bluuebunny/crossref_metadata_2025 huggingface dataset:
Bus Patronage in Great Britain: Econometric Analysis
Authors: Dargay Joyce , Hanly Mark
Published: April 2007

The demand for local bus services in Great Britain was investigated to obtain estimates of fare elasticities for use in policy calculations to project the change in bus patronage nationally as a result of a given average fare change, and to explore possible variation in the elasticity. The estimation of bus fare elasticities was based on annual national and regional aggregate data for the years 1974 to 1996 on bus patronage, fares, and other relevant factors influencing bus use. The estimations used dynamic econometric models relating per capita bus patronage (all journeys) to real per capita income, real bus fares (average revenue per journey), and service level (bus vehicle kilometers). The results indicate that patronage is relatively fare-sensitive, with an elasticity for all Great Britain of −0.4 in the short run and −0.9 in the long run. The evidence suggests that the long-run values are at least twice the short-run elasticities and that the total response takes about 7 years. Indications are that full-fare passengers are less sensitive to fare changes than the average bus passenger. The strong negative relationship between automobile ownership and bus patronage in the long run is confirmed, although the short-run effect is negligible. The cross-elasticity between bus patronage and motoring costs appears to be negligible in the short run and to be about 0.3 to 0.4 in the long run.
Travel-Time Estimates Obtained from Intelligent Transportation Systems and Instrumented Test Vehicles: Statistical Comparison
Authors: Eisele William L. , Rilett Laurence R.
Published: April 2007

Accurate estimation of travel time is necessary for monitoring the performance of the transportation system. Often, travel times are estimated indirectly by using instantaneous speeds from inductance loop detectors and making a number of assumptions. Although these travel times may be acceptable estimates for uncongested conditions, they may have significant error during congested periods. Travel times also may be obtained directly from intelligent transportation systems (ITS) data sources such as automatic vehicle identification (AVI). In addition, mobile cellular telephones have been touted as a means for obtaining this information automatically. Data sources that collect travel-time estimates directly provide travel-time data for both real-time and off-line transportation system monitoring. Instrumented test vehicle runs are often performed to obtain travel-time estimates for system monitoring and other transportation applications. Distance measuring instruments (DMIs) are a common method of instrumentation for test vehicles. DMI travel-time estimates are compared with AVI travel-time estimates by using a variety of statistical approaches. The results indicate that the travel-time estimates from test vehicles instrumented with DMI are within 1% of travel-time estimates from AVI along the study corridor. These results reflect that DMI is an accurate instrumented test vehicle technology and, more important, AVI data sources can replace traditional system monitoring data collection methods when there is adequate tag penetration and infrastructure. A method for identifying instrumented test vehicle drivers who may require additional data collection training is provided. The described procedures are applicable to any instrumented vehicle technique (e.g., the Global Positioning System) in comparison to any ITS data source that directly estimates travel time (e.g., mobile cellular telephones).
Estimating Travel Time Summary Statistics of Larger Intervals from Smaller Intervals Without Storing Individual Data
Authors: Park Dongjoo , Rilett Laurence R. , Pattanamekar Parichart , Choi Keechoo
Published: April 2007

Historically, real-time intelligent transportation systems data are aggregated into discrete periods, typically of 5 to 10 min duration, and are subsequently used for travel time estimation and forecasting. In a previous study of link and corridor travel time estimation and forecasting by using probe vehicles, it was shown that the optimal aggregation interval size is a function of the traffic condition and the application. It is expected that traffic management centers will continue to collect travel time statistics (e.g., mean and variance) from probe vehicles and archive this data at a minimum time interval. Statistical models are developed for estimating the mean and variance of the link and route or corridor travel time for a larger interval by using only the observed mean travel time and variance for each smaller or basic interval. The proposed models are demonstrated by using travel time data obtained from Houston, Texas, which were collected as part of the automatic vehicle identification system of the Houston TranStar system. It was found that the proposed models for estimating link travel time mean and variance for a larger interval were easy to implement and provided results that had minimal error. The route or corridor travel time mean and variance model had considerable error compared with the link travel time mean and variance models.
Prototype Classification Tool for Supporting Maintenance of Traffic Signal Timing Plans
Authors: Smith Brian L. , Hauser Trisha A. , Scherer William T.
Published: April 2007

Advanced traffic control systems, such as traffic signal systems, include large numbers of sensors intended to support the monitoring of traffic conditions. In addition, transportation agencies frequently archive data collected by these detectors, on the assumption that important information can be extracted from the archives with the proper tools. The development of a data mining tool intended to support the maintenance of traffic signal systems that operate in the time-of-day (TOD) mode by identifying when traffic conditions have changed significantly in a corridor is described. The data mining approach used is classification. A case study was conducted to demonstrate that accurate classification models can be developed by using archived data to map between a set of traffic conditions and the associated TOD interval or timing plan for which the conditions are best suited. The 92.4% classification rate achieved in the case study indicates that this data mining tool has the potential to effectively support TOD signal operations.
Use of Vessel Freight Data to Forecast Heavy Truck Movements at Seaports
Authors: Al-Deek Haitham M.
Published: April 2007

