bluuebunny/crossref_metadata_2025 huggingface dataset:
North American Free Trade Agreement Truck Highway Corridors: U.S.-Mexican Truck Rivers of Trade
Authors: McCray John P.
Published: April 2007

The dramatic growth in trade between the United States and Mexico from $12.39 billion to $56.8 billion of U.S. exports and $17.56 billion to $73 billion of U.S. imports between 1977 and 1996 and the implementation of the North American Free Trade Agreement (NAFTA) have focused attention on the impact that the truck-transported portion of this trade has on U.S. highways. State and federal highway administrators are concerned with the planning implications this additional unexpected traffic may have on the transportation infrastructure. Public advocacy groups want additional highway funds to promote one NAFTA highway corridor over others in an effort to stimulate additional economic development. Most of these groups advocate a north-south route through the United States between Canada and Mexico that follows the alignment of an existing federal highway number. Research conducted by the U.S. government under the 1991 Intermodal Surface Transportation Efficiency Act has failed to define NAFTA highway corridors adequately, leaving policy makers with little concrete information with which to combat the rhetoric of the trade highway corridor advocacy groups. A report is provided on research critical to the needs of both highway administrators and corridor advocacy groups, namely, the location of U.S.-Mexican trade highway corridors and the trade truck density along these corridors.
Axial-Torsional Testing System for Clay with Local Strain Measurement
Authors: Abrantes Antonio E. , Penumadu Dayakar
Published: April 2007

An axial-torsional testing system, consisting of an MTS loading frame (9.8 kN/113 N-m) and TestWare-SX control, was developed for evaluating the multiaxial behavior of cohesive soil. The capabilities of the testing system include automated control of three axes (axial load/displacement, torque/rotation, and confining pressure) under static and dynamic conditions. Description of a custom-designed triaxial-torsional shear cell developed for this study is presented. Uniform and reproducible specimens (hollow and full cylinder) were obtained with a slurry consolidation technique. As an example for implementing software control, procedures are described for performing K o consolidation with an electropneumatic transducer in conjunction with an automated volume change device. An optical technique developed by the authors for measuring local strains under axial-torsional loading is also described. Initial test results associated with an undrained constant rate of strain axial and pure torsional shear testing on isotropically consolidated hollow-cylinder kaolin clay are presented. Aspects associated with repeatability are discussed. The test results are being used to evaluate the influence of the inclination of major principal stress on the shear strength and pore pressure behavior of isotropically consolidated clay. A qualitative discussion related to global versus local deformation patterns of hollow-cylinder specimens under axial and torsional loading is also presented.
Design and Absolute Calibration of an Embedded, Wideband Velocity Sensor
Authors: Weiss Gregory G. , Glaser Steven D.
Published: April 2007

A unique embeddable high-fidelity transducer is introduced here, presenting design parameters and National Institute of Standards and Technology (NIST) calibration. Traditionally, acoustic emission studies are conducted by placing an array of sensors on the surface of the specimen being tested, but the physical constraints of many practical testing geometries preclude surface placement of sensors. Advantages of embedded sensors include the following: ( a) mode conversion is avoided so the measured waveforms are simpler and easier to interpret; ( b) the sensor(s) can be located close to the area of crack growth; ( c) a greater length of signal can be recorded before being contaminated by surface reflections/mode conversions; ( d) embedded sensors may be less susceptible to accidental movement or damage; and ( e) embedded sensors can be used when free surfaces are not accessible. To date no such transducers have been available. As a surface sensor, the device is sensitive to partial displacement; as an embedded sensor, the device is sensitive to particle velocity. The presented design yields sensitivity equal to commercial resonant devices (2.34-V output per mm per s embedded; 2.8 V/nm surface) while maintaining the high-fidelity of the NIST displacement sensors (±2.5 dB from 10 KHz to 1 MHz). The embedded response is calibrated with the theoretical solution for Lamb’s problems.
Granular Material Radial Deformation Measurements with a Circumferential Extensometer in Repeated Load Triaxial Testing
Authors: Tutumluer Erol , Garg Navneet , Thompson Marshall R.
Published: April 2007

