bluuebunny/crossref_metadata_2025 huggingface dataset:
A New View of the Male/Female Pay Gap
Authors: Baker Michael , Drolet Marie
Published: January 2011

We construct a new time series on the Canadian female/male pay ratio. The new series is based on wage data rather than the earnings data that have been used in the past. Wages more closely correspond to the price of labour, while earnings combine information on the price of labour with information on decisions of how much to work. Our results reveal significant differences between the wage- and earnings-based series. Most importantly, the wage series reveals that women have continued to make progress over the last 15 years.
Policy Risk and Private Investment in Ontario's Wind Power Sector
Authors: Holburn Guy , Lui Kerri , Morand Charles
Published: January 2011

Even though governments may adopt favourable regulatory policies for renewable power generation, their ability to encourage private sector investment depends also on the presence of regulatory governance institutions that provide credible long-term commitments to potential investors. In the case of Ontario we contend that, despite large market potential and comparatively strong regulatory incentive policies, weak regulatory governance is one factor that has accounted for the challenges in attracting and implementing large-scale private investment in power generation at a reasonable cost. A unique survey of 63 wind power firms that assessed private sector opinions about the investment environment for renewable energy provides empirical support for our arguments. Firms rated the stability of regulatory policy, compared to a range of factors, among the weakest aspects of Ontario's business environment. However, policy stability ranked among the most important factors in firms' assessments of the attractiveness of alternative jurisdictions in their location decisions. Subsequent interviews revealed that firms have responded to this risk by explicitly pricing it into wind project financial models in Ontario—implying higher wind power prices for ratepayers—and by directing investment funds to other jurisdictions. We argue that policy stability in Ontario may be improved by devolving greater decision-making authority to regulatory agencies in the energy sector and by strengthening their institutional independence.
Quantifying Non-Tariff Trade Barriers: What Difference Did 9/11 Make to Canadian Cross-Border Shopping?
Authors: Ferris J. Stephen
Published: January 2011

In this paper I quantify the effect of the tightening of the security precautions post-9/11 on the volume of cross-border shopping from Canada into the United States. Using an extended version of the cross-border shopping model of Ferris (2000) , the results suggest that the events of September 11th, 2001, precipitated a drop of between 300,000 and 600,000 same-day cross-border travellers per month or roughly a quarter of the previous volume.
Implications of the Introduction of the Goods and Services Tax for Families in Canada
Authors: Curtis Lori J. , Kingston-Riechers JoAnn
Published: January 2011

We use the Quadratic Almost Ideal Demand System and the Canadian Family Expenditure Survey to investigate the welfare change for households, particularly those with children, attributable to the introduction of the Goods and Services Tax (GST) in Canada. We calculate the welfare change by estimating the expenditure difference necessary to maintain pre-GST indirect utility. We find that two in three households and one in three low income households were made worse off by the introduction of the GST. The figures are similar for households with children. More specifically, the stated policy goal of increasing the welfare of low and middle income households was not achieved.
A Curious Jumble: The Canadian Approach to Online Consumer Health Information
Authors: Harris Roma , Bella Leslie
Published: January 2011

As part of a larger e-health strategy, Canadian governments have invested millions in online health information services for the lay public. These services are intended to reduce demands on the primary health care system by encouraging greater individual responsibility for health and are often promoted using the language of personal empowerment. In this paper, we describe how lay searchers generally look for online health information and discuss the disempowering challenges they are likely to face in (a) locating Canadian government-sponsored health information sites and (b) finding useful information on these sites to address everyday health concerns. We conclude with several recommendations for policy changes.
Evaluation of Probing versus Coring for Determination of Portland Cement Concrete Pavement Thickness
Authors: Allison Gyude W. , Whited Gary C. , Hanna Awad S. , Nasief Haidy Gerges
Published: January 2011

The Wisconsin Department of Transportation (DOT) has used contractor probing measurement of fresh portland cement concrete pavement to determine pavement thickness since 1998. Before that, the Wisconsin DOT used coring to measure thickness and determine payment for pavement. The probing method is nondestructive and has financial advantages for the Wisconsin DOT because it eliminates the costs of coring and reduces the expenses of contract administration. Probing also provides the contractor with immediate feedback on the depth of the pavement being constructed. A study was conducted to verify the reliability of probing measurement for determining pavement thickness and verifying contractors’ compliance with design requirements. To determine whether probing was still a viable method for use by the Wisconsin DOT in construction contract administration, core depths were compared with field-measured probe depths for 12 projects constructed between 2006 and 2008 across the state of Wisconsin. Sample means were compared, statistically calculated estimates of differences were examined, and a statistical analysis at the 95% confidence interval was carried out. According to these analyses, probing does provide an acceptable measure of pavement thickness. All contractor probe measurements and more than 80% of the Wisconsin DOT core samples showed that constructed pavement thickness exceeded the design thickness.
Combining Portable Falling Weight Deflectometer and Surface Wave Measurements for Evaluation of Longitudinal Joints in Asphalt Pavements
Authors: du Tertre Antonin , Cascante Giovanni , Tighe Susan L.
Published: January 2011