Ports are primary generators of truck traffic in the United States. Seaport operations will require operational and infrastructure changes to maintain the growth of international cargo operations. Truck trip generation models will provide transportation planners and public agencies with valuable information necessary for prioritizing funds for roadway upgrade projects and port infrastructure modifications. A new methodology is presented that combines backpropagation neural networks (BPN) and time series to forecast inbound and outbound heavy truck movements at seaports. The new method uses vessel freight data to identify which parameters are relevant for use as model input in predicting truck traffic at seaports. The method is successfully applied to five ports in Florida—Miami, Tampa, Palm Beach, Jacksonville, and Everglades—thus demonstrating its transferability. Details are provided for the Port of Everglades. The commodities at this port are classified into tons, barrels, and containers. It was found that the primary factors affecting truck traffic are imported containers, imported tonnage, imported barrels, exported containers, exported tonnage, and the particular weekday of operation. Separate BPN models were developed for inbound and outbound truck traffic at the ports. The new method forecasts that the Port of Everglades will have a 33% increase in average daily inbound heavy trucks and a 30% increase in average daily outbound heavy trucks by 2005 (2000 is the base year). The accuracy of the inbound and the outbound truck models is 93% and 92%, respectively.
Soil Nail Forces Caused by Frost
Authors: Kingsbury Don W. , Sandford Thomas C. , Humphrey Dana N.
Published: April 2007

Soil nailing can be an effective solution for wall construction but is not common in colder climates because unknown frost forces may occur in frost-susceptible soils behind the wall. Currently, no design criteria exist for these walls in frost conditions, but development of design guidelines under frost conditions would promote the use of this technology in cold climates. Soil nail head force results are presented for 3 years of monitoring of a soil-nailed wall in Moscow, Maine, in a frost-susceptible environment. Also, proposed methods for estimating nail head tensions arising from freezing in frost–susceptible conditions are discussed. Instrumentation was installed to determine the effectiveness of the wall’s facial insulation and to determine the effects of frost on an uninsulated wall. One monitoring station was insulated and the other comparable station was not. Instrumentation, including thermocouples, thermistors, vibrating wire strain gauges, piezometers, and earth pressure cells, revealed wall performance. During three milder than normal winters, frost action in the uninsulated areas produced tensions that exceeded design tensions. A portion of the annually induced nail head tensions was permanent and cumulative. Facial insulation minimized frost loads on nail and wall components below the top nail row. For frost-susceptible conditions, the magnitude of frost-induced maximum additional nail-head tension was related to the seasonal freezing index. The ultimate permanent nail head tension caused by frost was estimated from measurement data to be 2.5 times the peak seasonal tension increase.
Uncertainty Analysis for a Seismic Warning System
Authors: Jones Allen L. , Kramer Steven L. , Arduino Pedro , Eberhard Marc
Published: April 2007

Following the collapse of the Cypress structure, which killed 42 people in the 1989 Loma Prieta earthquake, the Washington State Department of Transportation (WSDOT) initiated a series of studies of the seismic vulnerability of the Alaskan Way Viaduct (AWV). The AWV, which carries nearly 100,000 vehicles per day, is one of only two north–south highways through downtown Seattle. The studies showed that this double-deck structure is vulnerable to extensive damage during and shortly after strong earthquake shaking. The structural vulnerabilities, associated with reinforced concrete details typical of 1950s construction, are exacerbated by the presence of highly liquefiable soils beneath the AWV, and by the seismic vulnerability of a seawall that is located immediately west of the AWV. To make decisions about closing the viaduct during or after an earthquake, WSDOT will need to have reliable and timely information about the likelihood of potential damage. To this end, a study was undertaken to develop design requirements for an instrumentation system that would detect the onset of soil liquefaction and provide input to a collapse warning system. Given the uncertainties associated with predictions of ground-shaking intensity, site response, liquefaction, and structural performance, it is difficult to predict levels of damage accurately. Therefore, an important part of this study was the identification and quantification of sources of uncertainty that needed to be considered in the development of a criterion for collapse potential. A framework based on the total probability theorem was developed to evaluate the probabilities of failure. For each source, a conditional probability distribution function was developed across the anticipated range in values. The results take the form of probabilities of liquefaction-induced collapse as a function of triggering criteria.
Piled Raft Behavior on the Crest of a Rock Slope
Authors: Choi Jin O , Sung Kwon Oh , Mo Kim Myoung
Published: April 2007

