a foundation for determining ramp metering rates and addressing the freeway characteristics that cause bottlenecks to form.