bluuebunny/crossref_metadata_2025 huggingface dataset:
Accelerated Alkali-Silica Reactivity Testing of Recycled Concrete Pavement
Authors: Gress David L. , Kozikowski Ronald L.
Published: April 2007

Techniques and procedures are investigated for assessing the alkali–silica reactivity (ASR) expansion potential of concrete that was made from recycled concrete aggregate, was known to have ASR, or was capable of ASR under conditions of increased alkalinity. Laboratory tests included evaluating prisms characterized by variable surface-to-volume ratios, increased temperature, microwave energy, increased alkali content, and ultrasonic energy. Standard 280-mm (11-in.) prisms with 76.2-mm (3-in.) faces, which were cast with four 6.35-mm (0.5-in.) parallel longitudinal holes, were shown to accelerate ASR and to lower the coefficient of variation of the expansion data. The expansions of 76.2-mm (3-in.) concrete cubes were found to be greatly accelerated, compared with standard prisms. Concrete prisms were subjected to AASHTO T303 and ASTM 1293 conditions and were compared to modified versions of the same tests. Modified AASHTO T303 and modified ASTM 1293 conditions were found to effectively accelerate ASR in concrete prisms cast with holes. Prisms that were sealed in evacuated plastic bags with water were found to effectively accelerate ASR expansion. Testing to date has eliminated the use of ultrasonic energy because it was shown to have no effect on ASR acceleration.
Artificial Neural Network for Enhancing Selection of Pavement Maintenance Strategy
Authors: Abdelrahim Ashraf M. , George K.P.
Published: April 2007

In the selection of an economical treatment for rehabilitation of a deteriorated pavement section, decision makers usually encounter various situations. Factors affecting selection of a flexible pavement maintenance strategy may include distress conditions, traffic volume, and road class, among others. Traditionally engineers make their selection on the basis of their experience and judgment and past maintenance data. Experts’ judgments are usually compromised in a group discussion to construct decision trees or decision matrices or even to develop knowledge-based expert systems. An artificial neural network is known to be an efficient technique for selection of an appropriate maintenance strategy. A genetic adaptive neural network training algorithm with a single hidden layer and sigmoid squashing function constitutes the network. The input vector represents the factors affecting maintenance strategy selection, and the output vector represents the appropriate maintenance strategy. A set of examples is derived from experts’ judgments with a total of 144 cases randomly divided into “in-sample” and “out-of-sample” data for training and testing purposes, respectively. The trained network successfully predicted 83 percent of the test cases. The remaining 17 percent of cases were one or two levels away from the expert judgments used in network testing. Neural networks provide an efficient and optimum solution for such complex problems with the added advantage of faster implementation and easier updating than with other traditional techniques.
Structured Approach to Managing Quality of Pavement Distress Data: Virginia Department of Transportation Experience
Authors: Larson Charles D. , Sami Naveed , Luhr David R.
Published: April 2007

The Virginia Department of Transportation (VDOT) Pavement Management Program has examined and improved the quality of condition data to carry out pavement performance analysis and multiyear work planning. In 1995 the agency changed the way it gathered pavement condition data, moving from subjective windshield surveys to using automated condition survey equipment. In 1997 the agency acquired the staff and resources to examine these data and respond to concerns of district personnel that the data were inconsistent and not representative of actual conditions. At that time, VDOT acknowledged the need for a formal and large-scale quality assurance program for its pavement condition data. It was shown in 1998 that standardization of test methods and calibration of equipment for roughness measurement yielded data of much higher quality than that in previous years. Quality data are crucial to the sound functioning of a pavement management system. It has been found that ( a) distress data quality is a serious problem and the data can potentially be bad enough to be completely useless and ( b) improving or reengineering distress data quality requires a significant effort. A structured approach to develop and implement a pavement distress data quality program at VDOT is described, including the processes, statistical details, and a clear vision of needs. Most important, this reengineering effort involves attending to the data collection process by building controls at critical junctures during the project in order to deliver a quality data product in time and on budget.
Using Duration Models to Analyze Experimental Pavement Failure Data
Authors: Prozzi Jorge A. , Madanat Samer M.
Published: April 2007

