bluuebunny/crossref_metadata_2025 huggingface dataset:
Calibration and Validation of Microscopic Traffic Flow Models
Authors: Brockfeld Elmar , Kühne Reinhart D. , Wagner Peter
Published: April 2007

Microscopic simulation models are becoming increasingly important tools in modeling transport systems. A large number of models are used in many countries. The most difficult stage in the development and use of such models is the calibration and validation of the microscopic submodels such as the car-following and gap acceptance models. This difficulty results from the lack of suitable methods for adapting models to empirical data. Recent progress has been made in calibrating a number of microscopic traffic flow models. Ten very different models have been tested with data collected via Differential Global Positioning System-equipped cars on a test track in Japan. To calibrate the models, the data of the leading car are fed into the model under consideration, and the model is used to compute the headway time series of the following car. The deviations between the measured and the simulated headways are then used to calibrate and validate the models. The calibration results agree with earlier studies as there are errors of 12% to 17% for all models, and no model can be denoted to be the best. The differences between individual drivers are larger than the differences between different models. The validation process gives acceptable errors from 17% to 22%. But for special data sets with validation errors up to 60%, the calibration process has reached what is known as "overfitting": because of the adaptation to a particular situation, the models are not capable of generalizing to other situations.
Safety Implications of Freeway Work Zone Lane Closures
Authors: Zhu Jun , Saccomanno Frank F.
Published: April 2007

In current freeway work zones, lane closure operations employ both left-lane and right-lane closure layouts. The safety implications of these two layouts are not well understood. First, the safety implications of work zone left-lane closures and right-lane closures for three-lane freeway segments are assessed. Lack of safety is measured on the basis of two traffic-flow characteristics: uncomfortable deceleration and speed variance. These characteristics are obtained for specific work zone layouts by using microlevel simulation (INTEGRATION). Second, an alternative, more channelized lane closure layout is proposed and its safety benefits are compared with those associated with the current leftlane and right-lane closures. The results of the simulation suggest that the proposed channelized lane closure layout results in lower values of uncomfortable deceleration and speed variance and thus improves safety for the three-lane freeway segment.
Evaluation of Interstate Highway Capacity for Short-Term Work Zone Lane Closures
Authors: Sarasua Wayne A. , Davis William J. , Clarke David B. , Kottapally Jayaram , Mulukutla Pawan
Published: April 2007

The need to maintain adequate traffic flow through short-term Interstate work zones is paramount on today's heavily traveled freeways. Numerous states have policies related to traffic flow thresholds, vehicle delay, and vehicle queue lengths that provide guidance on conditions when shortterm lane closures can be instituted. Generally, traffic flow threshold limits are a function of traffic-stream characteristics, highway geometry, work zone location, type of construction activities, and work zone configuration. A research study was initiated in South Carolina to examine quantitatively the development and implementation of a methodology for use in determining an updated lane-closure policy based on statespecific parameters. The study focused on determining the number of vehicles per lane per hour that can pass through short-term Interstate work zone lane closures with minimal or acceptable levels of delay. Research tasks included a survey of policies of other states, field-data collection, and methodology development. A methodology was developed with field data collected from 22 work zone sites along South Carolina's Interstate system. Data were obtained during a 12-month period from September 2001 to August 2002. Data collection procedures and data analysis methods employed in model development are summarized. Results of this study may be helpful to state highway agencies interested in developing similar research-based policy guidelines for short-term Interstate lane closures in their jurisdictions.
Determining Design Wind Loads for Work Zone Traffic-Control Devices
Authors: Bligh Roger P.
Published: April 2007

Proper traffic control and delineation are critical to achieving safety in work zones. In addition to being crashworthy, a barricade or temporary sign support should have the ability to withstand anticipated service loads. If a barricade or temporary sign support fails or overturns, it cannot perform its intended function and the safety of the work zone may be compromised. Currently, no guidance is provided on the service loads that should be used in the design of these work zone devices. Recommendations are provided for design wind loads for work zone traffic-control devices. The results from field trials indicate that truck-induced wind loading is not a critical design issue for barricades and barricades with signs. The recommendations are thus based on an analytical determination of design wind speeds associated with different recurrence intervals that correspond to the duration of work zone activities. Analytical case studies are presented for two common barricade designs, with consideration given to both structural capacity and overturn. Guidance on the amount of ballast required to prevent overturn is provided as a function of wind speed, barricade length, and sign mounting height.
Challenges of Unfamiliar Signalized Intersections for Pedestrians Who Are Blind: Research on Safety
Authors: Bentzen Billie Louise , Barlow Janet M. , Bond Tamara
Published: April 2007