Determination of both axial and radial specimen strains in a repeated load triaxial test is essential for properly characterizing the directional dependency of resilient granular material behavior. Radial deformation measurement is not yet included in the standard AASHTO test procedure. The method of measuring radial strains adopted in this study emphasizes the use of a contact-type specimen instrumentation technique with a circumferential chain extensometer. The circumferential extensometer was successfully used in repeated load triaxial testing to measure radial strains of three aggregate samples with different material types and properties. The accuracy of the measuring system was within 10−5 (in strains) when the smallest strains recorded were on the order of 10−4. Nonlinear stress-dependent models for properly characterizing the anisotropic granular material stiffnesses were developed from measured axial and radial strains. The vertical/horizontal stiffness ratios in the triaxial sample consistently increased with increasing principal stress ratios, which often occurs in pavements under wheel loading. In general, the repeatability in radial strain measurements was deemed to be satisfactory and more reliable strains were measured at low confining pressures.
Use of Seismic Pavement Analyzer To Monitor Degradation of Flexible Pavements Under Texas Mobile Load Simulator
Authors: Yuan Deren , Nazarian Soheil , Chen Dar-Hao , Hugo Fred
Published: April 2007

The seismic pavement analyzer (SPA) combines several wave propagation techniques in a single unit and can rapidly perform nondestructive tests to determine the condition of pavement. The modulus of each layer of pavements is a major parameter estimated with the SPA. The SPA and its portable version, the PSPA, have been used with the field operation of the Texas mobile load simulator (TxMLS) to detect the variation in properties of different layers with the number of axle loads applied to the pavement. The theoretical background related to the methods used with the SPA and PSPA is discussed. Results from tests of the SPA and PSPA at a TxMLS testing site are presented. The variation in moduli as a function of the deterioration of pavement is detected. The results have been compared with those obtained from direct seismic measurements made on the top of each layer to evaluate the accuracy of the devices. In general, a good agreement was achieved.
Performance of CAL/APT Drained and Undrained Pavements Under HVS Loading
Authors: Harvey J. , Louw L. , Guada I. , Hung D. , Scheffy C.
Published: April 2007

The Heavy Vehicle Simulator (HVS) test results of the first experiment of the California Department of Transportation (Caltrans) Accelerated Pavement Testing Program, known as CAL/APT, are presented. The Goal 1 experiment was designed to validate the existing Caltrans pavement thickness design method for drained (containing an asphalt treated permeable base layer) and undrained (containing aggregate base only) flexible pavements. The pavement performance results include fatigue crack development, surface profile, and vertical deflections. The observed performance of the two types of structures is compared. The effects of construction compaction of the asphalt concrete, bonding between asphalt concrete lifts, the relative performance of the drained and undrained structures under the controlled HVS environment, and comparison of the observed performance and performance expected by the thickness design procedure are presented and discussed.
Spring Load Restrictions in Finland: Current Policy and Research Implications
Authors: Isotalo Jukka
Published: April 2007

Roads in Finland are exposed to seasonal strength variation. Because of industrial policy, the maximum weight of heavy trucks is 60 metric tons all year. The policies applied by the Finnish National Road Administration (Finnra) to mitigate the effects of seasonal road strength variations on public roads, and the current research on the topic in Finland, are investigated. It has been estimated that the annual cost of road repairs because of spring damages is about $10 million under the present load restriction policy. The costs for road repairs would be $35 million without restrictions. The annual additional cost for all heavy transport is estimated at $15 million. An internal Finnra survey revealed that $80 million to $100 million is needed to repair all known frost-susceptible road sections. Finnra load restrictions are intended to prevent damage to roads by heavy vehicles during spring thaw. The restrictions will reduce and possibly eliminate increases in annual road maintenance costs. On the other hand, the restrictions will allow a minimum standard for vital transport. Finnra’s Road Structures Research Programme (TPPT) studies improvements in the durability, strength, and economy of road structures. A key part of the TPPT project concerns problems associated with frost, especially durability against frost action. The most important factors of frost action on roads are the freezing index, duration of frost and thaw seasons, surface temperature, and ground water level. Methods for testing and calculating frost effects are discussed, as are the questions that must be answered before more precise models can be published.
Using Advanced Driving Simulator as Design Tool in Road Tunnel Design
Authors: Lidström Mats
Published: April 2007

To obtain more information for tunnel design problems, a virtual model of some proposed tunnel designs was developed to demonstrate the design in advance and to be used as a platform for future tunnel research projects. By combining this model with an advanced driving simulator, the designers can virtually drive through their drawings before construction work is started. In comparison with traditional animation techniques, an interactive virtual model combined with a driving simulator has proved to be useful in many aspects. It is an excellent tool for testing proposed positions of road signs in the tunnel. It is easier to compare alternative sign positions with the three-dimensional virtual tunnel model than with ordinary drawings. Some visual traps not foreseen in the original sign-position design were corrected after detection in the simulator. Traffic engineers reported that they became involved in the tunnel design process at an earlier stage than before, enabling them to work in the final tunnel environment long before the actual tunnel was built. The ability to work early in the design process makes it possible for traffic engineers, architects, and safety engineers to evaluate their designs while other solutions still can be considered.
Generic Multimedia Database for Highway Infrastructure Management
Authors: Wang Kelvin C. P. , Li Xuyang , Elliott Robert P.
Published: April 2007

