bluuebunny/crossref_metadata_2025 huggingface dataset:
Advanced Fiber-Reinforced Polymer-Wood Composites in Transportation Applications
Authors: Dagher Habib J. , Bragdon Melanie M. , Lindyberg Robert F.
Published: April 2007

Six wood-fiber-reinforced polymer (FRP) composite projects have been conducted over the past decade with three types of technologies developed at the University of Maine. The three featured technologies are ( a) tension-reinforced glulam beams with preconsolidated E-glass FRP (GFRP) panels, ( b) tension-reinforced glulam beams and panels with wet-impregnated E-glass fabrics, and ( c) stress-laminated lumber using GFRP tendons. Through these six demonstration projects, it has been shown that properly designed wood-FRP composites are structurally feasible, durable, and cost-effective in selected applications.
Modeling the Response of Reinforced Concrete Bridge Beam-Column Joints Subjected to Earthquake Loading
Authors: Lowes Laura N.
Published: April 2007

Experimental investigation of the response of older and newly constructed reinforced concrete beam-column bridge joints indicates that inelastic joint action may contribute to global bridge response under earthquake loading. A model is proposed to simulate the response of these components under reversed-cyclic loading. This model provides a simple representation of the primary mechanisms that determine inelastic behavior: failure of the joint core under shear loading and anchorage failure of reinforcement embedded in the joint. The model is implemented as a 4-node, 12-degrees-of-freedom element that is appropriate for use with typical hysteretic beam-column elements in two-dimensional nonlinear analysis of reinforced concrete structures. A simple calibration procedure is proposed to define load-deformation response on the basis of material, geometric, and design parameters. The proposed joint model and calibration procedure are evaluated through comparison of simulated and observed response for a subassemblage tested in the laboratory. This comparison shows that this relatively simple model and calibration procedure can be used to simulate the fundamental characteristics of beam-column joint response under reversed-cyclic loading.
Transport in Delhi, India: Environmental Problems and Opportunities
Authors: Kumar Bose Ranjan , Sperling Daniel
Published: April 2007

Delhi is a rapidly expanding megacity. Population and vehicle use continue to expand, and vehicles are the principal source of severe air pollution. Yet vehicle ownership is still a fraction of that in industrialized countries. The complexities of Delhi’s transport sector are examined, along with what kind of a future is likely and how it might be altered. Indian transportation experts and political leaders were interviewed, historical data analyzed, and various policy options and strategies reviewed. Because of large institutional, political, economic, and technological uncertainties as well as limited knowledge of travel behavior and preferences, two scenarios were created to characterize what is likely and what is possible. The “business-as-usual” scenario extrapolates from present trends in Delhi, modified to reflect existing policies and commitments. It results in dramatic increases in vehicle use, translating to about a fourfold increase in transport-related greenhouse gas (GHG) emissions between 2000 and 2020. The second scenario is premised on strong political and institutional leadership to enhance the economic, social, and environmental performance of Delhi’s transportation system in which car use decreases and transit and bicycle use increase. Even with this aggressive shift toward more environmentally benign transportation, GHG emissions more than double during the 20-year period. Under any plausible scenario, GHG emissions will soar, but the lower GHG path leads to far fewer emissions and much lower transport and energy costs.
Soak Distribution Inputs to Mobile Source Emissions Modeling: Measurement and Transferability
Authors: Venigalla Mohan M. , Pickrell Don H.
Published: April 2007

Soak period distribution is a key input for modeling the emissions factors for mobile sources. Methods for deriving soak period distributions from travel survey data are discussed. Data from the 1995 Nationwide Personal Transportation Survey (NPTS) were analyzed to derive soak times. Detailed analyses were conducted to relate soak time variability to geographic, trip-purpose, and time-of-day variables. The findings reinforce the prevailing general guidance on inputs to modeling the emissions from mobile sources. That is, whenever possible, local data should be used to derive soak distribution inputs to the emissions models. Alternatives are offered to accurate but more expensive local surveys as well as to the roughly aggregate and potentially inaccurate national defaults on soak period inputs to emissions factor models such as MOBILE6. On the basis of a detailed statistical analysis, a grouping scheme is devised to consolidate soak distribution inputs by time period. The grouping scheme will enhance the utility of survey data in deriving the soak distributions and reduce the effort in providing soak distribution inputs to MOBILE6. The soak periods derived from the NPTS data also can be used for deriving the operating-mode fractions inputs needed for MOBILE5B and modal emissions models.
Alternative Methodology for Collecting Local Vehicle Start Information for Use in MOBILE6
Authors: Everett Jerry , Sacs lan
Published: April 2007

