bluuebunny/crossref_metadata_2025 huggingface dataset:
Train Dispatching Effectiveness with Respect to Communications-Based Train Control: Quantification of the Relationship
Authors: Smith Michael E. , Resor Randolph R. , Patel Pradeep
Published: April 2007

This analysis presents a methodology for measuring the efficiency of train dispatching as a product of three variables: (a) the type of train control system (measured by latency, defined here as the interval between occurrence of a schedule deviation and initiation of corrective action); (b) the physical capacity of the route (track kilometers per route kilometers); and (c) train minutes per route kilometer (a measure of both capacity and dispatcher competence). A mathematical relationship among these three variables is postulated, and a log-log regression analysis is used to develop coefficients that relate each of the three independent variables to dispatching efficiency. To do this, actual train-movement data and minimum train running times for 28 U.S. Class I railroad line segments are used. Results of the regression analysis indicate a statistically valid relationship among latency, track capacity, traffic volume, and dispatching effectiveness. Dispatching effectiveness, calculated by placing track kilometers per route kilometer, train minutes per route kilometer, and latency at their mean values, was 71.3 percent (the mean latency was about 17 min). At a latency of 3.5 min, average effectiveness is 81.3 percent. Examples of the trade-off between latency and effectiveness and between track capacity and effectiveness also can be calculated. For the average line, when latency is progressively reduced from the current value of 15 min to 3.5 min, dispatching effectiveness increases from 71.3 to 81.3 percent. When track kilometers per route kilometer are increased from the average value of 1.3 to 2.0 (double-tracking the entire railroad, holding all other values constant) dispatching effectiveness can be increased from 71.3 to 89.5 percent—a larger increase than that realized from a reduction in latency, but at much higher cost. To quantify the dollar benefits of such an increase in dispatching effectiveness for U.S. railroads, further analyses were carried out. Based on a previous study of Burlington Northern operations, train delay costs ranged from $163/hr to $266/hr. To simplify calculations, a value of $200/hr is used. According to U.S. railroad statistics, there are about 21 million train hours of traffic each year. Benefits available from installing communications-based train control are calculated in terms of additional train minutes per route kilometer available with an increase in dispatching effectiveness based on this analysis. Based on this analysis, it should be possible to save (1 − 0.713/0.813) or 12.3 percent of total train hours. The benefit of this would be $200 × 0.123 × 21 × 10 or $520 million annually. The Association of American Railroads has estimated the cost of positive train control for the entire U.S. railway network to be between $843 million and $1.1 billion.
Fiber-Optic Sensing Technology for Rail-Buckling Detection
Authors: Signore James M. , Abdel-Maksoud Mohamed G. , Dempsey Barry J.
Published: April 2007

Buckling and cracking of steel rails is a contributing factor in accidents on railroads today. Detection and notification of buckled track sections before a train reaches these locations will significantly increase rail safety. A fiber-optic-based sensing system, with the fiber affixed to a beam, was developed and evaluated to detect buckled regions. The purpose of this research is to evaluate the sensitivity of the fiber-optic sensing system to buckling of a long structural member. Numerous facets of fiber-optic sensing have been explored. Fiber-to-steel bonding techniques were examined and tested. Full-scale laboratory testing was conducted by elastically buckling a 24.4-m-long (80-ft) wide-flange section with hydraulic rams. Typical measurement accuracy within 10 percent of theoretical predictions was achieved by optical time domain reflectometry techniques. For field testing, however, a more robust solution is sought and is currently under development. It is suggested that a lower-cost fiber break or bend detector is a suitable option. The optical fiber will break or bend at the location of rail elongation in the buckled area, allowing the detection equipment to locate the buckled area.
High-Visibility Clothing for Daytime Use in Work Zones
Authors: Dan Turner Jonathan Dan , Simmons Carole J. , Graham Johnny R.
Published: April 2007

High-visibility safety clothing serves an important role in protection of personnel in highway construction. A total of 236 fatalities in highway and street construction were reported for 1992–1993 by the Laborers’ Health and Safety Fund of North America, which puts the fatality rate of private-industry highway construction at twice that of other private-industry construction. A field study was conducted to determine the most conspicuous color of safety clothing for daytime use in the work zone. The 11 colors studied included 8 fluorescent (F1) colors (green, yellow-green, yellow, yellow-orange, red-orange, a combination of red-orange with yellow-green, red mesh over white background, and pink), two non-fluorescent colors (yellow and orange), and one semifluorescent color (yellow). Subjects were required to look through a shutter, which opened for 300 msec at 30.5-m intervals, as the researcher drove 32 km/hr toward a work zone. Subjects were instructed to indicate the point at which they first identified safety clothing in the scene. These detection distances were recorded for each color in each of four work zones. F1 red-orange was found to have the highest mean detection distance, and it was significantly different from every color except the F1 red mesh, F1 yellow-green, and F1 red-orange/F1 yellow-green combination. Each of these colors is recommended for use in safety garments with the exception of F1 red mesh, because the mesh may not perform well if worn over darker clothing.
Factors Associated with Privatization of Winter Maintenance Functions at Local Government Level
Authors: Harrier Kirk R. , Randolph Dennis A.
Published: April 2007