Images of highway right-of-way are used widely by highway agencies through their photologging services to obtain visual information for the analysis of traffic accidents, design improvement, and highway pavement management. The video data usually are in analog format, which is limited in accessibility and search, cannot automatically display site engineering data sets with video, and does not allow simultaneous access by multiple users. Recognizing the need to improve the existing photologging systems, the state highway agency of Arkansas sponsored a research project to develop a full digital, computer-based highway information system that extends the capabilities of existing photologging equipment. The software technologies developed for a distributed multimedia-based highway information system (MMHIS) are presented. MMHIS removes several limitations of the existing systems. The advanced technologies used in this system include digital video, data synchronization, high-speed networking, and video server. The developed system can dynamically link the digital video with the corresponding engineering site data based on a novel algorithm for the data synchronization. Also presented is a unique technique to construct a three-dimensional user interface for MMHIS based on the terrain map of Arkansas.
Treating Lead-Contaminated Soil by Stabilization and Solidification
Authors: Long Richard P. , Zhang Xinguo
Published: April 2007

Soil in and near transportation facilities often is contaminated with lead because lead once was used as a base for gasoline and paint. Dealing with contaminated soil is difficult because the toxic material must be treated to protect the public from direct exposure. Stabilization and solidification is a promising technique for protecting the public from toxic materials in soils by decreasing the possibility of human exposure and decreasing the mobility of the contaminant. The results of a laboratory investigation of the feasibility of stabilization and solidification of contaminated soil using cement in combination with various additives are presented. Mobility of lead and other contaminants was measured by dynamic diffusion and compared with the standard test results of the toxic characteristic leaching procedure. Several additives were tried. Apatite and sodium silicate were found to be the most effective in reducing the mobility of the lead. The compacted dry density of the solidified soil had a great effect on the leaching characteristics. The leaching of lead from deteriorated solidified soil was simulated by crushing a sample containing apatite and conducting a dynamic diffusion test on the crushed sample. The diffusion coefficient was used to compare the effect of additives and other treatments.
Remediation of Soils Contaminated with Tetraethyl Lead by Electric Fields
Authors: Alshawabkeh Akram N. , Ozsu-Acar Elif , Gale Robert J. , Puppal Susheel K.
Published: April 2007

Four tests were conducted to investigate potential uses of electric fields for remediation of high buffering capacity soils contaminated with high lead concentrations (11 percent by dry weight). The soil samples were collected from a site in Louisiana where tetraethyl lead was used extensively for increasing the octane rating of leaded gasoline. Calcium was present at relatively high concentrations (9 percent by dry weight). Initial soil pH was basic (about 8.5). Two enhancement procedures were used: acetic acid for neutralizing the cathode and membranes to prevent migration of hydroxyl ions from the cathode. Current densities applied were in the order of 5 A/m2 to 10 A/m2. Tests were processed for up to 3,220 hours. Lead extraction rates were significantly affected by high calcium concentration. Energy expenditure was very high (up to 20 667 kWh/m3 in the unenhanced test). The study showed that the soil buffering capacity significantly affected energy requirements, cost-effectiveness, and success of the process. Efficient extraction of lead in soils will be controlled by the presence of high concentrations of soluble ions (such as calcium) in the soil.
Permeability Measurement of Base Materials Using Falling-Head Test Apparatus
Authors: Fwa T. F. , Tan S. A. , Chuai C. T.
Published: April 2007

The development of a new falling-head procedure for laboratory permeability measurement of pavement base materials is described. The main advantage of the falling-head test over the conventional constant-head test is its ability to determine permeability properties of the test material at different levels of hydraulic gradients in a single test. The test setup is simpler and the test duration is much shorter. Each test takes only a few minutes to complete. A large number of tests have been conducted with the proposed procedure on different materials, including compacted crushed stones, glass spheres, and cement stabilized base materials. The falling-head test results were verified by performing constant-head permeability tests on the same specimens at different hydraulic gradients. Analysis on the falling-head test data revealed that the relationship between specific discharge and hydraulic gradient over the range studied could not be represented by a single linear relationship as stated by Darcy’s law. The proposed approach can be a useful tool for determining the drainage properties of base materials within the range of hydraulic gradients encountered in actual pavements.
Variation of Soil Suction with Depth in Dallas and Fort Worth, Texas
Authors: Bryant John
Published: April 2007