An investigation was conducted on the behavior of a piled raft on a rock slope having asymmetric geometry, through field measurement analysis. The contact pressure of the raft on the ground and the axial load distributions of the piles were measured using pressure cells and strain gauges, respectively. The measured data were analyzed to determine the contribution ratios of raft and piles, the distributions of contact pressure and pile carrying loads, and the axial load distribution of the piles. The contribution load ratio of the raft to the sum of the raft and the pile loads increased from 7.8% to 14.7% as the total bearing load of the piled raft increased during the construction process. It was also found that the asymmetric geometry significantly influenced the distribution of contact pressure and pile loads. The axial load distribution of the piles was dependent on the position of the pile in the raft and the geometry of the rock slope.
Thermal Properties and Transient Temperature Response of Full-Depth Asphalt Pavements
Authors: Mrawira Donath M. , Luca Joseph
Published: April 2007

An improved laboratory test procedure for measuring thermal conductivity of asphalt concrete (AC) pavement is proposed. In this preliminary work, a simple device for thermal diffusivity of AC is developed and the corresponding thermophysical properties are measured. The measurement results indicate that the thermal conductivity and thermal diffusivity of AC are functions of compaction degree, degree of moisture saturation, and temperature. From the estimated thermal conductivity and the measured thermal diffusivity, the transient temperature response to changes in environmental conditions of an AC pavement is analyzed numerically with an incremental recursive method by applying the energy balance principle and the Fourier heat transfer equation. The analysis results show that an AC pavement undergoes diurnal temperature cycles whose amplitude decreases with depth and changes sharply at the pavement surface. In addition, with the changing frequency of the temperature, thawing and refreezing effects of the AC pavement increase progressively from January to March in New Brunswick, Canada.
Prediction of Traffic-Actuated Phase Times on Arterial Streets
Authors: Hale David , Courage Kenneth G.
Published: April 2007

Traffic congestion in U.S. cities has grown rapidly in recent years, and numerous solutions are needed to address the problem. New research is described for producing basic improvements in the practice of traffic signal timing design, which is one of the many available weapons for fighting congestion and delay. Models in the literature for predicting traffic-actuated phase times are oversimplified. In some cases, they do not recognize the signal settings associated with today’s controllers, which affect phase times. In other cases, models from the literature do not recognize operational effects (for example, progression, queue blockage, permitted left turn, critical movement, early return to green, and stochastic effects) that affect phase times or that are applicable only to isolated signals instead of coordinated signals. Consequently, the recommended average phase times are not practical, and the resulting performance estimates and timing plan designs are unlikely to materialize in the field. The overall goal of this research is to describe and demonstrate an improved methodology for predicting actuated phase times. An improved methodology is needed to improve the overall timing plan design process. Experimental results indicate an improvement in the accuracy of actuated phase time calculation based on the improved methodology.
Optimized Policies for Adaptive Control Strategy in Real-Time Traffic Adaptive Control Systems: Implementation and Field Testing
Authors: Gartner Nathan H. , Pooran Farhad J. , Andrews Christina M.
Published: April 2007

The real-time traffic adaptive control system (RT-TRACS) represents a new, state-of-the-art system in advanced traffic signal control. It was developed cooperatively by a team of U.S. academic, private, and public researchers under the guidance of FHWA. The system provides a framework to run multiple traffic control algorithms, existing ones as well as new adaptive algorithms, as they become available. The optimized policies for adaptive control (OPAC) strategy, which provides a dual capability of individual intersection control as well as coordinated control of intersections in a network, was the first adaptive algorithm implemented within the RT-TRACS framework. The operational features of the OPAC prototype version that was developed for RT-TRACS are presented, and its implementation in the Reston Parkway field research test bed in Northern Virginia is described. The implementation provided valuable insights into the performance of coordinated OPAC under various traffic conditions and site geometry. Observations indicate that the strategy was instrumental in reducing delays and stops, compared with a well-tuned fixed time system that was in place, while maintaining progression along the arterial. Valuable lessons were learned that should lead to improvements in future implementations of adaptive algorithms.
Toward Improved Traffic Safety: Road Use Perception and Behavior in Estonia
Authors: Antov Dago , Sööt Siim
Published: April 2007

Rapid increases in motorization have raised concerns about accidents and fatalities internationally. Even nations that are experiencing declining numbers of fatalities, such as Estonia, have made reducing fatalities a major public policy goal. Traffic fatalities declined from 491 in 1991 to 204 in 2000 in Estonia. The federal government is intent on another 50% decrease by 2010. Two steps are necessary to achieve this decrease: understanding of the perceptions of road use behavior and field observations of driving and pedestrian practices. In May and June 2001, 655 subjects were surveyed to assess their perceptions of road use behavior. Drunken driving, lack of seat-belt use in the rear seat, and speeding on rural roads were all perceived to be problems. Generational differences accounted for the greatest differences in perception. The young gave higher scores to most road use activities, suggesting that better driver education may be needed. The number of fatalities and field observation indicate that treatment of pedestrians is an area in need of attention, especially because of the perception that it is not a major problem. Pedestrians accounted for 39% of motor-vehicle-related fatalities in Estonia in 2000. In field observations, 70% of drivers were observed to be in violation of the law requiring them to yield to pedestrians. Pedestrians themselves are not without blame; in field observations, 26% of pedestrians were seen to be in violation at signalized crossings. Finally, speeding continues to be a perceived and observed problem.
Feasibility of Real-Time Remote Speed Enforcement for Work Zones
Authors: Fontaine Michael D. , Schrock Steven D. , Ullman Gerald
Published: April 2007