Predicting pavement performance under the combined action of traffic and the environment provides valuable information to a highway agency. The estimation of the time at which the pavement conditions will fall below an acceptable level (failure) is essential to program maintenance and rehabilitation works and for budgetary purposes. However, the failure time of a pavement is a variable event; terminal conditions will be reached at different times at various locations along a homogeneous pavement section. A common problem in modeling event duration is caused by unobserved failure events in a typical data set. Data collection surveys are usually of limited length. Thus, some pavement sections will have already failed by the day the survey starts; others will reach terminal conditions during the survey period, whereas others will only fail after the survey has been concluded. If only the failure events observed during the survey are included in the statistical analysis (disregarding the information on the events after and before the survey), the model developed will suffer from truncation bias. If the censoring of the failure events is not accounted for properly, the model may suffer from censoring bias. An analysis of the data collected during the Road Test sponsored by the American Association of State Highway Officials (AASHO) is presented. The analysis is based on the use of probabilistic duration modeling techniques. Duration models enable the stochastic nature of pavement failure time to be evaluated as well as censored data to be incorporated in the statistical estimation of the model parameters. The results, based on sound statistical principles, show that the failure times predicted with the model match the observed pavement failure data better than those from the original AASHO equation.
Investigation of Relationship Between Roughness and Pavement Surface Distress Based on WesTrack Project
Authors: Mactutis Joseph A. , Alavi Sirous H. , Ott Weston C.
Published: April 2007

Modern pavement rehabilitation and design methodologies require an adequate evaluation of the functional capacity of pavements. A key component of this functional capacity is the roughness of the pavement. The current standard for characterization of a pavement’s roughness is the international roughness index (IRI). Pavement roughness measurements were conducted at regular intervals during the application of approximately 5 million equivalent single-axle loads at the WesTrack Project, a full-scale flexible pavement accelerated loading facility located near Reno, Nevada. The results are presented of an investigation into the relationship between pavement roughness and pavement surface distress using WesTrack data. With a sample population of 317 observations, a relationship was found among the roughness (IRI) and the initial IRI, percentage of fatigue cracking, and average rut depth. A test of the relationship with data collected as a part of the Long-Term Pavement Performance Program indicates favorable results.
Mechanistic Roughness Model Based on Vehicle-Pavement Interaction
Authors: Saleh Mofreh F. , Mamlouk Michael S. , Owusu-Antwi Emmanuel B.
Published: April 2007

A mechanistic roughness performance model that takes into account vehicle dynamics was developed for use in flexible pavement design and evaluation. The model was developed in the form of a relation between roughness and number of load repetitions, axle load, and asphalt layer thickness. The model is completely mechanistic and uses vehicle dynamics analysis to estimate the dynamic force profile and finite element structural analysis to estimate the change of pavement surface roughness for each load repetition. The model makes use of the fact that pavement roughness changes the magnitude of the vehicle dynamic forces applied on the pavement and that the dynamic forces change the road roughness. The developed mechanistic roughness performance model can be used to estimate the 80-kN (18-kip) equivalent single-axle load for mixed traffic. The model can also be used to design pavement so that it will last for a certain number of load repetitions before reaching a predetermined roughness level. Performance-based specifications can be developed using the methodology presented in this study. The model has been calibrated and verified with field data elsewhere.
Evaluation of Relationship Between Profilograph and Profile-Based Roughness Indexes
Authors: Fernando Emmanuel G.
Published: April 2007

The relationship between the profilograph profile index (PI) and the international roughness index (IRI) is evaluated. To accomplish this evaluation, profile data taken on 48 overlaid test sections were used in profilograph simulations to predict the profilograph response to the measured profiles. The PIs determined were then correlated with IRIs computed from the profile data to evaluate relationships between these roughness statistics. The results show that the PI based on the null blanking band is more strongly related to the IRI than the corresponding index determined using the 5-mm blanking band. In view of the general acceptance of the IRI as a statistic for establishing surface smoothness based on profiles, the results suggest that a profilograph specification based on the null blanking band is preferable to a similar specification based on the 5-mm blanking band, which may mask certain components of roughness that are otherwise picked up if no blanking band is used.
Early Evaluation of Long-Term Pavement Performance Specific Pavement Studies-2, Colorado
Authors: Suthahar Nadarajah , Ardani Ahmad , Morian Dennis A.
Published: April 2007

The Long-Term Pavement Performance (LTPP) Program included the construction of rigid pavement sections for evaluation. These test sections, designated Specific Pavement Studies (SPS)-2, were constructed on the basis of an experiment matrix that includes pavement slab thickness [202 mm (8 in.) and 280 mm (11 in.)], base type (permeable asphalt-treated base, lean concrete base, and dense-graded aggregate base), widened lane of 4.27 m (14 ft) and state standard lane of 3.66 m (12 ft), and drainage (with and without pavement edge drains). In addition, a standard Colorado Department of Transportation design section was constructed to provide a performance comparison. The performance of these test sections after 4 years of service is discussed. The results are based on deflection, profile, and distress data collected by the LTPP Program. Virtually no distress and no change in ride quality are evident in these pavement test sections at this time. However, the evaluation of deflection data provides an early indication of anticipated variation in test section performance. Currently, no difference can be identified between the deflection magnitude of the widened-lane section and the state standard section with tied concrete shoulders. However, both these sections exhibit lower deflections at this time than those sections with untied shoulders. High deflections of 202-mm sections indicate that perhaps these sections do not provide adequate structural strength for this roadway.
Driver Braking Performance in Stopping Sight Distance Situations
Authors: Fambro Daniel B. , Koppa Rodger J. , Picha Dale L. , Fitzpatrick Kay
Published: April 2007