With the increasing cost of and dissatisfaction with services provided by government agencies, a new notion has appeared that gives hope to some and instills fear in others. Many believe that privatizing government services is the answer to the ills associated with today’s government-provided services. County road commissions in the state of Michigan are one of the many government entities examining privatization. High cost and poor service are concerns that have thrust road commission operations under the privatization spotlight. Snow and ice removal from roads is one operation currently under scrutiny. To come to conclusions about privatization and the winter maintenance services that road commissions perform, one must fully understand the road commission concept and how it functions within the state of Michigan as well as the idea of privatization. The nonquantitative factors that affect privatization at the local government level are described. Two road commissions in the state of Michigan and their winter maintenance operations are examined so that judgments can be made about the value of private delivery.
Paint-Line Retroreflectivity over Time
Authors: Scheuer Michael , Maleck Thomas L. , Lighthizer Dale R.
Published: April 2007

The Michigan Department of Transportation contracted with Michigan State University to evaluate the performance of highway paint-line material. Several types of pavement-marking materials were studied under a variety of conditions. The project’s goal is to help develop guidelines governing the cost-effective use of pavement-marking materials. Preliminary results indicate that retroreflectivity levels of paint lines did not vary as a function of material; pavement surface had little effect on lane-marking performance; and snowplowing and sanding appeared to be the main factors affecting the decay of lane line retroreflectivity.
Applicability of Superpave Binder Testing Protocols to Modified Binders
Authors: Bahia Hussain U. , Perdomo Dario , Turner Pamela
Published: April 2007

An effort is made to summarize current practices for modifying paving asphalts. The types and classes of modifiers used, or considered, for paving applications are reviewed. The applicability of the Superpave binder specification (AASHTO MP1) is reviewed critically, and the modified-asphalt characteristics that are not considered in this specification are evaluated. Conventional testing results of modified binders are compared with Superpave testing results. The results indicate that a variety of additives can be classified, on the basis of their composition and their effects on asphalts, as polymers (elastomeric and plastomeric), fillers, fibers, hydrocarbons, antistripping agents, oxidants, antioxidants, crumb rubber, and extenders. These additives vary significantly in their physical and chemical characteristics and are expected to have widely variable effects on performance-related properties of asphalts. The assumptions supporting the criteria in the Superpave binder specification may not be valid for some modified binder systems. Furthermore, the testing protocols included in the specification do not consider certain important characteristics that are typical of particular modified binders. Among these characteristics are strain dependency, thixotropy, loading-rate dependency, and time-temperature equivalency. Conventional measurements used currently by state departments of transportation such as ductility, elastic recovery, and resilience, were collected. The ranking of five modified systems on the basis of conventional and Superpave measurements was analyzed. The analysis does not indicate that the conventional test methods are consistent in their rankings, nor does it indicate that these measures add much to the information deduced from the Superpave data.
Use of Viscosity Standard Fluid To Control Quality of Rheological Measurements for Characterizing Asphalt Binders
Authors: Dongré Raj , Ramaiah Satish , D’Angelo John
Published: April 2007

The results of a study to establish a protocol for calibrating and maintaining Superpave rheometers are described. The reference standard material used was supplied by Cannon Instrument Co. The material (high viscosity standard) is designated as N2700000 and is supplied with ASTM traceable values of steady shear viscosity at various Superpave specification temperatures. The main objective was to determine whether sound calibration practices and adequate training can improve the repeatability and reproducibility of the rheological parameters required in the Superpave binder specification. Ten laboratories participated in the study. The results indicate that the viscosity standard can be used as a standard fluid to calibrate and maintain the Superpave rheometers. The repeatability and reproducibility data were compared with similar estimates reported by the AASHTO Materials Reference Laboratory. It was found that the reproducibility (between-laboratory variation) improved by a factor of two and repeatability (within-laboratory variation) improved modestly. With these results, a protocol for using the standard was also developed. Further analysis of results is under way to determine the frequency of calibration and maintenance required to obtain consistent rheological measurements. The results of this analysis and efforts to implement statistical process control charts for calibration and maintenance of rheometers using the standard reference fluid (Cannon N2700000 viscosity standard) are discussed.
Development of Superpave Direct Tension Test Device
Authors: Dongré Raj , D’Angelo John , McMahon Steve
Published: April 2007

