bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of Highway Congestion Index with Fuzzy Set Models
Authors: Vaziri Manouchehr
Published: April 2007

Development of a highway congestion index on the basis of expert and user opinions with fuzzy set theory was attempted. Forty 1-min videotape segments showing different highway traffic flow conditions were displayed to a group of highway experts and users. They were asked to complete the relevant questionnaires on the existence and acceptability of congestion for each video segment display. Five congestion-descriptive variables of travel speed, travel rate, delay rate, travel rate ratio, and delay ratio were determined for each video segment. Information about the values of congestion-descriptive variables for the displayed videos, questionnaire responses, and fuzzy set theory were used to develop congestion fuzzy set membership functions. The membership functions characterized the congestion intensity fuzzy values of “congested” and “unacceptably congested.” The membership functions were suggested as congestion indexes measured on a scale of 0 to 1. In the questionnaire, the surveyed group also provided opinions regarding the relative importance of the descriptive variables in explaining congestion. This information was used to determine average weighting values for the developed indexes. Using the average weighting values, overall indexes for “congested” and “unacceptably congested” were developed. The overall congestion indexes were also suggested for congestion intensity assessment and evaluation. The relationships between the Highway Capacity Manual levels of service and the developed congestion indexes were studied. The results were used to address some issues regarding normative index development. Although the study findings are based on a rather limited database and are location specific, the applied methodology can be used to capture congestion intensity perception in any future index development. The study index development was based on fuzzy set theory and is suggested as an alternative or complementary approach to past normative index development methods.
Detailed Observations of Saturation Headways and Start-Up Lost Times
Authors: Li Honglong , Prevedouros Panos D.
Published: April 2007

The analyses conducted in this research were based on three methodologies for the field measurement of saturation headways. The first method (M1), the one on which most past studies were based, measured the characteristics of Vehicles 4 to 12 in a standing queue. M2, the method found in the Highway Capacity Manual (HCM), counted all vehicles in a standing queue, regardless of queue length. M3 included arrivals that joined the standing queue as long as vehicles were up to 140 ft from the stop line. This study focused on one approach of a high-design intersection with heavy, random arrivals. The large number of observations and the practically ideal traffic conditions enabled the acquisition of several statistically significant results on saturation flow ( s), start-up lost time (SULT), and start-up response time (SRT): ( a) when long queues are present, the typical field measurement of s based on the first 12 vehicles is an overestimate of s for through vehicles and an underestimate of s for protected left-turning vehicles; ( b) the type of movement had a more dominant role in determining s than the level of saturation (or queue length); ( c) SRT displayed a bigger variation than headways— the left-turning movement had a significantly shorter SRT than the through movement did; and ( d) much higher SULTs were estimated in this study compared with those in the HCM.
Comparison of Delay on Arterials by Simulation and Highway Capacity Manual Computations
Authors: Prassas Elena S.
Published: April 2007

A comparison of delay on arterials was made using simulation and Highway Capacity Manual (HCM) computations. An extensive set of cases was defined over a range of flow rates, free-flow speeds, and signals per mile. Delay was calculated on the basis of the HCM computation for the specified signal progressions. The same cases were run using a specially revised version of the NETSIM microscopic simulation model. Detailed analysis showed that the discrepancies were traceable to the progression factor (PF). Corrections can be made (and are outlined) but must be done with care. There are a number of complex mechanisms at work. The primary result of this study may be clarifying the insufficiency in the current PF algorithm. The expectation that a single multiplicative factor could provide the needed correction to a long-link random-arrival steady-state delay model (that is, the existing HCM delay model), so that it could be a network-based model for delay estimation, appears to be simply unrealistic. For these and other reasons, research is focusing on the creation of a time-varying intersection delay model, building from basic principles.
Developing a Measure of Traffic Congestion: Fuzzy Inference Approach
Authors: Hamad Khaled , Kikuchi Shinya
Published: April 2007

Many measures have been proposed to represent the status of traffic conditions on arterial roadways in urban areas. The debate about what is the most appropriate measure continues. In a contribution to the debate, another approach was offered. Traditionally, two general approaches exist. One is based on the relationship between supply and demand. The other is a measure relative to the most acceptable status of service quality. The latter measure allows the public to relate to their travel experience. In either case, however, derivation of measures of congestion involves uncertainty because of imprecision of the measurement, the traveler’s perception of acceptability, variation in sample data, and the analyst’s uncertainty about causal relations. A measure is proposed that is a composite of two traditional measures, travel speed and delay. In recognition of the uncertainty, a fuzzy inference process was proposed. The inputs are travel speed, free-flow speed, and the proportion of very low speed in the total travel time. These values were processed through fuzzyrule-based inference. The outcome was a single congestion index value between 0 and 1, where 0 is the best condition and 1 is the worst condition. The process was demonstrated using real-world data. The results were compared with those of the Highway Capacity Manual. Although no conclusion can be drawn about the best measure of congestion, the proposed inference process allows the mechanism to combine different measures and also to incorporate the uncertainty in the individual measures so that the composite picture of congestion can be reproduced.
Proposed Level-of-Service Methodology for Toll Plazas
Authors: Klodzinski Jack , Al-Deek Haitham M.
Published: April 2007