The variation of soil suction and the estimate of constant soil suction with depth is used to design many slab-on-grade foundations and pavement moisture barriers. The Post-Tensioning Institute’s design procedures for slab-on-grade foundations and design of vertical pavement moisture barriers use the constant suction at depth to predict differential soil movements that influence shear, deflection, and moment magnitudes and the effective barrier depth. Constant soil suction estimates can be correlated to the climate or long-term weather conditions at any given site by using the Thornthwaite moisture index (TMI), which estimates the amount of net moisture surplus or deficit from precipitation and evapotranspiration of moisture from the ground surface. On the basis of the empirical curves, the constant value of total soil suction for the Dallas–Fort Worth, Texas (DFW) area is about 246 kPa based on an average TMI of 0. Analysis of more than 1,200 total soil suction laboratory tests performed on developed and undeveloped lots indicates that the measured average total soil suction value in the upper 6 m is closer to 979 kPa for the DFW area ranging between 55 kPa and 11,246 kPa during the 1995–1997 period. Some hypothesized reasons for the difference between the empirical and measured equilibrium (constant) soil suction values are amounts of clay, clay origin, variable plasticity indexes, soluble salt content, and equilibration curve differences.
Upgrading the Asphaltic Concrete Specification of the New Jersey Department of Transportation
Authors: Palise Frank , Strizki Brian J. , Weed Richard M.
Published: April 2007

An earlier upgrading of New Jersey’s specification for in-place air voids in asphaltic concrete pavement was made to strengthen the acceptance procedure and incorporate several advances in specification-writing technology. Modifications included changing to percent defective as the quality measure, switching to an equation-type pay schedule, adding a bonus provision for superior work, and including a remove-and-replace clause for seriously defective work. Changing from an acceptance procedure based on the sample mean to one based on percent defective essentially redefined the acceptable quality level from a percent defective value of 50 to a considerably more demanding value of 10. To allow the construction industry a chance to become familiar with this new requirement, a relaxed form of the pay schedule was initially adopted. Industry has subsequently had extensive experience with the new specification and the New Jersey Department of Transportation is now preparing to modify the specification further to provide an even stronger incentive to produce high-quality pavement. The modifications were developed by a joint task force representing the construction industry and the New Jersey Department of Transportation and include increasing the bonus provision, retaining the present pay schedule for quality that is only marginally deficient, changing to a more steeply descending pay schedule for seriously defective quality, and adding a more elaborate retest procedure to ensure that substantial pay reductions, when they occur, are truly warranted. In addition to controlling air voids, the new acceptance procedure also combines requirements for thickness and smoothness into a single composite pay equation. Operating characteristic curves are presented to demonstrate the capability of the new procedure.
Friction Testing of Tack Coat Surfaces
Authors: Paul Harold R. , Scherocman James A.
Published: April 2007

In response to litigation because of an accident case involving tack coat on a construction project, a field trial was evaluated to determine frictional characteristics of tack-coated surfaces. When a literature search on this topic returned little information, state Department of Transportation materials engineers were surveyed to determine the state of the practice with respect to tack coat operations. On the basis of the survey responses and the existing litigation, a field trial was conducted to evaluate friction numbers on tack coat materials. Variables included residual asphalt content (three levels); test time (three levels); combinations of wet, dry, and flushed surface conditions (seven levels); and replicate testing. It was found that at typical residual asphalt rates reported by states and specified in Louisiana, reduced friction capability existed for up to 7 h after application. With the friction numbers obtained, traffic should be maintained only at controlled low speeds if at all. However, the residual asphalt content appeared heavier than in typical practice. At residual application rates that were typical of practice, friction properties were produced that would allow traffic at moderate speeds. After several days, friction numbers returned to the original condition because of traffic or weather abrasion.
Alternate Methods To Determine Asphalt Content
Authors: Prowell Brian D.
Published: April 2007

A method was identified to determine asphalt content to replace chlorinated solvent extraction. Production of trichloroethane was banned on December 31, 1995, as part of the 1990 Clean Air Act Amendments. Initially, the study focused on evaluating the nuclear asphalt content gauge with Marshall plugs. During the course of the research, early data from the National Center for Asphalt Technology (NCAT) indicated that the ignition method was a promising alternative. Testing was conducted with three generations of ignition furnaces. Four aggregate types were evaluated with typical surface mix and base mix gradations found in Virginia. Samples for evaluation were produced at four asphalt contents for each mix design representing typical field variation around the optimum. Operator variance samples were tested nondestructively in the nuclear gauge and then destructively by solvent extraction and the ignition method. As a result of the research, a test method was developed using the ignition furnace with an internal weighing system. This method has been specified as a replacement for solvent extraction in Virginia.
Stone Matrix Asphalt: The Wisconsin Experience
Authors: Schmiedlin Robert B.
Published: April 2007