MOBILE is the regulatory model of emissions factors from mobile sources that the Environmental Protection Agency (EPA) requires all states except California to use in developing emissions inventories and performing conformity analyses. The agency released the latest version of the model, MOBILE6, early in 2002. It is dramatically different from previous versions of the model and allows users to provide local input data for new and revised variables. It also includes a mechanism for producing separate start emissions rates by hour of the day and vehicle class. The default data are based primarily on start data collected from a series of instrumented vehicle studies in two metropolitan areas. However, EPA explicitly warns of the limitations such “national averages” can have on effectively representing individual metropolitan areas. Finally, the resources used to acquire the default data may not be readily available to, or economically feasible for, many metropolitan planning organizations. An alternative procedure for collecting vehicle start profile data and a preliminary comparison of these profiles to the default values proposed for MOBILE6 are presented. Profiles representing vehicle start characteristics in Knoxville, Tennessee, were developed from collected data. The method of data collection varied considerably from EPA’s practices yet produced comparable results. The profiles developed were compared with EPA default data, and preliminary results indicate that the Knoxville profiles for average starts per day per vehicle were somewhat lower than the default “national average” values included in MOBILE6. Although the profiles for daily distribution of vehicle starts followed the general pattern of MOBILE6 default data, some differences were found.
Assessment of Platinum Availability for Advanced Fuel-Cell Vehicles
Authors: Tonn Bruce E. , Das Sujit
Published: April 2007

The supply and demand of platinum-group metals (PGMs) are assessed through 2030. Recent increases in PGM demand and tight supplies from the two main sources have caused platinum and palladium prices to rise substantially. Future PGM demand driven by new technologies could significantly outstrip supplies. Five scenarios are based on different assumptions about demand for platinum in automotive fuel cells, demand for new vehicles in developing countries, the market penetration of vehicles with fuel cells and advanced catalytic converters, and several other factors. The scenarios suggest a midterm boom in the PGM market caused by increasing demand for platinum for fuel-cell vehicles and an increased use of advanced catalytic converters containing high amounts of PGMs, which could squeeze supplies between 2005 and 2020. This period would potentially be followed by a bust in PGM demand by 2030, as recycling exerts an influence on overall demand in developing countries. Demand for PGMs could outstrip supplies regardless of the market penetration rates of fuel-cell vehicles because of the demand for relatively high amounts of PGMs for advanced catalytic converters. Future research should focus on assessing costs associated with increasing PGM production and on PGM market dynamics.
Condition-Based Method for Programming Road Infrastructure Maintenance
Authors: Evdorides H. T. , R. Kerali H. G. R. , Rivière N. , Ørnskov J. K.
Published: April 2007

This discussion deals with the development of models for the optimal timing and spatial location of road infrastructure maintenance projects considered in the RIMES (Road Infrastructure Maintenance Evaluation Study) project of the Framework IV Road Transport Programme of the Commission of the European Union. The proposed methodology uses engineering-driven criteria such as assessment of road condition data and associated empirical knowledge to facilitate the selection of road lengths in which a single maintenance solution may rectify a combination of the defects observed. Simple optimization procedures are presented that concern the evaluation of the data collected, the selection of the remedial treatments, and finally the realization of maintenance projects. These rules together with simple economic calculations establish a framework for roads and bridges works programming that is applicable on short-term programs. For each road unit associated with this process, an optimal set of data is defined that may be retrieved from an existing road management system. A number of screening techniques enable the identification of the pavements or structures requiring maintenance. Thereafter, an analysis is carried out based on these data to identify a works solution and to determine the engineering priority of the works identified. Economic indicators such as annualized costs are calculated to provide a common basis for assessing the viability of the investment. The output from the works-programming system is a set of maintenance projects scheduled over a period of time with associated estimates of costs calculated for each project and includes integration of pavements and bridges based on economic priorities.
Development of Roughness Thresholds for Preventive Maintenance Action Aimed at Reducing Dynamic Loads
Authors: Lee Doseung , Chatti Karim , Baladi Gilbert Y.
Published: April 2007

In this discussion, roughness threshold values and corresponding life extensions are determined using relative damage and reduction in pavement life concepts. Using the fourth power law the following were calculated and plotted for 333 sections: relative damages from the 95th percentile dynamic load at different roughness index values and the corresponding percent reduction in life. A newly developed roughness index, the dynamic load index (DLI), was used for this purpose. Estimates of pavement life extension resulting from smoothing its surface were then generated for different remaining service life (RSL) values. The results were presented in tables showing the expected life extension for a range of RSL and DLI values. These tables would enable a highway agency to determine when a particular pavement needs to be smoothed to obtain a given (desired) life extension. The analysis was done for the three pavement types (rigid, flexible, and composite). RSL values were calculated for 805-m (0.5-mi) sections using actual distress growth over time. The results showed that for rigid pavements, 17% to 51% of sections would have life extensions of more than 3 years depending on roughness level. For composite pavements, none of the sections would have life extensions of 3 years or more. For flexible pavements, 9% to 34% of sections would have life extensions of more than 3 years depending on roughness level. These results indicate that preventive maintenance by smoothing action is best suited for rigid pavements.
Use of Distress and Ride Quality Data to Determine Roughness Thresholds for Smoothing Pavements as a Preventive Maintenance Action
Authors: Lee Doseung , Chatti Karim , Baladi Gilbert Y.
Published: April 2007