Pedestrians who are blind or visually impaired often travel in areas that are unfamiliar to them and cross at signalized intersections. Results are reported of testing street crossing by blind pedestrians at complex, unfamiliar signalized intersections without accessible pedestrian signals. There will be further reports on these results. The focus is on descriptive analysis of broad measures of safety, orientation, and need for assistance in crossing. Objective data on 12 measures of street-crossing performance were obtained at four intersections (two in each of two cities). In each city, 16 blind participants crossed at unfamiliar, complex signalized intersections without accessible pedestrian signals. Results confirm that blind pedestrians have considerable difficulty locating crosswalks, aligning to cross, determining the onset of the walk interval, maintaining a straight crossing path, and completing crossings before the onset of traffic perpendicular to their path of travel. Accessible pedestrian signals will be installed at the four intersections, and postinstallation data will be used to determine recommendations for accessible pedestrian signal characteristics and installation.
Drivers' Perception of Pedestrians' Rights and Walking Environments
Authors: Sarkar Sheila , Andreas Marie
Published: April 2007

A pedestrian and traffic safety study was conducted in San Diego County, California, with 1,587 adult and teenage traffic violators who were attending traffic school. The surveys were disaggregated on the basis of respondents' demographic characteristics. There were 589 Spanish speakers and 998 English speakers. The surveys measured respondents' safe driving score and correlated the score with their assessment of safety and the level of aggression shown toward pedestrians in six photographs. Photographs were selected to depict certain pedestrian and driving environments and pedestrian-vehicle interactions. The photographs were used as a means of assessing the drivers' level of sensitivity to pedestrian environments. Respondents were asked to assess drivers' behaviors on certain roads, their levels of aggression toward pedestrians, and the quality of sidewalks. Responses to the photographs were analyzed with demographic differences (adults and teen, Spanish and English) and the safe driving measure scores. Significant differences were found in the responses on the basis of driving measure and demographic differences. Many respondents were unaware of California laws related to pedestrian's rights and duties when sidewalks are missing. They were also insensitive to pedestrian-driver conflict situations. Some of the lack in understanding or empathy toward pedestrians is due to inadequate treatment of pedestrian safety issues in the literature on aggressive driving. On the basis of this research, it is felt that aggressive acts toward pedestrians need to be included in the definition of aggressive driving so that drivers are made aware of the rights of pedestrians.
Frequency of Bicycle Commuting: Internet-Based Survey Analysis
Authors: Stinson Monique A. , Bhat Chandra R.
Published: April 2007

An ordered-response model is used in this research to evaluate the factors that affect frequency of bicycle use for a person's commute to and from work. Data used were gathered during an original survey effort conducted over the Internet in 2002. Empirical results are presented, and policy implications of these results for urban planning are discussed. In addition, deterrents and facilitators of bicycle commuting as reported by respondents in the survey are descriptively analyzed. Several findings from this research contribute to the state of the knowledge in bicycle commuting. First, the availability of showers or clothing lockers at the work place does not appear to inspire bicycle commuters to commute by bicycle more frequently. Second, using a bicycle for nonwork trip purposes increases an individual's frequency of commuting by bicycle to work. Other important results indicate that nonbicycle commuters either have misconceptions about the dangers of bicycling or else they lack convenient, safe route options for bicycling to work. Practitioners can use the ordered-response model to estimate an individual bicycle commuter's frequency of commuting by bicycle. The results can also help practitioners estimate the effects on nonmotorized mode share of programs that compete for funds to provide bicycling safety education, bicycle parking, and promotion of bicycling.
Online Recursive Algorithm for Short-Term Traffic Prediction
Authors: Yang Fan , Yin Zhaozheng , Liu Henry , Ran Bin
Published: April 2007

Short-term traffic prediction is of great importance to real-time traveler information and route guidance systems. Various methodologies have been developed for dynamic traffic prediction. However, many existing parametric studies focus on fixed-size data and presume time-invariant models. A proposed online adaptive model takes into account historical off-line data. A recursive algorithm is used to obtain computational efficiency and reduced storage. The algorithm is extended to a more general and flexible state-space model, and the predictions are computed recursively with a Kalman filter. A maximum likelihood off-line estimate of the noise covariance matrix and transition coefficients matrix is provided, as well as a recursive calculation of the optimal time-variant parameters on line. The result proves that the state-space model with the nonzero noise covariance matrix outperforms the other algorithms with loop detector data on Interstate 405 near Irvine, California.
Wavelet Transform for Feature Extraction to Improve Volume Adjustment Factors for Rural Roads
Authors: Yi Ping , Sheng Li , Yu Lei
Published: April 2007