Assumed driver braking performance in emergency situations is not consistent in the published literature. A 1955 study stated that in an emergency situation “it is suspected that drivers apply their brakes as hard as possible.” This idea differs from a 1984 report that states drivers will “modulate”their braking to maintain directional control. Thus, additional information is needed about driver braking performance when an unexpected object is in the roadway. In this research driver braking distances and decelerations to both unexpected and anticipated stops were measured. The study design allowed for differences in vehicle handling and driver capabilities associated with antilock braking systems (ABS), wet and dry pavement conditions, and the effects of roadway geometry. Vehicle speeds, braking distances, and deceleration profiles were determined for each braking maneuver. The research results show that ABS result in shorter braking distances by as much as 30 m at 90 km/h. These differences were most noticeable on wet pavements where ABS resulted in better control and shorter braking distances. Braking distances on horizontal curves were slightly longer than on tangent sections; however, they were not large enough to be of practical significance. Maximum deceleration during braking is independent of initial velocity, at least in the range of speeds tested. Differences were noted in individual driver performance in terms of maximum deceleration. Although maximum deceleration was equal to the pavement’s coefficient of friction for some drivers, the average maximum deceleration was about 75 percent of that level. Overall, drivers generated maximum decelerations from 6.9 to 9.1 m/s2. The equivalent constant deceleration also varied among drivers. Based on the 90-km/h data, 90 percent of all drivers without ABS chose equivalent constant decelerations of at least 3.4 m/s2 under wet conditions, and 90 percent of all drivers with ABS chose equivalent constant deceleration of at least 4.7 m/s2 on dry pavements.
Reliability Approach to Intersection Sight Distance Design
Authors: Easa Said M.
Published: April 2007

The intersection sight distance (ISD) design presented by AASHTO is based on extreme values of the component design variables such as design speed, perception–reaction time (a high percentile), and friction coefficient (a low percentile). A reliability method is presented, based on AASHTO, that does not rely on extreme values but instead considers the moments (mean and variance) of the probability distribution of each random variable. The method also accounts for correlations among the component random variables. In Cases I and II of AASHTO, the variations of the sight distance along both legs of the intersection are considered for both design and evaluation. For evaluation (involving an exiting obstruction), these variations are combined into a single variable that determines whether the corresponding sight line is obstructed. In Case III, only the sight distance leg along the major road has variations. The proposed method is straightforward and involves simple, closed-form mathematics for calculating sight distance and associated reliability. Sensitivity of ISD to various design variables is examined. ISD reliability-based values for various cases are presented from data reported in the literature, and results are compared with current AASHTO design values.
Mathematical Models of Vehicular Speed on Mountain Roads
Authors: Jose Andueza Pedro
Published: April 2007

Mathematical models were developed to estimate vehicular speed on curves and tangents in mountain roads. The 85th percentile speed for curves was estimated by using the radius of the curve under consideration, the radius of the previous curve, sight distance in the curve, and tangent length before the curve. The average speed was calculated by using the radius of the curve under consideration, the radius of the previous curve, and sight distance. The 85th percentile and the average speed were estimated by using the radius of the previous curve and tangent length. Speeds adopted by drivers respond not to engineer’s design speed but to geometric characteristics of the road. A design procedure is proposed that takes advantage of available design speed and driver behavior on the road at the same time. On a curve, drivers consider two efficiency measures: speed and comfort. On some curves, they prefer to feel a certain degree of discomfort in exchange for obtaining greater speeds. For some geometric conditions, drivers adopt a speed that sacrifices not only comfort but also safety.
Summary of Design Speed, Operating Speed, and Design Consistency Issues
Authors: Harwood Douglas W. , Neuman Timothy R. , Leisch Joel P.
Published: April 2007

