bluuebunny/crossref_metadata_2025 huggingface dataset:
Regional Concept for Transportation Operations
Authors: Berman Wayne , Smith Michael , Bauer Jocelyn K.
Published: May 2018

A regional concept for transportation operations (RCTO) presents a regional objective and what is needed to achieve that objective within a reasonably short time frame, possibly 3 to 5 years. It is a description of the desired state for transportation operations presented as an operations objective accompanied by a set of physical improvements that need to be implemented, relationships and procedures that must be established, and resource arrangements that are needed to accomplish the operations objective. An RCTO is created out of ongoing collaboration, primarily between managers responsible for operating the transportation system on a day-to-day basis, such as those for traffic operations, transit service, and public safety. Development of an RCTO should include participation by the regional planning organization to ensure consistency with the region's vision and goals. The scope of an RCTO reflects the nature of the collaborative activity. It guides the collaborative efforts of individual participants through a common approach to achieve a common objective. An RCTO can address a single service (e.g., traffic incident management, traveler information services, or electronic fare payment), a collection of related services (e.g., congestion management for arterials and freeways), or capabilities that cut across several services (e.g., wireless communications network, surveillance and control systems, or vehicle detection and locator systems). In addition, an RCTO can stimulate further collaborative activity, for example, expansion of incident management to include emergency management. An RCTO serves three important purposes: ( a) presentation of an operations vision and direction for the future of transportation systems management and operations based on a holistic view of the region; ( b) commitment from agencies and jurisdictions for a common regional approach to transportation management and operations, and ( c) an opportunity to strengthen the linkage between regional planners and managers responsible for transportation operations by providing a coherent operations strategy for consideration in the planning process. An RCTO can be used as significant input into the ongoing regional transportation planning and investment process by communicating with transportation planners about regional management and operations funding needs.
Performance of Transit Signal Priority with Queue Jumper Lanes
Authors: Zhou Guangwei , Gan Albert
Published: May 2018

Queue jumper lanes are a special type of bus preferential treatment that allows buses to bypass a waiting queue through a right-turn bay and then cut out in front of the queue by getting an early green signal. The performance of queue jumper lanes is evaluated under different transit signal priority (TSP) strategies, traffic volumes, bus volumes, dwell times, and bus stop and detector locations. Four TSP strategies are considered: green extension, red truncation, phase skip, and phase insertion. It was found that queue jumper lanes without TSP were ineffective in reducing bus delay. Queue jumper lanes with TSP strategies that include a phase insertion were found to be more effective in reducing bus delay while also improving general vehicle operations than those strategies that do not include this treatment. Nearside bus stops upstream of check-in detectors were preferred for jumper TSP over farside bus stops and nearside bus stops downstream of check-in detectors. Through vehicles on the bus approach were found to have only a slight impact on bus delay when the volume-to-capacity (v/c) ratio was below 0.9. However, when v/c exceeded 0.9, bus delay increased quickly. Right-turn volumes were found to have an insignificant impact on average bus delay, and an optimal detector location that minimizes bus delay under local conditions was shown to exist.
Analysis of Variations in Vehicle Ownership Expenditures
Authors: Thakuriah Piyushimita (Vonu) , Liao Yihua
Published: May 2018

There is significant concern about the high cost of vehicle ownership, although several authors have acknowledged in the literature that owning and operating a vehicle have accessibility benefits. This paper uses Consumer Expenditure Survey data to explore vehicle ownership expenditures of American households. Differences in vehicle ownership expenditures among urban and rural households are estimated in different regions of the United States, controlling for socioeconomic, demographic, life cycle, and other household factors. First, patterns in vehicle ownership expenses are examined over a year. Three models of expenditures for vehicle ownership are estimated: the first model is estimated by ordinary least squares, the second is a Tobit model estimated to take into account zero expenditures on vehicles by a segment of households during the survey year, and the third model is a two-stage sample selection model that explicitly models first the household vehicle ownership decision and then, given that first decision, the expenditure intensity decision for the subsample of households that own vehicles. It was found that locational and regional effects were not constant but that urban–rural differences depended on region, and differences among regions depended on whether a household was located in an urban or a rural area.
Analysis of Factors Affecting the Frequency and Type of Activity Schedule Modification
Authors: Joh Chang-Hyeon , Doherty Sean T. , Polak John W.
Published: May 2018

There is growing interest among the travel behavior community in activity scheduling and rescheduling behavior. This paper reports an analysis of activity modification behavior using extensive data for activity scheduling and rescheduling collected from a recent survey. Models that are developed describe the frequency and type of schedule modification. The analysis indicates that activity location and coscheduling with peers were much less frequently modified than activity timing and duration and that the degree of spatial flexibility of an activity plays an important role. The implications of these findings both for the modeling of scheduling and rescheduling behavior and for the development of scheduling support tools are discussed.
Are Car Users Too Lazy to Walk?
Authors: Loukopoulos Peter , Gärling Tommy
Published: May 2018