The redesign and evaluation of the Superpave direct tension test (DTT) are described. The prototype of the DTT device was developed during the Strategic Highway Research Program (SHRP). The DTT device, an integral part of the new Superpave asphalt binder specification, was developed to test asphalt binders and determine their failure properties, such as the stress and strain at failure. The strain at failure is used in the Superpave asphalt binder specification to determine the lowest temperature at which the asphalt can be used to avoid low-temperature thermal cracking. When the SHRP program was completed, an affordable specification version of the prototype SHRP-DTT device was introduced for field implementation. Unfortunately, this version was plagued with mechanical problems, producing excessive variability and inconsistency in data. The device also was less user-friendly than other test devices that were being implemented for the asphalt binder specification. These problems led to implementation delays and difficulties. The problems were addressed by FHWA in cooperation with Instron Corporation of Canton, Massachusetts (a manufacturer of materials testing equipment). On the basis of recommendations made by FHWA, Instron developed a new, easy-to-use specification-type DTT device. This device is compact (approximately one-tenth the size of the original) and uses a fluid-based temperature control system similar to that used in the bending beam rheometer. The new device also employs feedback elongation (strain) rate control. However, unlike the previous device, the new DTT uses an extensometer between the loading pins instead of a laser to measure elongation (strain). The evaluation and resulting recommendations by FHWA, which led to the development of the new specification-type devices are discussed. The repeatability and testing protocols also are discussed.
Production of Asphalt-Rubber Binders by High-Cure Conditions
Authors: Billiter T. C. , Davison R. R. , Glover C. J. , Bullin J. A.
Published: April 2007

A curing study was undertaken to determine the effect that asphalt composition, rubber content, rubber mesh size, curing time, curing temperature, and rate of mixing have on asphalt-rubber properties. Curing temperatures of 232°C or 260°C (450°F or 500°F) and a high-shear laboratory mixer were used to produce the asphalt-rubber blends. The properties studied were rubber dissolution; rubber settling; molecular weight distribution; and low-, intermediate-, and high-temperature rheological properties. Increasing the curing temperature from 232°C to 260°C (450°F to 500°F) drastically increased the rate of devulcanization and depolymerization of the rubber, whereas increasing the rate of mixing from 4,000 rpm to 8,000 rpm drastically decreased the settling rate of rubber in a binder. Lower-molecular-weight asphalts were better at devulcanizing the rubber; higher-molecular-weight asphalts were better at depolymerizing the rubber. These high-cure binders are homogeneous in appearance and slow to phase separate on standing; they have acceptable compaction viscosities at hot-mix temperatures, higher G*/sinδ at rutting temperatures, and lower stiffness at cold temperatures than does the base asphalt.
Alternative Fuel Vehicle Programs: Applicability of Government Incentives
Authors: Howell Doug , Chelius Michael
Published: April 2007

The effectiveness of state and local government programs that are intended to foster the use of alternative fuel vehicles (AFVs) and the use of government-based incentives to enhance the effectiveness of government AFV programs are analyzed. The findings from surveys of all 50 states of officials overseeing or managing state AFV programs are reported. The survey investigated AFV program motivation, financing, fuel tracking, barriers, applicability of incentives, and future needs. Research revealed that most AFV programs are in their infancy and are focused on basic needs, such as AFV procurement and refueling infrastructure development. Research also revealed that the federal AFV purchase and air quality mandates are the primary reason states engage in AFV activities, and federal funds are the primary funding source. Federal AFV purchase mandates are clearly stimulating activity; however, delay and modification of these mandates have a deleterious effect on state AFV programs. Many officials indicated that dual and bifuel AFVs do not use alternative fuels and that tracking of fuel use is limited. Political support, “fuel neutrality,” and increased AFV promotion were reported as important to program success. The authors conclude that both federal mandates and incentives are important, if not critical, for continued AFV progress at the state level. Using state programs as models, federal incentive programs should be flexible and fuel neutral, should reflect a “polluter pays” concept, should provide funds for federal mandates, and should address multiple federal goals.
Transitional Alternative Fuels and Vehicles Model
Authors: Leiby Paul , Rubin Jonathan
Published: April 2007

The Transitional Alternative Fuels Vehicle model simulates the use and cost of alternative fuels and alternative fuel vehicles over the period 1996 to 2010. It is designed to examine the transitional period of alternative fuel and vehicle use. It accounts for dynamic linkages between investments and vehicle and fuel production capacity, tracks vehicle stock evolution, and represents the effects of increasing scale and expanding retail fuel availability on the effective costs to consumers. Fuel and vehicle prices and choices are endogenous. Preliminary results that illustrate the role of potentially important transitional phenomena are discussed. This model extends previous, long-run comparative static analyses of policies that assumed mature vehicle and fuel industries. As a dynamic transitional model, it can help to assess what may be necessary to reach mature, large-scale, alternative fuel and vehicle markets, and what it would cost.
Forecasting Cost Path of Electric Vehicle Drive System: Monte Carlo Experience Curve Simulation
Authors: Lipman Timothy E. , Sperling Daniel
Published: April 2007

