bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Transportation Infrastructure and Location on Residential Real Estate Values: Application of Spatial Autoregressive Techniques
Authors: Haider Murtaza , Miller Eric J.
Published: April 2007

Proximity to transportation infrastructure (highways and public transit) influences residential real estate values. Housing values also are influenced by propinquity to a shopping facility or a recreational amenity. Spatial autoregressive (SAR) models were used to estimate the impact of locational elements on the price of residential properties sold during 1995 in the Greater Toronto Area. A large data set consisting of 27,400 freehold sales was used in the study. Moran’s I was estimated to determine the effects of spatial autocorrelation that existed in housing values. SAR models, using a combination of locational influences, neighborhood characteristics, and structural attributes, explained 83 percent variance in housing values. Using the “comparable sales approach,” a spatiotemporal lag variable was estimated for every property in the database. This research discovered that SAR models offered a better fit than nonspatial models. This study also discovered that in the presence of other explanatory variables, locational and transportation factors were not strong determinants of housing values. On the other hand, the number of washrooms and the average household income in a neighborhood were found to be significant determinants of housing values. Stepwise regression techniques were used to determine reduced spatial hedonic models.
Parameter Estimation Strategies for Large-Scale Urban Models
Authors: Abraham John E. , Hunt John Douglas
Published: April 2007

Large-scale urban models often are subdivided into simpler submodels. The parameters of these models can be estimated using approaches that differ in regard to whether the full modeling system is run during an estimation procedure or whether that overall estimation is performed simultaneously with the estimation of the individual submodels. There are also ways in which extra data or extra models can be used to further inform parameter values. Five different techniques are presented (“limited view,” “piecewise” “simultaneous,” “sequential,” and “Bayesian sequential”), and the statistical theory necessary to justify each technique concurrently is described. The practical advantages and disadvantages are discussed, and each technique is illustrated using a simple nested logit model example. The concepts then are further illustrated by describing the sequential parameter estimation process for a land use/transport interaction model of the Sacramento, California, region. The ideas and examples should help modelers place more of an emphasis on overall calibration, allow them to follow a more rigorous approach in establishing the parameters of large-scale urban models, and help them understand the theory and assumptions that they are implicitly adopting. Two techniques in particular are noted as worthy of future research in large-scale urban modeling: ( a) establishing the likelihood function based directly on the structural equations of the model, eliminating or reducing the need to “solve” for the model outputs during parameter estimation; and ( b) using Bayesian techniques to adjust parameters in an overall estimation without discarding what is already known about those parameters.
Adjusting Computer Modeling Tools to Capture Effects of Smart Growth: Or “Poking at the Project Like a Lab Rat”
Authors: Walters Gerard , Ewing Reid , Schroeer William
Published: April 2007

A developer in Atlanta, Georgia, asked the U.S. Environmental Protection Agency (EPA) to allow construction of a bridge that would make viable a proposed mixed-use development on an industrial site near downtown Atlanta. The construction would not be allowed, given Atlanta’s Clean Air Act conformity lapse, unless EPA found that the bridge, and the development it enabled, would reduce air emissions. EPA’s evaluation of the request was the agency’s first explicit examination, in a regulatory context, of urban planning as a means of reducing air pollution. As part of evaluating the developer’s petition, an EPA consultant team developed and applied innovative travel forecasting methods to accurately reflect the differences in transportation impacts among different development designs for the Atlantic Steel site. The methods also compare the impacts associated with developing the Atlantic Steel in-fill site with those of pushing the development into more remote “greenfield” areas of the region. The team devised a series of enhancements to the conventional travel forecasting methods, related to zone structure and trip-length profiles, network connectivity for intrazonal and neighboring-zone travel, representation of transit accessibility, influence of parking costs, recognition of nonmotorized travel, sensitivity to pedestrian environment factors, and sensitivity to site design based on the latest national research. With the help of these forecasting and analysis methods, the Atlantic Steel site studies show that certain site design amenities reduce travel. They also show that, when both regional location and site design enable people to travel by a mix of modes, measurably lower emissions and environmental impacts result.
Effective Transit Requires Walkable Communities: Land Use Lessons of Transport Patterns in Four World Cities
Authors: Konheim Carolyn S. , Ketcham Brian
Published: April 2007