The present study tested the hypothesis that frequent driving makes people averse to exerting physical effort through walking. In support of the hypothesis, the decrease in distance thresholds for driving associated with an increase in driving frequency was partially mediated by a measure of perceived exertion. Policy implications of the results are discussed with the suggestion that potentially effective means to decrease the frequency of short automobile trips may be through land-use planning strategies and demarketing strategies for car use.
Do Telecommunications Affect Passenger Travel or Vice Versa?
Authors: Choo Sangho , Mokhtarian Patricia L.
Published: May 2018

This study explores the aggregate causal relationships between telecommunications and travel in a comprehensive framework, considering their demand, supply, and costs, together with land use, economic activity, and sociodemographic variables. On the basis of a hypothesized conceptual model, composite indexes were developed for endogenous variable categories (telecommunications and travel demand, supply, costs, land use, and economic activity) by confirmatory factor analysis, with the use of national time series data (1950–2000) in the United States. Then, single-equation and structural equation models for telecommunications (telephone calls and mobile phone subscribers, separately) and travel were estimated, with the composite indexes and sociodemographic measures used as explanatory variables. Overall, the model results suggest that the aggregate relationship between actual amounts of travel and telecommunications is complementarity, not substitution. That is, as telecommunications demand increases, travel demand increases, and vice versa. In addition, it was found that the causal effects of travel demand on telecommunications demand were larger than those in the reverse direction.
Empirical Investigation of Online Searching and Buying and Their Relationship to Shopping Trips
Authors: Farag Sendy , Schwanen Tim , Dijst Martin
Published: May 2018

Searching product information or buying goods online is becoming increasingly popular and could affect shopping trips. However, the relationship between e-shopping and in-store shopping is currently unclear. The aim of this study is to investigate empirically how the frequencies of online searching, online buying, and nondaily shopping trips relate to each other, after controlling for sociodemographic, land use, behavioral, and attitudinal characteristics. Data were collected from 826 respondents residing in four municipalities (one urban, three suburban) in the center of the Netherlands, with the use of a shopping survey. Path analysis was used to model direct and indirect effects. The findings suggest that complementarity or generation between e-shopping and in-store shopping appears to be more likely than substitution. The more often people search online, the more shopping trips they tend to make. Individuals who frequently search or buy online tend to be male, young, single, adventurous, and frequent Internet users; have a high income; and have a positive attitude toward e-shopping. The residential environment affects e-shopping indirectly via Internet use; urban residents shop online more often than suburban residents do because urban residents use the Internet more often. Frequent in-store shoppers tend to be female and highly educated, have a high income, have no car, and have a positive attitude toward in-store shopping. It appears that for most individuals e-shopping is just another way of shopping, complementary to their in-store shopping.
Bus Rapid Transit and Light Rail
Authors: Bruun Eric
Published: May 2018

A parametric cost model was developed to provide both average and marginal cost estimates and to compare annual operating costs for light rail transit (LRT) and bus rapid transit (BRT) under an assumption of additional peak service on weekdays. The model uses readily available data from the U.S. National Transit Database. For illustrative purposes, it is applied to a hypothetical service network simulating universal coverage of a medium-sized metropolitan area with either LRT or BRT operating on trunk lines. The Dallas [Texas] Area Rapid Transit agency is selected for a computational example because it has representative, contemporary performance statistics for both LRT and bus. High and low operating cost estimates based on articulated buses were used for BRT because of a lack of an operational history. For an agency with a similar cost structure to the Dallas agency, both BRT and LRT have lower operating costs on a per space kilometer basis during base periods than do regular buses. Both LRT and the lower BRT cost estimates are comparable for adding service during peak periods. With the higher cost estimate, peak BRT costs 24% more than LRT. For trunk line capacities below about 1,600 spaces per hour, the headway-versus-cost trade-off favors BRT. Above 2,000 spaces per hour, BRT headways become so short that traffic signal priority may not be effective and revenue speed may decrease. The marginal cost of adding off-peak BRT service is substantially less than the average cost of regular buses, and the cost of LRT is even less. Peak fleet size seems to be an important driver of costs. Research methods to verify this are suggested.
Light Rail Lite or Cost-Effective Improvements to Bus Service?
Authors: Hess Daniel B. , Taylor Brian D. , Yoh Allison C.
Published: May 2018