Longitudinal joints in asphalt pavements typically have lower densities than the interior portion of the mat. Therefore, they tend to exhibit surface distresses such as cracking and raveling more rapidly. The objective of this study is to evaluate the ability of nondestructive testing (NDT) for assessing the relative condition of a longitudinal joint. NDT has been significantly developed for pavement evaluation during the past decade. Deflection and surface wave methods are the most commonly used for pavement evaluation. The portable falling weight deflectometer (PFWD) is increasingly used in quality control and quality assurance to provide rapid determination of the equivalent surface elastic modulus. However, the multichannel analysis of the surface waves (MASW) method consists of using ultrasonic transducers to measure surface waves traveling through the pavement and invert for the elastic modulus of different layers. This study presents results from both deflection and seismic methods to assess the quality of longitudinal joints. Both methods are performed at the same locations of the centerline of a test track. Pavement deflection is also measured on the wheelpath for comparison with previous data. Across the joint, changes smaller than 7% were observed in deflection values. These preliminary results cannot be directly related to joint quality because the contribution of sublayers to the modulus measured with the PFWD needs to be estimated. MASW measurements showed promising results for evaluating the attenuation of surface waves due to the joint. Further work is required to improve the coupling between the transducers and asphalt surface.
Construction Engineering for Horizontally Curved Steel I-Girder Bridges
Authors: Chavel Brandon , Tunstall Shawn , Fuller Jason , Bunner Matthew
Published: January 2011

The erection of horizontally curved steel I-girder bridges is inherently more complex than the erection of straight I-girder bridges of similar span lengths. Complexities associated with curved steel I-girder bridge erection are a direct result of the natural behavior of curved steel I-girders. The bridge erector and contractor is often directed to provide a construction plan, stamped and signed by a professional engineer, that details the steel erection procedure and provides calculations that demonstrate the girders and bridge components meet stability and structural capacity requirements. Bridge engineers must be aware of the complexities associated with the behavior of curved steel I-girders when they are developing erection plans. When these complexities are not considered by the contractor's engineer, significant problems or even a girder collapse can result. Currently, little guidance is given in design specifications and archival literature that illustrates what is required in the construction plans for curved steel I-girder erection and the calculations and design checks that should be carried out. This paper highlights aspects of curved steel I-girder bridge erection that should be considered by the contractor's engineer in the development of the steel erection plans for horizontally curved I-girder bridges in order to provide for a successful bridge construction project.
Effects of Cross-Frame on Stability of Double I-Girder System under Erection
Authors: Zhao Qiuhong , Yu Baolin , Burdette Edwin G.
Published: January 2011

Double-girder systems investigated here consist of two steel I-shaped straight girders connected by intermediate cross-frames. In the erection stage, loading on the girder system, consisting mainly of girder self-weight, may not be significant. However, the concrete deck typically is not present to provide continuous lateral support to girder flanges, and there may be fewer cross-frames than in the service condition, resulting in fewer discrete lateral constraints to girder flanges and torsional constraints to girder sections. Such conditions could contribute to significant lowering of lateral torsional buckling capacity of the girder system compared with the service condition, and the girder system may become unstable during construction if the girder span is too long or if cross-frames do not provide enough discrete lateral support. Thus, it is important to investigate the effects of cross-frames on the stability of double-girder systems during construction. The AASHTO load and resistance factor design code has no specific requirements for maximum allowable spacing of cross-frames. To identify the dominant parameters and quantify the effects of cross-frames on double-girder system stability, finite element analyses were conducted to investigate the effects of the area of the cross-frame braces and cross-frame spacing on lateral torsional buckling capacity of double-girder systems under self-weight. The area of cross-frame members had negligible effects, but cross-frame spacing above a certain value affects system capacity. A method is presented to determine maximum cross-frame spacing (i.e., minimum number of cross-frames) for double-girder systems during erection. The goal is to achieve construction safety and labor reduction at the same time.
Fatigue Performance of Groove-Welded Tube-to-End-Plate Connections in Highway Sign, Luminaire, and Traffic Signal Structures
Authors: Roy Sougata , Park Yeun-Chul , Sause Richard , Fisher John W.
Published: January 2011