Wavelet transform is a powerful technique for feature extraction from data that are characterized by frequent and large-scale fluctuations. This technique has been studied in recent years for incident detection and intelligent transportation systems data aggregation. Because of its attractive properties, such as time frequency localization, multirate filtering, and scale-space analysis as well as multiresolution analysis, this research explores the potential application of the technique to improve the accuracy of monthly and weekly adjustment factors in rural annual average daily traffic estimation. The technique was applied to data collected from automatic traffic recorder stations in northern Ohio, and the application showed that the technique could separate and filter out the high-frequency data oscillations and trace the changes in the fundamental pattern of traffic. The test results illustrated an impressive improvement, ranging from 10% to 20%, over conventional data estimation at those stations. This success shows that the proposed approach is feasible, and future improvements of the application of the technique can make it an effective tool for traffic volume estimation for rural highways.
Genetic Algorithm-Based Approach for Optimal Location of Transit Repair Vehicles on a Large Urban Network
Authors: Karlaftis Matthew , Kepaptsoglou Konstantinos , Stathopoulos Antony , Jha Manoj , Lovell David , Kim Eungcheol
Published: April 2007

Determining the optimal location of a fleet of vehicles is necessary in a number of potential applications, such as special repair vehicles for buses on a large public transportation network. The Athens Urban Transport Authority operates a large bus fleet over an extensive network for 19 h a day and serves a population of approximately 4 million people, all in a heavily congested road network. During the 2004 Summer Olympic Games, held in Athens, most spectators, employees, and volunteers were transported to and from Olympic Games venues by public transportation. Dedicated Olympic Games bus lines operated under a tight around-the-clock schedule. During normal operations and particularly during events such as the Olympic Games, incidents such as vehicle breakdowns and minor accidents can have a severe effect on the operation of the public transport network and can cause a significant decrease in the level of service. To help the authority locate bus repair vehicles over the entire network, a decision support system was developed on the basis of an embedded genetic algorithm used for obtaining optimal location solutions. The system's design and performance make it easy to operate under real-time conditions, which is useful for planning and for fast vehicle redeployment.
Estimation of Diesel Particulate Matter Concentrations in a School Bus Using a Fuel-Based Tracer: Sensitive and Specific Method for Quantifying Vehicle Contributions
Authors: Ireson Robert G. , Easter Michael D. , Lakin Michael L. , Ondov John M. , Clark Nigel N. , Wright David B.
Published: April 2007

Particulate matter from diesel exhaust (DPM) is a pollutant of increasing concern, but its concentrations are difficult to measure in the environment. There are no unique chemical characteristics for DPM, so elemental carbon (EC) and black carbon (BC) measurements have historically been used to estimate its concentrations. However, both methods have limitations, and neither is capable of identifying specific sources. That results in significant uncertainties in the inferred DPM concentrations. In this study an intentional fuel-based tracer, iridium, was used to mark the DPM from a school bus's exhaust. Emissions tests established the mass ratio of DPM-iridium in the exhaust. Iridium measurements inside the bus during normal operations could then be used to calculate DPM concentrations without the limitations of methods relying on nonspecific markers. Previous studies have attributed in-bus concentrations of more than 30 μ/m3 to the bus's exhaust, but they relied on nonspecific methods with a sensitivity of approximately 0.1 μ/m3. In this study the average measured DPMSB concentration was 0.22 μ/m3—about 1% of previous estimates. Measurement sensitivity was approximately 0.001 μ/m3—100 times better than that of other methods. The sensitivity and specificity achieved show that this tracer method can resolve major ambiguities and uncertainties in estimates of actual DPM concentrations. The ability to estimate accurately the contributions of different sources to DPM concentrations provides a needed tool to evaluate proposed emission reduction strategies reliably.
Transportation Control Measures: Federal Requirements and State Implementation Plan Development Considerations
Authors: Eisinger Douglas , Niemeier D. A.
Published: April 2007

U.S. transportation control measure (TCM) policies have evolved over the past several years, especially with respect to the identification of reasonably available control measures (RACM). U.S. TCM experiences are used to examine transportation conformity in light of two important emerging policy issues: identification of TCMs that are RACM and the substitution of TCMs in existing state implementation plans (SIPs). The issues associated with forming TCMs into SIPs while buffering against conformity difficulties are outlined against the background of recent U.S. Environmental Protection Agency (EPA) rulemaking actions, court decisions, research findings, and various state SIP adoption efforts. Factors that are related to TCM substitution and take into consideration EPA approval actions and recent considerations raised by public interest groups and planning agencies are identified. A process for identifying candidate TCMs for RACM analysis, explicit criteria for determining RACM TCMs, insights concerning TCMs that will be most effective, and case study-derived recommendations on how to structure SIP TCM commitments are provided.
Design of Robust Emission Reduction Strategies for Road-Based Public Transportation in Mexico City, Mexico: Multiattribute Trade-Off Analysis for Metropolitan Area
Authors: Mostashari Ali , Sussman Joseph M. , Connors Stephen R.
Published: April 2007