In this discussion, 462 pavement sections from 37 projects in Michigan were analyzed to investigate the interaction between pavement surface roughness and distress. The main hypothesis of this research is that an increase in roughness leads to higher dynamic axle loads, which in turn can lead to a tangible acceleration in pavement distress. If this relationship is established, then it will be possible to plan a preventive maintenance (PM) action to smooth the pavement surface. Such a PM action is bound to extend the service life of the pavement by several years. The objective of the research presented was to develop such roughness thresholds. The selected projects include 13 rigid, 15 flexible, and 9 composite pavements. The ride quality index (RQI) and distress index were used as measures of surface roughness and distress, respectively. To get a good relationship between distress caused by dynamic loading and surface roughness, dynamic-load-related distress types were extracted. The analysis showed very good relationships between distress and roughness for rigid and composite pavements ( R2 = 0.739 and 0.624). However, for flexible pavements there was significant scatter ( R2 = 0.375), reflecting the higher variability in flexible pavement distresses. A logistic function was used to fit the data, and roughness thresholds were determined as the RQI-values corresponding to peak acceleration in distress. These were determined to be 64 [international roughness index (IRI) = 1.99 m/km or 124 in./mi] for rigid pavements and 51 (IRI = 1.43 m/km or 89 in./mi) for composite pavements.
Weigh-in-Motion Applications for Intelligent Transportation Systems-Commercial Vehicle Operations: Evaluation Using WESTA
Authors: Trischuk Derek , Berthelot Curtis , Taylor Brian
Published: April 2007

An investigation was undertaken to sort the efficiencies of different types of weigh-in-motion (WIM) systems commonly used for enforcement of commercial vehicle operations. Weigh station microsimulation model WESTA (WEigh STAtion) was used. The investigation focused, in particular, on the effect WIM system accuracy has on the effectiveness of presorting commercial vehicles before they approach a weigh station. WESTA simulations were performed, with and without mainline WIM, on a typical commercial weigh station facility across a range of commercial truck volumes (200, 400, and 600 Class 9 trucks per hour) and WIM system accuracies (ASTM Type III and Type I WIM). Three evaluation criteria were used: ( a) number of compliant trucks required to report to the station, ( b) number of overweight trucks instructed to bypass the station, and ( c) time the weigh station remained open. It was found that weight enforcement efficiency improved with WIM. The improvements in efficiency translate into considerable savings for both the weight enforcement agency in relation to improved enforcement effectiveness and protection of the infrastructure and for the trucking industry in relation to reduced user-delay costs. It was also found that higher WIM system accuracy results in higher agency and user savings.
Trucking Trends and Changes That Affect Pavements
Authors: Hajek Jerry J. , Billing John R.
Published: April 2007

An overview of trends and ongoing changes in trucking that affect pavement design and performance is provided. Trucking is defined as an activity that encompasses both the properties of the truck fleet (truck size and weight and truck technology) and the operations of the motor carrier industry (truck volumes and loads). Trends in truck volumes, weights, and dimensions and changes in trucking that arise from economic and political changes, regulatory changes in vehicle weights and dimensions, and engineering changes in truck technology are described. Economic and political changes include restructuring in manufacturing industries, globalization and free trade, deregulation of the motor carrier industry, and effects of e-commerce. Engineering changes described include changes in tire technology, increased use of air suspension, greater use of 102-in. (2.59-m) trailer width, and increased use of tridem axles and liftable axles. Past trends and ongoing changes in trucking are used to estimate future changes and outline their potential effect on pavement design and performance.
Encapsulant Material Effects on Response of Fiber-Optic Traffic Sensors
Authors: Cosentino Paul J. , Criss George W.
Published: April 2007