A proposed macroscopic methodology for measuring the level of service (LOS) of toll plazas has been developed using delay as the measure of effectiveness (MOE). On the basis of field research and data analyses, the 85th percentile of the cumulative individual vehicular delay was found to be the most comprehensive measure for evaluating the LOS at a toll plaza. Other MOEs were examined but found to be less flexible with different plaza configurations and lane payment types. More than 55,000 individual vehicular records from three mainline toll plazas in Orlando, Florida, representing eight different plaza configurations with varied percentages of electronic toll collection (ETC) usage were used to validate the methodology. TPSIM, a toll plaza simulation model, was used to produce an additional 49 scenarios representing the three plazas with varied percentages of ETC usage and 21 additional plaza configurations. Service time was examined to determine the level at which a driver begins to feel discomfort and inconvenience at a toll plaza. An LOS hierarchy was established based on the conclusions of this analysis, feedback from professionals, and reference to the Highway Capacity Manual (HCM) 2000. The 85th delay percentile graphs from each of the plaza analysis results for LOS values were also observed to be similar.
Real-Time Inductive-Signature-Based Level of Service for Signalized Intersections
Authors: Oh Cheol , Ritchie Stephen G.
Published: April 2007

The Highway Capacity Manual (HCM) presents a procedure for estimating signalized intersection control delay, which is used to determine level of service (LOS) and to evaluate intersection performance. The HCM is used extensively by traffic engineers. However, it is intended as an offline decision support tool for planning and design. To meet user requirements of advanced traffic management and information systems, new LOS criteria are required for real-time intersection analysis. The objective of this research was to demonstrate a technique for development of such LOS criteria. The study used a new measure of effectiveness, called reidentification delay (RD), derived from analysis of vehicle inductive signatures and reidentification of vehicles traveling through a major signalized intersection in the city of Irvine, California. Two main issues regarding real-time LOS criteria were tackled. The first was how to determine the threshold values partitioning the LOS categories. To provide reliable real-time traffic information, the threshold values should be decided on so that RDs within the same LOS category would represent similar traffic conditions as much as possible. RDs in different LOS categories should also represent dissimilar traffic conditions. The second issue concerned the aggregation interval to use for RD in deriving LOS categories. An investigation of both fixed and cycle-based aggregation intervals was conducted. Several clustering techniques were then employed to derive LOS categories, including k-means, fuzzy, and self-organizing map approaches. The resulting real-time LOS criteria were then determined. The procedures used in this study are readily transferable to other signalized intersections for the derivation of real-time LOS.
Multiple Car-Following Data with Real-Time Kinematic Global Positioning System
Authors: Gurusinghe Gemunu Senadeera , Nakatsuji Takashi , Azuta Yoichi , Ranjitkar Prakash , Tanaboriboon Yordphol
Published: April 2007

The real-time kinematic differential Global Positioning System (GPS) has facilitated a new horizon in traffic engineering. Multiple car-following experiments conducted with a real-time kinematic GPS with 10 vehicles participating in a probing field gave high-quality results in headway, speed, relative speed, and acceleration. The expected accuracies for measuring position and speed were 10 mm and 0.16 km/h, respectively. The vehicles were driven in a loop consisting of two parallel straight sections connected by two semicircular curves. Different driving conditions were induced in the platoon by instructing the leading driver to follow predetermined speed variations. The experiments yielded sets of continuous observations. Headway, speed, and acceleration were measured using conventional equipment for the purpose of comparing accuracy. The accuracy of the data obtained using the GPS was superior to that of the same data obtained using conventional measurements. The variation in driving characteristics down the stream of vehicles was studied using the experimental data. The results showed that the reaction time between a change in relative speed and the corresponding change in acceleration varies during the driving process. The reaction time of individual drivers also changes along the platoon. The good-quality data were able to give high-resolution plots of acceleration and relative speed illustrating that both the reaction time and the functional relationship between acceleration and relative speed do not remain constant.
General-Purpose Methodology for Estimating Link Travel Time with Multiple-Point Detection of Traffic
Authors: Cortés Cristián E. , Lavanya Riju , Oh Jun-Seok , Jayakrishnan R.
Published: April 2007

