bluuebunny/crossref_metadata_2025 huggingface dataset:
Model for Estimating Increased Ridership Caused by Integration of Two Urban Transit Modes
Authors: Akin Darcin
Published: May 2018

A simple, practical tool based on integration (basically, shortening) of competing bus and minibus transit services is provided for estimating increased ridership on metro lines. A simple model is developed to estimate the increased ridership in the metro line of Istanbul, Turkey (7.9 km long and being extended), caused by integration with bus and minibus transit lines, and the benefits related to the intermodal integration are presented. To estimate the effectiveness of the integration action, ridership information in all modes before and after the integration was gathered and analyzed. It was found that the ridership-over-capacity (RoC) ratio in the metro lines was quite low (0.28) before the integration. On December 24, 2001, a partial integration was deployed by the bus operator of the metropolitan city when 11 bus and three minibus routes were integrated to the metro, which yielded significant increase in RoC (56%). The study also considered possible options for the development of a full intermodal plan. In this regard, existing bus and minibus transit lines were examined, and 33 bus and three minibus routes were recommended for integration. It was found that such integration would increase RoC from 0.28 to 0.76 without any significant increase in operating cost. Also, the city and private bus and minibus operators would save an estimated of $4.8 million a year from cuts in operating these services along the metro route. It was also estimated that the integration would lower the amount of bus traffic in downtown Taksim and Mecidiyeköy by approximately 25% and 38%, respectively.
Sketch Transit Modeling Based on 2000 Census Data
Authors: Marshall Norm , Grady Brian
Published: May 2018

Transit planners need cost-effective ways to evaluate a wide range of alternatives relatively quickly to identify potential transit systems that are likely to offer the greatest benefits for a given cost. A sketch transit planning model is described for the Washington, D.C., region that is based on the metropolitan planning organization's travel demand model structure and model networks but is estimated from more recent 2000 census data, better matches suburban transit ridership, is sensitive to land use effects, and is less costly to use. Similar transit sketch models could be developed and applied in other regions.
System Plan for California's Bay Area Regional Express Bus Service
Authors: Deakin Elizabeth , Shirgaokar Manish , Nuworsoo Cornelius , Golub Aaron , Finney Jean , Lew Wingate , Frank Becky , Cherry Chris , Higgins Nathan , Rubin Elihu , Valentin Thomas , Parks Kamala , Ng Willa , Wong Deborah
Published: May 2018

Express buses operating on freeways and arterials are an important part of many metropolitan area transit services. A regional express bus system plan for the San Francisco, California, Bay Area is presented; network, station and stop, operations, and user issues are addressed. Previous work had focused on high-occupancy vehicles on freeways; the current work expands the vision of the system to address the door-to-door trip and service on arterials. Gaps in the high-occupancy-vehicle network, priority treatment strategies, access modes and connections, station and stop design, park-and-ride lots, and public and private access services were analyzed, and other user and operator concerns were addressed. The plan was developed through a partnership that included the state transportation agency, the metropolitan planning organization, local transportation sales tax and congestion management agencies, and transit operators, with university researchers providing technical support and facilitation of meetings. On-board surveys and consumer focus groups were conducted along with stakeholder interviews, field studies, design evaluations, and simulation modeling. The plan not only produced valuable information for future improvements but also helped develop a high level of cooperation and consensus among the participating agencies. Both methods used and lessons learned from the Bay Area experience should be useful to other metropolitan areas and transit operators.
Measuring Impacts of High-Occupancy-Vehicle Lane Operations on Light-Duty-Vehicle Emissions
Authors: Krimmer Michael , Venigalla Mohan
Published: May 2018

High-occupancy-vehicle (HOV) lanes on urban highways have long been proved to increase the efficiency of highway operations, as measured by person throughput, vehicle occupancy, travel time, speed, and reliability. Operational measures of effectiveness, such as speed and travel time, for HOV facilities are superior to general purpose (GP) lanes, in which predominantly single-occupancy vehicles operate. Few studies have attempted to study the emissions on HOV facilities vis-à-vis their GP lane counterparts. In this research, differences in vehicle emissions between HOV lane and GP lane facilities were measured with portable emissions sensors. Several hundred miles of on-road emissions data were collected by vehicles instrumented with portable emissions-monitoring systems (PEMSs) operated in HOV and GP lanes during peak hours in the metropolitan Washington, D.C., area. Data were collected at HOV facilities with buffer separation and at HOV facilities with barrier separation (limited-access lanes). Experimental runs were conducted with pairs of nearly identical instrumented vehicles that simultaneously began trips in parallel HOV and GP lanes and ended them at a common location. The experimental design controlled for vehicle type and driver characteristics. Analysis identified the emissions profiles of vehicles operating in barrier-separated HOV lanes (I-95) and vehicles operating in buffer-separated HOV lanes (I-66). Experiences related to the experimental design with the PEMS, the field deployment of the PEMS, data collection, and analysis are discussed. Included in the discussion is a description of the application of a geographic information system for data reduction and analysis.
Impact of Electronic Toll Collection and Electronic Screening on Heavy-Duty Vehicle Emissions
Authors: Venigalla Mohan , Krimmer Michael
Published: May 2018