In 1991, the Wisconsin Department of Transportation and the asphalt paving industry in the state decided to construct a trial installation of an asphalt paving technology that had piqued the interest of a group of professionals who had recently toured Europe. The success of that initial trial was the basis of the decision to conduct a thorough evaluation of stone matrix asphalt (SMA). Subsequently, six projects were constructed at various locations around the state. Each project contained six test sections utilizing various fiber and polymer-modified SMA mixes. Besides evaluating the various types of SMAs, this research effort also contained elements for evaluating the impact of aggregate size and aggregate hardness on the effectiveness of the SMA mixes. These projects were constructed over a period of 3 years; the last one was constructed in 1994. All the projects were evaluated from the standpoint of ease of construction and performance. Although the ease of construction was to be evaluated mostly on a subjective basis, the performance measures were established to be objective and measurable. The performance measures were amount of cracking, friction characteristics, overall pavement distress, amount of rutting, noise impacts, and ride. Although the data collected so far are limited because of the short time the pavements have been in place, they point to an asphalt pavement that resists cracking and rutting, while providing a good ride and excellent frictional qualities. The SMAs demonstrate promise of being a durable and long-lasting asphalt pavement.
Household Travel, Household Characteristics, and Land Use: An Empirical Study from the 1994 Portland Activity-Based Travel Survey
Authors: Sun Xiaoduan , Wilmot Chester G. , Kasturi Tejonath
Published: April 2007

How a household’s travel behavior is influenced by its socioeconomic and land use factors has been a subject of interest for the development of travel demand forecasting models. This study investigates the relative importance of these factors based on the number of household daily trips and vehicle miles traveled (VMT). The travel data used in the study come from the 1994 Portland Activity-Based Travel Survey. In addition to income, vehicle ownership, and household size, other significant factors in household travel have been identified, such as the presence of car phones, dwelling type, home ownership, and even the length of resident’s time in the current home. Most important, this study has qualitatively revealed that land use makes a big difference in household VMT, whereas its impact on the number of daily trips is rather limited. After controlling for the land use variables, such as density and land development balance, it appears that there is little difference in household income distribution among three different land use areas. The household life stage/lifestyle appears to be more relevant to the residence location. And the land use development of the residence location imposes the greatest impact on the household daily VMT. The results from this study provide some empirical evidence to the development of travel forecasting models. Especially by examining the relationship between land use and household travel, the results shed light on how to incorporate land use factors into comprehensive travel demand models that can be used by policy makers in evaluation of alternative land use policies. This study serves as a step toward more comprehensive studies on transportation and land use. The results presented represent a preliminary analysis of an extensive data set; considerable additional analysis is already in process.
Urban Form and Vehicular Travel: Some Empirical Findings
Authors: Miller Eric J. , Ibrahim Amal
Published: April 2007

Some empirical findings are presented on the relationship between urban form and work trip commuting efficiency, drawn from the analysis of 1986 work trip commuting patterns in the greater Toronto area. Work trip commuting efficiency is measured with respect to the average number of vehicle kilometers traveled (VKT) per worker in a given zone. Preliminary findings include VKT per worker increases as one moves away from both the central core of the city and from other high-density employment centers within the region; job-housing balance, per se, shows little impact on commuting VKT; and population density, in and of itself, does not explain variations on commuting VKT once other urban structure variables have been accounted for.
Trip Generation and Parking Requirements in Traditional Shopping Districts
Authors: Steiner Ruth L.
Published: April 2007

The New Urbanists assume that if you build a village center or Main Street-style retail businesses in the middle of a residential neighborhood, it will, among other things, reduce the level of automobile usage. Based on the claim of reduced automobile travel, advocates suggest that parking requirements and transportation impact fees should similarly be reduced. Although it would be ideal to test these claims using New Urbanist development, current developments lack well-established retail businesses. Thus, this study considers these claims of the New Urbanists using six prototypical traditional shopping districts in the Oakland-Berkeley subarea of the San Francisco Bay Area. Each of these districts is surrounded by residential areas of moderately high density [between 5.3 and 8.5 persons per hectare (13–21 persons per gross acre)] and middle-class residents. These shopping areas vary in scale and mix of businesses covering the range of sizes and types espoused by the New Urbanists. The trip generation rates and parking needs for each of these prototypical shopping areas are calculated and compared with ITE-based rates for both an average hour and a daily rate. Based on these comparisons, a conclusion is reached that the claims of the New Urbanists for reduced parking and transportation fees cannot be wholeheartedly supported if the needs of the neighborhood are to be considered. Although many customers walk to these shopping areas, the trips by modes other than automobile are offset by a higher overall level of activity in the shopping area.
An Integrated Geographic Information System Solution for Estimating Transportation Infrastructure Needs: A Florida Example
Authors: Harter Gerald L.
Published: April 2007