A methodology was developed to find appropriate travel times for highway links using data from point detectors that could be at various points within the link or could even be outside the link. The travel times were found using a definition that the appropriate value is the one experienced by a virtual vehicle reaching the midpoint of the link at the midpoint of the time step. A simple iterative scheme was proposed to find the travel time profiles. The accuracy of the scheme depends on whether aggregated detector data or individual vehicle spot speeds are used. Comparison of estimated travel times with actual experienced travel times of all vehicles in a microscopic simulation showed the technique to give very good results, comparable with having a high number of probe vehicles reporting travel times.
Design and Implementation of Control-Theory-Based Microscopic Traffic Flow Model
Authors: Shi Huajing , Ziliaskopoulos Athanasios K.
Published: April 2007

A microscopic traffic flow model based on the constant-time-headway policy and McRuer’s man-machine crossover model was designed. Automatic control theory concepts were employed in the model formulation. The constant-time-headway policy was used to generate the command model of a human driver’s decision for vehicle acceleration or deceleration. This command is the input signal fed into the driver-vehicle dynamics suggested by the crossover model. The proposed model was mathematically formulated, designed, implemented, and numerically simulated. The stability properties and validity of the proposed model were analyzed on the basis of the simulation results. It was demonstrated that the proposed model can reproduce well-known traffic phenomena such as shock waves, intersection starting and stopping waves, and loop structures of flow-density and speed-density plots.
Review of Empirical Research on Congested Freeway Flow
Authors: Banks James H.
Published: April 2007

In a review of the empirical literature on congested freeway flow, with special emphasis on topics of current interest, including congested flow phases, congested-regime flow-concentration relationships, wave speeds, average time-gap behavior, and transitions between uncongested and congested flow, the most striking feature of the results is their diversity. Shapes of flow-concentration relationships vary among studies and sites, wave speeds vary, patterns of repetition in congested flow appear to vary widely, and flow breakdown occurs at a variety of locations and for a variety of reasons. The diversity of results seems to indicate a similar diversity of phenomena rather than the effect of methodological differences. For the most part, methodologies are simple and intuitive, and because of their simplicity, they are unlikely to result in variability of the magnitude found in the results. Several methodological features that could possibly distort results are noted but do not appear to be responsible for the diversity of results. A major limitation of research to date is a lack of systematic understanding of the relative frequency of occurrence of different congested-flow phenomena. Because abundant loop-detector data are now available, research into the frequencies of congested-flow phenomena is feasible; however, analysis of very large quantities of data will be required.
Application of Car-Following Systems in Microscopic Time-Scan Simulation Models
Authors: Cohen Stephen L.
Published: April 2007

A concept of a car-following system that consists of a car-following equation together with a set of constraints is appropriate for micro-simulation models. Recognition was given to the asynchronous condition in the leader-follower relationship as it relates to the internal dynamics in simulation models. The Pitt car-following equation and criticisms of it were evaluated. Two modifications to the Pitt car-following equation were introduced that address the criticisms. The first modification consists of a change in the method by which the perception-reaction time is handled, eliminating the requirement that it must be much less than the simulation time step and removing a discrepancy between the application of car-following and emergency deceleration. The second modification consists of a multiplicative factor, K, that addresses issues related to overdamping and the dead band, which have been raised concerning the original formulation of the Pitt model. An Excel spreadsheet was used to implement the car-following system, and a series of scenarios were simulated. The results of the scenarios indicated that the addition of the factor K has a substantial effect on the behavior of vehicles in a platoon when the leader of the platoon is subjected to a deceleration. Issues of calibration and validation were also addressed.
Dynamic Programming Approach for Online Freeway Flow Propagation Adjustment
Authors: Zhou Xuesong , Mahmassani Hani S.
Published: April 2007

An optimization framework for online flow propagation adjustment in a freeway context was proposed. Instead of performing local adjustment for individual links separately, the proposed framework considers the interconnectivity of links in a traffic network. In particular, dynamic behavior in the mesoscopic simulation is approximated by the finite-difference method at a macroscopic level. The proposed model seeks to minimize the deviation between simulated density and anticipated density. By taking advantage of the serial structure of a freeway, an efficient dynamic programming algorithm has been developed and tested. The experiment results compared with analytic results as the base case showed the superior performance of dynamic programming methods over the classical proportion control method. The effect of varying update intervals was also examined. The simulation results suggest that a greedy method considering the impact of inconsistency propagation achieves the best trade-off in terms of computation effort and solution quality.
Effect of Warning Timing on Collision Avoidance Behavior in a Stationary Lead Vehicle Scenario
Authors: McGehee Daniel V. , Brown Timothy L. , Lee John D. , Wilson Terry B.
Published: April 2007