The proliferation of electronic toll collection (ETC) mechanisms such as E-ZPass has a positive effect in reducing automobile emissions at toll plazas because of decreased acceleration, deceleration, and idling events. Modeling tools such as the California Modal Emissions Model can be used to measure the emissions impacts of ETC and other electronic screening (e-screening) facilities only on light-duty gasoline-fueled vehicle operations. No such tools exist for modeling of the emissions impacts of ETC and e-screening facilities on heavy-duty vehicle operations. This paper presents a speed profile discretization (SPD) technique for modeling emissions at ETC and e-screening facilities. The SPD technique is based on the MOBILE6.2 method of representing vehicle miles of travel in various speed bins. The technique defines an emissions influence zone within which speed profiles are altered and further determine vehicle emissions. With this technique, the emissions impacts of heavy-duty trucks at the toll collection plaza on the George Washington Bridge in New York City are estimated. The current mix of cash and E-ZPass transactions on the George Washington Bridge are shown to reduce emissions of volatile organic compounds (VOCs), hydrocarbons (HCs), and oxides of nitrogen (NOx) within the emissions influence zone. The degree of reduction is dependent on the speed with which E-ZPass vehicles are processed. If E-ZPass vehicles are processed at no more than 10 mph, reductions in VOC, CO, and NOx emissions are estimated to be 30.8%, 23.5%, and 5.8%, respectively. Results indicate that if E-ZPass allows vehicles to be processed at 20 mph, reductions in VOC emissions due to truck traffic alone could be as high as 50%.
Measuring and Modeling Emissions from Extremely Low-Emitting Vehicles
Authors: Barth Matthew , Collins John , Scora George , Davis Nicole , Norbeck Joseph
Published: May 2018

In recent years, automobile manufacturers have been producing gasoline-fueled vehicles that have very low tailpipe and evaporative emissions to meet stringent certification standards set by the U.S. Environmental Protection Agency and the California Air Resources Board. These extremely low-emitting vehicles are 98% to 99% cleaner than the catalyst-equipped vehicles produced in the mid-1980s. To understand better the emissions characteristics of these extremely low-emitting vehicles, as well as their potential impact on future air quality, researchers at the University of California, Riverside, have conducted a comprehensive study consisting of ( a) an emissions measurement program, ( b) the development of specific emissions models, and ( c) the application of future emissions inventories to air quality models. Results have shown that in nearly all cases, these vehicles have emissions that are well below their stringent certification standards, and the vehicles continue to have low emissions as they age. On the basis of the measurement results, new modal emissions models have been created for both ultra-low-emission-certified vehicles and partial-zero-emission-certified vehicles. The model results compare well with actual measurements. With these models, it is possible to predict accurately future mobile source emissions inventories that will have an increasing number of these extremely low-emitting vehicles in the overall vehicle population. It is expected that the large penetration of these vehicles into the vehicle fleet will have a significant role in meeting ozone attainment levels in many regions.
Evaluation of Emissions from New and In-Use Transit Buses in Mexico City, Mexico
Authors: Clark Nigel N. , Borrell Enrique Rivero , McKain David L. , Paramo Victor Hugo , Wayne W. Scott , Vergara Walter , Barnett Ryan A. , Gautam Mridul , Thompson Gregory , Lyons Donald W. , Schipper Lee
Published: May 2018

The West Virginia University Transportable Heavy-Duty Emissions Testing Laboratory was used to evaluate exhaust emissions from nine transit buses from six separate manufacturers, as commissioned by the Mexico City, Mexico, Secretariat of the Environment. The vehicles included a hybrid-drive diesel bus, two buses with lean-burn spark-ignited compressed natural gas (CNG) engines, and six buses powered by conventional diesel engines. Vehicle testing weights (curb weight plus passenger weight) ranged from 26,996 lb (12,256 kg) to 57,025 lb (25,889 kg), and passenger capacities ranged from 85 to 161. Two driving cycles, the European Transient Cycle (ETC, also known as the FIGE transient cycle) and a new, three-mode Mexico City Schedule, were used to simulate in-use driving conditions during emissions measurements. Diesel fuels with three different sulfur concentrations (15, 150, and 350 ppm) were also examined, and the lowest-sulfur fuel (15 ppm) was not found to have an appreciable direct effect on emissions. When the ETC was used, oxides of nitrogen (NOx) emissions varied from 5.5 to 11.6 g/mi, whereas particulate matter emissions varied from 0.02 to 0.86 g/mi. Significant differences in emissions and fuel economy for the two CNG buses raised the issue that fuel delivery systems must be optimized for operation at high altitudes. The differences in fuel economy and NOx emissions from the hybrid bus for congested and noncongested driving conditions were significantly less than those from the conventional diesel and CNG buses.
Ultrafine Particle Number Concentrations from Hybrid Urban Transit Buses
Authors: Vikara Derek , Holmén Britt A.
Published: May 2018