A comparison of transportation systems in the metropolitan areas of the world’s financial capitals—London, Paris, New York, and Tokyo—found that although all of the urban areas are spreading outward from their historical and economic cores, there are striking differences in their patterns of development—and the transport consequences. The principal determinant of travel demand and mode in the four cities is the extent to which housing and employment are clustered around transit. It appears that the more that daily trip needs can be met by walking, the more likely that longer trips will be made by transit than by automobile. This conclusion is drawn from the high transit use and low automobile use in the inner zones of New York, where there is the largest number of rapid-transit stations of all four cities. It is reinforced by comparisons of outer zones of New York and Tokyo with similar total population density but strikingly different configurations of settlement and greatly contrasting travel patterns. Extensive supporting data are reported. The land use configurations of each region are as much the product of institutional and economic forces as of each city’s geography, history, and culture. London, the urban area most similar to the New York region in size and culture, is responding to aggressive national policies that mandate land use plans to promote town centers and reduce travel demand. Long-range planning processes in Tokyo and Paris have achieved transit-oriented development even in their outer zones. In contrast, hundreds of municipalities in the 31 -county New York metropolitan area make reactive land use decisions influenced by incentives to sprawl inherent in the U.S. economy. Measures to offset these forces are recommended.
Sketch Planning a Street Network
Authors: Ewing Reid
Published: April 2007

A sketch planning methodology is used to determine the optimal spacing of through streets as a function of residential density. Unlike earlier efforts to relate street spacing to residential density, this methodology accounts for changes in mode share, trip length, time of travel, and intersection capacity as residential density increases. The methodology is transferable to other areas by modifying assumptions relating to travel demand and street network characteristics. Planners can derive their own spacing requirements for purposes of community master planning, site-plan review and approval, access management, or zoning and subdivision regulation.
Uncompacted Void Content of Fine Aggregate as Quality Indicator of Materials Used in Superpave Mixtures
Authors: Leomar Fernandes Jose , Roque Reynaldo , Tia Mang , Casanova Lorenzo
Published: April 2007

The uncompacted void content of fine aggregate, or fine aggregate angularity (FAA), was introduced in the Superpave mixture design system to screen smooth or rounded fine aggregates that may result in mixtures with low rutting resistance. The assumption is that fine aggregates with lower FAA values have lower shear strength (internal friction) and lower resistance to rutting. Continued implementation and evaluation of the Superpave system has led to numerous questions regarding the validity of this assumption and of the use of the FAA test in general. Nine fine aggregates were used to evaluate the FAA test and to determine whether it was a reliable indicator of fine aggregate shear strength. FAA tests were performed using three gradations and the three standard test methods (A, B, and C). Microscopic analysis was conducted to obtain independent visual measures of angularity and texture. Direct shear tests were performed at four confining stresses to determine shear strength parameters. Results indicated that FAA values were related to visual measures of texture and angularity. However, although FAA value contributed to shear strength, it appeared that other factors such as toughness, gradation, and packing characteristics of the fine aggregate overshadow its effect. For the fine aggregates tested, the FAA test rejected aggregates with high shear strength and accepted aggregates with low shear strength. It was concluded that FAA values alone may not be adequate to assess shear resistance of fine aggregate. Direct shear strength may be a better parameter, but additional work is required to evaluate its validity and feasibility.
Cold In-Place Recycling on US-283 in Kansas
Authors: Thomas Todd , Kadrmas Arlis , Huffman John
Published: April 2007

In 1997 an experimental partial-depth cold in-place recycling project was performed on US-283 in Kansas. Two sections approximately equal in length, one with Class C fly ash and the other with an emulsion with lime slurry, were recycled. On both sections a hot-mix asphalt overlay was placed after curing. Field observations in 1998 showed minor transverse cracking in the fly ash section, but no cracking was evident in the emulsion-plus-lime section. Transverse cracking increased in the fly ash section in 1999 and was noted for the first time in the emulsion-plus-lime section during this same evaluation. Longitudinal cracking in the wheel-paths of the fly ash section was also first observed in 1999. Rutting was not observed in either section during the evaluations. The results of Superpave indirect tensile testing in the laboratory confirmed that the fly ash section should crack before the emulsion-plus-lime section; laboratory testing with the Superpave shear tester and the asphalt pavement analyzer also indicated that the mixtures were not susceptible to rutting.
Sulfur-Modified Bottom Ash as Aggregate in Hot-Mix Asphalt Concrete: Field Demonstration Project
Authors: Estakhri Cindy K. , Saylak Donald
Published: April 2007