Warning timing and how drivers with and without forward collision warning (FCW) systems react when distracted at the moment a stationary vehicle is revealed directly ahead were investigated. The study was conducted using the Iowa Driving Simulator (IDS). The IDS was equipped with an FCW system that provided auditory warnings based on two warning criteria. A total of 30 subjects were split across three conditions—a baseline of 10 subjects (no warning display), and two warning conditions (early and late) with 10 subjects each. The two warning conditions differed by the duration of an a priori driver reaction component (1.5 and 1.0 s) in the warning algorithm. Drivers’ collision avoidance performance in the two warning conditions was compared with that in the baseline condition. Results indicated that the early warning condition showed significantly shorter accelerator release reaction times, fewer crashes, and less severe crashes than both the baseline condition and the late warning condition. The results indicate that the timing of a warning is important in the design of collision warning systems.
Effects of Memory Retrieval Load on Drivers’ Reproduction Performance Under Route Searching
Authors: Hagiwara Toru , Nakagawa Koji , Uchida Ken’etsu , Adachi Takeo , Kagaya Seiichi
Published: April 2007

Experiments were conducted using a personal computer to study the human factors involved in information processing during route searching. The primary objective was to investigate the effects of differences in the amount of memory retrieval load in terms of a given task. Two route-searching tasks were combined with two memory-reproducing tasks, for four types of tasks. The subjects used either a map guidance system or a voice guidance system to trace a predetermined route to the destination in a simulated driving test. In addition, the subjects were asked to perform memory-reproducing tasks using working memory. In these tasks, the subjects memorized the same number of traffic signs, but there was a difference in the memory retrieval process that the tasks demanded. The subjects were 62 students at Hokkaido University. Multiple analysis of variance was used to analyze the interaction effects and the main effects of tasks. The results indicated that the accuracy of route searching, the response time of route searching, and the accuracy of reproducing memorized traffic signs increased as the memory retrieval load decreased. This suggests that the memory retrieval process affects the performance of drivers’ information processing.
Comparison of Driver Braking Responses in a High-Fidelity Simulator and on a Test Track
Authors: Hoffman Joshua D. , Lee John D. , Brown Timothy L. , McGehee Daniel V.
Published: April 2007

The braking responses of drivers in the Iowa Driving Simulator (IDS) were compared with those of drivers on a test track. The braking profile of drivers was compared in last-minute braking situations in which drivers were instructed to brake “normally” or “hard.” Although the motion and visual cues in the IDS are imperfect, the data agree in many respects. The general pattern of results is similar, with the initial speed and lead vehicle deceleration affecting drivers on the test track and in the simulator in a similar way. In several experimental conditions, the similarity of the responses went beyond the general pattern of response. The mean values were almost identical in several instances, and the values were frequently well within the confidence intervals. Although the simulator and test track drivers performed similarly, differences are apparent from the onset of braking, through the braking process, and in the outcome of the braking event. The instructions concerning normal and hard braking had little influence on the behavior of drivers in the simulator. Contributors to these differences include the limited visual and vestibular cues in the simulator and the extended practice on the test track.
Traveler Response to New Dynamic Information Sources: Analyzing Corridor and Areawide Behavioral Surveys
Authors: Yim Youngbin , Khattak Asad J. , Raw Jeremy
Published: April 2007

Intelligent transportation systems present a well-known innovation opportunity to address urban congestion and allow greater access to transportation networks. New sources of travel information are emerging rapidly, and they are likely to significantly affect traveler decisions and transportation network performance. To assess the value and impact of these new sources, a comprehensive conceptual model is developed on the basis of information processing and traveler response. Specifically, the model accounts for the effect of information source, content, and quality on information access and travel behavior. Empirical evidence from several behavioral surveys conducted in the San Francisco Bay Area between 1995 and 1999 is presented. The surveys used innovative methods to study the response of the whole population, the response of people more inclined to use information technology (early adopters), and traveler decision making in high-benefit incident situations. The conceptual model helps to integrate and interpret empirical findings from the surveys. The issues of access to new and conventional technologies and services, their current market penetration levels, switching behavior concerning new information sources and information service providers, desired information content, and willingness to pay for dynamic information are discussed. The opportunities and limitations of new technologies and the implications for future technology implementations are described.
Data-Consistent Fuzzy Approach for Online Driver Behavior Under Information Provision
Authors: Peeta Srinivas , Yu Jeong W.
Published: April 2007