Recent studies have focused on mass-based quantification of gas and particulate matter (PM) transit bus exhaust emissions under laboratory dynamometer testing conditions because transit buses frequent heavily populated areas and are major contributors to the ambient fine particles in urban regions. This study examines the ultrafine particle (particle mobility diameters of <100 nm) number concentrations and size distributions for conventional diesel and hybrid electric diesel transit buses by the use of onboard exhaust measurements with a scanning mobility particle sizer from TSI, Inc., operated in single-diameter mode. The buses were run on three bus routes (freeway commuter, local, and high-grade arterial routes), with different fuels (No. 1 diesel and ultra-low-sulfur diesel), and with and without diesel particulate filter (DPF) aftertreatment at different points throughout the study. This is the first urban bus emissions study conducted with buses traveling on actual bus routes. Particle number distributions varied by route but not by bus type or fuel sulfur content. Particle number concentrations were higher, on average, for high-load routes (freeway 65-mph commuter and steep-grade routes). There were no significant differences in particle number distributions between the 2003 parallel hybrid electric and the 2002 conventional diesel bus types, likely because of the similar diesel engine specifications and a hybrid control strategy that was not optimized for particulate emissions benefits. For both bus types, use of a DPF resulted in 95% to 99% number concentration reductions for particles of all diameters sampled (10 to 130 nm) on all routes. The study results point to DPFs as a cost-effective solution for achieving particulate emissions control from diesel transit buses.
Cleaner Buses for Mexico City, Mexico
Authors: Schipper Lee , Guy John , Balam Marco , Kete Nancy , Mooney John , Bertelsen Bruce , Noriega Diana , Weaver Christopher
Published: May 2018

In the Mexico City, Mexico, metropolitan area (MCMA), particulate matter pollution is estimated to cause 4,000 excess deaths and the loss of 2.5 million days from work each year. Emissions from diesel-powered buses and trucks are a major source of this air pollution. This paper summarizes the results from a pilot project aimed at testing whether advanced pollution-reducing technologies for diesel trucks and buses currently in use in the United States and Europe will work on Mexican buses and under Mexico City operating conditions. Diesel engines are the workhorses of buses in MCMA and many other regions; operators, vehicle and engine makers, and fuel suppliers have waited for each other to offer improved technologies. In this pilot project, 20 working buses in the Red de Transporte de Pasajeros del Distrito Federal (the Mexico City Diesel Bus Company) fleet were retrofitted with emissions control equipment and fueled with ultra-low-sulfur diesel fuel (ULSD). Results from emissions testing demonstrate that catalyst-based, diesel particulate filters can reduce particulate matter mass emissions by almost 90%. The project demonstrates that it is possible to have extremely clean buses operating in Mexico City by using commercially available technology and ULSD fuel. Even under Mexico City operating conditions and at Mexico City's altitude of 2,240 m, the existing buses in commercial service can greatly reduce the emissions of the pollutants dangerous to human health.
New Methodology for Development of Regional Vehicle-Mapping Tables for MOBILE Emissions Model
Authors: Park Hyungjun , Qi Yi , Smith Brian L. , O'Meara Kevin
Published: May 2018

Among the many input factors to the MOBILE emissions model, vehicle miles traveled (VMT) fractions (the percentage of VMT for different types of vehicles by roadway functional classes) plays an important role because different types of vehicles produce emissions at different rates. In addition, since the vehicle classification scheme of MOBILE is different from the FHWA vehicle types used in traffic data collection, a vehicle-mapping table that converts VMT fractions from FHWA types to MOBILE types deserves special attention. The research described in this paper produced a new methodology to develop a vehicle-mapping table by using readily available data sources, namely, ( a) vehicle registration data from the Department of Motor Vehicles of Virginia and ( b) Vehicle Inventory and Use Survey data from the Bureau of the Census. To evaluate the new methodology, a vehicle-mapping table for Virginia was developed and then compared with three commonly used mapping-table methodologies. In addition, on the basis of the four vehicle-mapping tables, VMT fractions, emissions rates, and final emissions for the Hampton Roads region of Virginia were estimated. An analysis of the results illustrates that use of the proposed mapping-table development methodology affects VMT fraction estimates. In turn, the VMT fraction estimates result in significant differences in the emissions rate estimates generated by the MOBILE model.
Energy and Environmental Impacts of Roadway Grades
Authors: Park Sangjun , Rakha Hesham
Published: May 2018