The use of bottom ash in road construction as an aggregate for both roadway surfaces and base courses has been limited because of its absorbency and friability. The former tends to increase asphalt binder demand, and the latter adversely affects its ability to withstand the crushing effects of traffic loads. Nevertheless, bottom ash is lighter in weight and generally much cheaper than conventional quality aggregates such as crushed limestone, sand, and gravel. Research was undertaken to upgrade the load-bearing characteristics of bottom ash and maximize its use in asphaltic concrete mixtures through sulfur modification. The process essentially coats the ash with liquid sulfur, which, upon cooling, fills the voids on the surface of the particles while increasing their crushing resistance. The results of laboratory investigations indicate that asphaltic concrete mixture designs in which bottom ash represents 50 to 100 percent of the aggregate fraction can be achieved. Sulfur-modified bottom ash (SMBA) mixtures compare favorably with typical Texas Department of Transportation surface course mixtures in terms of strength, durability, and asphalt demand. Results of a field demonstration project in which SMBA was incorporated into hot-mix asphalt concrete are presented. An asphalt batch plant was successfully used to incorporate the sulfur into the bottom ash and produce the hotmix asphalt concrete. The mixture was successfully placed as a 50-mm (2-in.) overlay on an existing asphalt surface at the entry to the asphalt plant facility, and adequate density was achieved with standard compaction equipment. The SMBA hot-mix overlay is currently under traffic by heavy haul trucks entering the plant facility, and early indications of performance are good.
Effects of Water Saturation Level on Resistance of Compacted Hot-Mix Asphalt Samples to Moisture-Induced Damage
Authors: Choubane Bouzid , Page Gale C. , Musselman James A.
Published: April 2007

The Florida Department of Transportation (FDOT) initiated monitoring of its first Superpave section on I-75 in Columbia County for stripping potential using AASHTO T 283, which specifies that all conditioned test samples be saturated to between 55 and 80 percent based on 7 ± 1 percent air voids. A fairly large saturation range is allowed because it was thought that mixtures may have different percentages of permeable air voids. However, the potential interaction between air void content and the level of saturation has not been fully investigated. It is also not clear whether test results from samples saturated to 55 percent are comparable with those of the same mixture saturated to 80 percent for a similar air void content. Therefore, although FDOT adopted AASHTO T 283, it also initiated a parallel study on the effects of different degrees of saturation on moisture damage. Findings are reported of both the ongoing monitoring of the I-75 project for potential stripping and the investigation of the effects of different levels of saturation on moisture susceptibility test results as determined using AASHTO T 283.
Suitability of Asphalt Pavement Analyzer for Predicting Pavement Rutting
Authors: Choubane Bouzid , Page Gale C. , Musselman James A.
Published: April 2007

Findings are summarized from an investigation performed to evaluate the suitability of a wheel-tracking device known as the asphalt pavement analyzer (APA) for assessing the rutting potential of asphalt mixes. The evaluation process consisted of correlating the APA’s predicted rutting with known field measurements. The correlation between beam and gyratory samples and the testing variability were also investigated. In addition, the APA test results were compared with those obtained using the Georgia loaded-wheel tester. The findings of this investigation indicated that the APA may be an effective tool to rank asphalt mixtures in terms of their respective rut performance. However, for each mixture type, the APA testing variability was significant between tests and between the three testing locations within each test. Differences in rut measurements of up to 4.7 and 6.3 mm were recorded for beam and gyratory samples, respectively. Therefore, using the APA as a clear pass-or-fail criterion for performance prediction purposes of asphalt mixtures may not be appropriate at this time. It should be noted that these findings are based on data collected on three mixes. Therefore, it is suggested that the APA testing variability (testing and testing locations within the device) be further assessed with a wider range of mixtures. The intent of such an assessment should not only be to correlate the APA results with field data but also to develop potential pass-or-fail limits and procedures.
Device for Measuring Shear Resistance of Hot-Mix Asphalt in Gyratory Compactor
Authors: Guler Murat , Bahia Hussain U. , Bosscher Peter J. , Plesha Michael E.
Published: April 2007

The development of a gyratory load-cell and plate assembly (GLPA) to measure the shear resistance of hot-mix asphalt mixtures is described. The GLPA is a simple tool that allows the measurement of the eccentricity of the resultant load applied by the gyratory compactor in real time during compaction. The GLPA is inserted on top of the mixture specimen in the compaction mold, requiring no changes in the compaction procedure. The results from the GLPA give a continuous measure of the resistance of asphalt mixtures to shearing under gyratory loading at a fixed angle. On the basis of a simplified analysis, it is hypothesized that the bulk shear resistance estimated from the GLPA is a good indicator of the compactibility of asphalt mixtures and their potential resistance to rutting under traffic. The shear resistance and volumetric characteristics of a number of trial mixtures fabricated in the laboratory were tested to show the utility of the GLPA. The results show that the shear resistance is highly sensitive to gradation, asphalt content, and temperature. They also indicate that there are interactive effects of these factors that are independent of the volumetric properties. Although the relationship between the results of the GLPA and the field performance of mixtures is yet to be determined, this device has the potential to be a low-cost and effective tool to complement the current volumetric mixture design procedure. It provides a tool to measure an important mechanical property that is a good indicator of bulk shear resistance of asphalt mixtures.
Specimen Geometry Study for Direct Tension Test Based on Mechanical Tests and Air Void Variation in Asphalt Concrete Specimens Compacted by Superpave Gyratory Compactor
Authors: Chehab Ghassan R. , O’Quinn Emily , Richard Kim Y.
Published: April 2007