Bus rapid transit (BRT) is growing rapidly in popularity because it is viewed widely as an efficient and effective means to improve both transit service and patronage. This paper argues that two distinct views of BRT are emerging: ( a) BRT as a new form of high-speed, rubber-tired, rail-like rapid transit and ( b) BRT as a cost-effective way to upgrade both the quality and image of traditional fixed-route bus service. These two views carry different price tags because the cost of planning, constructing, and operating BRT depends on the complexity of new service features and on rises for BRT that offer service characteristics approaching those of light rail. This study fills a gap in the literature on the costs of BRT by examining in detail component costs–-actual costs for recently implemented services and projected costs for planned new services–-for a sample of BRT systems in North American cities. The study examined BRT costs of 14 planned and recently opened BRT systems to determine how the wide range of BRT service and technology configurations affect costs. The study found that although some of the most successful and popular new BRT systems are high-quality services operating in mixed traffic and implemented at relatively low cost, most BRT projects on the drawing boards are more elaborate, more expensive systems than many currently in service. Most new BRT projects emphasize elaborate LRT-type improvements to lines and stations in one or a few corridors rather than less splashy improvements (such as next-bus monitors, signal preemption, queue-jump lanes, and so forth) affecting more lines and modes in local transit networks. Among the 14 systems examined here, most could be characterized as light rail lite.
Study of Park-and-Ride Facilities and Their Use in the San Francisco Bay Area of California
Authors: Shirgaokar Manish , Deakin Elizabeth
Published: May 2018

Park-and-ride lots are important support facilities for transit and ride-sharing in the San Francisco Bay Area of California. The authors designed and carried out the region's first large-scale, detailed study of park-and-ride facilities and users. Three Bay Area Rapid Transit (rail) station parking lots were also surveyed. The user survey results showed that almost all the parking users were commuters; at the freeway lots, half were transit users and the remainder were organized and casual car-poolers. Most drove alone to the park-and-ride lot and made long trips to work, many more than 30 mi one way. Users had concerns about lot security, the lack of lighting, and the quality of transit services offered. Analysis of focus group data determined that schedule adherence rather than frequency was the cause of most concerns. Participants expressed a willingness to pay for parking that was fenced, security patrolled, and lighted, with shelters for waiting. Together, the surveys and focus groups have provided insights into ways to improve the park-and-ride lots and the services offered there, as well as on how travelers view transit and carpooling options. The results provide a sound basis for planning improvements.
PhillyCarShare
Authors: Lane Clayton
Published: May 2018

One year into a carsharing program in Philadelphia, Pennsylvania, compelling evidence of reduced vehicle ownership, reduced vehicle miles traveled (VMT), and social change was uncovered through member surveys and detailed usage data. Each PhillyCarShare vehicle replaced an average of 23 private vehicles. Members giving up cars overwhelmingly reported driving less and replacing automobile trips with a variety of modes (transit, walking, taxi, and to a lesser extent biking). However, members who simply gained access to cars used PhillyCarShare primarily to substitute for modes that most resemble driving (taxis, borrowing or renting, and to a lesser extent transit). The average monthly VMT increase of members gaining access to a car was limited to 29.9 mi, whereas the monthly VMT decrease of members who gave up a car appeared to be several hundred miles but not greater than 522 mi. After joining, PhillyCarShare members made travel decisions more judiciously, expressed greater awareness of transportation costs, and valued environmental friendliness far more than previously. Members also preferred residential locations near PhillyCarShare locations. Motivation for joining varied greatly by income, eventual change in car ownership, and age. Convenience was valued highly by all groups, especially former car owners. Affordability was usually second most important. Comparison with other U.S. carsharing organizations revealed advanced education to be the strongest demographic of membership, followed by nonauto commuting and living in small or nontraditional households. In contrast to Europe's early members, American first adopters appeared more concerned with personal utility than social or environmental benefits; they were motivated more by convenience and less by affordability, possibly because of much lower costs of driving in the United States.
Impact of Transit Fare Increase on Ridership and Revenue
Authors: Hickey Robert L.
Published: May 2018

On May 4, 2003, the Metropolitan Transportation Authority's New York City Transit subsidiary (NYCT) raised its subway and bus fares for the first time since discounted and unlimited-ride MetroCards (electronic fare cards) were introduced between July 1997 and January 1999. Before the 2003 fare increase, the agency did not have any experience with either the direct ridership effects of price changes for unlimited-ride passes or the shift of customers when prices of different fare media increased at different rates and customers could shift from one fare medium to another. Partly on the basis of work done by other transit agencies, NYCT developed a spreadsheet model that used direct fare elasticities to estimate absolute ridership loss and used trip diversion rates (similar to cross-elasticities) to estimate the likelihood that passengers would shift from a fare instrument with a larger percentage increase to one with a smaller increase. The actual shift of customers between fare instruments after the fare increase was greater than projected, with the result of a lower than expected systemwide average fare. The negative revenue impact from the lower average fare was mostly offset by a lower than expected ridership decline. The estimated fare elasticities were below the average of historical NYCT fare elasticities and suggest that customers using unlimited-ride passes were less sensitive to fare changes.
Elastomeric Bearings for Steel Trapezoidal Box Girder Bridges
Authors: Bradberry Timothy E. , Cotham Jeffery C. , Medlock Ronald D.
Published: May 2018