Although roadway grades are known to affect vehicle fuel consumption and emissions rates, there do not appear to be any systematic evaluations of these impacts in the literature. Consequently, this paper addresses this void by offering a systematic analysis of the impact of roadway grades on vehicle fuel consumption and emissions rates by using the INTEGRATION microscopic traffic simulation software. The energy and emissions impacts are quantified for various cruising speeds, under stop-and-go conditions, and for various traffic signal control scenarios. The study demonstrates that the impact of roadway grade is significant, with increases in vehicle fuel consumption and emissions rates in excess of 9% for a 1% increase in roadway grade. Consequently, a reduction in roadway grades in the range of 1% can offer savings that are equivalent to those offered by various advanced traffic management systems.
Variability in Traffic Flow Quality Experienced by Drivers
Authors: Ko Joonho , Guensler Randall , Hunter Michael
Published: May 2018

Freeway operating conditions are typically evaluated on the basis of the level-of-service (LOS) concept, which is defined according to traffic density, a macroscopic traffic parameter. Although density may provide general estimates of current traffic conditions, it generally fails to communicate the variability in the quality of traffic flow experienced by individual drivers. This variability may be caused by factors that are not effectively captured by density, such as travel lane, vehicle position within a platoon, and characteristics of roadway geometry. This paper investigates the variability of traffic flow quality as indicated by measurements of speed and acceleration noise (standard deviation of acceleration) on the basis of field data obtained from instrumented vehicles equipped with Global Positioning System devices. The microscopic measures observed from individual vehicles are compared with density-based LOS, which are calculated with data from the Atlanta, Georgia, traffic-monitoring system. The comparison indicates that under the same LOS condition, drivers may experience significant differences in the quality of traffic flow. In addition, the comparison indicates that drivers under different density-based LOS conditions may experience a similar level of traffic flow quality. The variability generally becomes larger as traffic conditions worsen.
New Formulation to Analyze Signalized Approaches
Authors: Lieberman Edward , Chang Jinil
Published: May 2018

The procedures generally used in calculating capacity, level of service, saturation flow rate, delay, queue lengths, and signal timing for approaches to signalized intersections are based on disaggregating traffic flow into lane groups. These procedures can be complex if the approaches exhibit geometries with lanes that are both exclusive (i.e., dedicated to servicing a single traffic movement) and shared (i.e., servicing at least two traffic movements). The complexity is exacerbated if the signal timing contains multiple phases servicing the approach, particularly if both permitted and protected signal phases are involved. Finally, the averaging of the differing flow characteristics on each lane making up a lane group could yield results that are unrealistic. The Highway Capacity Manual (HCM) devotes many pages in Chapter 16 and its appendices to delineating these procedures. To a large extent, the HCM uses queue accumulation polygons as part of these procedures and is now considering an extension called the incremental queue accumulation method. This paper presents a new formulation that yields estimates of the traffic demand in each lane, by turn movement, for virtually all geometric configurations of signalized approaches and for all signal phasing plans. The formulation also yields the saturation flow rates by lane and the required signal phase durations for any stated phasing plan. The basis for this method is a variation of Wardrop's laws. The formulations are presented for common approach configurations, and illustrative numerical examples are presented to demonstrate their applicability.
Including Exiting Vehicles in Capacity Estimation at Single-Lane U.S. Roundabouts
Authors: Mereszczak Yuri , Dixon Michael , Kyte Michael , Rodegerdts Lee , Blogg Miranda
Published: May 2018

The current model used in the United States to predict approach capacity at a single-lane roundabout uses information about entry driver behavior in response to the circulating traffic stream only. There is no procedure for including exiting vehicles in capacity estimation. Exiting vehicles are vehicles that leave the circulating stream of traffic by maneuvering into the exit lane at a roundabout approach. Exiting vehicles are known to have an effect on capacity at roundabout approaches in other countries, but their effect in the United States is not known. The purpose of this research is to determine whether including exiting vehicles improves capacity estimation at a roundabout approach. An exploration of the relationships of the proportion of exiting vehicles and the width of the splitter island to approach capacities is included. Capacities were estimated both with and without exiting vehicles as part of the conflicting flow and compared with measured field capacities. The findings demonstrate that capacity estimates with exiting vehicles result in improved prediction of the actual capacity of a roundabout approach over estimates without exiting vehicles. The proportion of exiting vehicles in the major stream and the width of the splitter island appear to provide some benefit in capacity prediction, but exactly how these parameters can be incorporated into the capacity prediction process must be further explored.
Rural Freeway Level of Service Based on Traveler Perception
Authors: Washburn Scott S. , Kirschner David S.
Published: May 2018

The concept of level of service (LOS) is meant to reflect the trip quality a traveler will experience on a roadway or other transportation facility. The objective of this study is to provide insight into how road users perceive trip quality on rural freeways and to examine how the existing service measure (density) relates to the perceived trip quality. Study participants were shown a series of video clips of rural freeway travel from a driver's perspective. They then filled out survey forms indicating their opinion of the trip quality provided by the conditions in the video clip. The survey participants were also asked to give background information about themselves and their driving habits. The data from the surveys were analyzed on the basis of an ordered probit model. The first model used only density as a predictive factor. The second took other roadway and traffic characteristics into account, and the third examined all the significant factors obtained from the survey. The “density only” model confirmed that density is a strong indicator of travelers’ perceptions of trip quality. The other models showed the significance of other traffic and roadway factors in the perception of trip quality, as well as some socio-economic information and personal driving habits. A set of LOS thresholds was also calculated for the “density only” model on the basis of the survey participants’ responses. The resulting thresholds were considerably lower than the Highway Capacity Manual (HCM) thresholds for all LOS rankings. This suggests that travelers’ tolerance of congestion is lower on rural freeways than the HCM indicates.
Measures of Effectiveness for Level-of-Service Assessment of Two-Lane Roads
Authors: Romana Manuel G. , Pérez Ignacio
Published: May 2018