Reliable materials characterization and performance prediction testing of asphalt concrete requires specimens that can be treated as statistically homogeneous and representative of the material being tested. The objective of this study was to select a proper specimen geometry that could be used for uniaxial tensile testing. Selection was based on the variation of air void content along the height of specimens cut and cored from specimens compacted by the Superpave gyratory compactor (SGC) and on the representative behavior under mechanical testing. From measurement and comparison of air void contents in cut and cored specimens, it was observed for several geometries that sections at the top and bottom and those adjacent to the mold walls have a higher air void content than do those in the middle. It is thus imperative that test specimens be cut and cored from larger-size SGC specimens. Complex modulus and constant crosshead-rate monotonic tests were conducted for four geometries—75 × 115, 75 × 150, 100 × 150, and 100 × 200 mm—to study the effect of geometry boundary conditions on responses. On the basis of graphical and statistical analysis, it was determined that there was an effect on the dynamic modulus at certain frequencies but no effect on the phase angle. Except for 75 × 115 mm, all geometries behaved similarly under the monotonic test. From these findings and other considerations, it is recommended that the 75- × 150-mm geometry, which is more conservative, and the 100- × 150-mm geometry be used for tensile testing.
Asphalt Mix Evaluations: Case Study at San Francisco International Airport
Authors: Monismith Carl L. , Harvey John T. , Guada Irwin M. , Long Fenella , Vallerga Bernard A. , Nokes William A. , Jew Adlai
Published: April 2007

A forensic study of asphalt mix performance at the San Francisco International Airport (SFIA) using the simple shear test developed by the Strategic Highway Research Program is described. The study examined taxi ways subjected to stationary and slow movements of heavy aircraft wheel loads and covered a period of about 2.5 years. The results of the study indicate the need to modify (or change) current FAA criteria for mix design of asphalt mixes for heavy-duty airfield pavements, particularly for taxi ways used for takeoff operations and subjected to stop-and-go operations of heavy aircraft like the Boeing 747-400. Information presented suggests that the simple shear test conducted in repeated loading while the height of the specimen is maintained constant (RSST-CH) can be used as a replacement for the current FAA mix evaluation procedure using the Marshall test. Mix design criteria are presented and are based on satisfactory performance of a high-stability mix introduced at SFIA for taxiways.
Numerical and Graphical Method to Assess Permanent Deformation Potential for Repeated Compressive Loading of Asphalt Mixtures
Authors: Bhairampally Rajesh K. , Lytton Robert L. , Little Dallas N.
Published: April 2007

Repeated-load permanent deformation testing has long been a popular way to characterize the performance of asphalt mixtures and to account for damage that leads to rutting. A number of empirical models have been used to fit repeated-load permanent deformation data. One such model, developed by Tseng and Lytton in 1989, fits permanent deformation data of most asphalt mixtures well. However, some mixtures exhibit a rate of damage that is in excess of that predicted by the 1989 Tseng and Lytton model. A numerical adaptation of the Tseng and Lytton empirical model is presented that readily characterizes such damage-susceptible mixtures. The excessive rate of damage is explained and reconciled in terms of plastic work theory and dissipated strain energy. The numerical approach is used to demonstrate the corrective effects of two types of additives to the mixtures: a recycled coproduct and hydrated lime.
Findings on the Approach Process Between Vehicles: Implications for Collision Warning
Authors: Brackstone Mark A. , Sultan Beshr , McDonald Michael
Published: April 2007

Over the past 10 years there has been a growing body of research into modeling and describing driving behavior, particularly for situations that occur on motorways. This interest has arisen from the need to assess safety and capacity benefits that could be produced by changes to road design, operation, signage, and in-vehicle advanced transport telematics, such as collision warning (CW) or autonomous cruise control. For the most part these investigations have focused on “close” or “car” following, which describes the maintenance of a time- or distance-based following headway. However, often overlooked, and of equal importance, is the “approach” process, describing how a driver decelerates when approaching a slower vehicle. There are several competing theories of the behavioral basis underlying this process, including, for example, those based on time-to-collision or optic flow. There are, however, very few data against which such models can be assessed and systems designed. Presented are the results from an exploratory, instrumented vehicle study designed to assess approach mechanisms. The two key features of the process are explored: the circumstances under which driver deceleration is instigated, and the process governing the control of the deceleration itself. Finally, there is a brief assessment of the implications of these findings for the design of CW systems, in which realistic warnings may prove vital to their acceptance by the driving public.
Emergence of a Cognitive Car-Following Driver Model: Application to Rear-End Crashes with a Stopped Lead Vehicle
Authors: Misener James A. , Tsao H.-S. Jacob , Song Bongsob , Steinfeld Aaron
Published: April 2007