Fiber-optic traffic classification and weigh-in-motion sensors were developed, constructed, and deployed in Florida. As vehicles pass over the sensors, deformations occur, causing light in the fibers' glass core to be refracted into the fibers' surrounding media. A data-acquisition system records change in the sensors' light intensity and uses computerized algorithms to determine axle presence or weights. Various encapsulation materials were available for securing sensors. Field trials indicated that the stiffness of these materials would greatly affect the sensors' output signal. This laboratory study focused on determining suitable candidate encapsulants on the basis of their elastic modulus. The study was conducted on six candidate encapsulants. Fifty-four sensors 200 mm (8 in.) in length were tested at pneumatic pressures of 665 kPa (95 psi) to evaluate the encapsulants. Polymers with elastic moduli from 3500 to 70 000 kPa (500 to 10,000 psi) were evaluated to determine their effects on the sensors' response in rigid materials. To determine relationships between encapsulant modulus and stress attenuated to the sensor, sensors were placed in the grooved bottom of an aluminum testing block with 12.6-, 25.4-, and 38.0-mm (0.5-, 1.0-, and 1.5-in.) grooves and tested pneumatically in a pressure vessel. Pressure transmitted to the sensors at the various depths was evaluated, showing that as the elastic modulus increased from 3500 to 10 500 kPa (500 to 1,500 psi) there was a significant decrease in the percent stress transferred. Moduli in excess of 10 500 kPa (1,500 psi) yielded minimal increase in percent stress transferred.
Measurement of Vertical Compressive Stress Pulse in Flexible Pavements: Representation for Dynamic Loading Tests
Authors: Loulizi Amara , Al-Qadi Imad L. , Lahouar Samer , Freeman Thomas E.
Published: April 2007

Testing at Virginia Smart Road allowed determination of the vertical compressive stress pulse induced by a moving truck and by falling weight deflectometer (FWD) loading at different locations beneath the pavement surface. Testing was performed on 12 different flexible pavement sections. Stress and temperature were measured using pressure cells and thermocouples, respectively, that had been installed during construction of the road. Target testing speeds were 8 km/h, 24 km/h, 40 km/h, and 72 km/h. The considered depths below the pavement surface were 40 mm, 190 mm, 267 mm, 419 mm, and 597 mm. A haversine or normalized bellshape equation was found to be a good representation of the measured normalized vertical compressive stress pulse for a moving vehicle. Haversine duration times varied from 0.02 s for a vehicle speed of 70 km/h at a depth of 40 mm to 1 s for a vehicle speed of 10 km/h at a depth of 597 mm. For the FWD loading, a haversine with a duration of 0.03 s was found to approximate the induced stress pulse at any depth below the pavement surface. Currently, laboratory dynamic testing on hot-mix asphalt (HMA) specimens is performed using a haversine wave at loading duration of 0.1 s. Because HMA is a viscoelastic material, the loading time affects its properties and, therefore, it is recommended that the loading time of HMA dynamic tests be reduced to 0.03 s to better match loading times obtained from moving trucks at average speed and from FWD testing.
Accelerated Pavement Testing of Drained and Undrained Pavements Under Wet Base Conditions
Authors: Bejarano Manuel O. , Harvey John T.
Published: April 2007

The California Department of Transportation requires that all new flexible pavements include a 75-mm layer of asphalt-treated permeable base (ATPB) between the asphalt concrete and aggregate base layers. The purpose of the ATPB layer is to intercept water entering the pavement, either through cracks in the asphalt concrete or through high-permeability asphalt concrete, and to transport it out of the pavement before it reaches the unbound materials. Results are presented of a study using heavy vehicle simulator (HVS) trafficking to evaluate the performance of drained and undrained flexible pavements under wet conditions. A drained structure is a pavement section that contains an ATPB layer between the asphalt concrete and aggregate base. An undrained structure is a pavement section that does not contain an ATPB layer. Wet conditions intend to simulate approximate surface infiltration rates that would occur along the northwest coast of California during a wet month for a badly cracked asphalt concrete layer. Results of the accelerated pavement testing indicate that ATPB strips under combined conditions of wet base and heavy loading. Drained and undrained sections have similar pavement lives; however, the primary mode of failure for the drained section was surface rutting and for the undrained sections it was fatigue cracking.
Macro-Level Analysis of Factors Related to Areawide Highway Traffic Congestion
Authors: Hahn Elisabeth , Chatterjee Arun , Sue Younger Mary
Published: April 2007