Fatigue performance of full penetration groove-welded tube-to-end-plate connections was evaluated by parametric studies verified by laboratory testing of full-scale galvanized cantilevered highway sign and signal and high-level luminaire structures. In the absence of sufficient experimental basis, the fatigue resistance of this connection detail in the existing AASHTO specification is defined as Category E. Fatigue performance of tube-to-end-plate connections in thin-walled tubular structures is governed by secondary out-of-plane bending stress, the magnitude of which depends on relative stiffness of the tube and end plate. In some groove-welded connections, the backing ring is welded to the tube wall, adding more variability in fatigue performance of the connection. Twenty-three full-size specimens composed of five configurations of the groove-welded connections were fatigue-tested under constant amplitude loading simulating wind-induced aeroelastic oscillations, such as galloping and vortex shedding, that are typically experienced in service. Variation in six parameters of the connection geometry were considered: diameter of tube, thickness of tube, thickness of end plate, diameter of end plate opening, number of anchor bolts, and height of backing ring. The research results demonstrated that with a suitable combination of the geometric parameters, the constant amplitude fatigue threshold of the groove-welded tube-to-end-plate connections can exceed that of AASHTO Fatigue Category D for sections widely used in highway sign, luminaire, and traffic signal structures. The local stress-based approaches provided reasonable lower bound estimates of fatigue performance of the connection detail for different geometric configurations.
Use of Alkali–Silica Reaction-Affected Recycled Concrete Aggregate in Hot-Mix Asphalt
Authors: Mukhopadhyay Anol K. , Geiger Brian J. , Button Joe
Published: January 2011

The effects of using alkali–silica reaction-affected recycled concrete aggregate (ASR-RCA) in hot-mix asphalt (HMA) were investigated. The goal of the study was to determine if the asphalt binder provided sufficient moisture protection to prevent reexpansion of existing ASR gel or occurrence of new ASR. Expansion tests were performed with a dilatometer on RCAs to determine the possibility of new ASR occurring in reactive aggregates in the HMA. Micro-Deval and freeze–thaw tests measure higher mass loss in ASR-RCAs than that in virgin aggregates, which is caused by preexisting aggregate microcracks and ASR gel in ASR-RCAs. Moisture damage testing indicated good moisture resistance of HMA mixtures made with ASR-RCA, especially when compared with virgin siliceous aggregate. Expansion testing indicated that both ASR-RCAs were still reactive with 0.5 N sodium hydroxide (NaOH) solution saturated with calcium hydroxide (CaOH2) at 60°C. Expansion testing of HMA specimens in NaOH + CaOH2 solution at 60°C indicated a reaction between the asphalt binder and the solution, but little ASR. However, expansion testing in deicer solution at the same temperature indicated that some ASR may have occurred along with the primary binder-solution interaction. The volume change characteristics associated with the binder–solution interaction with and without ASR was supported by the change in pH and alkali concentration of the test solution. The potential distress mechanisms are identified, and possible remedial measures as guidelines are recommended for the use of ASR-RCA in HMA.
Measurement of Water Diffusion in Asphalt Binders Using Fourier Transform Infrared–Attenuated Total Reflectance
Authors: Vasconcelos Kamilla L. , Bhasin Amit , Little Dallas N.
Published: January 2011

The presence of moisture in asphalt mixtures deteriorates their structural integrity. Moisture also acts as a catalyst to promote other forms of pavement distresses. Two critical factors influence the rate and intensity of moisture-induced damage: (a) the speed of moisture transport within the asphalt mixture and binder and (b) the influence of moisture on the cohesive and adhesive properties of the constituent materials. Quantifying these factors is essential to understand, model, and mitigate moisture-induced damage in asphalt mixtures. The experimental and analytical procedures used to measure diffusivity of the asphalt binder are presented. Fourier transform infrared–attenuated total reflectance spectroscopy was used to monitor the diffusion of water into thin films of asphalt binder. The diffusion process was characterized by changes in the portions of the spectra that correspond to the presence of water. Two models were used to fit the data obtained: a diffusion model that followed Fick's second law and a dual mode diffusion model with two diffusion coefficients (D1 and D2) and weighting factor X1. Four asphalt binders were evaluated (AAB, AAD, AAF, and ABD), and all presented better fitting under the dual mode diffusion. Diffusivities of asphalt binders AAB, AAD, and AAF were statistically similar, but diffusivity of asphalt binder ABD was different from that of the others.
Influence of Aging Temperature on Rheological and Chemical Properties of Asphalt Binders
Authors: Huang Shin-Che , Grimes Will
Published: January 2011

Four asphalts used in field pavements were aged at a laboratory in a pressure-aging vessel (PAV) at several temperatures for various lengths of time. The chemical (infrared spectra) and rheological properties of these aged asphalts were compared. Results showed that the same PG graded asphalts from different crude sources had significant differences in their rheological behavior and chemical properties after long-term oxidative aging. Asphalt per se had approximately the same aging rheological pattern regardless of aging temperature. Laboratory PAV aging at 80°C for 504 h was found to produce stiffer material than the same material subjected to the same PAV aging at 100°C for 100 h. The plot of G* complex modulus versus phase angle was found particularly useful for characterizing the asphalt binder rheology in terms of long-term aging characteristic. Additionally, the aging shift factor, generated from the aging master curve, was used to characterize the modulus changes with respect to aging and to compare effects of aging on different materials. Furthermore, results indicated a linear relationship between the change of rheological property and the change of chemical property (carbonyl index) with respect to long-term aging. It was verified that sulfoxide was formed easily with aging. However, sulfoxides also decomposed at longer aging times.
Estimation of Reclaimed Asphalt Pavement Binder Low-Temperature Properties without Extraction
Authors: Ma Tao , Mahmoud Enad , Bahia Hussain U.
Published: January 2011