Rear-end crashes are a major roadway safety problem, and the potential of crash countermeasures to address this has long been recognized. High-frequency or severe-consequence scenarios are focused on the general lead-vehicle-not-moving (LVNM) case and specific crash scenarios. Operating scenarios are identified, and frequencies are assessed. From these, a small number of prevalent LVNM crash scenarios are identified as the focus for subsequent model development and crash counter-measure efforts. These scenarios suggest nominal atmospheric, roadway, lighting, vehicle, and driver conditions in designing cost-effective safety features to avoid LVNM rear-end crashes. From this, emergent models for cognitive car following are developed, based on fusing current knowledge. This will serve as a foundation for further model development efforts as well as for future human-factors experiments.
Response to Simulated Traffic Signals Using Light-Emitting Diode and Incandescent Sources
Authors: Bullough John D. , Boyce Peter R. , Bierman Andrew , Conway Kathryn M. , Huang Kun , O’Rourke Conan P. , Hunter Claudia M. , Nakata Akiko
Published: April 2007

Simulated light-emitting diode (LED) traffic signals of different luminances were evaluated relative to incandescent signals of the same nominal color and at the luminances required by the specifications of the Institute of Transportation Engineers. Measurements were made of the reaction times to onset and the number of missed signals for red, yellow, and green incandescent and LED signals. Measurements also were made of subjects’ ability to correctly identify signal colors and of their subjective brightness and conspicuity ratings. All measurements were made under simulated daytime conditions. There were no significant differences in mean reaction time, percentage of missed signals, color identification, or subjective brightness and conspicuity ratings between simulated incandescent and LED signals of the same nominal color and luminance. Higher luminances were needed for the yellow and green signal colors to ensure that they produced the same reaction time, the same percentage of missed signals, and the same rated brightness and conspicuity as a red signal at a given luminance. Equations fitted to the reaction time data, the missed signals data, and the brightness and conspicuity ratings for the LED signals can be used to make quantitative predictions of the consequences of proposed changes in signal luminance for reaction time, brightness, and conspicuity.
Freight Travel Demand Modeling: Synthesis of Approaches and Development of a Framework
Authors: Pendyala Ram M. , Shankar Venky N. , McCullough Robert G.
Published: April 2007

It is increasingly being recognized at all levels of decision making that freight transportation and economic development are inextricably linked. As a result, many urban entities and states are embarking upon comprehensive freight transportation planning efforts aimed at ensuring safe, efficient, and smooth movement of freight along multimodal and intermodal networks. Over the past few decades there has been considerable published research on (1) freight transportation factors, (2) freight travel demand modeling methods, (3) freight transportation planning issues, and (4) freight data needs, deficiencies, and collection methods. A synthesis of the body of knowledge in these four areas is provided with a view to developing a comprehensive statewide freight transportation planning framework. The proposed framework consists of two interrelated components that facilitate demand estimation and decision making in the freight transportation sector.
Modeling Behavioral Aspects of Urban Freight Movement in Supply Chains
Authors: Boerkamps Jeroen H. K. , van Binsbergen Arjan J. , Bovy Piet H. L.
Published: April 2007

Decision makers in freight transportation need to assess new distribution systems and the impacts of changes in the freight distribution environment on infrastructure needs and usage, logistical performance, emissions, and energy use. There is a need, therefore, for behavioral models that can predict goods flows and vehicle flows in both current and future situations. This research outlines a conceptual framework consisting of the markets, actors, and supply chain elements of freight movement. Supply chains are constructed by linking distribution channels (of different logistics characteristics) between different activity types, such as consumers, supermarkets, stores, offices, distribution centers, and factories. The framework outlined in this research was used to develop the GoodTrip model—a demand-driven, commodity-based freight movement model that incorporates supply chains. Starting with consumer demand, the model estimates goods flows and simulates vehicle tours. The open architecture of the model allows mixed use of empirical data, behavioral models, and scenario-type assumptions. The behavioral models will be developed in future research. In its first application, the GoodTrip model was used to compare the logistical performance and external impacts of three types of urban distribution systems: the traditional system and two concepts using urban distribution centers (one using vans, the other using automated underground vehicles). The results show considerable differences in the performance and effects of the alternatives, especially when they are applied to different types of distribution channels, such as food retail stores or bookstores.
Perceived Value of Time for Truck Operators
Authors: Kawamura Kazuya
Published: April 2007