The relationship between traffic congestion, travel demand, and supply of roadways is investigated by use of the travel rate index, a congestion measure developed by researchers at the Texas Transportation Institute. Data for the top 138 urbanized areas (by population) were assembled for developing a least-squares regression model. The travel rate index was selected as the response (dependent) variable. A variety of explanatory variables were used to address highway and transit supply and travel demand-related factors. The partial regression coefficients measured the effect of each explanatory (independent) variable on congestion (as measured by travel rate index), holding all other independent variables constant. The results of the multiple regression analysis indicated a negative correlation between freeway lane miles and combined travel rate index. Additionally, a strong positive correlation was observed between combined travel rate index and population density and net land area. A positive correlation was observed between combined travel rate index and bus transit service revenue miles. Principal arterial lane miles and rail transit revenue miles variables were not observed to be significant for explaining traffic congestion and were removed entirely during the stepwise regression. The results indicated that the best predictors among the tested variables were freeway lane miles, population density, net land area, and bus revenue miles. When used together, these predictors accounted for approximately 61% of the total variation in the dependent variable, combined travel rate index.
Can Online Grocers Deliver?: Some Logistics Considerations
Authors: Lin Iris I. , Mahmassani Hani S.
Published: April 2007

The logistics and distribution factors that play a role in the commercial viability of online grocers, and the level of service delivered to customers, are considered. The two business operation models studied are the pureplay model in which the grocer handles the entire shopping experience, and the multichannel model, in which the grocer combines the convenience of online shopping with the stability and leverage of brick-and-mortar stores. The trade-offs that exist for specific delivery policies associated with each type of model are examined. Factors that influence trade-offs are highlighted and include number of demands, number of depots, number of vehicles at each depot, duration of time windows, and road network topology. The commercial viability of each model is examined, and sensitivity analysis to the total demand under different logistical factors is performed. The results illustrate the root causes for the difficult times experienced by this segment of the business-to-consumer electronic commerce sector. Providing the high level of service and convenience (in the form of specific and tight delivery time windows) desired by online customers often results in higher delivery costs, which directly affect the profitability of the operation.
Transferability of Nationwide Personal Transportation Survey Data to Regional and Local Scales
Authors: Reuscher Timothy R. , Schmoyer Richard L. , Hu Patricia S.
Published: April 2007

The development of a system for using Nationwide Personal Transportation Survey (NPTS) data to estimate regional or local travel behavior—vehicle and person trips and miles of travel—is detailed. This system can be used by state or municipal transportation planners. The census tracts were classified into groups, or clusters, that tend to be homogeneous for individual travel behavior. These census tract clusters were based on household income, employment rate, number of household vehicles, and area type (urban, suburban, or rural). NPTS data were used to estimate driving characteristics for each of the clusters derived in the classification step. How well the goal of estimating regional or local travel characteristics was achieved by using standards computed from an independent survey from Baton Rouge, Louisiana, and by using independent data from three add-on components of the NPTS itself was assessed. Estimates computed from the NPTS data by using the census tract cluster method were compared with estimates computed from the standards and with estimates computed from the NPTS data by using competing methods in which households were classified by size of the metropolitan statistical area, census division, or census region. It was found that in most cases the census tract clustering method predicted travel better than the other methods, with small sample sizes generally being the cause when the census tract method was not the best.
Urban Transportation Planning for Air Quality Management: Case Study in Delhi, India, of Role of Social and Economic Costs in Welfare Maximization of Mobility Choice
Authors: Kokaz Karolin , Rogers Peter
Published: April 2007

Recent economic expansion and population growth in developing countries have had a big impact on the development of large cities like Delhi, India. Accompanied by Delhi’s rapid spatial growth over the last 25 years, urban sprawl has contributed to increased travel. The vehicle fleet projected at current growth rates will result in more than 13 million vehicles in Delhi in 2020. Planning and managing such a rapidly growing transport sector will be a challenge. Choices made now will have effects lasting well into the middle of the century. With such rapid transport growth rates, automobile emissions have become the fastest increasing source of urban air pollution. In India, most urban areas, including Delhi, already have major air pollution problems that could be greatly exacerbated if growth of the transport sector is managed unwisely. The transport plans designed to meet such large increases in travel demand will have to emphasize the movement of people, not vehicles, for a sustainable transportation system. Therefore, a mathematical model was developed to estimate the optimal transportation mix to meet this projected passenger-km demand while satisfying environmental goals, reducing congestion levels, and improving system and fuel efficiencies by exploiting a variety of policy options at the minimum overall cost or maximum welfare from transport. The results suggest that buses will continue to satisfy most passenger transport in the coming decades, so planning done in accordance with improving bus operations is crucial.
Teleworkers, Trips, and Telecommunications: Technology Drives Telework—But Does It Reduce Trips?
Authors: Pratt Joanne H.
Published: April 2007