Transportation-related air pollution is one of the major problems facing many megacities in developing as well as developed countries. The design of air quality strategies for the road-based public transportation system in the Mexico City metropolitan area (MCMA) is considered. An analysis is done of 28 different emission reduction strategies consisting of bundles of technological and supply and demand management emission reduction policies across alternative future development scenarios of the MCMA in the 2000-2025 period. The analysis combines demand modeling, fleet evolution modeling, mobile-source emissions modeling, and trade-off analysis to evaluate the impact of these emission reduction strategies and to determine their cost-effectiveness. The combined use of scenario analysis and multiattribute trade-off analysis is a unique approach that allows the design of strategies that are robust across a range of future uncertainties. Results of the analysis show that combinations of aggressive technological and supply and demand management strategies are needed to achieve sustained emission reductions in the 2000-2025 period. The recommendation calls for combinations of strategies that rely on aggressive hybrid vehicle introductions, catalyst and particulate matter and nitrogen oxide filter retrofitting, dedicated busways, public transportation fare integration, and subsidies and fuel taxes. These combined strategies can reduce transportation emissions by more than 85%. Results also indicate that even the most aggressive strategies fail to achieve sustained emission reductions in the case of urban sprawl and the rapid growth in transportation demand.
Streamlining the National Environmental Policy Act Process Through Cooperative Local-State-Federal Transportation and Land Use Planning
Authors: Johnston Robert A. , McCoy Mike , Kirn Marjorie , Fell Matthew
Published: April 2007

The U.S. Environmental Protection Agency, FHWA, and California Department of Transportation have initiated a demonstration in California called Partnership for Integrated Planning. The purpose of this program is to obtain early involvement from local, state, and federal agency staff to help in planning for transportation infrastructure, urban growth, and resource protection together, rather than just to negotiate over permits for major infrastructure at the project stage. A report on this demonstration project is provided. The project applies a simple urban growth model based on a geographic information system to evaluate a transportation plan and projects in Merced County (population 211,000 in 2000). Interviews with agency participants show that, in general, resource agency personnel have limited involvement with transportation planning and transportation planners have limited knowledge of environmental planning; they therefore need to develop methods for identifying their concerns for 20-year planning purposes. Planning for resource protection for a whole county is quite different from arguing for maximum protection of resources at the project scale. The early steps in building the model and acquiring data sets are reviewed.
Eight-Step Process for Assessing Indirect and Cumulative Impacts of Transportation Projects
Authors: Grimes Gail , Pesesky Larry , Lane J. Scott , Szwarckop Cindy
Published: April 2007

In 1999 the North Carolina Department of Transportation (NCDOT) established a joint-agency task force spearheaded by its project development and environmental analysis branch with the purpose of formulating a strategy to deal with indirect and cumulative impacts (ICI) of transportation projects. According to the Council of Environmental Quality, indirect effects are caused by the action, are later in time or farther removed in distance, but are still reasonably foreseeable. A cumulative impact is the impact on the environment that results from the incremental impact of the action when added to other past, present, and reasonably foreseeable future actions regardless of what agency or person undertakes the action. The task force found that while there was ample evidence to support the need to develop guidance on ICI, there was not sufficient national or out-of-state experience available to guide ICI analyses in North Carolina. Responding to that need, NCDOT contracted with the Louis Berger Group to develop guidance materials on ICI policy analyses for its staff and stakeholders. The eight-step process for assessing indirect and cumulative impacts of transportation projects is described and summarized, and a case study of a proposed bridge replacement project in Sunset Beach, North Carolina, is provided.
Development of the Displaced Right-Turn Intersection
Authors: Simmonite Brian F. , Chick Marcus J.
Published: April 2007

The displaced right-turn concept is an innovative traffic signal intersection being developed for the United Kingdom highway network by the Highways Agency. The concept of the displaced right turn has been considered since the 1950s as an alternative intersection design to traditional at-grade and grade-separated intersections. It enables one or more conflicting movements to take place away from the main intersection at a new crossover intersection, which reduces the number of conflicts at the central node. Tests have shown intersection capacity can increase with a footprint similar to a large roundabout and only a small increase in costs.
Highway Design Consistency: Refining the State of Knowledge and Practice
Authors: Hassan Yasser
Published: April 2007

Highway collisions are a major source of societal losses, both social and economic. Among the promising approaches to improve highway safety performance is the concept of highway design consistency. Several research efforts have concentrated on translating this concept into quantitative guidelines. However, a number of concerns and challenges in applying the concept and the guidelines still persist and may limit their applicability. Such challenges were identified with the objective of recommending the optimum way to overcome them and establish priorities for future research. The challenges focus on the optimum criteria and parameters to be used in consistency evaluation, models to estimate these parameters, and the relationship between the criteria and safety performance.
Formulation of Analytical Time-Varying Intermodal Person Trip Assignment Model
Authors: Chang Elaine , Ziliaskopoulos Athanasios
Published: April 2007