Value of time for trucks was estimated from stated preference data collected in California. Truckers were asked about a choice between an existing free road versus a toll facility for different combinations of travel time and cost. Estimation was based on the point of diversion at which the switch of facility occurred in the stated preference questions and also on the use of a modified logit model in which the coefficients to be estimated were assumed to be distributed lognormally across the population. Comparisons between data sets that were segmented according to business type, shipment size, and the method of driver compensation indicated that for-hire trucks tend to have higher values of time than private ones and the companies that pay drivers hourly wages have higher values of time than those who pay commissions or fixed salary.
Modeling Inertia and Compliance Mechanisms in Route Choice Behavior Under Real-Time Information
Authors: Srinivasan Karthik K. , Mahmassani Hani S.
Published: April 2007

This research examines route choice, in the presence of real-time information, as a consequence of two underlying behavioral mechanisms: compliance and inertia. The compliance mechanism reflects the propensity of a user to comply with the information supplied by advanced traveler information systems (ATIS). The inertial mechanism represents the tendency of users to continue on their current paths. These two mechanisms in route choice are neither mutually exclusive nor collectively exhaustive. A framework is proposed to model these mechanisms explicitly. The proposed framework decomposes the route choice into two states by exploiting the user’s path choice structure (resulting from the current choice prior to the decision of interest) and the information supplied by ATIS. In each state, the mechanisms are incorporated by associating their utilities with those that reflect the specific attributes of the alternative paths. The resulting nested choice structure is implemented using the multinomial probit model. This framework is illustrated using route choice data obtained from dynamic interactive simulator experiments. The empirical results strongly support the simultaneous presence of both the compliance and inertia mechanisms in route choice behavior. The results also indicate that information quality, network loading and day-to-day evolution, level-of-service measures, and trip-makers’ prior experience are significant determinants of route choice through the inertial and compliance mechanisms. These findings have important implications in travel behavior forecasting, ATIS design and evaluation, demand management, and network state prediction.
Route Choice Model with Inductive Learning
Authors: Nakayama Shoichiro , Kitamura Ryuichi
Published: April 2007

In this study drivers are assumed to reason and learn inductively based on the theory of cognitive psychology. The model system is basically a production system, a compilation of if-then rules in which the rules are revised by applying genetic algorithms. The behavior of drivers and network flow through Monte Carlo simulation using the model system is examined. The intention of this research is to shed light on the behavior of a driver-network system from a new standpoint, one different from that of equilibrium analysis. This research views drivers’ behaviors as psychological and heterogeneous rather than economical and homogeneous. The results of the numerical experiments can be summarized as follows: (1) network flow does not necessarily converge to the user equilibrium; (2) drivers form a delusion, an extremely biased perception of travel time as a result of experiencing excessive travel times on early parts of the simulation in which little experience had been gained; (3) the delusion is dissolved by switching routes capriciously; and (4) without caprice drivers continue to travel on the same route because of their delusions and develop the habit of choosing the same route, thus freezing their behaviors. These results indicate that system behavior is much more complex and dynamic than implied by equilibrium analysis.
Anticipated Travel Time, Information Acquisition, and Actual Experience: Hanshin Expressway Route Closure, Osaka-Sakai, Japan
Authors: Fujii Satoshi , Kitamura Ryuichi
Published: April 2007

Travel time is one of the most fundamental and important determinants of travel behavior. However, the travel time on which a travel decision is based is a subjective one (i.e., it is an anticipated travel time). A conceptual model of the formation of an anticipated travel time through information acquisition and initial driving experience is proposed. Day-to-day data of anticipated travel times were collected during a closure of the Hanshin Expressway Sakai Route, a toll road connecting the central business districts of Osaka and Sakai, which is located approximately 20 km south of the Osaka route closure. A test was conducted of the information dominance hypothesis (i.e., as drivers acquire more information on travel time, they can predict travel time more precisely and refer less to anticipated travel times used in the past to anticipate travel times) and the experience dominance hypothesis (i.e., influences of information not from driving experience on anticipated travel time is weaker with actual driving experience than without actual experience). Although word of mouth information does not have impacts consistent with these two hypotheses, results with other types of information support both hypotheses.
Aggregate- and Disaggregate-Based Travel Time Estimations: Comparison of Applications to Sustainability Analysis and Advanced Traveler Information Systems
Authors: Zietsman Josias , Rilett Laurence R.
Published: April 2007