Work-at-home data from federal and proprietary survey series are analyzed to determine why counts of people who work at home do not agree and to gain new insight into the impact of technology and telecommunications on telework and trip reduction. Questions were added to surveys including the American Housing Survey, Current Population Survey, and nationwide personal transportation survey by using a piggybacking strategy. The analysis found that the total number of persons who work at home as a percentage of total workers appears to be holding steady at about 16% to 17%. Similarly, the number of employees doing any work at home has not markedly increased. Work at home during the business day has risen sharply, apparently because of the increased availability of personal computers and the Internet in homes, but the rise may be leveling off. The analysis suggests that the occupational groups most likely to increase in numbers and frequency of teleworking are managerial and professional groups and sales. Countertrends that may decrease telework are discussed. The analysis illustrates the value of adding work-at-home questions to employment, housing, and technology surveys as well as to travel surveys. It emphasizes the need for consistency in questioning over time and the elimination of the use of jargon from surveys so that trends can be monitored.
Development of a Comprehensive Regional Congestion Management System: Lessons in Integrating System Management with Planning and Programming
Authors: Matley Ted , Saladino David
Published: April 2007

A remaining management system requirement is for major metropolitan areas to develop congestion management systems (CMS). These systems must identify and evaluate congestion and select mitigation strategies on the basis of systemwide analysis. In addition, congestion relief strategies must be selected that emphasize operational and demand management strategies in favor of, or in coordination with, new highway capacity. The CMS provides a level of analysis on a regional scale, but it can also guide additional studies that may be required at the subarea, corridor, or project level. This provides an important link between regional and subregional planning efforts and ensures that the policies to guide strategy selection are maintained throughout the process. In addition, a well-designed CMS can eliminate duplication of effort and support later major investment study or National Environmental Policy Act of 1969 planning work to streamline the planning effort. The CMS is an integrated part of the metropolitan planning process, but congestion mitigation must be considered in a larger context and with consideration given to other planning factors. WILMAPCO developed a four-step CMS process that included system identification, congestion identification, strategy evaluation, and system monitoring. The CMS was also developed through a strong interagency effort, including the input of planning and project development staff at member implementing agencies, who have the responsibility to use the CMS products to guide further planning and project development efforts. Although additional work is required, the WILMAPCO CMS will support planning work and influence policy debate regarding transportation investment priorities and regional quality-of-life goals.
Interregional Corridors: Prioritizing and Managing Critical Connections Between Minnesota’s Economic Centers
Authors: Zemotel Linda M. , Montebello David K.
Published: April 2007

Growth trends in Minnesota emphasize the need to ensure that travel on highway corridors linking regional trade centers in the state is safe, reliable, and efficient. In 1999, the Minnesota Department of Transportation initiated an interregional corridor study to define a system of interregional corridors that connect important regional trade centers. Minnesota’s effort to develop the interregional corridor system, performance expectations, and principles and policies for managing and guiding development along these corridors is described. The interregional corridor system and the corresponding management principles and policies were developed in several phases: ( a) definition of regional trade centers, ( b) identification of the interregional corridor system, ( c) development of interregional corridor principles and policies, and ( d) development of a corridor management plan guide. The study developed performance measures and performance targets to identify mobility risk corridors, which are corridors that perform below target speed or have a risk of signal proliferation. Methods used at a sketch-planning level to identify priority routes and performance levels are described. The study developed a more uniform process for developing corridor management plans.
Application of Dwell Time Functions in Transit Assignment Model
Authors: Aashtiani Hedayat Z. , Iravani Hamid
Published: April 2007

The transit assignment process applied as part of the development of the Tehran transportation model is described. The process includes development of various models for dwell time as a function of transit volume. Dwell time is the time a transit vehicle spends at a stop to allow passengers to alight and board. This method was implemented by using EMME/2 transportation planning software. The calculation of dwell time is necessary in modeling transit assignment because an accurate estimation of dwell time will lead to more precise transit assignment results. The area analyzed in the model comprises various transportation analysis zones in the city of Tehran. The model output was shown to be statistically significant. Calculations were found to be valid when compared with observed data.
Performance Programming: Guiding Resource Allocation to Achieve Policy Objectives
Authors: Straehl Sandra S. , Neumann Lance A.
Published: April 2007

The Montana Department of Transportation’s (MDT) performance programming process (P3) is defined as “a method to develop an optimal investment plan and measure progress in moving toward strategic transportation system goals.” Transportation goals are based on the policy directions defined in the statewide long–range transportation plan. The distribution of funding is established through a series of trade-off analyses based on analyzing how the program can best meet overall performance goals. P3 allows system performance to be tracked over time and for various policy options to be systematically analyzed. In addition, P3 commits projects to the Statewide Transportation Improvement Program, whose contribution to system performance was estimated through an analytical process. A case study of the MDT process is provided. The Montana context that led to the development of P3 and the key steps of P3 are described, and the impact of the process on MDT decision making is explained. A discussion of implementation issues and next steps in MDT’s incremental implementation of this process is provided.
Internet Outreach in Statewide Long-Range Planning: New Jersey Experience
Authors: Lebeaux Pamela , Meheski Joseph , Stuart Jennifer , Christians Robin
Published: April 2007