The future costs of electric-drive vehicles, like those of any new technology, are uncertain. One method for forecasting cost reductions uses the concept of the experience curve. Experience curves take into account scale economies, technological improvements in production processes, improvements in product design, and improved efficiency of workers and production management. The future manufacturing cost of an innovative new technology—the synchronous, brushless permanent magnet electric vehicle drivetrain—is analyzed using experience curves and a Monte Carlo simulation technique. Based on experience curve theory and the assumptions used in the analysis, a drop in manufacturing cost is predicted—from today’s $12,000 (with low-volume, hand-built production) to a cost of about $1,200 to $1,700 when full-scale economies and manufacturing experience have been realized. This cost range implies eventual high-volume prices of $1,500 to $2,100 once corporate profit and warranty costs are included. In an ongoing study at the University of California, Davis, experience curve analyses are being integrated with a detailed vehicle cost model to develop short- and long-term cost forecasts for complete electric vehicles.
Use of Episodic Controls to Reduce Frequency and Severity of Air Pollution Events
Authors: Jorquera Mario E.
Published: April 2007

Most common urban air pollution episodes occur during readily identifiable meteorological conditions that contribute to the problem. In contrast, most air pollution controls concentrate on permanent curtailments of emissions. The argument is put forth that episodic emission control strategies can be an effective supplement to traditional measures, at a fraction of the cost. Questions regarding the legality of episodic controls have been the main barrier to their implementation. These legal issues are discussed. In addition, the forecasting and modeling implications of episodic controls are considered. Several areas have implemented episodic air pollution controls or used accurate short-term forecasts to warn the public through health advisories of pending air pollution events. Some of these success stories are highlighted. A scheme for assisting the prediction of emissions reductions based on the degree to which episodic measures are voluntary or mandatory is proposed. This method may help resolve emission reduction credit and enforcement issues, making approval of episodic measures for state implementation plans and conformity more likely. The transportation sector has the potential to make episodic measures successful. Furthermore, some of these measures are eligible for federal transportation dollars. The potential for funding transportation-related episodic controls is explored. While episodic controls cannot replace traditional controls, they can be an incremental or short-term solution that may evolve into, or be used in conjunction with, other plans. Transportation professionals are incited to develop creative short-term solutions to the pervasive, yet short-term, problem of urban air pollution.
Implications of Transient Mode Duration for Spatially Disaggregated High-Resolution Emission Inventory Studies
Authors: Venigalla Mohan , Pickrell Don
Published: April 2007

High resolution emission inventory studies, such as urban air-shed modeling, often use spatially disaggregated emission parameters in the form of link-specific emissions. A key input variable that influences operating mode mix on highway links is the transient mode duration (TMD) in which start-related emissions occur. The TMD variable also establishes the emission rates to be embedded in emission factor models. The basic emission rates built into the MOBILE model are based on a TMD of 505 seconds, which was based on the federal test procedure (FTP). For newer vehicles, it is indicated that the TMD is much less than 505 seconds. This study examines the effects of variations in TMD on the distribution of cold and hot transient VMT on network links, as well as their effect on overall emissions. A network assignment model developed to track operating modes of vehicles on network links was used on a large California city network. The MOBILE model was used to derive bag-specific emission rates. The experiment includes a series of traffic assignment runs with varying TMD and postprocessing of the assignment output. Link-specific distribution of operating mode mix and total emissions were derived. It is indicated that TMD significantly influences the distribution of operating modes, as well as total emissions. The results indicate that as the TMD decreases, the share of cold transient VMT from freeways diminishes, while that of the local roads increases. It was indicated that total emissions on various link groups may fall within a range of 90 to 300 percent of the total emissions derived from the present FTP duration of 505 seconds. It is recommended that the transient mode duration variable be reexamined for deriving emission rates to be embedded in the future versions of emission factor models.
Analysis of Modal Emissions From Diverse In-Use Vehicle Fleet
Authors: Barth Matthew , Younglove Theodore , Wenzel Tom , Scora George , An Feng , Ross Marc , Norbeck Joseph
Published: April 2007