Traditionally, bridge bearings supporting steel trapezoidal box girders (tub girders) consist of fabricator-designed mechanical devices, such as pot or disc bearings, that may be guided or unguided and are expensive to fabricate and place. Performance of these bearings has been mixed: some are maintenance-free and others require significant maintenance, repair, or replacement. In Texas, bridge bearings supporting concrete and steel superstructure types are typically steel-laminated elastomeric bearings that are tapered or have a constant thickness. Recently, the Texas Department of Transportation has used these structurally engineered elastomeric bearings for tub girders in place of mechanically engineered pot or disc bearings. This paper describes the rationale for the application of elastomeric bearings to tub girders and outlines design recommendations that are based on the use of elastomeric bearings for the tub girder direct connectors of the interchange of US-290 and I-35 built in Austin in the late 1990s and placed in service in 2001.
Design of Cantilevered Overhead Sign Supports
Authors: Fouad Fouad H. , Calvert Elizabeth
Published: May 2018

The AASHTO 2001 Standard Specifications for Structural Supports for Highway Signs, Luminaires and Traffic Signals include revised wind load provisions and new criteria for fatigue design. These provisions and criteria differ considerably from those in previous editions of the specifications, and their impact on the design of cantilevered overhead sign supports has not been fully studied. This study assesses the effect of these provisions and criteria on the design of cantilevered overhead sign support structures with the horizontal support composed of a four-chord truss. Wind and fatigue load design calculations of typical structures, located at sites across the United States, were performed with the design provisions of the 2001 supports specifications and compared with design in accordance with the previous edition of the specifications. The induced forces in the primary members of the cantilevered sign support structure were calculated, and corresponding member sizes and weights were estimated. The results of the study demonstrated the effect of the wind and fatigue load provisions on the design of cantilevered overhead sign support structures.
The 17th Street Bridge in Atlanta, Georgia
Authors: Jeakle David L.
Published: May 2018

The new 17th Street Bridge provides a vital link between midtown Atlanta, Georgia, and the proposed Atlantic Station development. The project was presented to the community as an opportunity to create a signature structure for Atlanta–-a gateway into the city. The community was extensively involved in the development of the bridge. Through a series of community workshops, focus groups, and architectural task groups, the bridge was defined and detailed, and pedestrian mobility and safety were the focus of the final product. The resulting bridge, though significantly different from the original vision, has met with approval from the community.
Design and Field Monitoring of Horizontally Curved Steel Plate Girder Bridge
Authors: Domalik Daniel E. , Shura Jason F. , Linzell Daniel G.
Published: May 2018

Bridge 207 is a two-span horizontally curved steel plate girder bridge near Port Matilda, Pennsylvania. Although the curvature is not severe, the curvature combined with the unequal span balance caused an unusual distribution of force effects in the girders. A global twisting of the superstructure was caused by the unequal vertical deflections in the two spans. The computer program BSDI-3D was used to analyze the curved superstructure. To account for the out-of-plumb condition of the girders in their final condition, additional lateral flange bending moments were calculated. The magnitude of the additional lateral moments was a function of the vertical bending moments and the degree of twist in the girder. Field monitoring of the structure is focusing on the effects of curvature during construction. This is being accomplished by developing a detailed time line of superstructure erection and deck placement and through monitoring of the bridge by using vibrating wire strain gauges and tiltmeters positioned at critical locations on the girders and cross-frames. Field data were recorded before and after critical construction events, such as girder erection, cross-frame and formwork placement, and the deck pour. This information is being used to determine the effects of curvature on the cross-frames during construction by using axial stresses and strains and on the girders by using warping stresses and strains.
Alternate Approach to Approximating Deteriorated Steel Beam End Capacity
Authors: Van De Lindt John W. , Ahlborn Theresa M. , Kethu Sridhar
Published: May 2018