The New Jersey Department of Transportation (NJDOT) recently tested the use of a public involvement website devoted to statewide long-range planning. The website, www.njchoices.com, was launched in April 2000 as a cornerstone of the public involvement program for the current plan update. This initiative allowed NJDOT to explore the use of Internet technology for dialogue concerning long-range investment priorities. In addition, NJDOT gained a better understanding of the technical and administrative requirements of maintaining an interactive site. Along with information on the planning process and statewide transportation issues, the website included mechanisms through which users could voice their concerns. Innovative features included a transportation budget game, an interactive demographic map, and an animated tutorial on the sources of traffic growth. These features received more use than an online survey on transportation priorities or a virtual suggestion box for user comments. Between April 2000 and July 2001, the website recorded 9,209 user sessions, reaching a broader audience than traditional outreach methods for statewide planning. Usage was shown to be strongly associated with publicity for the site. Other findings concern ways to integrate web-based and traditional outreach methods, the importance of user testing of site content, and the need to establish an organizational framework for institutionalization of the website.
Transportation Policies in Bogota, Colombia: Building a Transportation System for the People
Authors: Ardila Arturo , Menckhoff Gerhard
Published: April 2007

Innovative policies implemented in Bogota, Colombia, during the 3-year (1998-2000) administration of Mayor Enrique Peñalosa were intended to transform a car-centered transportation system into a people-oriented one. To achieve this, the administration established policies in seven areas: institutional strengthening, restraining private car use, public space, mass transit, nonmotorized transport, road maintenance, and traffic management. Bogota’s transportation system was to become more people friendly by emphasizing the construction of busways and bike paths and by clearing sidewalks of parked cars and street vendors. Moreover, the administration took the lead in taking space away from cars. Success is difficult to appraise given the short time elapsed. What is clear, however, is that people supported the measures once they saw results, and the mayor left office with a record approval rating. The busway project, Transmilenio, is the prime example. Decisive and persistent leadership, political will, and strong institutions were the critical factors contributing to success.
Multimodal Investment Choice Analysis for Washington State Transportation Projects: Phase I Results
Authors: Young Rhonda , Barnes Jennifer , Rutherford G. Scott
Published: April 2007

Launched in 1999, the Multimodal Investment Choice Analysis (MICA) project is a computer-based tool being developed to assist the Washington State Department of Transportation, the Washington State Transportation Commission, and the Washington State legislature in making state transportation funding decisions. The function of MICA is to summarize the multimodal budgetary trade-offs that will result from varying funding allocation and priority scenarios. MICA’s methodology is based on benefit-cost and goal achievement analyses. The project recently completed the first phase of research. The analysis methodology for the MICA project is outlined, and key findings from the first phase of this effort are highlighted. Tasks for the second phase of the research project are also discussed. Although challenges remain, the results of the Phase I research effort indicate that development of a multimodal analysis tool appears feasible.
A Tale of Two Plans: Determinants of Plan Implementation
Authors: Ardila Arturo
Published: April 2007

By comparing two transportation plans, one implemented and the other forgotten on a bookshelf, the case of Bogota, Colombia, offers the opportunity to understand the determinants underlying effective plan implementation. Results suggest that a plan will be implemented if the planning process is politically and financially realistic. These two initial characteristics should be self-evident, because without adequate funding or political conditions, no policy can be implemented. The analysis highlights the importance of two additional factors for successful project implementation: the existence of a minimum level of institutional capacity, and that the overall planning and implementation exercise is driven by the desire to implement the project.
Travel Demand Modeling and Conformity Determination: Atlanta Regional Commission Case Study
Authors: Rousseau Guy , Clymer Tracy
Published: April 2007

The Atlanta Regional Commission (ARC) regional travel demand model is described as it relates to its link-based emissions postprocessor. In addition to conformity determination, an overview of other elements is given. The transit networks include the walk and highway access links. Trip generation addresses trip production, trip attraction, reconciliation of productions and attractions, and special adjustments made for Hartsfield Atlanta International Airport. Trip distribution includes the application of the composite impedance variable. In the mode choice model, home-based work uses a logit function, whereas nonwork uses information from the home-based work to estimate modal shares. Traffic assignment includes preparation of time-of-day assignments. The model assigns single-occupancy vehicles, high-occupancy vehicles, and trucks by using separate trip tables. The procedures can accept or prohibit each of the three types of vehicles from each highway lane. Feedback between the land use model and the traffic model is accounted for via composite impedances generated by the traffic model and is a primary input to the land use model DRAM/EMPAL. The land use model is based on census tract geography, whereas the travel demand model is based on traffic analysis zones that are subareas within census tracts. The ARC model has extended the state of the practice by using the log sum variable from mode choice as the impedance measure rather than the standard highway time. This change means that the model is sensitive not only to highway travel time but also to highway and transit costs.
Enhancing Public Involvement Through Full Utilization of Communications Technology
Authors: Russell Scott , Herzer Jeffrey K.
Published: April 2007