This paper presents an alternative way of using average travel speed and percentage of traffic in platoons [the two measures of effectiveness currently in Highway Capacity Manual (HCM) methodology] to evaluate level of service. The definition of a threshold speed that is acceptable to users is implied. Travelers expect different things of different roads, and in the case of two-lane highways the desire to pass and the stress or mild frustration of being delayed are not a function only of headway or of the difference between actual and desired travel speed. Therefore, simplistic approaches do not accurately reflect the point of view of the roadway user. The procedure can be adapted to various two-lane highway types. It could be used for Types I and II already in HCM procedure and for other types that may be considered in the future.
Queue Length Models for All-Way Stop-Controlled Intersections
Authors: Tian Zong , Kyte Michael
Published: May 2018

The analytical procedures for all-way stop-controlled intersections in the 2000 edition of the Highway Capacity Manual (HCM) lack a model to estimate the 95th percentile queue length. This is considered a major shortcoming of the procedures, since queue length is one of the key parameters used in the traffic engineering design process. This paper provides an assessment of three queue length models for potential application at all-way stop-controlled intersections. One is the theoretically based queue length model included in the HCM for two-way stop-controlled intersections, and the others are empirically based models: a model based on simulation and a newly calibrated model based on field data. The three models were compared on the basis of field data from 18 sites. All the models produce queue length results that closely match the field data. The queue length model for two-way stop-controlled intersections was developed with a sound theoretical basis; therefore, it is recommended that this model be adopted for analyzing all-way stop-controlled intersections in the HCM. However, the empirical models are easy to use and proved to be of the same level of accuracy. The empirical models can be used as an alternative, especially when a quick estimation of the queue length is desired.
Simple Methodology for Evaluating Toll Plaza Operations
Authors: Aycin Murat F.
Published: May 2018

Currently, the Highway Capacity Manual does not provide any tools for the analysis of toll plazas, specifically for the calculation of queue delay. Calculating delay experienced by vehicles in the plaza is a difficult task because of large variations in plaza design and operations; therefore, various simulation models such as TPSIM, WATSim, AIMSUN, and VISSIM are used extensively for toll plaza modeling. However, the performance of these models depends on their calibration and assumptions. As a result, the model results could differ greatly from reality, and the user would not have a means to evaluate their accuracy in the absence of field data. To solve this problem, a methodology has been developed to determine capacity, queuing patterns, and delays of toll plazas by considering the approach roadway conditions and traffic demand characteristics. This methodology, which is suitable for manual calculation, is suggested to improve users’ understanding of toll plaza operations and to provide a means of evaluating simulation results. The application of this methodology to the Throgs Neck Bridge toll plaza in New York City shows that the queuing pattern and delays can be estimated accurately for the a.m. peak period.
Sensitivity of Simulated Capacity to Modification of VISSIM Driver Behavior Parameters
Authors: Lownes Nicholas E. , Machemehl Randy B.
Published: May 2018

This paper presents a sensitivity analysis of VISSIM simulation capacity output under various values of driver behavior parameters. The analysis is undertaken for a simulation developed for the interchange of US-75 and SH-190 (George Bush Turnpike) north of Dallas, Texas. For each driver behavior parameter, including look-back distance, variations in simulated capacity are noted as the particular parameter is modified. The analysis of each parameter is completed with all parameters other than the one under investigation held at their calibrated values. The information presented in this paper is intended to aid practitioners developing and calibrating VISSIM simulation models in understanding the particular driver behavior parameters and the impacts on capacity of modifying the parameters. This work is also intended as a building block in the possible development of a quantitative, optimization-based calibration method for the VISSIM driver behavior parameters.
Evaluation of Performance Measures for Two-Lane Expressways in Japan
Authors: Catbagan Jerome L. , Nakamura Hideki
Published: May 2018

Two-lane expressways exist as provisional sections for future expansion to four-lane expressways in Japan, although recently such roadway types have been considered for construction for permanent use. Their highway classification may fall somewhere between common (multilane) expressways and ordinary two-lane highways, with full access control and high speed limits but with only one lane per direction of travel. Since this type of highway is unique, methodologies for service level measurement of other uninterrupted-flow facilities are not applicable. Percent time spent following, for instance, is estimated with significant consideration of the opposing flow rate, which has practically no effect on driving conditions since a median barrier is present in all sections. The goal of this study is to analyze and compare possible performance measures that would best describe the traffic operational characteristics of two-lane expressways. Among the performance measures considered, follower density had much promise, having shown strong relationships with flow rate. Since the available data were only those taken during off-peak periods, further observations of follower flow must be made during congested or near-congested flow to establish follower density and volume relationships for all traffic conditions.
Capacity of Small Roundabouts with Two-Lane Entries
Authors: Lindenmann H. P.
Published: May 2018