A fuzzy approach to predict online driver routing decisions under information provision is proposed. The problem is characterized by subjectively interpreted and linguistic data, limited data on qualitative variables, and the need for computational efficiency to enable real-time deployment in a traffic control framework. The appropriateness of a fuzzy model to address these characteristics is highlighted. The proposed model enables theoretical consistency with the underlying behavioral mechanisms revealed through the available data. This is done by transforming the probabilities obtained from the data to possibilities, and then constructing membership functions. An S-shaped curve is proposed as a more robust behavioral indicator than the often-used triangular and trapezoidal shapes for these functions, while retaining their analytical tractability, computational efficiency, and ease of construction. In general, the approach suggests membership functions that are consistent with actual data. The model is analyzed using on-site stated preference data on variable message sign driver route diversion attitudes and is compared with a probabilistic discrete choice model for the same data. The results indicate that the fuzzy model performs more robustly for these data. When its computational efficiency and modularity are factored in, it may represent a better alternative to model online driver routing behavior in the context of real-time deployment.
Flashing Messages, Flashing Lines, and Alternating One Line on Changeable Message Signs
Authors: Dudek Conrad L. , Ullman Gerald L.
Published: April 2007

Results of human factors laboratory studies conducted in Texas pertaining to the display of messages using the following dynamic characteristics of changeable message signs (CMSs) are presented: (a) the effect of flashing an entire one-frame message, (b) the effect of flashing one line of a one-frame message; and (c) the effect of alternating text on one line of a three-line CMS while keeping the other two lines of text the same. Two hundred sixty Texas drivers were recruited in Dallas, El Paso, Fort Worth, Houston, and San Antonio to participate in the laboratory studies designed to simulate these CMS characteristics on laptop computers. The drivers responded to questions designed to determine the level of recall and comprehension of the information contained in the message. Response times, message format, and sign operating preferences were also collected. The results showed that in the laboratory setting, flashing a one-frame message did not adversely affect driver recall or comprehension to a significant degree compared with when the message was not flashed. However, average reading times were significantly higher when the message was flashed. Flashing one line of a three-line message appeared to adversely affect recall of parts of the message. In addition, average reading times were significantly higher for the flashing line message. Alternating one line of text and keeping the other two lines constant did not adversely affect message recall. However, average reading times increased significantly.
Cleaning of Matched License Plate Data
Authors: Clark Stephen D. , Grant-Muller S. , Chen Haibo
Published: April 2007

Three methods for identifying outlying journey time observations collected as part of a motorway license plate matching exercise are presented. Each method is examined to ensure that it is comprehensible to transport practitioners, is able to correctly classify outliers, and is efficient in its application. The first method is a crude method based on percentiles. The second uses a mean absolute deviation test. The third method is a modification of a traditional z- or t-statistical test. Results from each method and combinations of methods are compared. The preferred method is judged to be the third method alone, which uses the median rather than the mean as its measure of location and the inter-quartile range rather than the standard deviation as its measure of variability. This method is seen to be robust to both the outliers themselves and the presence of incident conditions. The effectiveness of the method is demonstrated under a number of typical and atypical road traffic conditions. In particular, the method is applied to a different section of motorway and is shown to still produce useful results.
Transit Vehicles as Traffic Probe Sensors
Authors: Cathey F. W. , Dailey D. J.
Published: April 2007

New algorithms are presented that use transit vehicles as probes for determining traffic speeds and travel times along freeways and other primary arterials. A mass transit tracking system based on automatic vehicle location data and a Kalman filter used to estimate vehicle position and speed are described. A system of virtual probe sensors that measure transit vehicle speeds by using the track data is also described. Examples showing the correlation between probe data and inductance loop speed-trap data are presented. Also presented is a method that uses probe sensor data to define vehicle speed along an arbitrary roadway as a function of space and time, a speed function. This speed function is used to estimate travel time given an arbitrary starting time. Finally, a graphical application is introduced for viewing real-time speed measurements from a set of virtual sensors that can be located throughout King County, Washington, on arterials and freeways.
Enabling and Managing Greater Access to Transport Data Through Metadata
Authors: Wigan Marcus , Grieco Margaret , Mine Julian
Published: April 2007