In 1991, one of the most important pieces of legislation was signed into law. The Intermodal Surface Transportation Efficiency Act (ISTEA) requires traffic and systems management monitoring of pavement, bridges, safety, congestion, public transportation facilities, and intermodal facilities. These systems call for coordinated efforts to collect, manage, analyze, and store transportation-related data. GIS-T (geographic information system for transportation) is one of the tools that will be used extensively in upcoming years to manage the information requirements of ISTEA. GIS, coupled with an integrated server-client-based information system, will become the standard, replacing many existing stand-alone, subgroup level applications. A summary is provided that discusses the development of an integrated GIS-T system, Transportation Planning and Analysis Software (TPAS), developed for the Florida Department of Transportation. TPAS was developed to manage, calculate, and store roadway characteristics to estimate immediate and long-term infrastructure needs. The system calculates roadway level of service, identifies deficiencies, and recommends improvements to meet operating standards, and, finally, calculates costs of the proposed improvement. Deficient segments, as well as road improvements and costs, can then be displayed on GIS maps in an automated fashion. In the past, these calculations were completed by using spreadsheet and manual methods. TPAS combines all of these procedures and develops maps in a fraction of the time. TPAS seamlessly integrates an ArcView GIS application with a knowledge-based expert system programmed in Visual Basic. This application provides an efficient, cost-effective solution for a once tedious and time-consuming task.
Case Study in the Application of Adjusted Census Data for Planning Projects
Authors: Siaurusaitis Victor J. , Saben Larry J.
Published: April 2007

The reasons for differences between locally collected data and the 1990 census data, as determined from a detailed analysis of model development efforts in a planning study, are detailed. Agencies around the country are beginning to use census data that have been adjusted based on newly released Federal Highway Administration publications. The recently completed Transportation Planner’s Handbook on Conversion Factors for the Use of Census Data has been published to assist planners in using the 1990 census to develop and calibrate local travel demand models. Collecting new data to complete the development of a local model is not always an option. The 1990 census provides another source of information to assist in traffic model estimation. Potential users of the census need to be aware that there would appear to be a variance between results obtained from the census journey-to-work files and locally developed home interview surveys, even after the use of the census adjustment factors. The project in Atlanta, Georgia, involved detailed traffic model development and calibration, in conjunction with factor-adjusted census data. Because of the intimate understanding of the data for the study area, and the development of the model set from the beginning, differences between the locally collected data and census were explainable. Possible problems that can arise when comparing the data as they relate to geography, data definition, and accuracy of the data collection process are detailed.
Annual Average Daily Traffic Prediction Model for County Roads
Authors: Mohamad Dadang , Sinha Kumares C. , Kuczek Thomas , Scholer Charles F.
Published: April 2007

A traffic prediction model that incorporates relevant demographic variables for county roads was developed. Field traffic data were collected from 40 out of 92 counties in Indiana. The selection of a county was based on population, state highway mileage, per capita income, and the presence of interstate highways. Three to four automatic traffic counters were installed in each selected county. Most counters installed on the selected road sections were based on the standard 48-hour traffic counts. Then, the obtained average daily traffic was converted to annual average daily traffic by means of adjustment factors. Multiple regression analysis was conducted to develop the model. There were quantitative and qualitative predictor variables used in the model development. To validate the developed model, additional field traffic data were collected from eight randomly selected counties. The accuracy measures of the validation showed the high accuracy of the model. The statistical analyses also found that the independent variables employed in the model were statistically significant. The number of independent variables included in the model was kept to a minimum.
Performance Measures: Linking Outputs and Outcomes To Achieve Goals
Authors: Abbott Eugene E. , Cantalupo Joseph , Dixon Linda B.
Published: April 2007

Measuring transportation system performance improves accountability, provides an opportunity for advocacy, and has been recognized in U.S. federal policy as an integral part of transportation planning. Meaningful performance monitoring requires measures that examine the range of activities that produce the transportation product. The link between the transportation product and the agency goals is critical to the success of monitoring efforts. Consistency in definitions and approaches among agencies can help to advance the performance monitoring process and build a body of knowledge through shared experiences. The Delaware Department of Transportation developed a tiered system of performance measures that uses both outcome and output indicators corresponding to goals, strategies, policies, and actions found in its statewide long-range transportation plan. Outcome performance measures monitor the achievement of goals and strategies, whereas output measures indicate progress achieved through specific policies and actions. These outputs, when aggregated, can create the desired outcomes. The measures must be based on realistic and reasonably attainable data that provide the means to monitor plan implementation and determine necessary changes throughout the process or at regular update cycles. The chosen measures meter the agency’s outputs that can be modified each year in the capital improvement program and project prioritization processes. The tiered system and implementation approach for Delaware’s performance monitoring system emphasizes the need for both outcome and output measures. The Delaware effort also highlights needs for consistent approaches, uniform definitions, and continued research to advance the effectiveness of performance monitoring efforts.
Effectivity and Impact of Participative Planning
Authors: Van Zuylen Henk J.
Published: April 2007