Six papers in this Record were presented at a conference session during the January 1994 TRB annual meeting. They address various aspects of the relationships among design speed, operating speed, and design consistency. All six papers are examined to show the interrelationships of design speed, operating speed, and design consistency; what changes are needed in the current design process and current design policies; how the concept of design consistency can produce better designs; and what research is needed to develop these concepts further. The improvements involve three key principles. First, design speeds must not be arbitrary but must be selected realistically based on projected operating speeds. Second, if lower design speed is used, all aspects of the roadway and its environment must be consistent with the lower speed. Third, large differences in operating speed between successive roadway elements represent design inconsistencies that can lead to safety problems. These principles can be used to develop a design process that leads to safer, more efficient, and more consistent designs. The TRB Committees on Operational Effects of Geometrics (A3A08) and on Geometric Design (A2A02) jointly sponsored the January 1994 conference session to call attention to the many unresolved issues about the roles of design speed, operating speed, and design consistency in creating highway designs that operate efficiently and safely and meet the needs of drivers. Originally, two alternative topics were considered: relationship of design speed and operating speed and the role of formal design consistency criteria in creating good highway designs. These topics were so interrelated that it was difficult to address one without the other. A key insight from the papers was that in a consistent design the design speed selected for use in determining the geometrics of the facility is similar to the operating speed of the completed facility. To call attention to the central role of several speed-related parameters in creating consistent designs, the session was titled “Speed.” Key points of the papers are summarized, generalizing the principles and philosophy for creating consistent designs, and suggesting directions for research to develop the ideas into practical design policies that highway engineers can apply.
Noise Issues of Concrete-Pavement Texturing
Authors: Jaeckel John R. , Kuemmel David A. , Becker Yosef Z. , Satanovsky Alex , Sonntag Ronald C.
Published: April 2007

The second phase of a project researching the texture and noise characteristics of portland cement concrete (PCC) pavements was sponsored by the Wisconsin Department of Transportation and FHWA. The team of Marquette University and HNTB Corporation measured and analyzed the noise and texture parameters of 57 test sites in Colorado, Iowa, Michigan, Minnesota, North Dakota, and Wisconsin. Conclusions pertaining to tire-and-pavement noise were drawn using data from several types of acoustical tests, including objective noise measurements (exterior and interior), subjective noise evaluations, and a prominent frequency analysis. Texture parameters of all test sites were measured with the road surface analyzer (ROSAN). ROSAN texture measurements proved invaluable in analyzing why different textures exhibited different noise characteristics. Both uniform and random transverse tining provide higher interior and exterior noise levels than skewed or longitudinal tining. Transverse tining, even in some random-spaced textures, can cause a discrete frequency or whine. As the depth and width of tining increased, so did the noise levels. Randomly spaced patterns are sensitive to spacing. Ground PCC pavement exhibited no discrete frequencies. Recommendations include the need for better quality control over tining and a wet-pavement-accident study of longitudinal tining. If noise considerations are paramount, longitudinal tining is recommended. If texture is paramount, skewed tining is recommended. If a skew is not possible, then carefully constructed random transverse is recommended.
Major Investment Studies—Hit or MIS?: Southern California Experience
Authors: Yoshizumi Steven A. , David Freytag F.
Published: April 2007

The major investment study (MIS) formally came into being with passage of the 1991 Intermodal Surface Transportation Efficiency Act. Federal, state, metropolitan planning organizations (MPO), and local regulations and guidelines say little about how sponsoring agencies should conduct a MIS. The MPO guidelines even state that “no one size fits all.” But because there are few specific requirements of the MIS process, a lot can be learned from MISs that have been completed. Three MISs were undertaken recently in Southern California: The Corridor (Orange County CenterLine), the Interstate 5 Corridor, and the State Route 22/West Orange County Connection Major Investment Studies. Lessons learned from these three MISs include the following: ( a) The process needs to begin with the identification of problems, not solutions; ( b) it is important to define the roles of the various participating agencies early in the process; ( c) integrating the planning and environmental-analysis processes can simplify the processes and reduce redundancy; ( d) criteria must be relevant to the study area and should differentiate between the alternatives; and ( e) outreach should focus on opinion setters and decision makers to gain worthwhile input and to build consensus. By applying the lessons learned in these three MISs, future corridor studies might achieve the successes and avoid the failures illustrated by these three case studies.
Fatigue Cracking in Rigid Airfield Pavements at Large Commercial-Service Airports
Authors: McNerney Michael T. , Frank McCullough B.
Published: April 2007

Fatigue of airport pavements is an important consideration in the analysis of high-traffic pavements. The current pavement condition index (PCI) method of pavement evaluation does not adequately evaluate fatigue cracking of airport pavements and should be considered for modification. Recent field inspections by the authors of Atlanta Hartsfield International Airport, Dallas–Fort Worth International Airport, and Albuquerque International Sunport have shown the fatigue cracking in thick concrete pavements to be prevalent. However, it is not normally recorded in a normal PCI inspection because the crack widths are less than 3 mm (1/8 in.). A properly designed, constructed, and maintained pavement should theoretically fail only in fatigue because all other distresses caused by construction deficiencies, material deficiencies, environmental distresses, and maintenance deficiencies would be avoided. Therefore, it is important for the management of airport pavements that receive high levels of traffic to consider fatiguecracking distress. In practice, it is not possible to sample 100 percent of pavements to fully evaluate all hairline cracking. However, a geographical distribution of pavement control sections can be established and monitored for changes over time. The PCI should be revised or a new distress identification method should be developed to account for fatigue cracking.
International Nature of the Tren Urbano Project in San Juan, Puerto Rico
Authors: William Vigrass J. , González Sergio L.
Published: April 2007