MetadatA—information about data sets—allow clear understanding of exactly what the elements and structure of a given data set entail. Metadata in conjunction with XML-based specifications, schemas, and tools allow a high level of automated and validated interworking between different types and sources of data. This is an issue of emerging importance to transportation, traffic, and planning, and the communities they serve, as these areas are all data intensive but with very different views of the world. The potential of this linkage is outlined, and a progression is made through a simple example metadata specification for nonmotorized transport, the agreements developed by the geospatial community for geographic data and the transport layers within them, and the formal XML document. The XML specification and validation approach now makes possible and practical a more effective and more accessible use of the information in the multiple fields linked through their involvement in transportation. The key outcome required is a vocabulary (or integrated vocabularies) of globally agreed-upon metadata element definitions for the various fields in and overlapping transportation. The advent of formal document specifications of which XML is a widely used example would then allow a significant expansion of the accessibility, use, and reuse of such data to the great benefit of the user, policy, and analysis user communities.
Effect of Field Setup on Accuracy of Traffic Data Collection Using Machine Vision Technology
Authors: Nadella Sunita , Herman Lloyd A.
Published: April 2007

Video traffic data were collected in 24 combinations of four different camera position parameters. A machine vision processor was used to detect vehicle speeds and volumes from the videotapes. The machine vision results were then compared with the actual vehicle volumes and speeds to give the percentage errors in each case. The results of the study provide a procedure with which to establish camera position parameters with specific reference points to help machine vision users select suitable camera positions and develop appropriate measurement error expectations. The camera position parameters that were most likely to produce the least overall volume and speed errors, for the specific site and field setup with the parameter ranges used in this study, were the low height of approximately 7.6 m (25 ft), with an upstream orientation (traffic moving toward the camera), a 50-mm (midangle) focal length, and a 15° vertical angle.
Time-Use Metadata
Authors: Harvey Andrew S.
Published: April 2007

Time-diary data provide a complete sequential record of all activities of individuals, including travel, for a period of 24 or 48 h or longer. Hence, time-use data have much to offer travel behavior analysts and modelers. The pool of time-use data is rapidly increasing. Additionally, comparability between time-use data and travel data is growing, largely because of the expanding volume of activity data collected in travel surveys. One challenge is to ensure that the data and time-use, travel, and other researchers can be brought together in the most efficient manner. This task requires the development of both study-level and variable-level metadata standards. Much work, providing a basis for the development of time-use metadata standards, has already been undertaken in collateral fields. Arguments are made for exploration, application, and expansion of existing work, to establish time-use metadata standards. A consolidation of efforts is proposed between time-use and travel behavior data professionals to ensure that each field has the optimum opportunity to identify, locate, evaluate, and access useful data in either field.
Real-Time Traffic Measurement from Single Loop Inductive Signatures
Authors: Oh Seri , Ritchie Stephen G. , Oh Cheol
Published: April 2007

Accurate traffic data acquisition is essential for effective traffic surveillance, which is the backbone of advanced transportation management and information systems (ATMIS). Inductive loop detectors (ILDs) are still widely used for traffic data collection in the United States and many other countries. Three fundamental traffic parameters—speed, volume, and occupancy—are obtainable via single or double (speed-trap) ILDs. Real-time knowledge of such traffic parameters typically is required for use in ATMIS from a single loop detector station, which is the most commonly used. However, vehicle speeds cannot be obtained directly. Hence, the ability to estimate vehicle speeds accurately from single loop detectors is of considerable interest. In addition, operating agencies report that conventional loop detectors are unable to achieve volume count accuracies of more than 90% to 95%. The improved derivation of fundamental real-time traffic parameters, such as speed, volume, occupancy, and vehicle class, from single loop detectors and inductive signatures is demonstrated.
Design Characteristics of National Travel Surveys: International Comparison for 10 Countries
Authors: Kunert Uwe , Kloas Jutta , Kuhfeld Hartmut
Published: April 2007

In Germany a national travel survey (NTS) was planned for 2002 and was preceded by a pilot study in 2001. As part of this pilot study the state of the practice for NTS in several countries was examined through contact with relevant institutions and persons via the Internet. A structured questionnaire was used for these consultations. The participants in nine countries provided the relevant information describing their NTS. It was found that the core substance of the data gathered by the NTS is similar and that different additional aspects of travel may be covered in the surveys. However, the survey procedures and data collection instruments employed in the fieldwork show wide variety. Numerous survey design elements and combinations thereof are applied (mailback, computer-assisted telephone interviewing, personal interview). Institutional contexts appear to be important for the scope and continuity of the NTS.
Spatial Behavioral Data: Collection and Use in Activity Scheduling Models
Authors: Kreitz Marion , Doherty Sean T.
Published: April 2007