Studies have shown that a large percentage of vehicles involved in work zone crashes are traveling at excessive speeds. Although traditional speed enforcement has been shown to reduce speeds through the work area, enforcement under these conditions can be dangerous to both the motoring public and enforcement officers. The work zone layout often limits the locations at which an officer can set up to enforce the speed limit and the locations at which violators can be stopped. Automated speed enforcement technology could help eliminate the need to stop violators in a work zone, but it is not currently a popular concept in the United States because of concerns about motorist privacy. Researchers hypothesized that this technology could be useful for work zone enforcement if adapted to a more real-time operation. The initial testing of the concept of remote speed enforcement is summarized. An automated speed enforcement system (consisting of digital video and lidar technology) was meshed with a wireless communications system. The unit determined when vehicles exceeded a certain speed threshold. If a vehicle was detected as exceeding the threshold, a digital photograph was taken of the violator. This photograph was then transmitted to an observer stationed downstream of the site. The technical feasibility of the system was assessed through field tests. Focus groups of law enforcement personnel were used to determine potential acceptance of the system in the law enforcement community. Recommendations for future improvements and possible applications of the system are made.
Pedestrian Collision Prediction Models for Urban Intersections
Authors: Lyon Craig , Persaud Bhagwant
Published: April 2007

In more recent safety analysis methods, collision prediction models can be used for identifying intersections with promise of safety improvement and for evaluating the effects of treatment. Considerable effort has been directed at developing collision prediction models, but little has been directed at pedestrian collisions. Collisions involving motor vehicles and pedestrians pose a significant safety problem, principally in urban areas, where the levels of vehicle-pedestrian conflicts are high. Data from Toronto, Canada, are used in the development of pedestrian collision prediction models for three- and four-legged urban intersections, with and without signal control. These models, which relate safety to pedestrian and vehicle traffic volumes, can be used to identify locations that might be targeted for treatment and to help evaluate treatment effects. Models are developed by using pedestrian and vehicular volumes and vehicle volumes only. It is seen that the use of pedestrian volume information results in a much richer model, emphasizing the importance of collecting this information in routine traffic counting programs. An important issue for collision prediction models is transferability to other jurisdictions. This is especially important in the case of pedestrian collision models, because many jurisdictions may not have data sets containing sufficient collisions and pedestrian volume counts with which to calibrate reliable models. Data from the city of Hamilton, Ontario, were used to test the transferability of the Toronto four-legged signalized intersection model. The test was successful: the recalibrated Toronto models predicted collision numbers that were very close to those predicted by the model calibrated directly for the Hamilton data.
Calibration and Validation of Microscopic Traffic Simulation Tools: Stockholm Case Study
Authors: Toledo Tomer , Koutsopoulos Haris N. , Davol Angus , Ben-Akiva Moshe E. , Burghout Wilco , Andréasson Ingmar , Johansson Tobias , Lundin Christen
Published: April 2007

The calibration and validation approach and results from a case study applying the microscopic traffic simulation tool MITSIMLab to a mixed urban-freeway network in the Brunnsviken area in the north of Stockholm, Sweden, under congested traffic conditions are described. Two important components of the simulator were calibrated: driving behavior models and travel behavior components, including origin–destination flows and the route choice model. In the absence of detailed data, only aggregate data (i.e., speed and flow measurements at sensor locations) were available for calibration. Aggregate calibration uses simulation output, which is a result of the interaction among all components of the simulator. Therefore, it is, in general, impossible to identify the effect of individual models on traffic flow when using aggregate data. The calibration approach used takes these interactions into account by iteratively calibrating the different components to minimize the deviation between observed and simulated measurements. The calibrated MITSIMLab model was validated by comparing observed and simulated measurements: traffic flows at sensor locations, point-to-point travel times, and queue lengths. A second set of measurements, taken a year after the ones used for calibration, was used at this stage. Results of the validation are presented. Practical difficulties and limitations that may arise with application of the calibration and validation approach are discussed.
Prediction of Asphalt Mix Fatigue Life with Viscoelastic Material Properties
Authors: Lee Hyun , Richard Kim Y. , Lee Seung
Published: April 2007