Corrosion of steel beams caused by deicing media is a common problem in northern and mountainous regions of the United States. A common problem is deterioration of steel beam ends in the web and flange near or directly above the bearing area. This results in decreased shear capacity, web-crippling, and web-buckling capacity. This paper presents the results of a study sponsored by the Michigan Department of Transportation (MDOT) to provide the structural analyst with a simplified, accurate, rapid, and slightly conservative approach for computing the reduced capacity of a rolled steel section. The approach is based on the results of several hundred three-dimensional finite element analyses for a suite of 16 typical steel bridges. The most common shapes and locations for steel beam end deterioration were identified by reviewing detailed inspection reports. Finite element analyses for the steel beam ends with simulated damage of various sizes and shapes was performed with the finite element software ABAQUS. A small experimental program focused on a selected beam to check the validity and accuracy of the finite element approach. Design charts were developed for an array of damage cases, which enable the analyst to simply apply a factor to the undamaged buckling capacity of the beam. The approach is compared to MDOT's current technique to demonstrate its efficiency and potential cost savings.
Live Load Deflection Performance of Glued Laminated Timber Girder Bridges
Authors: Hosteng Travis , Phares Brent , Wipf Terry , Ritter Mike , Wood Doug
Published: May 2018

To demonstrate and possibly to promote the increased use of timber bridges in U.S. transportation systems, various agencies, including the United States Department of Agriculture Forest Products Laboratory and FHWA, have supported research to develop improved glued laminated timber bridges. This project is part of this research and identifies acceptable live load deflection characteristics of timber bridges. The relationship between live load deflection and the condition of the asphalt wearing surface is of particular interest. To accomplish this, eight glued laminated timber girder bridges were selected for testing. The performance of the bridges was investigated under live load tests and through bridge inspections. The structures were load tested with fully loaded tandem-axle dump trucks, and global and differential deflection data were collected. Field tests revealed that a significant amount of the asphalt wearing-surface deterioration is the result of differential deck panel deflection.
Simple Rating System for Identification of Failure-Critical Culverts and Small Structures
Authors: Wissink Katherine , McKee Meghan , Houghtalen Robert , Sutterer Kevin
Published: May 2018

Although bridges are a highly visible and crucial part of the highway infrastructure, smaller structures typically classified as culverts exist in even greater numbers. Nearly invisible to the public, culverts are crucial components of highways. Failure of culverts can lead to flooding, roadway damage, interruption of traffic, and even fatal accidents. Several states have implemented successful culvert inspection programs, but others are only beginning to formalize their culvert inspection and maintenance. Even after periodic inspection programs are in place, planners need a tool for consistent guidance to identify structures most in need of attention. This paper reports on a simple rating system based on a new culvert inspection program recently implemented by the Indiana Department of Transportation. The rating system uses weighting factors that can be adjusted by the user to provide an overall rating of a culvert based on ratings of specific characteristics of a culvert. The tool can be used to provide a consistent comparison with other culverts across the state and to provide quality control of the inspectors’ overall rating as entered into a database.
Effect of Coarse Aggregate Morphology on the Resilient Modulus of Hot-Mix Asphalt
Authors: Pan Tongyan , Tutumluer Erol , Carpenter Samuel H.
Published: May 2018

The resilient modulus measured in the indirect tensile mode according to ASTM D 4123 reflects effectively the elastic properties of asphalt mixtures under repeated load. The coarse aggregate morphology quantified by angularity and surface texture properties affects resilient modulus of asphalt mixes; however, the relationship is not yet well understood because of the lack of quantitative measurement of coarse aggregate morphology. This paper presents findings of a laboratory study aimed at investigating the effects of the material properties of the major component on the resilient modulus of asphalt mixes, with the coarse aggregate morphology considered as the principal factor. With modulus tests performed at a temperature of 25°C, using coarse aggregates with more irregular morphologies substantially improved the resilient modulus of asphalt mixtures. An imaging-based angularity index was found to be more closely related to the resilient modulus than an imaging-based surface texture index, as indicated by a higher value of the correlation coefficient. The stiffness of the asphalt binder also had a strong influence on modulus. When the resilient modulus data were grouped on the basis of binder stiffnesses, the agreement between the coarse aggregate morphology and the resilient modulus was significantly improved in each group. Although the changes in aggregate gradation did not significantly affect the relationship between the coarse aggregate morphology and the resilient modulus, decreasing the nominal maximum aggregate size from 19 mm to 9.5 mm indicated an increasing positive influence of aggregate morphology on the resilient modulus of asphalt mixes.
Assessment of Distress in Conventional Hot-Mix Asphalt and Asphalt–Rubber Overlays on Portland Cement Concrete Pavements
Authors: Rodezno Maria Carolina , Kaloush Kamil E. , Way George B.
Published: May 2018