The initial phase of a long-term project with national implications for the improvement of transportation and air quality is described. The overall objective of the research is to develop and verify a computer model that accurately estimates the impacts of a vehicle’s operating mode on emissions. This model improves on current emission models by allowing for the prediction of how traffic changes affect vehicle emissions. Results are presented that address the following points: vehicle recruitment, preliminary estimates of reproducibility, preliminary estimates of air conditioner effects, and preliminary estimates of changes in emissions relative to speed. As part of the development of a comprehensive modal emission model for light-duty vehicles, 28 distinct vehicle/technology categories have been identified based on vehicle class, emission control technology, fuel system, emission standard level, power-to-weight ratio, and emitter level (i.e., normal versus high emitter). These categories and the sampling proportions in a large-scale emissions testing program (over 300 vehicles to be tested) have been chosen in part based on emissions contribution. As part of the initial model development, a specific modal emissions testing protocol has been developed that reflects both real-world and specific modal events associated with different levels of emissions. This testing protocol has thus far been applied to an initial fleet of 30 vehicles, where at least 1 vehicle falls into each defined vehicle/technology category. The different vehicle/technology categories, the emissions testing protocol, and preliminary analysis that has been performed on the initial vehicle fleet are described.
Modeling Framework for Estimating Emissions in Large Urban Areas
Authors: Skabardonis Alexander
Published: April 2007

A modeling framework has been developed to produce detailed emission inventories for large urban areas. Relationships were developed between the time spent in each driving mode (cruise, acceleration, deceleration, and idle) and basic link characteristics based on simulations of selected real-world surface street networks and freeway sections using the TRAF-NETSIM and INTRAS microscopic models, supplemented by field data. These relationships were then incorporated into a specially written computer program as a postprocessor to the Urban Transportation Planning System type of four-step travel demand models. The integrated model was successfully applied to the 1,120-zone Metropolitan Transportation Commission San Francisco Bay Area network to generate vehicle activity estimates.
Binary Recursive Partitioning Method for Modeling Hot-Stabilized Emissions From Motor Vehicles
Authors: Washington Simon , Wolf Jean , Guensler Randall
Published: April 2007

An alternative statistical modeling approach, hierarchical tree-based regression (HTBR), is presented for developing modal correction factors for hydrocarbon (HC) emissions from motor vehicles. The term modal refers to operating modes of vehicle activity such as cruise, idle, deceleration, and acceleration. Explanation of the statistical theory is provided, followed by a presentation of specific modeling results for HCs. The modeling results are based on 4,800 vehicle emissions tests representing 29 laboratory testing cycles. HTBR methods are indicated to overcome statistical difficulties that are problematic for classical ordinary least-squares (OLS) regression, a commonly applied statistical technique for analyzing emissions data. HTBR methods are more adept at treating interactions and monotonic transformations on independent variables, better at handling categorical independent variables with more than two levels, not adversely affected by multicollinearity, and good at capturing nonadditive behavior across the range of independent variables. Unfortunately, HTBR theory is less well developed than OLS regression theory, and statistical parameter properties, such as efficiency, unbiasedness, and consistency, need further development. The HTBR modeling results for HCs are insightful. Hydrocarbon emissions from normal-emitting motor vehicles are most sensitive to changes in power (instantaneous speed2 ƃ acceleration) requirements of a given driving sequence, while high-emitting vehicles are sensitive to both the amount of idle activity and positive kinetic energy (instantaneous speed ƃ acceleration) in a given driving sequence. Vehicle model year, engine size (cubic centimeters of displacement), curbside weight, and fuel delivery type (fuel injected, throttle body injected, carbureted), also were indicated to influence emission rates. Finally, high- and normal-emitting vehicles are sensitive to different operational and vehicle specific factors.
Cost Estimates of Transport Air Pollution in Santiago, Chile
Authors: Zegras Christopher , Litman Todd
Published: April 2007

Findings from a study that attempts to monetize the costs of transport air pollution in Santiago, Chile, are presented. The costs per pollutant used in the study come from a 1994 World Bank study estimating morbidity and mortality costs of air pollution in Santiago, based on productivity losses and treatment costs. Using MOBILE-derived vehicle emissions factors and estimated vehicle distances traveled by various vehicle types, the total estimated transport pollution costs incurred in 1994 are presented. Also presented are estimated average air pollution costs per passenger kilometer traveled for pre- and post-EPA87 standard autos and taxis and pre–and post–EPA91 standard buses, as well as for Santiago’s Metro (urban heavy rail). Future air pollution trends in Santiago are discussed, and a theoretical discussion of the potential application of these cost estimates for transportation policy making in the city is provided.
Emissions Reductions From Vehicle Retirement Programs
Authors: Deysher Beth , Pickrell Don
Published: April 2007