An analytical formulation of the intermodal dynamic traffic assignment problem is presented. The model is a cell transmission-based, single-destination, system optimal integer linear programming formulation for a multimodal network of cars and buses. The computational tests demonstrate interesting insights into the complex interactions between travelers' intermodal path choices and traffic movements. Specifically, as with many analytical time-varying traffic models, the constraints regulate flow, while the objective function provides an incentive for travelers to progress on least-cost paths toward the cost-free trip termination cells. It is found that difficulties relate to this reliance on costs to advance travelers and vehicles; for example, the non-first-in-first-out propagation of buses ahead of automobiles is a result of the higher cost incurred by numerous riders on a single bus vehicle. Similarly, the model's tendency to hold buses at bus stops or force buses to skip bus stops results from a difference in costs incurred by travelers who would be better served by the holding of the bus or by the skipping of a stop. On the basis of the findings on the model's behavior, recommendations are made for the future development of time-varying intermodal routing problems.
Stochastic Transportation Network Design Problem with Spatial Equity Constraint
Authors: Chen Anthony , Yang Chao
Published: April 2007

Equity issues and demand uncertainty are two important issues in the network design problem (NDP). Spatial equity in NDP is concerned with the benefit distribution among network users. By considering demand uncertainty, a more realistic evaluation of the network performance given a network improvement plan can be obtained. Two stochastic models that consider both spatial equity and demand uncertainty are formulated: an expected-value model and a chance-constrained model. Both models are solved by a simulation-based genetic algorithm procedure. The genetic algorithm is used to solve NDP, and stochastic simulation is used to simulate the demand uncertainty. The results of numerical experiments are provided to demonstrate the significance of the equity issue and demand uncertainty in NDP.
Taxi Dispatch System Based on Current Demands and Real-Time Traffic Conditions
Authors: Lee Der-Horng , Wang Hao , Cheu Ruey Long , Teo Siew Hoon
Published: April 2007

The existing taxi dispatch system that taxi operators in Singapore use to handle current bookings was studied. This dispatch system adopts the Global Positioning System and is based on the nearest-coordinate method: the taxi assigned for each booking is the one with the shortest, direct, straight-line distance to the customer location. However, the taxi assigned under this system often is not capable of reaching the customer in the shortest time possible. An alternative dispatch system is proposed, whereby the dispatch of taxis is determined by real-time traffic conditions. In the proposed system, the taxi assigned the booking job is the one with the shortest time path, reaching the customer in the shortest time. This dispatch ensures that customers are served within the shortest period of time and increases customer satisfaction. The effectiveness of both the existing and the proposed dispatch systems is investigated through computer simulations. The results from a simulation model of the Singapore central business district network are presented and analyzed. Data from the simulations show that the proposed dispatch system is capable of being more efficient in dispatching taxis more quickly and leads to more than 50% reductions in passenger pickup times and average travel distances. A more efficient dispatch system would result in higher standards of customer service and a more organized taxi fleet to meet customer demands better.
Moving Bottlenecks in Lighthill-Whitham-Richards Model: A Unified Theory
Authors: Leclercq Ludovic , Chanut Stéphane , Lesort Jean-Baptiste
Published: April 2007

A unified general framework for the moving-bottleneck models based on the Lighthill-Whitham-Richards theory is proposed. It is shown that all existing models may be considered as particular cases of the general model, differing only by the phenomenology involved, that is, by the shape of the flow-density relationship used for the restricted section. Possible generalization of the model through various flow-density relationships is discussed, as well as the possibilities of experimental validation.
Modeling Queues at Signalized Intersections
Authors: Viti Francesco , van Zuylen Henk J.
Published: April 2007

Traffic control is one of the most effective techniques for a road manager to adapt network capacity to flow. It also provides possibilities to modify users' choices of modes and routes. An important area of research is formed by the dynamic assignment problem, in which the effect of delays at controlled intersections is taken into account. This problem requires realistic queuing models. If the degree of saturation of an intersection is close to or larger than 1.0, the queue size has a dynamic character. The case in which the initial queue is nonzero is similar. Existing queue models have important limitations. A Markov model was developed to calculate the dynamics of the queue. It appears that the variance of the queue length is an important determinant of queue dynamics. The case of decreasing queues is analyzed and shows that available models in this case underestimate the mean values and are barely applicable in modeling time-of-day dynamics. An approximate expression for the case of decreasing queues is provided and analyzed with its parameters. Finally the same approach also suggests an approximate formulation for the evolution of the standard deviation with time and provides better knowledge of the uncertainties at signalized intersections. The analytical model introduced is suited for application in dynamic assignment problems.
Traffic Flow on Freeway Upgrades
Authors: Brilon Werner , Bressler Andrea
Published: April 2007