An overview of the Tren Urbano project in San Juan, Puerto Rico, is presented. Phase 1 will be a 17-km rail rapid transit line from Bayamon to Sagrado Corazon in metropolitan San Juan. The line is standard gauge, third-rail-powered, 750-Vdc, rail rapid transit, fully grade-separated. An initial fleet of 64 cars was ordered, and an option for 10 more has been exercised. The project has been bid as a design-build-operate-maintain effort, with Siemens Transportation Systems, Inc., as the prime contractor. Work has been divided into six segments and bid by local contractors. Through the Systems Turnkey and Test Track contract, Siemens is responsible for all systems elements, including cars, power supply, signals, train control and communications, the yard and shop, and about 2 km of main line with two passenger stations. Systems elements are described, with emphasis on their origin in various countries in addition to the United States. The need for Buy America compliance is mentioned. Some car-borne equipment was designed and initial units were built overseas, with most production being done in U.S. plants owned or contracted by the suppliers. By using international sources, Siemens was able to be the lowest bidder and yet provide a quality system to meet the contract requirements.
Beyond Design-Build-Operate-Maintain: New Partnership Approach Toward Fixed Guideway Transit Projects
Authors: Wiss Ronald A. , Roberts Richard T. , David Phraner S.
Published: April 2007

New methods of contractor procurement and project development are evolving. From turnkey to the latest design-build-operate-maintain (DBOM) processes, this evolution focuses on reducing costs, shortening project duration, and better allocating risk among private and public participants. One of the newest developments in the evolving DBOM procurement process is described. The process is being developed and refined in several projects in New Jersey. This new approach is a major change in project initiation and motivation—a more bottom-up, decentralized project development and implementation process. Beginning as a public-private partnership bill (A-2560) in New Jersey’s statehouse, as an effort to quickly advance a wide array of transportation initiatives, the new procurement process modified the state transportation statute to encourage more initiative and participation by the private sector in transportation projects. In consultation with private-sector interests, rail transit operators, and New Jersey Department of Transportation (NJDOT) leaders, the chairman of the Assembly Transportation Committee crafted the bill. After approval by both houses and signature by the governor, the new statute was used to solicite project proposals. Various consortia responded, representing 13 initiatives, two of which are considered rail transit new starts. The North Jersey Rapid Rail (NJRR) proposal, as a case study, demonstrates how the bottom-up, “beyond DBOM” process is working. NJRR is an initiative of a consultant-contractor consortium working with two transit-dependent counties (Bergen and Passaic) and NJDOT. A freight railroad is part of the team. The initiative is a devolution of risk and responsibility to a more local level and a reversion to earlier private partnerships. During the first half of the 20th century, most of the rail transit infrastructure in North America was designed built, operated, and maintained efficiently by private-sector consortia consisting of finance, transit operating, utility, and construction interests. From the vantage point of one millennium ending and a new one beginning, this research is retrospective as well as futuristic.
Miami Downtown People Mover Operations: Initial Segment Versus Full System
Authors: Bondada Murthy V. A. , Fialkoff David R.
Published: April 2007

The Miami, Detroit, and Jacksonville downtown people movers (DPM) were implemented in the United States in 1986, 1987, and 1989, respectively. Because capital at that time was insufficient to build full systems, the most feasible initial segments were built. These segments were the first part of larger DPM networks planned for the downtown areas. In 1994, the Miami system was expanded, and the Jacksonville system is now being expanded. These extensions to the Miami and Jacksonville DPMs will complete the systems as originally planned. Compared with the initial segments, the full systems are expected to improve downtown circulation for both the users of the initial segments, and new riders of the expanded systems. The larger systems also are more cost-effective in construction and operation than the smaller systems (initial segments). The Miami DPM, known locally as the Metromover, is the first DPM in the United States. Its initial segment operated for 8 years (1986–1994), and the full system has operated since 1994. The operations of the initial and full systems are compared to assess the increased downtown circulation and cost-effectiveness with respect to capital and operating costs.
Capital Costs and Ridership Estimates of Personal Rapid Transit
Authors: Yoder Supin L. , Weseman Sidney E. , DeLaurentiis John
Published: April 2007