A simplified fatigue model is presented that can predict the fatigue life of asphalt mixes using viscoelastic properties only. This fatigue model was originally developed with the elastic-viscoelastic correspondence principle and continuum damage mechanics and was reduced to a simple version that can predict fatigue life with viscoelastic properties only. On the basis of the experimental study conducted on 12 different types of asphalt mixes, it was observed that the fatigue behavior of asphalt mixes is affected by both the viscoelastic properties and the fatigue characteristics, but mostly by the viscoelastic properties. In addition, it was found that the coefficient of conventional strain-based fatigue models could be expressed in terms of viscoelastic material properties. In the verification study, the fatigue model was able to predict the fatigue life of various types of mixes at the same level of prediction accuracy without change in model coefficients. The fatigue model was also able to accurately predict the changes in the fatigue life of an asphalt mix due to the changes in the volumetric mix properties.
Surrogate Safety Measures from Traffic Simulation Models
Authors: Gettman Douglas , Head Larry
Published: April 2007

Safety is emerging as an area of increased attention and awareness within transportation engineering. Historically, the safety of new and innovative traffic treatments has been difficult to assess, primarily because of a lack of good predictive models of crash potential and a lack of consensus on what constitutes a safe or unsafe facility. An FHWA-sponsored research project investigated the potential to derive surrogate measures of safety from existing traffic simulation models. These surrogate measures could then be used to support evaluations of various traffic engineering alternatives, including facilities that have not yet been built and strategies that have not yet been used. Each surrogate measure is collected on the basis of the occurrence of a conflict event, which is an interaction between two vehicles in which one vehicle must take evasive action to avoid a collision. The surrogate measures that are proposed as the best are time to collision, postencroachment time, deceleration rate, maximum speed, and speed differential. Time to collision, postencroachment time, and deceleration rate can be used to measure the severity of the conflict. Maximum speed and the speed differential can be used to measure the severity of the potential collision (by use of additional information about the mass of the vehicles involved to assess momentum). After the simulation model is executed for a number of iterations, a postprocessing tool would be used to compute the statistics for the various measures and perform comparisons between design alternatives.
Practical Procedure for Calibrating Microscopic Traffic Simulation Models
Authors: Hourdakis John , Michalopoulos Panos G. , Kottommannil Jiji
Published: April 2007

Since the use of simulation is becoming widespread in traffic engineering practice, questions about the accuracy and reliability of its results need to be addressed convincingly. A major criticism related to this issue is proper calibration of the simulation parameters as well as validation, which is often not done or dealt with in an ad hoc fashion. A complete, systematic, and general calibration methodology is presented for obtaining the accuracy needed in high-performance situations. A technique for automating a significant part of the calibration process through an optimization process is also presented. The methodology is general and is implemented on a selected simulator to demonstrate its applicability. The results of the implementation in two freeway sections of reasonable size and complexity, in which detailed data were collected and compared with simulated results, demonstrate the effectiveness of the manual calibration methodology. For instance, through calibration the average volume correlation coefficient on 21 detecting stations improved from 0.78 to 0.96. Comparable results were obtained with the automated calibration procedure with significant time savings and reduced effort.
Determination of Depth of Surface Cracks in Asphalt Pavements
Authors: Underwood Shane , Kim Y. Richard
Published: April 2007

Nondestructive measurement of crack depths of asphalt pavements in situ could be a valuable tool for engineers in rehabilitation planning. Such measurements currently must be made by first coring or trenching a pavement and then measuring the crack by hand. Two methods for performing this task nondestructively are presented. The two methods, surface wave and ultrasonic, use the slowing effect that a crack has on a wave. Two signal-processing techniques were used to analyze the surface wave method—the fast Fourier transform (FFT) and the short kernel method (SKM). The FFT method provided a frequency spectrum that was used to find the energy carried by specific frequencies. The percent energy reduction (PER) was computed and plotted at each crack depth; this plot revealed that PER values increase as crack depth increases. The SKM method showed the wave velocity to decrease as the crack depth in creased. By comparing the wave velocity of the cracked pavement with that of the undamaged pavement, a phase velocity ratio plot was developed and was shown to be adequate for predicting crack depth. Ultrasonic testing proved to be a simpler and more direct method than surface wave testing. It was not necessary to know the wave properties of an undamaged pavement with this method, and a quantitative prediction of crack depth was obtained. While encouraging results were observed with both methods, ultrasonic testing showed the most promise for application because of the commercial availability of ultrasonic meters and the direct prediction of crack depth.
ACS-Lite Algorithmic Architecture: Applying Adaptive Control System Technology to Closed-Loop Traffic Signal Control Systems
Authors: Luyanda Felipe , Gettman Douglas , Head Larry , Shelby Steven , Bullock Darcy , Mirchandani Pitu
Published: April 2007