Traffic flow characteristics on freeway upgrades in Germany were analyzed, and a combination of measurements, analyses of continuous counting results, and microscopic simulations was performed. From these results a macroscopic traffic flow model for freeway upgrades based on a two-stage linear speed-density relation was developed. All relevant external influences such as degree of gradient and length of upgrade together with traffic flow parameters such as volume or proportion of heavy vehicles may be included through specific parameters. On the basis of this analysis, it was found that capacity depended solely on the degree of the gradient. Capacity was not influenced by gradient length. Velocity, however, was determined not only by the degree of the gradient but also by the length of the upgrade (up to L ≤ 4,000 m). Results were formulated to be ready for application in practice. They form, for instance, the basis of the chapter on freeways in the new German version of the U.S. Highway Capacity Manual, Handbuch für Bemessung von Straßenverkehrsanlagen.
Making Buses Better in Chicago: Strategic Implementation of Customer-Derived Performance Measures from 1995 to 2001
Authors: Foote Peter J.
Published: April 2007

The Chicago Transit Authority (CTA) used customer-derived performance measures to evaluate CTA bus and rail operations in a series of biennial random-digit-dial telephone surveys (1995 to 2001). These measures were used to develop customer-focused bus service improvement initiatives, the impact of which was measured in subsequent surveys. The methods described succeeded in nearly doubling CTA bus customer satisfaction levels by 2001. There were many positive impacts, not the least of which was significant growth in annual bus ridership. By the end of 2002, CTA had experienced 5 consecutive years of bus ridership growth after many years of bus ridership decline. The development and use of customer-derived performance measures, management application of research findings, methods used to prioritize survey results into actionable programs, and key results are discussed. Among the points discussed are critical definitions of customer satisfaction and loyalty, grouping of customer-derived performance attributes into performance dimensions, and benefits of geographic market segmentation techniques in focusing management initiatives.
Steam Versus Electric Versus Internal Combustion: Choosing Vehicle Technology at the Start of the Automotive Age
Authors: Loeb Alan P.
Published: April 2007

The choice of engine technology for the automobile is currently at issue, but not for the first time. When the automobile was introduced to the United States in 1895, it was not apparent what engine technology would prevail. Steam, electric, and internal combustion engines all had their own merits. But within a few years internal combustion had eclipsed its rivals to become the single commercially viable engine technology. Many factors that affected the choice of internal combustion have been noted in the literature and in the popular press; here a model integrates all these factors into a single comprehensive framework. The critical years when the technology choice occurred are pinpointed, and a new, comprehensive framework is used to identify the key factors that determined the choice.
History of the Highway Trust Fund
Authors: McDaniel Wayne , Coley Meredith
Published: April 2007

The Federal Highway Trust Fund (the fund), which contains receipts from highway user fees (such as gasoline and heavy vehicle use fees), was established by Congress in 1956. Its principal purpose was to finance the construction of the Interstate highway system, and its creators' original intention was to terminate the fund when that effort was accomplished. However, the fund has since morphed into an ongoing method of financing a broad range of federal transportation programs and now comprises both a highway account and a mass transit account. Over the years, the structure of the taxes supporting the fund and the rules governing its expenditures and administration have changed, sometimes significantly. Among the most significant changes were a series of increases to tax levels and transfers to the fund (major increases occurred in 1959, 1961, 1966, 1982, and 1997), the imposition of obligation limits in 1974, and the restoration of the user fee concept in 1998. The congressional authorizing acts that provided for these and other revisions to the fund's funding levels and administrative procedures from 1956 to 2003 are documented. The fund's history is a particularly topical subject because Congress continues to address extensions to the fund, the fund's supporting revenues, and the transportation programs it finances.
Best Practices in Consultant Management at State Departments of Transportation
Authors: Cochran Jamie A. , Crocker John , Kingsley Gordon , Wolfe Patrick
Published: April 2007

The Georgia Department of Transportation (GDOT) has been experiencing a significant increase in the number of consultants that it is using, and there is an attendant need to manage these consultants better. Best practices in consultant management within state departments of transportation (DOTs) were examined, and the consultant program at GDOT was examined in detail. DOTs with innovative programs and with similarities to GDOT were identified, and site visits and interviews with relevant DOT personnel were conducted at the Florida, Ohio, and Pennsylvania DOTs. The results of the review of consultant programs and the detailed on-site interviews revealed that successful consultant management programs shared the characteristics of transparency, regularity, independence, and consistency. This finding will help GDOT reform its consultant management program to cope with the increased use of consultants and improve delivery of services to the citizens of Georgia.
Highway Improvements and Land Development in Minnesota's Greater Twin Cities Area, 1970-1997
Authors: Smith Laura J. , Adams John S. , Cidell Julie L. , VanDrasek Barbara J.
Published: April 2007