The use of reclaimed asphalt pavement (RAP) as a component of asphalt mixes is a common practice. Generally, the use of RAP is expected to reduce the total cost of pavement construction, conserve natural resources, and protect the environment. However, estimating the properties of the aged binder in RAP is a challenging problem. Extraction and recovery of the binder is the current method used to estimate these properties. The unknown effects on the binder properties of using solvents to extract and recover the binder are a concern; thus, development of new methods to estimate the RAP binder properties without altering them is necessary. Introduced is the development of a new testing procedure to estimate the low-temperature properties of the RAP binder without extraction or chemical treatments. The testing procedure uses the Superpave® bending beam rheometer (BBR) with minor modifications. Fresh binder and fine RAP materials mixed with fresh binder (referred to as RAP mortar) are tested in the BBR, and properties of the RAP binder are then estimated from the binder and mortar properties. The developed testing procedure went through several testing stages for selection of testing parameters, such as the RAP gradation to be included in mortar, testing load, and binder content. The final procedure developed was then verified, and its capability of capturing the aged low-temperature properties of the binder in RAP materials was confirmed.
Correlating Rheological and Bond Properties of Emulsions to Aggregate Retention of Chip Seals
Authors: Miller Timothy D. , Arega Zelalem A. , Bahia Hussain U.
Published: January 2011

The development of binder stiffness and bond strength is critical for new chip seals: loose aggregates must be minimized once a road enters into service. A new test protocol is presented: called the bitumen bond strength (BBS) test for evaluating emulsion setting behavior, the protocol can be used to evaluate aggregate retention and raveling potential of chip seals. The time required for the asphalt emulsion to gain adequate strength and adhesion to aggregate chips depends on aggregate–binder compatibility, environmental factors, and mechanical action. BBS test results demonstrate bond strength development over a full curing interval for a variety of materials and curing conditions. Results obtained using the BBS test are compared with dynamic shear rheometer strain sweep results to investigate a correlation between bond strength and the rutting parameter G*/sin δ. BBS test results are also correlated to aggregate loss as measured by the sweep test. This research may contribute to the ongoing development of specifications for construction and performance properties of asphalt emulsions used in surface treatments.
Backcalculation Method to Determine Effective Asphalt Binder Properties of Recycled Asphalt Pavement Mixtures
Authors: Bennert Thomas , Dongré Raj
Published: January 2011

State departments of transportation are beginning to require the use of higher percentages of recycled asphalt pavement (RAP) in hot-mix asphalt. To help implement higher RAP contents, better procedures are needed for evaluating the binder properties of higher RAP content asphalt mixtures without chemical extraction. In particular, new and innovative methods are required to determine how the addition of RAP influences mechanical properties of the composite (RAP + virgin) asphalt mixtures. A method is summarized for determining what is referred to as the effective asphalt binder stiffness properties of asphalt mixtures blended with RAP. The proposed extraction-less procedure uses the Hirsch model to backcalculate the asphalt binder stiffness (G*) from asphalt mixture stiffness (E*). In addition, an analytical procedure to determine the phase angle (δ) is discussed. Test data comparing predicted versus measured asphalt binder properties of plant-produced asphalt mixtures with 0% RAP are presented. Additional validation data are presented for plant-produced asphalt mixtures of varying RAP percentages. Examples of implementing the backcalculated binder properties in the Mechanistic–Empirical Pavement Design Guide, as well as comparing the backcalculated asphalt binder properties with mixture fatigue test results, are also shown and discussed.
Field Evaluation of High Reclaimed Asphalt Pavement–Warm-Mix Asphalt Project in Florida
Authors: Copeland Audrey , D'Angelo John , Dongré Raj , Belagutti Satish , Sholar Gregory
Published: January 2011