ACS-Lite is being developed by FHWA to be a cost-effective solution for applying adaptive control system (ACS) technology to current, state-of-the-practice closed-loop traffic signal control systems. This effort is intended to make ACS technology accessible to many jurisdictions without the upgrade and maintenance costs required to implement ACS systems that provide optimized signal timings on a second-by-second basis. The ACS-Lite system includes three major algorithmic components: a time-of-day (TOD) tuner, a run-time refiner, and a transition manager. The TOD tuner maintains plan parameters (cycle, splits, and offsets) as the long-term traffic conditions change. The run-time refiner modifies the cycle, splits, and offsets of the plan that is currently running based on observation of traffic conditions that are outside the normal bounds of conditions this plan is designed to handle. The run-time refiner also determines the best time to transition from the current plan to the next plan in the schedule, or, like a traffic-responsive system, it might transition to a plan that is not scheduled next in the sequence. The transition manager selects from the transition methods built in to the local controllers to balance the time spent out of coordination with the delay and congestion that is potentially caused by getting back into step as quickly as possible. These components of the ACS-Lite algorithm architecture are described and the similarities and differences of ACS-Lite with state-of-the-art and state-of-the-practice adaptive control algorithms are discussed. Closed-loop control system characteristics are summarized to give the context in which ACS-Lite is intended to operate.
New Algorithms for Filtering and Imputation of Real-Time and Archived Dual-Loop Detector Data in I-4 Data Warehouse
Authors: Al-Deek Haitham M. , Venkata Chilakamarri , Chandra Srinivasa Ravi
Published: April 2007

Loop detectors have been used to gather traffic data for over four decades. Loop data diagnostics have been extensively researched for single loops. Loop data diagnostics for the dual loops laid along 63 km (39 mi) of I-4 in Orlando, Florida, are specifically addressed here. In the I-4 data warehouse, dual-loop detectors provide flow, speed, and occupancy every 30 s. The mathematical relationships among flow, speed, occupancy, and average length of vehicles were used to flag bad data samples provided by a loop detector. A value called the entropy statistic is defined and used to determine the detectors that are stuck. Regression techniques were applied to fill the holes formed by the bad or missing samples. Various pairwise regression models were developed and described, and their performance on the loop data from January and February 2003 was analyzed. The best model was identified as the pairwise quadratic regression model with selective median, which is currently being used to impute missing data in real time. Results are presented of the application of these algorithms to archived loop detector data in the I-4 data warehouse.
Development and Calibration of a Large-Scale Microscopic Traffic Simulation Model
Authors: Jha Mithilesh , Gopalan Ganesh , Garms Adam , Mahanti Bhanu P. , Toledo Tomer , Ben-Akiva Moshe E.
Published: April 2007

The development and the calibration of a microscopic traffic simulation model, using MITSIMLab, for the entire metropolitan area of Des Moines, Iowa, are presented. The primary contributions include the application of a microscopic model on such a large-scale network and an effort for joint calibration of the model parameters and estimation of origin-destination flows. The application of microscopic traffic simulation models to very large networks such as this poses a number of methodological and practical challenges that are not faced with smaller applications. Solutions to these problems are both heuristic and analytical. The solutions presented are generic and hence applicable to any large-scale microscopic traffic modeling.
School Location and Student Travel Analysis of Factors Affecting Mode Choice
Authors: Ewing Reid , Schroeer William , Greene William
Published: April 2007

This study is the first to examine the relationship between mode of travel to school and the full range of factors that might affect mode choice. With data from Gainesville, Florida, a multinomial logit model was estimated to explain school mode choice for a sample of K-12 students. Students with shorter walk or bike times to school proved significantly more likely to walk or bike. If confirmed through subsequent research, this finding argues for neighborhood schools serving nearby residential areas. Students traveling through areas with sidewalks on main roads were also more likely to walk. If confirmed, this finding argues for "safe routes to school" sidewalk improvements. As noteworthy as the significant factors are those that did not prove significant. School enrollment was not significant after controlling for travel time between home and school. Larger schools may draw students from larger areas and thereby indirectly affect mode choices. But school size does not appear to have a direct effect on mode choices. Land use variables such as density and mix also were not significant. The travel behavior literature emphasizes the importance of such variables in travel decision making. Apparently, school trips are different. They tend to be unlinked to other activities, and thus reduce the need for proximity to other land uses. They are mandatory; thus the walking environment may be less important than it is with discretionary travel. And school trips involve children, who may be less sensitive to walking conditions than are their adult counterparts.
Manipulating power can affect memory conformity
Authors: Skagerberg Elin M. , Wright Daniel B.
Published: March 2007

Memory is malleable and open to influence between encoding and retrieval. Information about a past event given to us by, for example, a co‐witness can be incorporated into our own memory reports. Pairs of participants were shown 50 photographs of faces, given a power task where one had to be a designer (low‐power) and one a judge (high‐power), and then given a recognition test where one partner had to answer before the other. The individuals in the low‐power group were more influenced by their partner's responses than those in the high‐power group. This has important forensic, educational and organisational applications and shows that memory conformity can be manipulated by power. Copyright © 2007 John Wiley & Sons, Ltd.
Covalent Modification of Glassy Carbon Electrode with Aspartic Acid for Simultaneous Determination of Hydroquinone and Catechol
Authors: Wang Liang , Huang Peng‐fei , Wang Hong‐jing , Bai Jun‐yue , Zhang Li‐ying , Zhao Yu‐qing
Published: April 2007