Roundabouts have been a popular system for intersections outside downtown zones in urban areas in Switzerland for more than 10 years. One form of small roundabout becoming more common in Switzerland is the system with short two-lane approaches and a single-lane extrawide circulatory roadway. Research shows that small roundabouts with two-lane entries with a single-lane extrawide circulatory roadway have capacities 20% to 30% higher than those with single-lane entries, although the space requirements are almost identical. The fact that roundabouts with two-lane entries and a single-lane extrawide circulatory roadway have shown good performance with respect to capacity, traffic flow, and driver behavior, as well as a high level of safety, has led to an increasing use of this type of roundabout in Switzerland.
Methodology for Delay-Based Passenger Car Equivalencies for Urban Transit Buses
Authors: Rodriguez-Seda Jarice D. , Benekohal Rahim F.
Published: May 2018

A delay-based passenger car equivalent (D-PCE) methodology for stopping transit buses is presented in this paper. It is based on a D-PCE approach developed in 2000. Field data collected at a near-side bus stop in Chicago, Illinois, were used to determine the total additional delay experienced by bus queues and to illustrate the D-PCE methodology. The relationships between total additional delay, D-PCE, and the factors contributing to delay such as bus dwell time, the number of vehicles queued behind the bus, the bus position within the queue, and the bus arrival–departure time within the cycle were evaluated. The approach is illustrated for cases when the stopping bus was in the first position in the queue. It was found that a bus in first position replaces 5.9 passenger cars. It was also observed that the total additional delay and D-PCE values increased with the factors contributing to additional delay.
Blocked Time of Permitted Left-Turn Lane Group with Two Opposing Lanes for Two Arrival Types
Authors: Wang Ming-Heng , Benekohal Rahim F.
Published: May 2018

The blocked time is a portion of effective permitted left-turn green time blocked by opposing traffic until the left-turn vehicle can get an acceptable gap to complete a permitted left turn. In the Highway Capacity Manual, it is designated as the opposing approach queue clearance time, gq. The blocked time, denoted as gb, is a critical parameter in estimating delay for a signalized intersection because it affects not only left-turn saturation flow but also the shape of the delay area. This paper proposes a model for estimating blocked time for a left-turn lane group with two opposing lanes for well- and poorly coordinated signals. The proposed model was developed by directly considering the arrival types. Possible platoon arrival patterns during the green interval were categorized and then used to estimate the blocked time of the left-turn lane group. A comparison of the results from the proposed model and the existing models with CORSIM results indicated that the proposed model is more realistic in estimating the blocked time for left turns.
Impact of Geometric Factors on the Capacity of Single-Lane Roundabouts
Authors: Johnson Mark T. , Lin Ting-Li
Published: May 2018

Roundabout capacity is primarily estimated by gap-acceptance or by geometric models. The 2010 Highway Capacity Manual (HCM 10) uses a gap-acceptance model developed by Siegloch with empirically derived values of critical gap and headway for single-lane and two-lane entries. A geometric capacity model was developed by Kimber and Hollis that diverged from gap-based models. The capacity of up to four lane entries was empirically derived from six geometric parameters. In 2012 capacity data were collected as part of the FHWA project, Assessment of Roundabout Capacity Models for the Highway Capacity Manual. These data were used to produce HCM6, an update of the HCM 2010. In HCM6, a capacity curve was fitted through all the capacity data for single-lane roundabouts. The large scatter of data about the mean capacity line suggests that the single-lane roundabouts may be separated into different geometric types to improve accuracy. To investigate this hypothesis, the capacity data were separated into two geometrically distinct types of single-lane roundabouts: smaller, compact and larger, curvilinear. The range of data for the disaggregated and aggregated data was compared. Also, a capacity line was derived for each type using the geometric capacity model and compared with the disaggregated data with the HCM6 method. The results demonstrate that differences in geometry, absent in HCM6, explain the wide data range. This was further confirmed by the geometric model that gave a good fit to both sets of data. These results indicate that the accuracy of capacity prediction is improved by including geometric variation.
Data Quality of Travel Behavior Studies: Factors Influencing the Reporting Rate of Self-Reported and GPS-Recorded Trips in Persons with Disabilities
Authors: Neven An , Schutter Ine De , Wets Geert , Feys Peter , Janssens Davy
Published: May 2018