In December 2007, a portion of State Route 11 in Deland, Florida, was milled and repaved with 45% reclaimed asphalt pavement (RAP). These high RAP mixes were produced at lower than normal hot-mix temperatures and with foamed warm-mix asphalt (WMA) technology. This project was the first large production in which the Florida Department of Transportation (DOT) allowed the use of high RAP in combination with WMA. FHWA, in cooperation with Florida DOT and the National Center for Asphalt Technology, was on site for production and placement of the high RAP-WMA. Plant-produced mix was collected by FHWA for performance testing evaluation. Two mixes were produced: a high RAP–hot-mix asphalt (HMA) control mix and a high RAP-WMA mix. Performance tests conducted by FHWA included performance grade (PG) determination of binders, dynamic modulus, and flow number. PG results of the binders indicate that the high RAP-WMA mix is softer than the high RAP-HMA control mix. This is further confirmed by flow number results, where the high RAP-WMA mix had a lower flow number than the high RAP-HMA control mix did. Dynamic modulus results indicate that the high RAP-WMA mix is slightly softer than the high RAP-HMA control mix, especially at intermediate temperatures. Comparison of measured dynamic modulus results with those predicted using the Hirsch and Witczak models confirm that complete blending occurred in the high RAP-HMA control mix. However, incomplete mixing of RAP and virgin binders may have occurred in the high RAP-WMA mix.
Origin–Destination Matrix Generation from Boarding–Alighting and Household Survey Data
Authors: Blum Jeremy J. , Sridhar Anoop , Mathew Tom V.
Published: January 2011

Approaches to demand estimation for public transport systems often use either primarily boarding–alighting data counts or travel survey data, based on a sampling of households. However, in the absence of a mechanism to capture transfer trips, boarding–alighting data have difficulty providing accurate demand estimation for large, complex transit systems. Travel survey data also present challenges in the estimation of total demand, when the demand is extrapolated from a limited sample of the population. The errors in this extrapolation often limit the estimation of demand to a coarse-grained zone-to-zone travel, as opposed to a fine-grained bus–rail stop to bus–rail stop. This paper presents the hybrid demand estimation (HDE) algorithm that synthesizes both types of data to produce an accurate, fine-grained demand estimation. Initially, HDE uses boarding–alighting data and a fluid flow model to estimate direct trips that match passenger boarding and alighting counts. Then, in an iterative process, three heuristics are used to introduce transfer trips and alter the set of no-transfer trips to create a better match to the household survey data. Both boarding–alighting and household travel survey data were collected for the Greater Mumbai, India, metropolitan area. The HDE algorithm was evaluated for Mumbai's multimodal suburban rail and bus system. In this network, the HDE algorithm produced significantly better matches to both types of data than other heuristic approaches. The demand estimation produced by HDE deviated from boarding–alighting and survey data by less than 1% across a range of metrics.
Urban Travel Route and Activity Choice Survey
Authors: Frignani Martina Z. , Auld Joshua , (Kouros) Mohammadian Abolfazl , Williams Chad , Nelson Peter
Published: January 2011

This paper presents the results of an Internet-based prompted-recall activity travel survey using Global Positioning System (GPS) data collection combined with a short activity preplanning and scheduling survey. In addition to collecting traditional activity travel diary data, this survey collects basic information about activity planning and scheduling processes. Because aging is a growing concern among transportation planners, this survey has a special focus on the elderly population with about half of the survey sample consisting of elderly households. Respondents carried a portable GPS device for 14 consecutive days and at the end of each day uploaded the collected data to a website where the activity travel survey questionnaires were answered. Results indicate that the quality of the data collected is superior to other survey approaches and that the response rates are satisfactory considering the time commitment involved in participation. The results reinforce previous findings that GPS surveys have an improved ability to capture trips that are frequently underreported and provide valuable data about the activity planning and scheduling process itself. Respondents' feedback on their participation experience and fatigue and conditioning analysis reveal that this type of survey has great potential for data collections that last longer than 2 weeks.
Augmenting Transit Trip Characterization and Travel Behavior Comprehension
Authors: Chu Ka Kee Alfred , Chapleau Robert
Published: January 2011

Trips need to be described and have always been characterized by various levels of abstraction. It varies from a simple label such as home-based work to complete itinerary with sociodemographic characteristics of the trip maker and household. The rationale behind such classifications is that planners and modelers recognize that the demand of transportation is highly differentiated. It is hoped that additional attributes would provide a more complete portrait of the demand and an improved understanding of the underlying travel behavior. Passive data collection technologies bring an extra dimension to travel data acquisition. Multiday data, which are difficult to collect, become accessible. In public transit, a smart card automatic fare collection system with automatic vehicle location capability provides high-resolution longitudinal data on travel pattern but also suffers from the inherent limitations of passive methods. This paper proposes a methodology to enhance transit trip characterization by adding a multiday dimension to a month of smart card transactions. On the basis of an individual, anchor points—precise to an exact address—are detected. Boarding and alighting locations are described with respect to those anchors. The enhancement allows in-depth travel behavior analysis on a subgroup sharing a common anchor or an individual. The paper demonstrates the use of spatial statistics, spatial analyses with geographic information system, visualizations, and data mining to describe activity space and locations and departure time dynamics, and to derive monthly trip table, activity schedule, and behavioral rules for cardholders. The results offer promising insights to transit planning and the understanding of travel behavior.
Improving Data Quality, Accuracy, and Response in On-Board Surveys
Authors: Oliveira Marcelo G. Simas , Casas Jesse
Published: January 2011