The purpose of this study is to assess the way distresses are predicted by using the new Mechanistic–Empirical Design of New and Rehabilitated Pavement Structures (design guide), developed under NCHRP Project 1–37A. Two pavement sections were used: a conventional hot-mix asphalt reconstruction and an asphalt–rubber overlay on a portland cement concrete (PCC) pavement. The design guide does not include rehabilitation design for asphalt–rubber overlays. However, many large-scale asphalt–rubber overlays on interstate highways in Arizona have been built and monitored for performance, providing an opportunity to determine to what degree the design guide can predict their performance. The input data for both types of pavements were derived from two different projects on the same highway, Interstate 40. The actual data measurements that summarize the pavement performance were compared with calculated values obtained by using the design guide. Three pavement performance parameters were evaluated on the basis of the available data: rutting, cracking, and international roughness index (IRI). Rutting was one of the distresses that the design guide predicted more accurately. The fatigue cracking prediction, evaluated with Level-3 data input, was not accurate; future analysis should consider calibrated fatigue models for the different mixtures. The predicted IRI results differed from the actual measured field performance because of inaccurate distress prediction. The Arizona experience using asphalt–rubber overlays to rehabilitate aged PCC pavements has been successful. For that reason, a calibration process that allows the use of the asphalt–rubber mixtures in the design guide should be considered in the future.
Predicting Field Permeability from Testing Hot-Mix Asphalt Specimens Produced by Superpave Gyratory Compactor
Authors: Kanitpong Kunnawee , Bahia Hussain , Russell Jeffery , Schmitt Robert
Published: May 2018

This study was conducted to develop laboratory and field permeability testing procedures for design and quality control of Superpave® mixtures in Wisconsin. Sixteen mixes including fine-graded and coarse-graded mixes were evaluated. The in-place field permeability was measured by using the National Center for Asphalt Technology (NCAT) device, field cores were taken for measuring permeability in the laboratory by using the ASTM D5084 method, and laboratory compaction was used to prepare and test samples from loose mixtures recovered from the field. Two compaction procedures called Method A and Method B were used in this study to produce Superpave gyratory compacted (SGC) specimens that have thickness, air voids, and aggregate orientation similar to the field cores. Result indicates that Method B, based on the use of Ndesign gyrations for different sample sizes, can be used to produce samples that give permeability values similar to values measured for field cores. Results of this study also indicate a good relationship between field permeability (using the NCAT device) and lab permeability measured on field cores of fine-graded mixes with the amount passing No. 8 sieve (P8) higher than 45%. However, the relationship between field permeability and lab permeability measured on field cores of coarse-graded mix (P8 lower than 40%) is poor. It is concluded that the NCAT permeability device could possibly be used in the field for fine-graded mix (with P8 higher than 45%). However, to measure the field permeability of coarse-graded mix (P8 lower than 40%), there appears to be no current alternative better than taking field cores and testing them in the laboratory. For estimating permeability during mixture design, a simple method for preparing and testing permeability of SGC specimens and interpolating based on expected field density is introduced.
Investigation of the Fracture Resistance of Hot-Mix Asphalt Concrete Using a Disk-Shaped Compact Tension Test
Authors: Wagoner Michael P. , Buttlar William G. , Paulino Glaucio H. , Blankenship Philip
Published: May 2018

In recent years the transportation materials research community has focused a great deal of attention on the development of testing and analysis methods to shed light on fracture development in asphalt pavements. Recently it has been shown that crack initiation and propagation in asphalt materials can be realistically modeled with cutting-edge computational fracture mechanics tools. However, much more progress is needed toward the development of practical laboratory fracture tests to support these new modeling approaches. The goal of this paper is twofold: ( a) to present a disk-shaped compact tension [DC(T)] test, which appears to be a practical method for determining low-temperature fracture properties of cylindrically shaped asphalt concrete test specimens, and ( b) to illustrate how the DC(T) test can be used to obtain fracture properties of asphalt concrete specimens obtained from field cores following dynamic modulus and creep compliance tests performed on the same specimens. Testing four mixtures with varied composition demonstrated that the DC(T) test could detect the transition from quasi-brittle to brittle fracture by testing at several low temperatures selected to span across the glass transition temperatures of the asphalt binder used. The tendency toward brittle fracture with increasing loading rate was also detected. Finally, the DC(T) test was used in a forensic study to investigate premature reflective cracking of an isolated portion of pavement in Rochester, New York. One benefit of the DC(T) test demonstrated during testing of field samples was the ability to obtain mixture fracture properties as part of an efficient suite of tests performed on cylindrical specimens.
Assessing Transit Changes in Columbus, Ohio, and Sacramento, California
Authors: Schumann John
Published: May 2018