Transport models and their practical applications are becoming increasingly more sophisticated, thus requiring more precise input data, including spatial data. The development, testing, and assessment of a survey method with which to collect multiday information on activity–travel patterns with a high level of spatial detail and accuracy are described. The survey consists of a computer-assisted, self-completing weekly household activity-travel diary survey program combined with an interactive map for spatial data input and visualization. Compared with traditional paper-and-pencil surveys, more accurate spatial data is gathered through this survey, especially for activity locations, routes, and trip lengths, which a first trial on a small sample of 30 households clearly demonstrated. In addition, more details on activity and travel times were collected. Fatigue effects did not become evident, and the respondent burden was considered to be acceptable by the participants. Additional testing of the respondents’ map-handling abilities showed that people have different map-orientation aptitudes that depend on sociodemographic characteristics such as gender, income, and education. This suggests that maps incorporated in travel surveys should be adapted in different ways to accommodate different levels of map handling. Future household travel surveys, especially emerging computerized and Global Positioning System-supported methods, would appear to benefit from the integration of a spatial interface both to add detail and to reduce respondent burden. This is particularly important for activity-based or activity-scheduling surveys, which increasingly attempt to obtain higher amounts of precise and detailed information on individual behavior and choices.
Development of an XML-Based Specification for Traffic Model Data Exchange
Authors: Courage Kenneth G. , Washburn Scott S. , Kim Jin-Tae
Published: April 2007

The proliferation of traffic software programs on the market has resulted in many very specialized programs, intended to analyze one or two specific items within a transportation network. Consequently, traffic engineers use multiple programs on a single project, which ironically has resulted in new inefficiency for the traffic engineer. Most of these programs deal with the same core set of data, for example, physical roadway characteristics, traffic demand levels, and traffic control variables. However, most of these programs have their own formats for saving data files. Therefore, these programs cannot share information directly or communicate with each other because of incompatible data formats. Thus, the traffic engineer is faced with manually reentering common data from one program into another. In addition to inefficiency, this also creates additional opportunities for data entry errors. XML is catching on rapidly as a means for exchanging data between two systems or users who deal with the same data but in different formats. Specific vocabularies have been developed for statistics, mathematics, chemistry, and many other disciplines. The traffic model markup language (TMML) is introduced as a resource for traffic model data representation, storage, rendering, and exchange. TMML structure and vocabulary are described, and examples of their use are presented.
XML-Based Transit Timetable System
Authors: Sun Wu , Bernstein David
Published: April 2007

The Internet and the World Wide Web are used for a wide variety of transportation applications. Most of these applications use static HTML documents. However, outside of transportation, considerably more attention is being given to dynamic content and XML. A way in which these technologies can be used to provide transit timetable information on the web is explored. Specifically, the transit timetable system, an online interactive transit timetable information exchange and administration system that uses Java server pages and the transit timetable markup language, is described.
Decision Support System for Advanced Traffic Management Through Data Fusion
Authors: Klein Lawrence A. , Yi Ping , Teng Hualiang
Published: April 2007

The Dempster–Shafer theory for data fusion and mining in support of advanced traffic management is introduced and tested. Dempste–Shafer inference is a statistically based classification technique that can be applied to detect traffic events that affect normal traffic operations. It is useful when data or information sources contribute partial information about a scenario, and no single source provides a high probability of identifying the event responsible for the received information. The technique captures and combines whatever information is available from the data sources. Dempster’s rule is applied to determine the most probable event—as that with the largest probability based on the information obtained from all contributing sources. The Dempster–Shafer theory is explained and its implementation described through numerical examples. Field testing of the data fusion technique demonstrated its effectiveness when the probability masses, which quantify the likelihood of the postulated events for the scenario, reflect current traffic and weather conditions.
Integrated Sign Ordering System Through Networking and Rule Base Applications
Authors: Yi Ping , Zhang Yucheng , Devarakonda Saroja , Li Jianyun
Published: April 2007

The development and testing of an integrated sign ordering system (ISOS) framework are introduced. Based on advanced networking and database technologies and object-oriented and event-driven programming paradigms, this framework was built to assess the feasibility and effectiveness of implementing an information management system for the design, production, and application of traffic signs. By using this information system, data utilization can be automated locally and over the network among the district, the central office, and the sign shop that are involved in the ordering and production process of signs. Preliminary testing by using data from the Ohio Department of Transportation indicates that the ISOS model is feasible and practical. It enables accurate and reliable design data flows within the system and is very user friendly. With further enhancement to its functions, the ISOS model could be developed into an effective engineering tool for field applications.
Techniques for Building Multijurisdictional Geographic Information System Platforms for Transportation Analysis
Authors: Han Kai , Montufar Jeannette , Minty Scott , Clayton Alan
Published: April 2007