Transit agencies conduct origin–destination on-board surveys periodically to gather information regarding travel patterns and demographic data of their users and to collect customer satisfaction information. These surveys constitute a highly valuable means of obtaining important information on an agency's customers to provide a basis for effective transit planning and for regional travel demand modeling efforts. This paper describes the application of innovative technologies in the data collection process to improve data quality, data completeness, and data collection management. This includes the simultaneous collection of boarding and alighting count data at the stop level using Global Positioning System–enabled personal digital assistants, association of distributed surveys to boarding locations, and a web-based sample and productivity management system. These technologies allow for automatic collection of boarding location, arrival and departure times, and transit trip times. An imputation procedure was developed to derive the most likely alighting location of each collected sample. Joint application of these technologies reduces survey length and thereby minimizes respondent burden.
Semiautomatic Imputation of Activity Travel Diaries
Authors: Moiseeva Anastasia , Jessurun Joran , Timmermans Harry
Published: January 2011

The new generation of dynamic activity-based models requires multiday or multiweek activity–travel data. Global Positioning System (GPS) tracers may be a powerful technology to collect such data, but previous applications of this technology to collect data of full activity travel patterns (not just time, route, and location) still required a substantial amount of manual data imputation and processing and hence are still demanding for both respondent and researcher. A semiautomatic data imputation system would be a major breakthrough and would involve less respondent burden. This paper reports and illustrates the design of a system called TraceAnnotator that processes multiday GPS traces semiautomatically. The process of imputing transportation modes, activity episodes, and other facets of activity travel patterns is based on a learning Bayesian belief network (BBN), which represents the multiple relationships between spatial, temporal, and other factors, including errors in the technology itself. Activity type is identified by fusing GPS data with geographic information system land use data and personalized land use data. Land use data are built during the data collection process using reverse geocoding and an Internet-based prompted recall survey, which also allows checking and correction of any imputation errors. The prompted recall data are used to update the conditional probabilities of the BBN. Consequently, that the system can learn over time implies that imputation accuracy will improve over time, reducing respondent and researcher burden. A pilot study is presented and potential improvements of the learning algorithm are discussed.
Development of a Global Positioning System Web-Based Prompted Recall Solution for Longitudinal Travel Surveys
Authors: Greaves Stephen , Fifer Simon , Ellison Richard , Germanos George
Published: January 2011

This paper details the development of a Global Positioning System collection solution for a longitudinal (10-week) survey of driving behavior in Sydney, Australia: the primary purpose is to investigate behavioral responses to variable rate charging regimes. The study calls for data to be transmitted regularly (wirelessly) to check the quality of data as they are being collected and provide the basis for a web-based prompted recall (PR) survey in which participants can view their trips, confirm details, and provide information on who was driving, number of passengers, and trip purpose. Following details of the technological setup, details are provided of the data processing issues involved and the development of the PR survey. Pilot testing of the approach on 30 motorists demonstrates that contrary to popular belief, highly accurate data of this nature can be collected for several weeks with little respondent burden.
Modeling Network Impact in Area Surrounding Activity Center Caused by Special Events
Authors: Zhang Yucheng , Yi Ping , Kreider Kevin L. , Shao Chun , Norfolk Timothy S.
Published: January 2011

Although many traffic prediction models have been studied, much of the existing research considers traffic congestion primarily caused by construction and incidents. An effort to assess the impact of special events (ballgames, parades, conventions, etc.) in an urban area is needed. In this paper, a prototype model for traffic analysis under special events is proposed and tested. Unlike hydrodynamic modeling or the conventional microscopic approach by vehicle tracking, this model tries to decompose the overall system impact into the spatial effect of the special event network (SE network) and the temporal effect of the eventgenerated traffic. The model formulation is shown to possess a unique, physically meaningful solution to the underlying engineering problem. Using systemwide field data for model calibration, preliminary tests have shown encouraging results in predicting traffic impact on SE networks. Although further testing and improvement is needed, the proposed modeling approach has demonstrated its potential for extending to other applications such as disaster evacuation planning.
Multimodal Accessibility of Modern Roundabouts
Authors: (Xiao-Zhao) Lu George , Guan Fang , Noyce David A.
Published: January 2011