Preparing capital cost estimates for new transit technologies requires refining and refitting traditional estimation tools. The personal rapid transit (PRT) system project in Rosemont, Illinois—a suburb of Chicago near O’Hare International Airport—required (1) the development of estimates of PRT capital costs, (2) establishment of a reasonable cost range for the PRT system, and (3) an order-of-magnitude evaluation of existing cost projections. A method was developed to compare PRT system components (versus the entire system) with the components of existing automated-guideway transit (AGT) and automated people mover (APM) systems in North America. Seven components of the PRT, AGT and APM systems were examined—(1) guideways; (2) stations; (3) maintenance and control facilities; (4) power and utility systems; (5) vehicles; (6) command, control, and communications systems; and (7) engineering and project management. Three analysis techniques were used—(1) statistically significant regression analysis; (2) measurement of a central tendency for “comparable” systems; and (3) statistics from all AGT systems. The results show that the combination of the three techniques worked well for component-level studies and show promise for use in other cost analyses involving new technologies or application of existing technologies on a scale outside the bounds of previous experience. In addition to the cost study, a PRT ridership forecasting approach and projections were evaluated, providing another key element of decision support for potential PRT deployment in Rosemont.
No Turns Allowed: Controlling Vehicles Turning in Front of Light Rail Vehicles
Authors: Farrán José I.
Published: April 2007

A key attribute of light rail transit (LRT) is its ability to integrate well into urban environments, sharing the public right-of-way with motor vehicles, bicycles, and pedestrians. This characteristic has made LRT very successful in urban corridors that require a high-capacity mode of transportation operating in a shared (on-street or mall) right-of-way environment. Although LRT is an inherently safe mode of transportation, accidents do occur. Such accidents negatively affect not only the parties involved, but also the operation of the entire LRT system and the reputation of the transit property. LRT accident data indicate that the most prevalent type of light rail vehicle (LRV)-motor vehicle accident occurs when motor vehicles turn left or right across LRT tracks and collide with an LRV rapidly approaching the intersection. Five of the most-common types of such accidents are identified, and traffic control devices and techniques are recommended to improve safety by conveying to the motorist the higher level of risk in violating a left or right turn signal prohibition.
Washington State Ferries: Performance Measures and Information Support
Authors: Gihring Celine K. , Greene William
Published: April 2007

Washington State Ferries’ (WSF) newest performance measures emanate from broader issues in transportation planning and a public mood toward less government. A multimodal transportation perspective and program accountability are now key concepts in management within Washington State government. The development of performance measures is guided by WSF’s strategic plan, which sets out the mission, goals, and strategic initiatives of the organization. The process uses three techniques to maximize success—alignment (of goals, measures, and actions), feedback, and oversight. Although the final set of performance measures leaves room for improvement, particularly with regard to output versus outcome, these measures represent significant change for WSF. Performance measurement makes WSF accountable to the ferry rider and the taxpayer. Implementation of performance measures soon leads to the issue of data support and information systems. The goal of measurement is decision support. Without good data or a good information system that manages the data, the decision support function is nullified. The ferry system has had variable experience in information technology projects. Taking advantage of lessons learned and using a comprehensive, deliberate approach, WSF is proposing an information model that uses industry best practices and a user-driven system.
Pedestrian Travel Potential in Northern New Jersey: A Metropolitan Planning Organization’s Approach to Identifying Investment Priorities
Authors: Matley Ted M. , Goldman Lois M. , Fineman Brian J.
Published: April 2007

At metropolitan planning organizations such as the North Jersey Transportation Planning Authority (NJTPA), planning investments to support pedestrian trips for a large and diverse metropolitan area would be an intractable challenge without an open, coordinated, and cooperative approach and a strong information foundation. To address this challenge, NJTPA has adopted an innovative approach using regional analysis and priority setting to guide planning activity for a very local scale. The design and initial applications of this approach are described. Areas with proximity and connectivity features supporting pedestrian activity were identified using data available at the regional level. The data were analyzed within a pedestrian potential index (PPI) comprising four key indicators: population densities, employment densities, land use mix, and street network density, all analyzed at the census tract level. Thresholds were set to begin to find priority areas in which investment in pedestrian strategies would be more likely to generate a high return in terms of walking trips generated. The analysis also allows local planners to understand how their communities compare in relative levels of density, land use mix, and network connectivity. This information can help planners identify areas for planning activities that would address these factors and encourage walking trips. With the first results from application of the PPI, NJTPA has solicited feedback from state and local planning partners. With subsequent refinement, this analysis will be finalized for the region and incorporated in the next update of the NJTPA Regional Transportation Plan.
Automated Detection of Pedestrians in Conjunction with Standard Pedestrian Push Buttons at Signalized Intersections
Authors: Hughes Ronald , Huang Herman , Zegeer Charles , Cynecki Michael
Published: April 2007