This paper compares the changes experienced by transit systems in two state capitals of similar size: Columbus, Ohio, and Sacramento, California. Over the past two decades, Sacramento added a light rail transit (LRT) starter line and experienced significant ridership growth on its multimodal rail and bus system, while Columbus remained all-bus and experienced a decline in patronage. Reasons underlying the divergent performances of these two systems are analyzed and discussed. It is concluded that, in Sacramento, willing political leadership took good advantage of a one-time opportunity for federal funding to build an LRT starter line; that adding LRT made transit more visible and effective and encouraged voter approval of additional local operating and capital funding; and that all of this resulted in a synergy that attracted more riders to the total LRT and bus transit system and led to extension of the rail system to a third corridor in 2003. Although planning for LRT was begun in Columbus during these same years, a serious interruption in the flow of local funds hampered transit development, required cuts in bus service, and prevented development of that region's planned LRT line. Columbus currently has an LRT project in preliminary engineering, and recent reports suggest a consensus to proceed may be emerging.
Training Professionals for Cross-Boundary Planning
Authors: Schrijnen Pieter M.
Published: May 2018

For decades, Dutch transport policies have been dominated by two themes: congestion and environment. Extensive research has revealed planning concepts that can improve the performance of transportation networks and reduce the environmental impact of traffic and transport by using spatial planning policies. Such concepts were introduced in the Dutch policy realm with little success, and there remains a lack of cooperation between the fields of traffic and transport and spatial planning and between various levels of government–-at the cost of accessibility and the environment. The recent shift in Dutch traffic and spatial policies to decentralize power and policy implementation from the national to the regional level might encourage regional transport and spatial planners to integrate the policy realms toward cooperation or even to collaboration. This article describes the design of training for transport engineers and spatial planners to improve their abilities to cooperate successfully and to work more effectively on the regional themes of accessibility and environmental impact. The training focuses on projects that can be characterized as cross-boundary cooperation. The training is based on the theories and practices of the learning organization and on a constructivist perspective on learning.
Georgia's Commute Atlanta Value Pricing Program
Authors: Ogle Jennifer , Guensler Randall , Elango Vetri
Published: May 2018

The Commute Atlanta program is an instrumented vehicle research program funded by the FHWA Value Pricing Program and the Georgia Department of Transportation. A major objective for the multiyear program is to assess the effects of converting fixed automotive costs into variable driving costs. The main research hypothesis is that given a per mile pricing system, participants will modify their driving patterns in an effort to reduce their total costs, pocketing the savings. The Commute Atlanta project includes the parallel collection of instrumented vehicle data, household sociodemographic surveys, 2-day travel diaries, and employer commute options surveys. The research team will monitor the changes in driving patterns and will use statistical analyses of household characteristics, vehicle travel, and relevant employer survey data to examine the relationships between the incentives offered and subsequent travel behavior changes. This paper focuses on the recruitment methods and travel diary response rates for the 2-day diary surveys conducted in February and March 2004. As in other instrumented vehicle studies, researchers collected data that allow the comparison of reported diary travel with monitored vehicle travel. However, this paper focuses on a new type of comparison. Because the households had been recruited into the study 8 months before the diary study and their vehicles were transmitting activity data, the research team could examine whether there were differences in household vehicle activity between that 77% of households that completed the diary data collection and the 23% that did not. The differences were significant at both the high and low ends of the travel-reporting spectrum and may have some major implications for evolving household travel survey methods.
Nonmetropolitan Consultation in Arizona
Authors: Kresich Dianne
Published: May 2018

What began as compliance with the federal mandate for consultation with nonmetropolitan officials is evolving in Arizona into an enthusiastically embraced opportunity to build positive relationships between state, regional, and local jurisdictions. This case study in the implementation of this federal requirement shows how the process provides a meaningful opportunity for local officials to offer input into transportation planning and programming. The study also demonstrates the role of the consultation process in establishing trust and cooperation on the part of local governments and in developing greater understanding of local needs on the part of state transportation agencies.
New Capital Cost Table for Highway Investment Economic Analysis
Authors: Alam Mohammed (Maks) , Timothy Darren , Sissel Stephen
Published: May 2018