As increased traffic congestion becomes an issue in more and more cities across the country and especially in rapidly growing suburban areas, the following questions are often asked. How are improvements in highway transportation and patterns of land development in suburban and exurban areas related? Do road improvements encourage land development, or vice versa? The key question of leads and lags between transportation and development within cities and townships of the greater Minneapolis-St. Paul metropolitan area was investigated for five time intervals between 1970 and 1997. Correlation and regression analyses were used to measure the strength and causality of relationships between highway improvements and the timing and levels of residential, industrial, commercial, and office development. Although statistical relationships describing correlations of leads, lags, and contemporaneous change were found to be highly significant, the measures of those relationships were seldom constant. They differed from one time period to the next, from one location to another within specific time periods, and from one type of development to another. The weakest relationships occurred in the most recent era (1990s) for all development types. Generally, industrial development seemed to be most influenced by transportation and location over the eras, followed by office and commercial construction. New housing seemed to be least affected by transportation and location; this finding may have major implications for addressing issues of traffic congestion.
Comprehensive Data Collection to Support Asset Management at Virginia Department of Transportation
Authors: Larson Charles D. , Skrypczuk Oleh
Published: April 2007

In 1996 the Virginia Department of Transportation (VDOT) initiated an Inventory and Condition Assessment System (ICAS) project, designed to collect inventory, condition, and location information for a comprehensive set of assets and allow this information to be stored, accessed, and used in strategic and tactical day-to-day asset management decision making. ICAS requirements included an accurate and complete inventory of roadway infrastructure assets (number and description), an accurate location of these assets (georeferenced through global positioning satellites), an assessment of their condition (damaged, blocked, rusted, etc.), and a central relational database to store the collected information. The project encompassed all roadway assets within highway fence-line boundaries. VDOT used a prime contractor and team of subcontractors to perform data collection and systems development. The ICAS project concluded in November 2002, and the following deliverables were received and accepted by the agency: a complete inventory of highway-maintainable assets in three counties, a comprehensive data dictionary, a process for the consistent measurement of asset conditions, a statewide process for managing asset information, modern information technology tools to access the information, tools to support use of multiple location-reference systems, and statewide centerlines for the entire highway network. The results achieved and lessons learned from this complex project are documented.
Disabled Access to Ferry Transit: New York-New Jersey Harbor Private Ferries
Authors: Chapman David S.
Published: April 2007

Passenger ferries in the New York-New Jersey Harbor have proliferated in recent years and now carry almost 67,000 passengers each day, with more than 50 vessels serving 39 routes. With 1.6 million disabled individuals in New York City alone, accessibility is a key concern. The U.S. Access Board, a federal agency tasked with developing accessibility standards, is in the process of developing accessibility standards for passenger vessels. A milestone in this process was reached with the December 2000 publication of recommended vessel accessibility guidelines by the board's Passenger Vessel Access Advisory Committee (PVAAC), an assembly of representatives from the disabled community and the passenger vessel industry. The PVAAC recommendations are applied to the smallest vessel in the New York-New Jersey Harbor private transit ferry fleet, providing insights into the design challenges of small passenger vessel accessibility. The intention is to heighten the awareness of such design challenges among the disabled, vessel operators, and marine designers and to spur the development of innovative solutions.
Multiobjective Model for Locating Automatic Vehicle Identification Readers
Authors: Chen Anthony , Chootinan Piya , Pravinvongvuth Surachet
Published: April 2007

The problem of locating automatic vehicle identification (AVI) readers on a transportation network is one worth considering. AVI readers are strategically located to catch a maximum number of trips and cover a maximum number of origin-destination (O-D) pairs using a minimum number of AVI readers. There are three possible objectives when deciding locations for AVI readers: (a) a minimum number of AVI readers, (b) maximum O-D coverage, and (c) a maximum number of trips (or AVI readings). To satisfy all three objectives as much as possible, the problem is formulated as a multiobjective integer-optimization problem. A distance-based genetic algorithm is applied to solve this multiobjective AVI reader-location problem by explicitly generating the nondominated solutions. Numerical results are presented to demonstrate the feasibility of the proposed multiobjective model. The procedure proposed holds great promise for the development of a well-configured AVI system that can achieve a balance between quality and cost of coverage (i.e., trade-off between cost and coverage requirements).
South Jersey Real-Time Motorist Information System: Technology and Practice
Authors: Ozbay Kaan , Bartin Bekir , Chien Steven
Published: April 2007