In persons with disabilities, the accuracy of self-report data collection methods in travel behavior studies may be influenced by disease-related dysfunctions. The present study determines in detail whether disease-related physical, cognitive or psychosocial impairments contribute to the reporting rate of subjective self-report travel diaries and objective GPS tracking devices, besides socio-demographic and trip-related characteristics. The reporting rate of both data collection methods was analyzed in 108 persons with Multiple Sclerosis with various disability severities during a seven-day data collection period. The results demonstrated that there was only limited influence of disease-related dysfunctions on the reporting rate of both data collection methods, as well as only limited significant differences between subgroups with various disability severity. Overall, the data quality of the diary was higher than the quality of the GPS data: 66% of the trips were reported in both data collection methods, while overall more than one fifth of all trips were forgotten and not registered by GPS, and 11% were forgotten and not reported in the diary. Self-report travel diaries seemed to be more suitable for persons with a higher disability severity, as these persons more often forgot to take their GPS device with them when making a trip because of several organizational issues related to their mobility limitations.
Quantifying the Effect of On-Street Parking Information on Congestion Mitigation using a Driving Simulator
Authors: Ahangari Samira , Chavis Celeste , Jeihani Mansoureh , Moghaddam Zohreh Rashidi
Published: May 2018

This study investigates travelers’ reactions to different types of information, in deciding their parking choice behavior and its effect on circulation time, through a driving simulator and a stated preference (SP) survey. In the simulator-based driving experiments, we develop a 3.47 mile2 network in the Chinatown area of Washington, D.C., with different scenarios of traffic, driving conditions, and information provision. The parking information is provided using a variable message sign (VMS) and mobile application. In all scenarios, participants can choose from three parking options with different prices and different walking distances to the destination (Verizon Garage, 11th St. Garage, and on-street parking). A sample of 76 participants with diverse socio-economic backgrounds who in total conducted 636 experiments is used. We applied a multinomial logistic regression model, linear regression, and t-test to analyze the collected data. We conclude that types of information and age are important determinants of drivers’ parking choice and compliance behaviors. In addition, the results show that the existence of information decreases the circulation time. In addition, the parking choice behavior revealed through the driving simulator is shown to be significantly different from that stated in the survey questionnaire.
Carsharing Trip Characteristic Analysis: Do Users Choose Carsharing Rather Than Taxi to Economize?
Authors: Hui Ying , Liu Cuiyi , Ding Mengtao
Published: May 2018

Carsharing and taxi are both shared or public car services in urban transportation systems, which means they have a lot in common. In particular, the narrow price gap between carsharing and taxi or public transit in China makes them similar. Trip characteristics analysis and market segmentation are needed, to investigate why and when travelers choose carsharing rather than taxi. In this study, vehicle GPS data and operation order data of a round-trip carsharing system in Hangzhou, China, is used to obtain information on 13,338 valid trips. The trips are divided into three groups based on the travel cost comparison with taxi. Then, an artificial neural network model is developed to analyze group characteristics. The trip characteristics concluded from the model, and analysis on typical service stations, reveal that carsharing has its price advantage on simple long-distance trips during off-peak hours, which is called the regular market. Carsharing’s extended market, in which travel cost is higher than by taxi, covers two types of trips: One involves short driving distance (around 20 km) and long stopping time, and tends to occur in areas in which it is difficult to hail a taxi during peak hours; the other involves very short driving distance (around 10 km), more activity spots and very low travel cost (around 25 CNY). The results of this study can help carsharing operators to extend and adjust their business. Also, these results can contribute to help city administrators to reach better decisions.
The Potential of Metering Roundabouts: Influence in Transportation Externalities
Authors: Fernandes Paulo , Teixeira João , Guarnaccia Claudio , Bandeira Jorge M. , Macedo Eloísa , Coelho Margarida C.
Published: May 2018

Roundabouts are increasingly being used on busy arterial streets for traffic calming purposes. However, if one roundabout leg is near a distribution hub, for example, parking areas of shopping centers, the entry traffic volumes will be particularly high in peak hours. This paper investigated a partial-metering-based strategy to reduce traffic-related costs in a corridor. Specifically, the resulting traffic performance, energy, environmental, and exposure impacts associated with access roundabouts were studied in an urban commercial area, namely: (a) to characterize corridor operations in terms of link-specific travel time, fuel consumption, carbon dioxide and nitrogen oxides emissions, and noise costs; (b) to propose an optimization model to minimize these outputs; and (c) to demonstrate the model applicability under different traffic demand and directional splits combinations. Traffic, noise, and vehicle dynamics data were collected from a corridor with roundabouts and signalized intersections near a commercial area of Guimarães, Portugal. Microscopic traffic and emission modeling platforms were used to model traffic operations and estimate pollutant emissions, respectively. Traffic noise was estimated with a semi-dynamical model. Link-based cost functions were developed based on the integrated modeling structure. Lastly, a sequential quadratic programming-type approach was applied to find optimal timing settings. The benefit of the partial-metering system, in terms of costs, could be up to 13% with observed traffic volumes. The efficiency of the proposed system increased as entering traffic at the metered approaches increased (~7% less costs). The findings enable quantification of metering benefits near shopping areas.
Framework for Estimating the Impact of Camera-Based Intelligent Transportation Systems (ITS) Technology on Incident Duration
Authors: Moylan Emily , Chand Sai , Waller S. Travis
Published: May 2018