Glassy carbon electrode (GCE) is covalently modified with aspartic acid (Asp). The modified electrode is used for the simultaneous electrochemical determination of hydroquinone (HQ) and catechol (CC) and shows an excellent electrocatalytical effect on the oxidation of HQ and CC by cyclic voltammetry (CV) in 0.1 mol/L acetate buffer solution (pH 4.5). In differential pulse voltammetric (DPV) measurements, the modified electrode could separate the oxidation peak potentials of HQ and CC present in binary mixtures by about 101 mV though the bare electrode gave a single broad response. A successful elimination of the fouling effect by the oxidized product of HQ on the response of CC has been achieved at the modified electrode. The determination limit of HQ in the presence of 0.1 mmol/L CC was 9.0 × 10‐7 mol/L and the determination limit of CC in the presence of 0.1 mmol/L HQ was 5.0 × 10‐7 mol/L. The proposed method has been applied to the simultaneous determination of HQ and CC in a water sample with simplicity and high selectivity.
Nutritional status of Ribeirinhos in Brazil and the nutrition transition
Authors: Piperata Barbara A.
Published: April 2007

Anthropometric and household data (size, composition, economic activity) were collected from a population of Ribeirinhos living in a rural setting in the eastern Amazon. Data are compared to international reference standards and to other Amazonian populations with the goals of increasing our understanding of the Amazon's largest ethnic group and identifying the relationship between changes in subsistence strategies and nutritional status. Data on height, weight, skinfolds, and circumferences were collected from 471 adults and subadults. The population showed a high degree of stunting with an average HAZ below −2.0 for all age groups over 3 years, and 60% of adult men and 70% of adult women were stunted. Wasting was rare. Average skinfold thicknesses and upper‐arm muscle area were near or below average but within the normal range compared to the reference standard, indicating adequate energy and protein stores. Thirty‐one percent of males and 29% of females were overweight/obese, and the highest average BMIs were found among men and women in their 40s. Adult males who participated in wage labor had higher weights, BMIs, and UMA values, and were more likely to be overweight and obese compared with those who did not work in wage‐labor jobs. Children of fathers who worked in wage labor had higher BMI and UMA values, but there was no significant effect on the nutritional status of other adults in these same households. Signs of the nutrition transition were most noticeable among adult males involved in wage labor because of changes in their diet and activity patterns. Am J Phys Anthropol, 2007. © 2007 Wiley‐Liss, Inc.
The Enantioselective Morita–Baylis–Hillman Reaction and Its Aza Counterpart
Authors: Masson Géraldine , Housseman Christopher , Zhu Jieping
Published: April 2007

The development of asymmetric Morita–Baylis–Hillman (MBH) reactions has evolved dramatically over the past few years, parallel to the emerging concept of bifunctional organocatalysis. Whereas organocatalysis is starting to compete with metal‐based catalysis in several important organic transformations, the MBH reaction belongs to a group of prototypical reactions in which organocatalysts already display superiority over their metal‐based counterparts. This Minireview summarizes recent mechanistic insights and advances in the design and synthesis of small organic molecules for enantioselective MBH and aza‐MBH reactions.
Solvent‐free cyanosilylation of ketones with (CH3)3SiCN (TMSCN) catalyzed by NbF5
Authors: Kim Sung Soo , Rajagopal Gurusamy , George Soney C.
Published: April 2007

The addition of TMSCN to ketones catalyzed by dispersed NbF5 gave corresponding cyanohydrin trimethylsilylethers with excellent yield (>90%). Cyano transfer occurs within 30 min at room temperature in the presence of 1 mol% of NbF5 under solvent‐free conditions. These conditions are extremely mild, simple, and tolerate various functional groups. Copyright © 2007 John Wiley & Sons, Ltd.
Preparation and characterization of castor oil‐based polyurethane/poly(o‐methoxyaniline) blend film
Authors: Alves William F. , Kanda Darcy H. F. , Malmonge Luiz F. , Malmonge José A. , Mattoso Luiz H. C.
Published: April 2007

Blends made up of castor oil‐based polyurethane (PU) and poly(o‐methoxyaniline) (POMA) were obtained in the form of films by casting and characterized by FTIR, UV‐Vis‐NIR spectroscopy, and electrical conductivity measurements. Doping was carried out by immersing the films in 1.0M HCl aqueous solution. Chemical bonds between NCO group of PU and NH group of POMA were observed by means of FTIR spectra. The UV‐Vis‐NIR spectra indicated that the presence of the PU in the blend does not affect doping and formation of the POMA phase. The electrical conductivity research was in the range of 10−3 S/cm. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
N‐(4‐(4‐(2‐Halogenophenyl)piperazin‐1‐yl)butyl) Substituted Cinnamoyl Amide Derivatives as Dopamine D2 and D3 Receptor Ligands
Authors: Saur Oliver , Hackling Anneke E. , Perachon Sylvie , Schwartz Jean‐Charles , Sokoloff Pierre , Stark Holger
Published: April 2007