A process of participative planning has been developed in the Netherlands according to a relatively new model. A literature study and a survey have been executed to assess the effectivity of the process and the contingency factors with regard to developing support in the group of participants for the plans. The process appears to be very effective. It appears to be important to use contingent processes and techniques: situations with a high technical complexity should be dealt with in a different way from situations in which the social complexity is dominant. The dynamics of mental images could be studied with the results of the survey. Recommendations for the approach of participative planning are derived from the analysis of these dynamics. The participants of the planning process appear to have undergone a learning experience that makes them more tolerant with respect to the planning product and more critical with respect to the planning process.
Review of Long-Range Transportation Plans of Florida’s Metropolitan Planning Organizations
Authors: Mierzejewski Edward A. , Marshall Margaret A.
Published: April 2007

On behalf of the Florida Department of Transportation and the Florida Metropolitan Planning Organization Advisory Council, the Center for Urban Transportation Research (CUTR) conducted a review of each of the state’s 25 metropolitan planning organization (MPO) long-range transportation plans and the state’s 2020 Florida Transportation Plan (FTP), to compare the policy directions of the documents and suggest areas for consideration and inclusion in future plan updates. To gain a comprehensive understanding of the issues and concerns facing MPOs in Florida, each of the state’s 25 MPO long-range transportation plans was reviewed, and telephone interviews were conducted with each of the MPO executive directors or designated staff members. Following the telephone interviews, the plans were reexamined to determine the extent to which the issues or problems stated in the interviews were described in the plans. CUTR identified the concerns common to the majority of metropolitan regions, including funding shortfalls, determination of innovative financing strategies, involvement of the public, maintenance of a mobility/livability balance, and air quality conformance. Many of the metropolitan regions also identified the Intermodal Surface Transportation Efficiency Act’s planning factors, the consideration of alternative land use scenarios, differences in project selection criteria, and intergovernmental coordination as other areas of importance during plan development. The study offered suggestions to improve integration of the various MPO plans with the FTP, and to suggest improvements to the MPO long-range plans. Items for future consideration include placing greater emphasis on policy trade-offs and less reliance on transportation planning models; applying the principles of strategic planning to the transportation planning process; and incorporating a strong visioning process. Additional recommendations include incorporating current issues and problems into the long-range plans; streamlining the reporting of performance measures; standardizing when plans are updated, as well as how costs and revenues are reported; and reporting financial information by responsible agency and facility type.
Travel Patterns of Older Australians in an International Context: Policy Implications and Options
Authors: Rosenbloom Sandra , Morris Jennifer
Published: April 2007

International data and data from a major household travel survey undertaken in Melbourne, Victoria—the Victorian Activity Travel Survey (VATS)—are used to address the following questions: ( a) to what extent can older people meet their own transportation needs when they cannot drive, and ( b) what special safety concerns are raised now and in the future by the growing number of older drivers. VATS data show that Australian travel patterns parallel those observed in other developed countries: older people are increasingly more reliant on the car. The number of trips that will be lost when they must give up or reduce driving is substantial. Policy makers must start now to understand the dimension of the problem and the ways in which it can be addressed.
Factor Analytic Approach to Incorporating Systematic Taste Variation into Models of Residential Location Choice
Authors: William Sermons M. , Koppelman Frank S.
Published: April 2007

In the development of residential location choice models, multicollinearity among measures of socioeconomic status and family status prohibits the inclusion of a large number of these attributes in a single specification. Alternative methods of representing these attributes with a smaller number of summary or representative measures are tested. Factor analysis is performed on the census tract–level family status and socioeconomic status variables to produce factor scores that are used in residential location choice models. The factor analysis results are also used to select one representative socioeconomic status variable and one representative family status variable to be used in choice models. These approaches are tested against a base model that uses a full set of 11 attributes. To incorporate systematic taste variation, the factors and representative variables are interacted with individual household income and life-cycle characteristics. The factor analysis approach provides a clearer interpretation of the influence of socioeconomic status and family status than inclusion of multiple variables, which obtains many nonsignificant and counterintuitive parameters. The factor scores are preferred over the use of a single representative variable, which is not readily interpreted with respect to impact of the variables it represents.
Assessment of JOBLINKS Demonstration Projects: Connecting People to the Workplace and Implications for Welfare Reform
Authors: Goldenberg Leslie , Zhang Jane , Dickson Charles
Published: April 2007