Modern roundabouts have become popular in North America during the past decade. This popularity can be attributed to their great success in Europe and Australia. There has been significant debate, however, over their accessibility for pedestrians. With almost uninterrupted traffic flows, roundabouts make it difficult for the visually impaired to determine safe gaps, as they rely on auditory cues alone. Such crossing is particularly complicated by ambient noises and circulating vehicles on busy urban roundabouts. Various pedestrian signals have been installed at roundabouts overseas. The United States Access Board published a draft guideline proposing pedestrian signals at all roundabout crossings to ensure access for the visually impaired. Roundabout operations can be a complex process of transporting multimodal travelers. There is increased interest in harnessing artificial intelligence to address issues to improve transportation systems. This research developed a crosswalk signal and introduced fuzzy logic control (FLC) into the signal timing to accommodate roundabout users. The system was assessed against the Pedestrian User-Friendly Intelligent (PUFFIN) crossings under varied geometries under different traffic conditions. The objective was to identify potential treatments for improving roundabout accessibility, safety, and efficiency. The results reveal that “distant” layout reduces vehicle delays and queue lengths when the FLC signal is applied, especially under saturated traffic conditions. From safety and operational perspectives, the FLC signal outperforms PUFFIN. The FLC signal implements the signal timing effectively, decreases pedestrian delay, and maintains adequate vehicle circulation. Multimodal traveler needs at a modern roundabout are satisfied in manifold ways.
How Far Out of the Way Will We Travel?
Authors: Winters Meghan , Teschke Kay , Grant Michael , Setton Eleanor M. , Brauer Michael
Published: January 2011

Current travel demand models are calibrated for motorized transportation and do not perform as well for nonmotorized modes. Little evidence exists on how much, and for what reasons, the routes people travel deviate from the shortest-path or least-cost routes generated by transportation models. This paper investigates differences in total distance, road type used, and built environment features for shortest-path routes versus actual routes for utilitarian bicycle trips (n = 50) and car trips (n = 67) in Metro Vancouver, Canada. Bike trips were, on average, 360 m longer than the shortest possible route; car trips were 540 m longer. Regardless of mode, people do not detour far off the shortest route: detour ratios (actual distance/shortest distance) were similar, with three-fourths of trips within 10% of the shortest distance and at least 90% within 25%. Differences in the built environment measures en route suggest why bike commuters chose to detour: the actual routes had significantly more bicycle facilities (traffic-calming features, bike stencils, and signage) than did the shortest-path routes. Compared with shortest-path routes, cyclists spent significantly less of their travel distance along arterial roads and significantly more along local roads, off-street paths, and routes with bike facilities. As expected, car trips were more likely to be along highways and less likely to be along local roads than predicted by the shortest route. The results illustrate factors that might be included in travel models to more accurately model nonmotorized transportation and provide guidance for how dense bike facilities need to be when infrastructure to support cycling is designed.
Automated Bicycle Counts
Authors: Nordback Krista , Janson Bruce N.
Published: January 2011

Quantifying bicycle use is fundamental to understanding bicycle travel. Methods of counting bicycles vary from limited-time, manual counts to permanent overhead imaging sensors. One common permanent counting method uses inductive loops embedded in the pavement to count cyclists on paths. Although inductive loop detectors have been found to be a highly accurate method of counting bicycles under ideal test conditions, their accuracy after years of use has not been systematically studied. This study focuses on bicycle counts collected by the City of Boulder, Colorado, since 1998, on multiuse paths with inductive loop detectors. To estimate the accuracy of the devices in use, two individuals manually counted path users at six locations. On average, the loop detectors counted 4% fewer bicycles than the manual counters at the same locations. Of the 22 detector channels with sufficient counts to judge their accuracy, roughly 68% were considered accurate. The most dramatic inaccuracies were caused primarily by detector settings and software-related problems. This study found that inductive loop detectors can provide accurate measures of bicycle use on a pathway, but only when detectors are properly installed, calibrated, maintained, and free of external interference.
Multimodal Travel Choices of Bicyclists
Authors: Kuhnimhof Tobias , Chlond Bastian , Huang Po-Chi
Published: January 2011

Cycling demand has been growing in recent years in Germany. Today, during an average week, about 30% of the German population, including all age classes and rural as well as urban populations, use the bicycle as a means of transportation. Cyclists use their bicycles on average 3 days per week for about 30% of their trips. The bicycle, however, is a mode used for specific segments of everyday travel, particularly short distances, unlike the car, which is almost universal. Hence, cyclists exhibit multimodal travel behavior (i.e., they combine the bicycle with other modes and switch to public transport or the car when the bicycle is not suitable). The domain of the bicycle as a means of transport is a radius around home that on average is about 3 to 5 km, dependent on the urban form. Within this radius, the car with its flexibility is the only serious competitor to nonmotorized modes. For the neighborhood-oriented travel of cyclists, public transport performs well only in specific niches, such as travel at night or commuting to school or university. Here, public transport and the bicycle are competitors. Nevertheless, from a system perspective they are allies: each provides important components for a multimodal mobility tool kit that enables travelers to cultivate mobility that is less automobile oriented.
Latent Bicycle Commuting Demand and Effects of Gender on Commuter Cycling and Accident Rates
Authors: Twaddle Heather , Hall Fred , Bracic Blanka
Published: January 2011