A series of eight substituted N‐(4‐(4‐(2‐halogenophenyl)piperazin‐1‐yl)butyl)‐3‐phenylacryl amide derivatives have been synthesized and screened for binding affinities at dopamine hD2 and hD3 receptors. All compounds have shown high to remarkable receptor affinities and some have led to distinct selectivity for D3 receptors. Highest D3‐receptor affinity has been observed for 3‐(4‐aminophenyl)‐N‐(4‐(4‐(2‐fluorophenyl)piperazin‐1‐yl)butyl)acryl amide (hD3 Ki 0.9 nM; hD2 Ki 17.4 nM). Selectivity ratio has been best for 3‐(4‐chlorophenyl)‐N‐(4‐(4‐(2‐fluorophenyl)piperazin‐1‐yl)butyl)acryl amide with a 56‐fold preference for hD3 versus hD2. A functional activity test has been performed by a mitogenesis test for N‐(4‐(4‐(2‐fluorophenyl)piperazin‐1‐yl)butyl)‐3,3‐diphenylacryl amide, which, surprisingly, has shown full agonist properties.
Environmental management and strategy in the face of regulatory intensity: radioactive contamination in the US steel industry
Authors: Clemens Bruce Wayne , Papadakis Maria
Published: April 2007

Recent business literature argues that several incentives drive firms to cooperate with government environmental regulators and regulation without pressure from the government. This study explores and tests such arguments using a metric called regulatory intensity. The study uses survey data from the radioactive scrap metal industry. The findings challenge the recent literature that ‘going green pays’. The study found that strong government actions (regulatory intensity) are related to firm cooperation. Firms seem to adopt cooperative strategies when coerced to do so by the government. Copyright © 2007 John Wiley & Sons, Ltd and ERP Environment.
Football hooliganism: comparing self‐awareness and social identity theory explanations
Authors: Van Hiel Alain , Hautman Lobke , Cornelis Ilse , De Clercq Barbara
Published: March 2007

The emergence of research interest in group violence in general and football hooliganism in particular has been explained by various models generally relying on situational or individual differences accounts. Yet, these two research traditions have largely evolved independently, showing little or no interaction. In the present study (N = 109), we integrate measures of these two approaches and the results reveal that social identity was more predictive of self‐reported physical aggression than of loss of private and public self‐awareness. Moreover, attitudes towards violence were the most marked predictor variables of both physical and verbal aggression. In the discussion, the moderator effect of social identity and attitudes about violence on physical aggression is elaborated upon. Copyright © 2007 John Wiley & Sons, Ltd.
Determination of 77Se—77Se and 77Se—13C J‐Coupling Parameters for the Clusters [Re5OsSe8(CN)6]3‐ and [Re4Os2Se8(CN)6]2‐.
Authors: Ramaswamy Kannan , Tulsky Eric G. , Long Jeffrey R. , Kao Jeff L.‐F. , Hayes Sophia E.
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Antimony‐121 Moessbauer Spectral Study of α‐Zn4Sb3.
Authors: Hermann Raphael P. , Grandjean Fernande , Chen Tsi‐Chi , Brown Dennis E. , Johnson C. E. , Snyder G. Jeffrey , Long Gary J.
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
A Percolative Ferromagnetic—Ferroelectric Composite with Significant Dielectric and Magnetic Properties.
Authors: Huang Jiquan , Du Piyi , Hong Lanxiu , Dong Yanling , Hong Maochun
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Synthesis, Structure, and Electronic and Physical Properties of Tl2TeS3, the First Characterized Thallium(I) Thiotellurate(IV).
Authors: Rieger Franziska , Mudring Anja‐Verena
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Polystyrene‐Supported Proline and Prolinamide. Versatile Heterogeneous Organocatalysts Both for Asymmetric Aldol Reaction in Water and α‐Selenenylation of Aldehydes.
Authors: Giacalone Francesco , Gruttadauria Michelangelo , Marculescu Adriana Mossuto , Noto Renato
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
An Unusual β‐Vinyl Effect Leading to High Efficiency and Enantioselectivity of the Amidase, Nitrile Biotransformations for the Preparation of Enantiopure 3‐Arylpent‐4‐enoic Acids and Amides and Their Applications in Synthesis.
Authors: Gao Ming , Wang De‐Xian , Zheng Qi‐Yu , Wang Mei‐Xiang
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Electrooxidative Cyclization of Hydroquinolyl Alcohols.
Authors: Okimoto Mitsuhiro , Yoshida Takashi , Hoshi Masayuki , Hattori Kazuyuki , Komata Masashi , Numata Kaori , Tomozawa Kenta
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.