Transportation analysis involving multiple jurisdictions requires data sharing and spatial data interoperability among geographic information system (GIS) data sets. Data sharing and spatial data interoperability issues related to multijurisdictional transportation analysis are discussed. Specific techniques based on practical data-sharing, problem-solving experience are developed. To further enhance the data-sharing process, a conceptual framework is established to guide technique implementations. Regional GIS transportation (GIS-T) platforms integrated from various data sources by applying the framework and the associated techniques are also presented. To better support different transportation applications, an open GIS-T platform is proposed, consisting of a series of customized base maps, each tailored to suit individual applications and, as a whole, linked together by inherently established interoperability.
Temporal Data Constructs for Multidimensional Transportation Geographic Information System Applications
Authors: Koncz Nicholas A. , Adams Teresa M.
Published: April 2007

Presented are the essential temporal data constructs for providing solutions for transportation applications that use dynamic data, such as facility management systems, safety and incident management, transportation planning, and intelligent transportation systems. These temporal data constructs are categorized as time stamps, temporal topology, and temporal referencing. The characteristics of these constructs are described, and two geospatial standards that appear to support these constructs are reviewed. A new approach specialized for transportation applications that builds on the temporal data constructs of these standards is provided through the multidimensional location referencing system data model.
Object-Oriented Geographic Information System Data Model for Transit Trip-Planning Systems
Authors: Huang Ruihong , Peng Zhong-Ren
Published: April 2007

Efficiency is essential to Internet transit trip-planning systems. High-quality data models of transit networks hold the key to efficiency of data querying and network analysis. Because of the schedule control and dynamic nature of the transit network, highway-based generic network models cannot be directly implemented by transit systems. In the process of developing an Internet transit trip-planning system, an object-oriented geographic information system data model, which handles the dynamic nature of transit systems, was developed. In this data model, the entire transit network and its components are modeled as space–time entities (objects) that have start times, end times, and spans of lifetime. A time map object controls the creation and destruction of these objects. Therefore, in the process of network search, only active components of the system (i.e., with transit services available) are built into the network topology. This has greatly reduced data redundancy and enhanced network search efficiency. The data model showed good performance when it was implemented in an online trip-planning service for Waukesha Metro Transit, Wisconsin.
Spatial Transferability of the Albatross Model System: Empirical Evidence from Two Case Studies
Authors: Arentze Theo , Hofman Frank , van Mourik Henk , Timmermans Harry
Published: April 2007

Results of a test of the spatial transferability of Albatross are reported. Albatross is a rule-based model for predicting transportation demand developed for the Dutch Ministry of Transport, Public Works, and Water Management. The test first uses the choice rules extracted from data pertaining to Hendrik-Ido-Ambacht to predict activity–travel patterns in Voorhout and Apeldoorn and then assesses the correspondence between observed and predicted activity–travel patterns in the latter municipalities. Results of this test indicate that the spatial transferability of the model is satisfactory.
Transit’s Value-Added Effects: Light and Commuter Rail Services and Commercial Land Values
Authors: Cervero Robert , Duncan Michael
Published: April 2007

Transit-oriented development has gained favor as a means of reducing traffic congestion, promoting affordable housing, and curbing sprawl. The effects of proximity to light and commuter rail stations are modeled as are the effects of freeway interchanges on commercial-retail and office properties in fast-growing Santa Clara County, California. From hedonic price models, substantial capitalization benefits were found, on the order of 23% for a typical commercial parcel near a light rail transit stop and more than 120% for commercial land in a business district and within 0.25 mi of a commuter rail station. Such evidence is of use not only to developers and lenders but also to transit agencies facing lawsuits over purported negative externalities associated with being near rail. It can also help in the design of creative financing, such as value-capture programs.
Household Travel Behavior in Developing Countries: Nested Logit Model of Vehicle Ownership, Mode Choice, and Trip Chaining
Authors: Dissanayake Dilum , Morikawa Takayuki
Published: April 2007

A nested logit (NL) model is proposed to analyze household travel behavior in developing countries. There has been an increase in vehicle ownership and chronic congestion in urban areas of such countries. The investigation is focused mainly on household travel behavior variations relating to vehicle ownership, mode choice, and trip-chaining considerations; an NL approach is used. The nest structure consists of two levels: the upper level represents car ownership, motorcycle ownership, and no-vehicle ownership choices, and the lower level shows household-based mode choices. Because the sharing of a vehicle by family members for multiple destinations is very popular in developing countries, trip chaining by primary and secondary household members is one of the mode-choice options considered in the proposed model. The developed NL model is also applied for analyzing congestion-reduction policy using a “push and pull” strategy, in which a road-pricing scheme is considered for car and motorcycle travel in the central business district together with fare reduction in public transportation. The model and the policies are verified using the Bangkok metropolitan region as a case study.