Automated pedestrian detection systems provide the means to detect the presence of pedestrians as they approach the curb prior to crossing the street, and then these systems call the Walk signal without any action required on the part of the pedestrians. These detectors can also extend the clearance interval in order to allow slower persons to finish crossing. Whether automated pedestrian detectors, when used in conjunction with standard pedestrian push buttons, would result in fewer overall pedestrian-vehicle conflicts and fewer inappropriate crossings (i.e., pedestrians’ beginning to cross during a Don’t Walk signal) was evaluated. Before and after video data were collected at intersection locations in Los Angeles, California (infrared and microwave), Phoenix, Arizona (microwave), and Rochester, New York (microwave). The results indicated a significant reduction in vehicle-pedestrian conflicts, as well as a reduction in the number of pedestrians beginning to cross during the Don’t Walk signal. The differences between microwave and infrared detectors were not significant. Detailed field testing of the microwave equipment in Phoenix revealed that fine-tuning of the detection zone is still needed in order to reduce the number of false calls and missed calls.
Coordinating Traffic Signals for Bicycle Progression
Authors: Taylor Dean B. , Mahmassani Hani S.
Published: April 2007

Traffic signal coordination that provides either ( a) progression for bicycles or ( b) simultaneous progression for bicycles and automobiles traveling on the same facility is analyzed. A conceptual foundation, consisting of three primary contributions, is developed for analyzing bicycleautomobile mixed-traffic progression along signalized streets. First, the principal considerations for bicycle progression are articulated. Second, several concepts and techniques that provide improved (or alternative) multiobjective solutions are presented and analyzed. Third, a multiobjective formulation framework for solving the mixed-traffic design problem is proposed. This framework formally incorporates the elements that were introduced as part of the first two contributions and provides a method to handle the inherent competing objectives of the situation. Additionally, important practical aspects of designing and implementing bicycle progression systems, such as handling bicycle speed variability and selecting appropriate facilities for initial (or test) projects, are identified and discussed.
Creating a Synthetic Household Travel and Activity Survey: Rationale and Feasibility Analysis
Authors: Greaves S. P. , Stopher P. R.
Published: April 2007

Proposed is a new approach for developing the travel survey data required for use in local travel-demand models. Using readily available local sociodemographic information in conjunction with a freely available national travel survey, a simulation procedure is described to create, in effect, a synthetic household travel survey. The reasons for interest in such a procedure are outlined, including the costs and difficulties associated with gathering high-quality travel data. Consideration is then given to alternatives for local model development, such as the use of national data averages and borrowed models. The simulation procedure is then described and tested in a region that has recently completed a travel survey; this provides a direct source of comparison of the merit of the approach. Trip production models are then built using the synthetic data set. The case study results show that the synthetic data ( a) offer significant improvements over the use of borrowed models and ( b) estimate new models that are similar to those same models estimated using the local travel survey data. It is concluded that these results show that the approach has considerable promise. Finally, some future directions are described, including the planned extension of the approach to other regions.
Picking Publics Properly: An Artful Science
Authors: Sarra Comeau Philancy , Rodriguez Donald
Published: April 2007

Choosing appropriate publics in the life cycle of an issue is a critical component for a successful public involvement program. The research presented provides an exploratory analysis of 15 public involvement experts’ experiences, attitudes, and beliefs about this critical process. What factors do experts consider when choosing publics for participation in management decisions? What characteristics of the public and outside influences should be considered? How do experts determine a public’s type and level of involvement? How do experts determine what stage an issue reached in its life cycle? Do these concepts, if not addressed properly during the decision process, lead to unsuccessful public participation programs? Four generalizations were developed from this exploratory analysis: ( a) experts attempt to be as inclusive as possible when choosing publics based on a public’s perceived salience and interest in an issue and group composition; ( b) issue development directly affects how experts choose publics for public involvement processes; ( c) issue development occurs through various communication methods driven by affected values and beliefs; and ( d) improper choices of publics for public involvement processes can lead to failure. A public involvement model is proposed that illustrates the effects of issue development and level of involvement on these processes. Management implications include a necessity to understand how the issue is developing; which underlying affected values and beliefs are driving current communication activities; and the various publics’ perspectives regarding their level of involvement and preferred participation level.
Propensity to Work from Home: Modeling Results from the 1995 Nationwide Personal Transportation Survey
Authors: Drucker Joshua , Khattak Asad J.
Published: April 2007