Travel time estimation is important for a wide range of applications, including advanced traveler information systems (ATIS), sustainability analysis, and discrete choice modeling. Approaches to travel time estimation traditionally have been based on aggregate data sets that examine travel times over a number of days or travel times in previous time intervals. Automatic vehicle identification data make it possible to analyze travel time data at a totally disaggregate or individual commuter level. It is postulated in this research that the capability of modeling travel characteristics on a disaggregate level can improve the accuracy with which performance measures are quantified. The test beds examined are a 22-km section of the I-10 corridor and a 21-km section of the US-290 corridor in Houston, Texas. It was found that aggregation across days, which does not consider the effect of individual days, is 63 percent less accurate than aggregation by days, which does consider the effect of individual days. Even though the latter technique was found to be more accurate, it was illustrated that 40 percent of the regular commuters’ travel times are statistically different from these aggregate estimates. Similarly, for travel time variability, it was found that for approximately 20 percent of the cases the travel time standard deviations for regular commuters are statistically different from the aggregate estimates. These results illustrate the uniqueness of an individual commuter’s travel patterns and emphasize the benefit of conducting analyses at the level of the individual commuter for both ATIS and sustainable transportation.
Analysis of Time Allocation, Departure Time, and Route Choice Behavior Under Congestion Pricing
Authors: Yamamoto Toshiyuki , Fujii Satoshi , Kitamura Ryuichi , Yoshida Hiroshi
Published: April 2007

Driver behavior under congestion pricing is analyzed to evaluate the effects of alternative congestion pricing schemes. The analysis, which is based on stated preference survey results, focuses on time allocation, departure time choice, and route choice when a congestion pricing scheme is implemented on toll roads in Japan. A unique feature of the model system of this study is that departure time choice and route choice are analyzed in conjunction with the activities before and after the trip. A time allocation model is developed to describe departure time choice, and a route and departure time choice model is developed as a multinomial logit model with alternatives representing the choice between freeways and surface streets and, for departure time, the choice from among before, during, or after the period when congestion pricing is in effect. The results of the empirical analysis suggest that departing during the congestion pricing period tends to have higher utilities and that a worker and a nonworker have quite different utility functions. The comparative analysis of different congestion pricing schemes is carried out based on the estimated parameters. The results suggest that the probability of choosing each alternative is stable even if the length of the congestion pricing period changes, but a higher congestion price causes more drivers to change the departure time to before the congestion pricing period.
Content of Variable Message Signs and On-Line Driver Behavior
Authors: Peeta Srinivas , Ramos Jorge L. , Pasupathy Raghubhushan
Published: April 2007

Variable message signs (VMS) are programmable traffic control devices that convey nonpersonalized real-time information on network traffic conditions to drivers encountering them. Especially useful under incidents, VMS aim to influence driver routing decisions to enhance network performance. This study investigates the effect of different message contents on driver response under VMS. Presumably, if the message content is a significant factor in driver response, the traffic controller can use it as a control variable to influence network traffic conditions positively without compromising the integrity of information. This issue is addressed through an on-site stated preference user survey. Logit models are developed for drivers’ diversion decisions. The analysis suggests that content in terms of the level of detail of relevant information significantly affects drivers’ willingness to divert. Other significant factors include socio-economic characteristics, network spatial knowledge, and confidence in the displayed information. Results also indicate differences in the response attitudes of semitrailer truck drivers compared to other travelers. They provide substantive insights for the design and operation of VMS-based information systems.
Anticipatory Optimization of Traffic Control
Authors: van Zuylen Henk J. , Taale Henk
Published: April 2007

Traffic control and travelers’ behavior are two mutually influential processes with different objectives. Decisions made in traffic control influence travelers’ possibilities in choosing their preferred mode, route, and time of departure; and the choices made by travelers influence the optimization possibilities for traffic control. This research presents the results of simulation studies and a mathematical analysis of this bilevel optimization problem. Under certain conditions, multiple stable situations are possible, but some of these situations are sensitive to small disturbances by which the system moves away from the original equilibrium state. There appears to be a nonlinear relationship between system parameters and the character and location of the equilibrium situations. The details of the travel time model appear to have a large influence. If road authorities want to optimize traffic control, they have to anticipate the reaction of travelers. This makes the optimization process much more complicated. Iterative optimization, where traffic control is adjusted as soon as traffic conditions change, generally does not lead to a system optimum. Methods are therefore necessary that allow for the optimization of traffic control while taking into account that traffic flows will change as a result of traffic control.
Effect of Residential Location and Access to Transportation on Employment Opportunities
Authors: Thakuriah Piyushimita , Metaxatos Paul
Published: April 2007