JOBLINKS demonstration projects tested the means of providing transportation services to disadvantaged individuals, particularly welfare recipients trying to make the transition to employment and self-sufficiency. In 1995–1996, 10 demonstration projects were funded in 6 states. After each project an independent assessment yielded the following findings: ( a) Transportation made a difference in enabling disadvantaged people to obtain work. In several demonstration projects, the transportation services provided through JOBLINKS enabled individuals to get a job or to increase work to a full-time basis. ( b) Transportation solutions were most effective in the presence of three key factors: availability of jobs in the local labor market at shift times that could be served by available drivers and vehicles, access to job-ready workers with transportation barriers who would be suited for these jobs, and coordination among transportation providers, human services agencies, and employers. In the absence of these factors, transportation linkages played an important role in getting disadvantaged populations to job preparation services. Many of the JOBLINKS projects concentrated on and were very successful at carrying those who were not job ready to educational institutions, job-training providers, and job club sites. ( c) Transportation is a necessary component in the package of services needed to implement welfare-to-work programs. Welfare-to-work policy emphasizes getting people into work environments. There are serious implications of this policy for both welfare agencies and transportation providers. Future efforts to meet the transportation needs of people who are struggling to become independent of welfare should focus on innovative ways to get them to workplaces.
Job Accessibility in the San Juan Metropolitan Region: Implications for Rail Transit Benefit Analysis
Authors: Zhang Ming , Shen Qing , Sussman Joseph
Published: April 2007

Public transportation investment is made primarily because of its potential social and economic benefits. Properly identifying and measuring these benefits has been the central concern in rail transit investment. The social aspects of the benefits, however, have not been well examined. In this research on the potential benefits of Tren Urbano (a new rail transit system proposed in San Juan, Puerto Rico), accessibility measures are utilized as a key analytical tool. An analysis of Tren Urbano’s effects on employment accessibility in the region is presented. The results show that there is a need for lower-income workers to improve their accessibility to jobs. Tren Urbano will enhance employment accessibility at the regional level and for all income groups as well. The results also reveal spatial inequity in the distribution of the potential benefits, even though the eventual outcome will be dependent on the actual distribution of ridership. Efforts should be made to channel the potential benefits of transportation investment toward socially targeted populations. Integrating the rail system with other transit modes and formulating favorable land use policies are critical to enhance accessibility.
Environmental Management in Transit Turnkey Procurements
Authors: Mendes Diana C. , Bay Paul N. , Byrne William D.
Published: April 2007

A discussion is presented of how environmental and community issues affect project planning and development, and ideas are presented on how to proactively manage the environmental compliance process to capitalize on the flexibility and advantages of a turnkey approach and at the same time reduce the potential for major project risk factors to jeopardize successful project implementation. On the basis of the experience of traditional and turnkey projects during the project development process, major project risk factors (cost, delay, and public relations risks), which need to be identified and acknowledged as early as possible in the project development process, are explored. Mechanisms to compensate for these risk factors need to be developed and incorporated into the design of the turnkey procurement process. Assigning responsibility for environmental management functions to the parties best equipped to resolve the issues likely to arise at each stage of the development process is also important. Whereas reactive environmental management exposes projects to high levels of risk and has the potential to jeopardize attainment of turnkey objectives, proactive environmental management has the potential to support the turnkey concept by reducing the risks associated with environmental issues.
Forecasting Paratransit Ridership Using Discrete Choice Models with Explicit Consideration of Availability
Authors: Benjamin Julian , Kurauchi Shinya , Morikawa Takayuki , Polydoropoulou Amalia , Sasaki Kuniaki , Ben-Akiva Moshe
Published: April 2007

In most developed countries, the population of the elderly and disabled is growing rapidly. These individuals require transportation service suited to their needs. Such service may be provided by applying emerging technologies to dial-a-ride transit. This research develops a methodology to quantitatively evaluate the impact of paratransit services on a traveler’s mode choice behavior. The mode choice model explicitly considers availability of alternative modes and includes latent factors to account for taste heterogeneity. Stated preferences are also used to elicit preferences for new paratransit services. The methodology is empirically tested with data collected in Winston-Salem, North Carolina. The model system developed is applied to evaluate the effect of improving service attributes and the impact of the introduction of new cost-effective modes on modal shares. Results of the policy analysis indicate that ( a) transit policy changes, such as fare reduction, would have little effect on automobile driver and automobile passenger shares; ( b) an improved reservation system for dial-a-ride services would produce shifts in mode share; ( c) the proposed new bus deviation service was favored; ( d) free bus service reduces dial-a-ride share; and ( e) an increase in awareness of a dial-a-ride system would significantly increase its share.