Communications technology applications such as websites and e-mail play an increasingly important role in public involvement programs. Most significant projects that include public involvement offer at least a website and e-mail. Many also produce multimedia CDs and place interactive kiosks throughout communities. This proliferation of communications technology applications is creating new opportunities and new demands on the public involvement process. Although this technology enhances public access to projects, it also requires creative approaches for presenting information and documenting public comments. Public involvement and technology professionals must work together closely to ensure that communications technology applications create effective interaction between members of the public, projects, and clients and to ensure that technology enhances public involvement activities for the widest audience possible. Examples of current communications technology applications, guidelines that ensure that technology enhances public involvement activities, and processes that ensure online public involvement activities are effectively documented are presented, along with examples of client-side applications to ensure effective use of online input. Case studies that illustrate these principles and offer guidance concerning when and where technology can replace or supplement traditional public involvement approaches are presented.
Accuracy of Global Positioning System for Determining Driver Performance Parameters
Authors: Ogle Jennifer , Guensler Randall , Bachman William , Koutsak Maxim , Wolf Jean
Published: April 2007

Global Positioning System (GPS) technology can continuously monitor the time and location of vehicle usage. By recording and analyzing detailed vehicle activity data, researchers can analyze the safety and environmental implications of driver behavior and trip-making patterns. In 2000, NHTSA awarded the Georgia Institute of Technology a contract to equip 1,100 vehicles with a GPS-enhanced device to collect speed and location data. The objective was to acquire more accurate information on the role of excessive speed on crash frequency and severity. GPS technology allows the researcher to continuously measure driver speed, acceleration, and location. When merged with roadway characteristics within a geographic information system (GIS) environment, determinations of driver risk-taking behavior can be made. Second, continuous logging of GPS data allows researchers to capture high-resolution vehicle activity immediately before a crash event, reducing the potential error and bias introduced during determination of precrash speed estimates. Until May 1, 2000, the military degraded the position accuracy of GPS signals for commercial use, known as selective availability. For researchers, life without selective availability is a great improvement. Travel routes can clearly be discerned without the addition of differential correction units. The accuracy of speed, acceleration, and position data obtained from GPS signals for use in determining driver performance parameters without selective availability were tested. The test included four GPS packages, both corrected and uncorrected, simultaneously validated against a distance-measuring instrument. Equipment configuration, data collection methods, and sources of error are reported. The results suggested that non-corrected data can be used to obtain data within a reasonable range of the application requirements. Even without selective availability, GPS accuracy is still problematic in urban canyons and under heavy tree canopies. Although filtering for urban canyon outliers is labor intensive in a continuous monitoring situation, improvements in GIS hold promise for automation of this task.
Optimal Speed Limits: Limits of Optimality Models
Authors: Elvik Rune
Published: April 2007

Recent estimates of optimal speed limits on public roads in Norway and Sweden are presented. An optimal speed limit is set to minimize the total costs to society of transport. Travel time, vehicle operating costs, road accidents, traffic noise, and air pollution were considered in the determination of optimal speed limits for Norway and Sweden. Most of these effects do not have market prices but they have been valued monetarily, chiefly by means of stated preference surveys. Four perspectives in determining speed limits are compared: ( a) the societal perspective, which includes all effects of speed; ( b) the road user perspective, which leaves out those effects that can reasonably be assumed to be external from the road user’s point of view—chiefly the environmental impact; ( c) the taxpayer perspective, which leaves out all effects whose costs can be regarded as having already been paid through taxes imposed on the use of motor vehicles; and ( d) the residential perspective, according to which the effects of speed are assessed from the point of view of residents along a road. These perspectives are found to give different results. In general the road user perspective and the taxpayer perspective result in the highest speed limits, the residential perspective in the lowest. In some cases, in particular for motorways (freeways), the variation in the total costs of travel is found to be very small for speeds in the range of 70 to 110 km/h, almost making the choice of an optimal speed limit in this range the toss of a coin. According to the societal perspective, optimal speed limits are close to current speed limits in Norway, except on rural highways, where a reduction from 80 to 70 km/h would be optimal. In Sweden, optimal speed limits according to societal perspective are lower than current speed limits on rural highways but are higher than current speed limits in urban areas.