Safety is a major motivator of intelligent transportation systems (ITS) projects, and most efforts have addressed the potential to avoid incidents. Managing and reducing the duration of incidents is another key application for ITS despite challenges in distinguishing the true versus the reported duration of an incident. This paper presents a framework for modeling the impact of camera-based (closed-circuit television or CCTV) ITS technology on incident duration including an increase in the reported duration and a reduction in the true duration. The framework is validated against a data set of 121,793 accidents in New South Wales, Australia, covering 4.5 years. The results demonstrate that the use of CCTVs for incident duration contributes a 4.5 min reduction in average duration (as earlier detection can lead to more efficient clearance) and a 9% reduction in variance in the duration (as a uniform detection method supports standardized response procedures). These impacts are only visible when the 8.5 min median detection delay (the difference between the recorded duration and the true duration) is modeled and accounted for. These results offer a quantitative support tool for decision makers wishing to assess the value of incident-detection ITS projects.
When patients fall in love in a group—A challenge to group analysis
Authors: Warhaftig Aran Liat
Published: May 2018

Nitsun pioneered the positive consideration of desire and intimacy in the group and Moeller discussed the conductor falling in love himself, but apart from those authors, the group-analytic literature rarely discusses the subject of romance in groups. This article explores the positive value of the elaboration of falling in love between group members, both to the ‘couple’ and to the group as a whole. Furthermore, I argue the group’s contribution as a post-Oedipal object to its participants, which can strengthen their experience as subjects worthy of mature love and desire. I describe a vignette in which I granted the ‘couple’ the opportunity to meet once outside the group, on the condition they later reintroduce material to the group. This decision will be discussed regarding the conductor’s role in situations of romantic coupling. In addition to the view of keeping firm boundaries of the group and encouraging open discussion regarding love and desire as part of the development of the erotic self, I analyse the importance of enactments to the emergence of dissociated experiences. In this case I see my enactment as an expression of my ‘emotional participation’. In contrast to Grossmark, I claim that enactments cannot always be contained by the conductor and therefore might impact his behaviour as well as the setting.
Peer Tutoring to Facilitate Cognitive Diffusion of English as a Foreign Language Learning: Using Speech Translation and Shadowing in Familiar Authentic Contexts
Authors: Hwang Wu-Yuin , Nguyen Thi-Huyen , Pham Xuan-Lam
Published: May 2018

Learning and cognitive ability are necessarily connected. Learning occurs when people engage in a series of cognitive processes. In this study, we examined how English as a foreign language (EFL) learners’ cognitive abilities diffuse (i.e., change) effectively from a basic level (i.e., Remember, Understand) to a more advanced level (i.e., Apply) with the assistance of a peer-tutoring strategy that pairs high-achieving students with lower achieving students and asks them to use the mobile application, ezTranslate, in a familiar, authentic context. The results showed that the experimental students (i.e., the students who received peer tutoring) significantly outperformed the control students (i.e., the students who worked individually) on the posttest. Furthermore, throughout the learning activity, the majority of the experimental students’ cognitive abilities transitioned from a basic to a higher level. Given these results, we suggested that peer tutoring is particularly advantageous because it helps students engage in high-level cognitive learning. By including mobile technology support with peer tutoring, teachers can utilize their students’ differing abilities to promote collaborative learning, which results in not only successful learning but also encourages positive social interaction and results in high-level cognitive learning.
L’effet du nombre d’images d’ingrédients sur l’évaluation de l’emballage et le choix du produit
Authors: Thomas Fanny , Capelli Sonia
Published: May 2018

Résumé

Dans le contexte très concurrentiel du marché des produits alimentaires, les consommateurs peuvent rencontrer des difficultés à traiter en profondeur les informations présentées sur un emballage. Cette recherche examine comment le nombre d’ingrédients représentés sur un emballage, outre la représentation du produit entier, influence son efficacité en fonction de la motivation du consommateur (via la faim), de son opportunité (via la charge cognitive) et de sa capacité (via le besoin de cognition : Need For Cognition –NFC) à traiter l’information. Trois études démontrent que, sous charge cognitive élevée, les emballages présentant plusieurs ingrédients induisent plus d’imagerie mentale gustative, ce qui accroît l’intention d’achat et améliore l’évaluation du goût du produit. Pour les consommateurs à NFC élevé (vs. faible), sous forte charge cognitive, l’emballage qui n’illustre pas d’ingrédient (vs. 5 ingrédients) est préféré lorsque les consommateurs sont motivés par la faim. Sous faible charge cognitive et quel que soit le NFC, l’information est traitée de façon centrale et l’évaluation ne dépend pas du nombre d’images d’ingrédients représentées.