The FHWA maintains the Highway Economic Requirements System (HERS) model to enable the estimation of highway investment requirements for the biennial Status of the Nation's Highways, Bridges, and Transit: Conditions and Performance report to Congress. The HERS logic relies on the application of benefit–cost analysis to evaluate and select the best set of roadway improvements for systemwide implementation. Benefits of roadway improvements are calculated from user and agency cost savings (including externalities), and cost is considered simply the capital cost of the improvement. The current research seeks to improve the knowledge of the unit capital costs of improvements modeled in HERS with the use of as-built road construction cost data previously developed for FHWA and bid–schedule data published by various highway agencies. The construction cost dataset used contained detailed data on more than 2,500 construction projects in six states; however, it lacked enough samples to apply either econometrics or generalized statistical analysis to make reliable estimates for all roadway improvement and cost categories in HERS. Both deterministic and probabilistic methods were applied to engineering specifications along with bid–schedule data on various roadway improvement projects to generate capital cost data for each of the classification variables. The final cost table data developed resulted in national highway improvement capital cost data that most realistically corresponded with a typical cost variation across land terrain and urban population density for a given improvement type. For some classification variables the new cost data are 60% to 150% higher than the previous HERS cost estimates.
Public Infrastructure and Economic Productivity
Authors: Baird Brian A.
Published: May 2018

Economists’ interest in the question of public infrastructure productivity has grown steadily since the 1980s. This paper reviews the literature on this topic with a particular focus on transportation's economic impact. Cumulative evidence reveals that, first, estimates of the elasticity of output with respect to public capital have declined over time and are currently in-distinguishable from zero. Second, highways have local negative spillover effects that arise from economic activities being drawn to infrastructure-rich locations at the expense of adjacent areas. Third, transportation infrastructure is subject to congestion, which reduces the productivity of such infrastructure even when stocks remain constant. Finally, highways consistently enhance the productivity of manufacturing firms even when they do not do so for firms in other sectors.
The Highway Development and Management System in Washington State
Authors: Li Jianhua , Muench Stephen T. , Mahoney Joe P. , Sivaneswaran Nadarajah , Pierce Linda M. , White George C.
Published: May 2018

The Highway Development and Management System (HDM-4) developed by the World Bank is a powerful pavement management software tool capable of performing technical and economic appraisals of road projects, investigating road investment programs, and analyzing road network preservation strategies. Its effectiveness is dependent on the proper calibration of its predictive models to local conditions. Although significant work has been done in calibrating and applying HDM-4 worldwide (especially in developing nations), no substantial effort has been made within the United States. This paper describes the calibration and application of HDM-4 (Version 1.3) to the Washington State Department of Transportation's (WSDOT) road network. WSDOT hopes to use HDM-4 to supplement its existing Washington State Pavement Management System (WSPMS) in long-term pavement performance and financial needs. Significant findings are that ( a) HDM-4 can be used to analyze the WSDOT road network, ( b) HDM-4 was successfully calibrated for the network, ( c) the network requires calibration factors significantly different than HDM-4 default values, ( d) software issues seem to prevent use of HDM-4 portland cement concrete pavement analysis, and ( e) WSDOT can use HDM-4 to predict pavement preservation budgets quickly, select optimal preservation strategies under varying budget levels, and assist in determining the long-term effects of different funding scenarios on the road network.
Stability of Freeway Bottleneck Flow Phenomena
Authors: Öğüt K. Selçuk , Banks James H.
Published: May 2018

Data for 44 days from five extended freeway sections around bottlenecks in the San Diego, California, area were analyzed to determine the stability of the point of initial flow breakdown and the feasibility of using similar data for more extensive research into the stability of bottleneck flow phenomena. The ultimate goal of such research is to shed light on the nature of transitions from uncongested to congested flow. Analysis of speed drop sequences suggests that there is rarely a single bottleneck location within critical freeway sections. This in turn suggests that many bottlenecks should be thought of as extended sections rather than points or isolated segments. This suggests an understanding of flow transitions intermediate between the conventional view that flow breaks down consistently at a few locations and the view that flow breakdown is spontaneous and that congested flow is self-organized. Data similar to those used in this study are adequate, but not ideal, for further investigation of the stability of bottleneck flow phenomena. Specific limitations relate to the locations of detector stations and the presence of chronic data errors. This approach to the study of bottlenecks can be improved by combining direct observation with analysis of loop detector data and by using cumulative flow counts to estimate changes in the numbers of vehicles stored in freeway segments.
Prediction of Arrival Profiles and Queue Lengths along Signalized Arterials by using a Markov Decision Process
Authors: Geroliminis Nikolaos , Skabardonis Alexander
Published: May 2018

An analytical methodology for prediction of the platoon arrival profiles and queue length along signalized arterials is proposed. Traffic between successive traffic signals is modeled as a two-step Markov decision process (MDP). Traffic dynamics are modeled with the use of the kinematic wave theory. The MDP formulation allows prediction of the arrival profiles several signals downstream from a known starting flow. This modeling approach can be used to estimate queue lengths and predict travel times, even in cases in which data from loop detectors are unknown, inaccurate, or aggregated. The proposed model was applied to two real-world test sites. The queues estimated with the model are in close agreement with the results from microscopic simulation.