Nonattainment areas taking advantage of EPA’s modified enforcement of the 1990 Clean Air Act mandates for unpopular emissions control measures will be required to identify alternative measures to reduce emissions, and several areas have indicated their intention to implement scrappage programs for older vehicles as a means of “replacing” the emissions reductions originally expected to result from these other measures. The potential reductions in fleetwide motor vehicle emissions from scrappage of all older light-duty vehicles in a typical urban area’s fleet are analyzed, and the sensitivity of those reductions to the timing of the program’s implementation and to alternative assumptions about more intensive use of vehicles remaining in the fleet are explored. The cost-effectiveness of such a program in reducing ozone precursor emissions is investigated and the reliability of estimates of the program’s effectiveness developed by using the MOBILE5a vehicle emissions model are evaluated. The likely emissions reductions from even so comprehensive a vehicle scrappage program cannot replace those anticipated to result from measures such as enhanced inspection and maintenance and sales of reformulated gasoline, but smaller-scale retirement programs may be a cost-effective element of a larger package of emissions reduction strategies.
Queueing Algorithm for Calculating Idling Emissions in FLINT—the FLorida INTersection Air Quality Model
Authors: Al-Deek Haitham M. , Wayson Roger L. , Cooper C. David , Keely Deb , Traynelis Richard , Liu Pwu Sheng , Malone Linda C. , Datz Amy
Published: April 2007

The theoretical development of the queueing model used in the FLINT (FLorida INTersection) air quality model is described. FLINT is an area source model used to predict carbon monoxide concentrations for under-saturated and oversaturated traffic conditions at signalized intersections. In the FLINT model, deterministic queueing is used to estimate the queue length for cases of undersaturated conditions. In oversaturated cases, a cycle failure method has been developed to estimate queue length. In addition, a new concept is presented for calculating idling time for each vehicle’s position in the queue during both the red and the green phases of the traffic signal cycle. A limited set of undersaturated cases from monitoring data in Melrose Park, Illinois, was used to compare the predicted queue lengths with the measured queue lengths for several air quality models. It was found that FLINT predicted the queue length within one vehicle of the observed queue length. The same cases were tested using CAL3QHC, TEXIN2 intersection air quality models, and the American Automobile Manufacturers Association (AAMA) simulation model. It was found that predictions of the AAMA and the FLINT models were very close to the measured queue lengths in cases of undersaturated conditions. Moreover, although the FLINT and the AAMA models use a different approach to estimate queue length, their predicted queue lengths were very close in oversaturated cases. However, the predicted queue lengths of CAL3QHC were too long for oversaturated cases.
Perspectives on Driver Preferences for Dynamic Route Guidance Systems
Authors: Schofer Joseph L. , Koppelman Frank S. , Charlton William A.
Published: April 2007

Insights about the design of route guidance systems based on the needs and desires of drivers who are familiar with the travel network are provided. Results from the ADVANCE Intelligent Transportation System operational test, in which more than 100 drivers used vehicles equipped with dynamic route guidance systems for 2-week periods, suggest that such drivers value real-time traffic information, and they want to incorporate their own knowledge and perspectives into the development of route plans, which they expect to be superior to those prepared by the navigation computer. This suggests that future route guidance systems likely to be targeted at familiar drivers should be based on a sharing of tasks between computer and driver that takes greater advantage of driver knowledge than that considered in current designs. Specifically, the driver should be able to take more responsibility for route planning, with the computer responsible mainly for traffic congestion data acquisition, organization and storage, and evaluation of driver-defined routes.
PLANiTS: Structuring and Supporting the Intelligent Transportation Systems Planning Process
Authors: Khattak Asad J. , Kanafani Adib
Published: April 2007

PLANiTS (Planning and Analysis Integration for Intelligent Transportation Systems) is a process-based computer system that supports a series of mutually interdependent steps progressing toward developing and programming transportation improvement projects. It is a tool that translates problems and goals to performance measures, examines possible competing and complementary transportation improvement actions, systematically evaluates the impacts of actions using models and knowledge, and supports human interactions between stakeholders. The PLANiTS methodology is nonincremental because it integrates existing knowledge about transportation with analysis using models with deliberation and issue resolution. To link planning and modeling, PLANiTS has a policy base that contains contemporary performance measures, an action base containing conventional and Intelligent Transportation Systems actions, a methods base that facilitates modeling, a case that has qualitative and quantitative information about historical cases, and a set of computer-based communications tools. This comprehensive methodology will likely expedite the implementation of intelligent technologies by systematically examining their trade-offs with more conventional transportation improvement actions. PLANiTS’s structure, functionality, and application are described. Transportation improvement projects are represented as planning vectors in PLANiTS. A vector permits users to examine the effects of chosen transportation actions in terms of performance measures within an environment. Users must specify the actions, performance measures, and the environment, each in terms of their spatial, temporal, and user dimensions. Then they can analyze the planning vector with models and case-based reasoning. During the process of planning vector specification and analysis, stakeholders at different locations can communicate by sending and receiving messages and sharing the planning vector. Users at different locations can examine and review the results and iterate in an open and deliberative planning environment. Overall, PLANiTS facilitates transportation planning processes by combining analysis and deliberation.
Evaluating Effectiveness of Real-Time Advanced Traveler Information Systems Using a Small Test Vehicle Fleet
Authors: Saricks Christopher L. , Schofer Joseph L. , Sööt Siim , Belella Paul A.
Published: April 2007