Women who have been on public assistance need to obtain and maintain steady employment because they stand to lose their public benefits and also because it is the only way out of poverty. Although the sociodemographic and general economic influences on job retention have been examined in the literature, the effects of transportation and of place of residence in a metropolitan area vis-à-vis entry-level job locations have not been studied systematically. Four sets of factors—transportation, location, sociodemographic, and family effects—are examined for their effect on job retention. In particular, it was found that employment security for female welfare clients or former clients does not come from job retention (i.e., tenure with the same employer) but from “employment retention” (i.e., jobs with different employers, possibly with a trend toward upward mobility). The effects of transportation and location on job and employment retention are complex. Although access to a vehicle is important for increasing employment retention, even more important is the number of job opportunities accessible by private vehicle or public transit within a tolerable travel time. Female welfare clients who retain a job longer and hold more jobs within a 2-year period are more likely to live in subareas of the metropolitan area with greater access to jobs within reasonable travel times; the competition for those jobs from other low-income individuals is low. Furthermore, female welfare clients with a high school diploma, when given the appropriate accessibility and location opportunities, enjoy increased job retention.
Women’s Travel Patterns and the Environment: An Agenda for Research
Authors: Schintler Laurie , Root Amanda , Button Kenneth
Published: April 2007

Demographic change, new family structures, and concerns about personal safety are contributing to a growing use of motorized transportation by women. The increasing importance of women as travelers has implications for the ways in which transportation policy must be reviewed in an era when sustainable development has become a key issue. An appreciation of the particular nature of women’s travel behavior, and their designed behavior, could facilitate an easier path to sustainability. The travel patterns, needs, and psychology of women are examined, as well as the influence of these patterns and behavior on efforts to promote sustainable development. Women’s travel patterns differ in important ways from those of men. In particular, gender differences arise in ( a) the distance traveled, ( b) the mode of travel, and ( c) the complexity and purpose of trip making. The particular psychology of women contributes to these patterns. In comparison with men, women tend to be prone to ambivalent feelings, but their analysis of these feelings can prompt leaps in thought and creative solutions to problems. In addition, women are more risk averse than men. Risk aversion may affect women’s travel decisions—for example, when security is a concern. Changes in the economy also are placing new demands and constraints on women, their lives, and their travel patterns. Future research on women and transportation should focus on the psychological aspects of women’s travel, the special travel needs and circumstances of women, and the influence of changing economic conditions on women’s travel patterns and the environment.
Impact of Emergency Vehicle Preemption on Signalized Corridor Operation: An Evaluation
Authors: Nelson Eric J. , Bullock Darcy
Published: April 2007

A case study that examines the impact of emergency vehicle preemption on closely spaced arterial traffic signals is reported. The study was conducted on State Route (SR) 26, a principal arterial and main thoroughfare that connects Interstate 65 with US-52 on the east side of Lafayette, Indiana. Four coordinated intersections along SR-26 were examined by using seven preemption paths and three different transition algorithms (smooth, add, and dwell). The number of preemption calls in the simulation period varied from one to three for equal simulation periods. The findings generally show that a single preemption call had a minimal effect on the overall travel time and delay through the network. The results also indicate that the smooth transitioning algorithm performed the best with most scenarios and paths for both the arterial and the side streets. When multiple emergency vehicles preempt at closely spaced time intervals, the impact of preemption was more severe. For the network studied, the most severe impact on arterial travel time observed was an increase in the average arterial travel time on the order of 20 to 30 s. The study focused on emergency vehicle preemption, but the general procedures described could also be applied to railroad preemption or transit priority.
Development and Evaluation of Intelligent Bus Priority Concept
Authors: Balke Kevin N. , Dudek Conrad L. , Urbanik Thomas
Published: April 2007

Development and laboratory testing of an intelligent concept for providing priority to buses at signalized intersections without disrupting progression are discussed. The concept used bus position information to predict when in the cycle a bus would arrive at the bus stop and stop line of a signalized intersection and to determine whether a bus needs priority. The strategy used to provide priority was selected on the basis of the estimated arrival time of the bus at the stop line. Priority was provided by using phase extension, phase insertion, and early return strategies without causing the controller to drop from coordination. Implementation of the strategies was accomplished through normal traffic-signal controller commands (such as Ring Force Offs and Phase Holds). Hardware-in-the-loop simulation studies were performed to evaluate the effectiveness of the concept with real traffic-signal controllers. The performance of the intelligent bus priority approach was examined at three volume-to-capacity levels: 0.5, 0.8, and 0.95. Significant reductions in bus travel times were achieved at all three volume-to-capacity levels by using the intelligent bus priority approach. Use of the intelligent bus priority approach resulted in only minor increases in total system stop delay and individual approach stop delays at volume-to-capacity levels of 0.5 and 0.8. The results of the simulation studies performed as part of this study suggested to the researchers that the intelligent bus priority approach could be used at moderate traffic levels (up to volume-to-capacity levels of 0.9 or less) without significantly affecting cross-street delays.