Working from home is regaining its popularity because of the advantages it presents for both employees and employers. Telecommunications technologies are enabling the new work-at-home phenomena. This study expands the existing body of work-at-home and telecommuting research by using data from the 1995 Nationwide Personal Transportation Survey to consider a larger sample and to include characteristics unavailable in previous analyses. The effects of socioeconomic, household, locational, and accessibility variables on individuals’ choices to work from home are estimated with ordered logit, ordered probit, and multinomial logit models, using a two-equation sample selection regression process. The three models give very similar results. They indicate that educational attainment and the presence of small children in the household encourage frequent working from home. Males and drivers choose to work from home more often than females or nondrivers, and the lack of free parking at work promotes home work. These findings bear implications for trip-generation forecasting and suggest directions for policies intended to influence commute travel.
Forecasting and Assessing the Mobility Effects of Teleservices: Scenario Approach
Authors: Martens M. J. , Korver W.
Published: April 2007

The information society is approaching; everything will change. New technology could enable commuters to decrease their number of physical trips. As a result of all kinds of new information and communication technology (ICT) services, it will be possible to live in the countryside and remain working in the city, 200 km (124 mi) away. The literature, especially scientific and empirical sources, however, tempers these expectations. The effects are limited, and there could be substantial side effects in the opposite direction, which could nullify the substitution effect. Given the discrepancies between expectations, one of the most important aspects of forecasting teleservices is uncertainty. This high uncertainty combined with high expectations often results in quasiaccurate forecasts or oversimplified speculation. The most important restriction in the many forecasts is the lack of complete and consistent future scenarios. A study that tried to address these restrictions by developing a scenario approach is reported. The approach is elaborated, using telecommuting as a case study. The study’s main conclusion is the confirmation that it is possible and useful to incorporate ICT services such as telecommuting into a scenario approach. The outcomes have additional value compared with estimates from literature because the magnitude of possible effects is considered instead of quasiaccurate predictions, the estimates are based on realistic and consistent societal scenarios, and the use of an operational transport model makes it possible to include second-order effects such as induced travel.
Selection of a Traffic Control Strategy for Long-Range Travel Forecasting
Authors: Horowitz Alan J. , Granato Sam
Published: April 2007

The problem of determining the number and placement of signals on traffic networks for long-range urban travel forecasting is addressed. An algorithm for determining the signalization strategy was developed and given a large-scale test on the network for a metropolitan area of about 150,000 people. The algorithm attempts to mimic the actions of traffic engineers as they make adjustment to the traffic system over a long period of time. Tests indicate that the algorithm produces a network that closely approximates one that has been optimized for vehicle hours traveled but still respects safety and fairness issues. The algorithm is highly computational, so limits needed to be arbitrarily placed on the precision of the traffic forecast, the precision of optimization steps, and the number of intermediate forecast years.
Development of a Statewide Truck Trip Forecasting Model Based on Commodity Flows and Input-Output Coefficients
Authors: Sorratini Jose A. , Smith Robert L.
Published: April 2007

This research attempts to improve the modeling of statewide truck travel demand models by using commodity flow data from the U.S. Census Bureau, a private freight database (TRANSEARCH), and input-output (I-O) coefficients. The standard urban transportation planning modeling process was applied at the state level to estimate heavy truck trips. Economic-based I-O software was used to derive the I-O direct matrix and the I-O direct coefficients at the state level for developing the trip attraction rates for 28 manufacturing sectors. The Commodity Flow Survey from the U.S. Census Bureau together with a private database developed for Wisconsin were used to develop the trip production rates. Transportation planning software (TRANPLAN) was used to distribute and assign truck trips generated at the zonal level. The selected-link function in TRANPLAN was used to adjust the initial productions and attractions in order to generate link volumes that match the actual ground counts for 40 selected links. The model only required two iterations of the selected link analysis in order to produce an acceptable match with the ground counts, compared with three iterations for two prior similar models. The rapid convergence provides clear evidence that the disaggregate trip generation models give better initial estimates of trip productions and attractions than was possible with the prior studies. A “back forecast” of 15 years to the year 1977 was found to be reasonable both in terms of the percent root mean square error by volume group and the performance measures for five screen lines.
External Urban Truck Trips Based on Commodity Flows: A Model
Authors: Fischer Michael , Ang-Olson Jeffrey , La Anthony
Published: April 2007

A procedure is described for incorporating interregional (external) heavy-duty truck trips in a regional travel-demand forecasting model. The procedure was developed as part of a comprehensive truck modeling effort conducted by the Southern California Association of Governments. The procedure is based on commodity flow forecasts and economic input-output modeling techniques. County-level commodity flows are disaggregated to the transportation analysis zone level using employment data, land use data, and commercial facility data. Input-output models are used to determine the portion of each inbound commodity that goes to final demand by consumers and the use of each commodity by industry sectors. Commodity flows then are converted to truck trips using commodity-specific estimates of the portion of tonnage carried in each truck weight class and the average truck payload for each weight class. These estimates are developed using data from the federal Truck Inventory and Use Survey and some truck origin-destination surveys performed at cordon points around the region. The model produces a set of trip tables that can be assigned to the regional roadway network using standard assignment techniques.