The South Jersey Real-Time Motorist Information System project is aimed at the rapid deployment of available intelligent transportation system surveillance and communication technologies to monitor traffic on the basis of need at various locations in the South Jersey highway network. The proposed system is a highly mobile traffic-surveillance design that includes mobile, self-sufficient, sensor units with communications and data-collection capabilities that allow the sensor unit to exchange information with the traffic-control center. The sensor units can be installed easily at any location on the transportation network without delays for establishing power and communication connections. This rapid-deployment capability meets the goal for easy-to-deploy traffic-surveillance units that can be used to manage the transportation system during any type of disaster. A technical overview and the advantages of this system and its evaluation procedure are presented. In addition, the problems faced and lessons learned during the implementation, along with future plans for deployment, are presented.
Measuring Change in Small-Scale Transit Accessibility with Geographic Information Systems: Buffalo and Rochester, New York
Authors: Grengs Joe
Published: April 2007

A new method has been developed to measure directly changes in transit accessibility—the combined spatial effect of shifts in land use patterns and transit service—between metropolitan jobs and census tracts with high proportions of the people who most depend on good transit. Through focused analysis of transit routes serving one neighborhood in Buffalo and one neighborhood in Rochester, New York, two main questions are addressed. First, did transit-dependent poor people who lived in inner-city neighborhoods lose capacity to access jobs by transit during the 1990s? Second, if so, how much of the reduction in accessibility was due to changes in transit service rather than to dispersion of land use? Steps include formulating a gravity model using geographic information systems (GISs), calculating an accessibility index at two times during the 1990s at the census tract level, and disaggregating the accessibility change into subcomponents of change in land use and change in transit service by holding relevant variables constant to a base year. Findings do not support the a priori expectations: the transit component of change does not appear to contribute to a loss in accessibility from high-poverty neighborhoods. The model provides insights into the causes of accessibility change, the geographic distribution of accessibility change, and better assessments of whether transit agencies are successfully adapting to changes in land use.
Policy Support for and Barriers to Transit-Oriented Development in the Inner City: Literature Review
Authors: Hess Daniel Baldwin , Lombardi Peter A.
Published: April 2007

The promise of transit-oriented development (TOD) for increasing transit ridership, enhancing economic development, and establishing a "sense of place" at transportation nodes has been well documented in the literature. However, the majority of research addresses TOD in greenfield sites located primarily in suburban places in growing regions. The policies that are widely believed to be supportive of TOD are examined, the gap in knowledge about TOD in established city neighborhoods is addressed, and the challenges of TOD in different urban settings are compared. Findings reveal that ( a) the literature appears to be consistent and confident in outlining the public policies that encourage TOD; ( b) researchers tend to focus on TODs in suburban and greenfield areas of fast-growing regions in the western and southern United States; ( c) TODs in older cities are not well publicized and are largely ignored by the literature; and ( d) researchers who study inner-city TOD usually focus on the lack of it, or any type of development, in economically depressed areas. The conclusion of several researchers that a strong local economy is key to successful TOD offers a clue as to why recently built TOD is largely absent from many older, slow-growth cities like Buffalo, New York, and St. Louis, Missouri. It also offers some insight into why the TOD trend is strongest in high-growth metropolitan areas like San Diego, California, and why it seems to skip struggling neighborhoods within them, like South Central Los Angeles, California. Although pre-1950s TOD is common in older cities, that ubiquity appears to reduce the publicity and attention given to more recent TOD in those places.
Planning Public Transport Networks for the 2004 Summer Olympics with Decision Support Systems
Authors: Karlaftis Matthew G. , Kepaptsoglou Konstantinos , Stathopoulos Antony , Starra Anna
Published: April 2007

During the 2004 Summer Olympics, in Athens, Greece, transit passengers will be mainly accommodated by public transportation modes. The large number of passengers expected to be carried, combined with the congested road network and limited parking spaces, will make it difficult for private vehicles to be used during the games; as such, use of mass transportation will be necessary. An extended public transportation network is being planned that consists of three lines of the Athens Metro, a suburban rail line, two tram lines, and 30 dedicated Olympic bus lines in addition to regular bus lines. Planning of the network is a complicated process with more than 30 Olympic bus lines connecting Olympic venues with Athens downtown, other venues, Metro stations, and park-and-ride areas. Metro lines will be operating 24 h/day, many hours near capacity. To assist in this effort, a decision support system was developed to help plan the Olympic public transportation network operations. The user-friendly system is supported by a graphical user interface and based on widely available software packages. Its capabilities include data storage, management, graphical analysis, analysis with the use of specialized algorithms, and extraction of proposed courses of action.