ADVANCE was an in-vehicle advanced traveler information system (ATIS) providing route guidance in real time that operated in the northwestern portion and northwest suburbs of Chicago, Illinois. It used probe vehicles to generate dynamically travel time information about expressways, arterials, and local streets. Tests to evaluate the subsystems of ADVANCE, executed with limited availability of test vehicles and stringent scheduling, are described; they provided useful insights into both the performance of the ADVANCE system as a whole and the desirable and effective characteristics of ATIS deployments generally. Tests found that the user features of an in-route guidance system must be able to accommodate a broad range of technological sophistication and network knowledge among the population likely to become regular users of such a system. For users who know the local network configuration, only a system giving reliable real-time data about nonrecurrent congestion is likely to find a market base beyond specialized applications. In general, the quality and usefulness of systemwide real-time route guidance provided by other means are enhanced significantly by even a small deployment of probes: probe data greatly improve static (archival average) link travel time estimates by time of day, although the guidance algorithms that use these data should also include arterial traffic signal timings. Moreover, probe- and detector-based incident detection on arterial networks shows considerable promise for improved performance and reliability.
Guidelines for Funding Operations and Maintenance of Intelligent Transportation Systems/Advanced Traffic Management Systems
Authors: Daniels Ginger , Starr Tim
Published: April 2007

As the deployment of intelligent transportation systems (ITS) technologies moves forward, the issue of sustaining and supporting traffic management systems after they have been constructed becomes increasingly critical. In the midst of limited funding, undocumented costs, competing maintenance needs, aging systems, and institutional barriers, the systems already under operation are struggling to meet the expectations conveyed during implementation. Planning for day-to-day performance and upkeep, despite the necessity, has been an unglamourous and apparently secondary consideration in the ITS implementation process. A well-run and well-maintained system not only serves the transportation system users as intended, but boosts the credibility of the program with the public. Conversely, systems that are plagued with inadequate staffing, persistent software bugs, and inoperable field devices will fail to provide high-performance services and will certainly tarnish the ITS initiative and the credibility of all transportation service providers. Quantifying and securing the funding necessary to operate and maintain ITS and advanced traffic management systems adequately is the first step, yet very little documentation is available to assist system operators. First, a mechanism is provided for estimating the costs required to operate and maintain ITS elements adequately; second, the funding issues are examined and guidelines are provided to address the obstacles that prevent adequate funding of traffic management operations and maintenance. Although the Texas Department of Transportation costs and procedures are examined, the research and recommendations will be useful to other state agencies.
Intelligent Transportation Systems and Sustainable Communities: Findings of a National Study
Authors: Jordan Daniel R. , Horan Thomas A.
Published: April 2007

The 1990s may well be remembered as the decade in which the idea of sustainability took hold in government, business, academia, and popular culture. In the United States, concerns with sustainability have entered policy discussions at various levels of government and sectors of the economy. The application of the sustainability paradigm to transportation has coincided with the advent of intelligent transportation systems (ITS). ITS—the application of advanced technologies (e.g., computers, communications, advanced sensors) to the surface transportation system—is a major new advanced transportation technology initiative that has become a highly touted prospect for improving the nation’s surface transportation system. ITS could have significant effects on the nation’s environment, economy, and society, and this has prompted widespread research and speculation on the range of potential ITS impacts. It has also brought ITS into the sustainability debate, and controversy exists over whether ITS will facilitate or undermine efforts to promote sustainable communities. A series of conceptual and applied exercises being done at the national level, as well as within Minnesota, on the implications of the sustainability paradigm on ITS are described. After the policy context surrounding ITS is introduced, key dimensions of the sustainability concept, particularly sustainable development and sustainable communities, are examined. The concept of sustainable communities is linked to transportation and ITS. In conclusion, findings on how ITS and other information technologies might promote sustainable communities are given, with special attention to the context of Minnesota’s ITS program.
Dynamic Traffic Assignment: Genetic Algorithms Approach
Authors: Sadek Adel W. , Smith Brian L. , Demetsky Michael J.
Published: April 2007

Real-time route guidance is a promising approach to alleviating congestion on the nation’s highways. A dynamic traffic assignment model is central to the development of guidance strategies. The artificial intelligence technique of genetic algorithms (GAs) is used to solve a dynamic traffic assignment model developed for a real-world routing scenario in Hampton Roads, Virginia. The results of the GA approach are presented and discussed, and the performance of the GA program is compared with an example of commercially available nonlinear programming (NLP) software. Among the main conclusions is that GAs offer tangible advantages when used to solve the dynamic traffic assignment problem. First, GAs allow the relaxation of many of the assumptions that were needed to solve the problem analytically by traditional techniques. GAs can also handle larger problems than some of the commercially available NLP software packages.
Macroscopic Modeling of Freeway Traffic Using an Artificial Neural Network
Authors: Zhang Hongjun , Ritchie Stephen G. , Lo Zhen-Ping
Published: April 2007