A recent survey by the City of Calgary, Canada, found that more than 75% of cyclists commuting to downtown Calgary are male. The intent of this research is to determine whether this is also true for cyclists commuting to a university campus located in the second most popular employment area of the city, what obstacles are preventing women from bicycling, and what measures could increase the number of female commuter cyclists. An online survey was conducted to collect information that allowed the grouping of respondents as potential, occasional, or regular cyclists. Analysis showed that women are more likely than men to be possible or occasional cyclists, while men are more likely than women to be regular cyclists. These findings suggest that if women's cycling needs were addressed, the modal share of bicycle commuting could be increased. Investigation of cycling barriers indicated that women are more concerned than men about safety issues associated with cycling, with being able to carry daily items while cycling, and with the need to fix their hair on arrival. In analysis of desired improvements, women were found to place a higher value on bicycle maps and literature but share similar facility preferences with men. High proportions of both genders indicated a desire for bicycle lanes, more pathways, and more direct bicycle routes. Analysis of falls and collisions suggested that men and women experience a similar number of falls per unit of exposure, while men experience more collisions per unit of exposure than women do.
Ṣūfī tafsīr Reconsidered: Exploring the Development of a Genre
Authors: Elias Jamal J.
Published: January 2011

Ṣūfī tafsīr on the Qur'an is widely accepted as a distinct scholarly or literary genre within the wider field of Islamic scholarship. Ṣūfī writers frequently describe themselves as participating within an identifiable tradition when they write commentaries on the Qur'an, and over the last century a number of scholars – writing from within the Muslim tradition and without – not only have accepted the notion of a millennium-long genre of Ṣūfī tafsīr, but also have sought to define and catalogue it. This paper explores and challenges such assumptions through a direct examination of examples of premodern Ṣūfī tafsīr literature, looking beyond the assumption that the Ṣūfī belief in multiple levels of meaning and existence necessarily impart an esoteric meaning to all writing on the Qur'an by Ṣūfīs. My purpose is to question the efficacy of thinking of Ṣūfī tafsīr as a genre, sui generis, by analysing the modern academic tradition of categorising Ṣūfī commentaries on the Qur'an in the light of writings by prominent Ṣūfīs, demonstrating how such works of commentary seem to contradict conventional wisdom concerning the existence of such a formal genre.
Qur'anic ‘jihād’: A Linguistic and Contextual Analysis
Authors: Haleem M.A.S. Abdel
Published: January 2011

The word jihād is one that has been much discussed. It is often interpreted with some degree of sensationalised polemic and has become, to some extent, divorced from its significance as a Qur'anic term. Our approach in this study is therefore to deal with the subject on the basis of the Qur'an alone, as a term which forms an important theme in the Qur'an, on the basis of close linguistic analysis of the text itself. In particular, our analysis will not ignore the linguistic context which is crucial in understanding any text. The picture that emerges from this study and this approach will differ from that held by many, both Muslims and non-Muslims, who have arrived at a perception of the meaning of jihād which differs from that which is actually found in the Qur'an.
The Meaning of the Qur'anic Word ‘dābba’: ‘Animals’ or ‘Nonhuman Animals’?
Authors: Tlili Sarra
Published: January 2011

The word dābba (‘animal’), both in its singular and plural (dawābb) forms, occurs in the Qur'an a total of eighteen times. In its Qur'anic context, dābba is often understood by Arabic mufassirūn, English-language translators and other Islamic scholars as a reference to nonhuman animals only, the implication being that the Islamic scripture does not consider humans to be part of the animal world. However, analysis of the Qur'anic contexts in which the animal concept is treated indicates that this scripture subscribes to the etymological (rather than the conventional) meaning of this word: any being that produces intentional movement, the primary meaning of the verb dabba, is a dābba. Thus, the so-called rational beings (humans, angels and jinn) are part of the animal world, an understanding that is plainly expressed in many medieval Arabic lexicons whose definitions are shaped by the Qur'anic treatment of the animal concept. Furthermore, evidence from within the Qur'anic text indicates that it seems to avoid lumping all animals into one indistinct group. Both these observations may have a significant impact on the status and potentially the welfare of nonhuman animals in the Islamic scripture, and therefore have implications for attitudes to animal welfare.
Taʾwīl and the Meaning of the Text in the Arabic Language: An Introduction to Understanding the Qur'an
Authors: al-Shāmī ʿAbd Allāh Muḥammad
Published: January 2011

The question of clarifying the meaning of a given Arabic text is a subtle one, especially as high literature texts can often be read in more than one way. Arabic is rich in figurative language and this can lead to variety in meaning, sometimes in ways that either adhere closely or diverge far from the ‘original’ meaning. In order to understand a fine literary text in Arabic, one must have a comprehensive understanding of the issue of taʾwīl, and the concept that multiplicity of meaning does not necessarily lead to contradiction. This article surveys the opinions of various literary critics and scholars of balāgha on this issue with a brief discussion of the concepts of tafsīr and sharḥ, which sometimes overlap with taʾwīl.