Traffic flow on freeways is a complex process that often is described by a set of highly nonlinear, dynamic equations in the form of a macroscopic traffic flow model. However, some of the existing macroscopic models have been found to exhibit instabilities in their behavior and often do not track real traffic data correctly. On the other hand, microscopic traffic flow models can yield more detailed and accurate representations of traffic flow but are computationally intensive and typically not suitable for real-time implementation. Nevertheless, such implementations are likely to be necessary for development and application of advanced traffic control concepts in intelligent vehicle-highway systems. The development of a multilayer feed-forward artificial neural network model to address the freeway traffic system identification problem is presented. The solution of this problem is viewed as an essential element of an effort to build an improved freeway traffic flow model for the purpose of developing real-time predictive control strategies for dynamic traffic systems. To study the initial feasibility of the proposed neural network approach for traffic system identification, a three-layer feed-forward neural network model has been developed to emulate an improved version of a well-known higher-order continuum traffic model. Simulation results show that the neural network model can capture the traffic dynamics of this model quite closely. Future research will attempt to attain similar levels of performance using real traffic data.
Developing a Market-Sensitive Intelligent Transportation Systems Educational Program
Authors: Boilé Maria P. , Spasovic Lazar N. , Pignataro Louis J.
Published: April 2007

Results of research undertaken to evaluate the educational needs of the emerging field of Intelligent Transportation Systems (ITSs) are presented, and whether course offerings in academic programs meet these needs is ascertained. A survey was conducted to determine needs for ITS education among public- and private-sector entities and to assess the perception of the academic sector on the type and level of ITS education to be offered. The results indicate that academic programs are aware of the educational needs of the private and public sectors in ITS and have been reacting to those needs. A traditional civil engineering curriculum is inadequate to educate engineers in ITS, thus the ITS educational program must be inter-(or cross-) disciplinary. Focus should be on the areas that are not traditionally part of civil engineering education such as communications, traffic surveillance, systems analysis, and social and institutional issues. The results are intended primarily to provide a guideline for universities to develop the content of an ITS program by identifying the type of program structure as well as the topics to be covered in the courses. A case study is presented of how such a program was implemented at the graduate level at the New Jersey Institute of Technology.
Cost-Benefit Analysis on Deployment of Automated Highway Systems
Authors: Ran Bin , Kenny Lee Kwun Yee , Dong Haikun
Published: April 2007

The optimal ranges of traffic flow and capacity will be determined for selected scenarios, in which different proportions of automated and conventional traffic will operate simultaneously in an automated highway system (AHS). It is found that there will be a substantial increase in the net benefit and the traffic flow and capacity ranges when there is a higher proportion of AHS traffic. The optimal range of capacity refers to the maximum range of traffic volumes, for which there will be some net benefit, which is the difference between the total cost and the total benefit for each flow. The total cost represents the production and operating costs of the infrastructure and the expenditure borne by the user, whereas the total benefit refers to the time saving to the user. It is concluded that more AHS vehicles should be produced in order to achieve economic efficiency, improved traffic capacity, and safety in travel.
Traffic Analysis for Highway-to-Highway Interchanges on Automated Highway Systems: Congestion in Absence of Dedicated Ramps
Authors: Ran Bin , Johnson Seth , Leight Shawn , Tsao Jacob H.-S.
Published: April 2007

Special connector ramps linking the automated lanes at automated highway–to–automated highway interchanges may be needed to enable continuous automated driving between two crossing highways. Although a typical cloverleaf configuration has only two levels and is more amenable for such additions, the sharp curvature of this design usually imposes constraints on traffic speed and flow. Because of these constraints, most highway–to–highway interchanges in urban areas have straighter lanes but tend to involve three or more levels. Building the additional connector ramps to accommodate eight high-speed turning movements at an area where the geometry is already complex could be difficult or costly. Therefore, proponents of automated highway systems (AHS) face a major dilemma. This dilemma is studied, including the impact of not providing automated connector ramps on the manual and AHS traffic on manual lanes at or near a highway-to-highway interchange. It is shown that, with a typical cloverleaf design, in the absence of the additional connector ramps, any moderate to heavy AHS-changing traffic could severely disturb the flow of through traffic, seriously exacerbate congestion, and possibly cause a traffic breakdown at the interchange area. These effects will most likely negate any mainline throughput benefits for which an AHS is designed.