The influence of bus service satisfaction on university students' mode choice

The purpose of this study was to determine the relationship between bus service satisfaction and the transport mode of choice among university students in Qatar. The degree of bus service satisfaction was collected directly from questionnaire surveys, in which university students were asked questions in relation to their satisfaction with the bus service they used and their transport mode of choice. These questions were categorized into three factors according to confirmatory factor analysis: service at bus stops, service of busses, and service of drivers. Furthermore, the students were asked which mode of transport they used given the choice between public and private transport. This study presents a structural equation model to determine how much bus service satisfaction affects people's decisions about their transport mode. The results from the analysis showed that three key factors—namely, service at bus stops, service of busses, and service of bus drivers—were strongly correlated to the mode of choice. In particular, the bus stop was strongly associated with ease of use, shade, cleanliness, safety, and crowdedness level, while the bus itself influenced reliability, travel time, and frequency. Complying with traffic laws and the driver's attitude were also important contributors to the level of bus service satisfaction. Ultimately, this study will be beneficial for policy/decision‐makers. It will allow them to determine what needs to be accomplished to encourage people to use public transportation. Copyright © 2016 John Wiley & Sons, Ltd.     

A Modeling Framework for Bus Rapid Transit Operations Evaluation and Service Planning

Abstract

In this paper, we present a dynamic traffic assignment-simulation modeling framework (DYNASMART-P) to support the evaluation and planning of Bus Rapid Transit (BRT) services in urban transportation networks. The model represents the different characteristics associated with BRT operations such as: exclusive right-of-way lanes, limited-stop service, signal prioritization at congested intersections, and enhanced bus stops to reduce passenger boarding times. A set of simulation experiments is conducted using the model to study the impact of introducing a hypothetical BRT service in the Knoxville area in the State of Tennessee. In these experiments, the different operational characteristics of BRT are evaluated in terms of potential impact on transit ridership and on the interacting auto traffic. The results illustrate the advantages of BRT for increasing transit ridership and improving overall system performance.     

Four-step travel demand model implementation for estimating traffic volumes on rural low-volume roads in Wyoming

This study develops a four-step travel demand model for estimating traffic volumes for low-volume roads in Wyoming. The study utilizes urban travel behavior parameters and processes modified to reflect the rural and low-volume nature of Wyoming local roads. The methodology disaggregates readily available census block data to create transportation analysis zones adequate for estimating traffic on low-volume rural roads. After building an initial model, the predicted and actual traffic volumes are compared to develop a calibration factor for adjusting trip rates. The adjusted model is verified by comparing estimated and actual traffic volumes for 100 roads. The R-square value from fitting predicted to actual traffic volumes is determined to be 74% whereas the Percent Root Mean Square Error is found to be 50.3%. The prediction accuracy for the four-step travel demand model is found to be better than a regression model developed in a previous study.     

氧传感器在电控发动机中的工作特性研究

有关氧传感器正常工作和信号缺失对电控发动机的动力性、经济性和排放性能以及三元催化转换器转化效果等指标的影响的实验研究表明,氧传感器是否正常工作对三元催化器的转化效果影响较大.     

Experimental study of the flow induced by a vehicle fan and the effect of engine blockage in a simplified model

Fans are often tested without downstream blockage and, thus, the performance is considerably different when the fan is mounted in a vehicle as part of a cooling system and where high blockage effect is present downstream. The aim of the present work is to analyze by laser Doppler velocimetry LDV measurements the topology of the flow induced by a fan incorporated in a simplified underhood model reproducing engine blockage and to study the blockage effect of the engine positioning on the flow induced by the fan. The distance between the fan and the engine block affects the mean flow axial velocity U. The vertical velocity component W is greatly influenced by the variation of the distance between the fan and the engine block, both in magnitude and topology.     

片体间距对高速三体船水动力性能影响的比较分析(英文)

This paper numerically investigates the influence of separation variation of the outriggers on the hydrodynamic performance of a high speed trimaran (HST) aiming at improving its applicability in diverse realistic disciplines. The present investigation was performed within the framework of the 2-D slender body method (SBM) by calculating the resistance of three symmetric trimaran series moving in a calm free surface of deep water. Each trimaran series comprises of 4681 configurations generated by considering 151 staggers (50%≤α≤+100%), and 31 separations (100%≤β≤400%) for 81 Froude numbers (0.20≤Fn≤1.0). In developing the three trimaran series, Wigley-st, AMECRC-09, and NPL-4a models were used separately for both the main and side hulls of each individual series models. A computer macro named Tri-PL was created using the Visual Basic for Applications. Tri-PL sequentially interfaced Maxsurf then Hullspeed to generate the models of the three trimaran series together with their detailed hydrostatic particulars, followed by their resistance components. The numerical results were partially validated against the available published numerical calculations and experimental results, to benchmark the Tri-PL macro and hence to rely on the analysis outcomes. A graph template was created within the framework of SigmaPlot to visualize the significant results of the Tri-PL properly.     

Effectiveness of enforcement resources in the highway patrol in reducing fatality rates

Motor vehicle crashes are a leading cause of death in the United States. Wyoming initiated a safety study to investigate the underlying causes of high crash rates since it has one of the highest fatality rates in the nation. Research has shown relationships between increased enforcement activity and road crash/fatality reduction. However, little research has attempted to quantitatively measure the impact of various forms of police enforcement, such as the percentage of enforcement time and the quantity of resources, on fatality rate. Therefore, this study was set forward to fill this gap. Data from the highway patrol in Wyoming and the surrounding states were used in this study. Although Wyoming and these nearby states have very similar features in terms of geography and weather, they are different in terms of road mileage and traffic. Therefore, the data was normalized based on highway mileage and miles traveled. Enforcement efforts were compared in terms of allocated enforcement budget, number of sworn officers, and time spent patrolling. The results indicated that there are negative relationships between fatality rate and budget, number of officers, and active hours on the field. This paper also investigated which variable is the best predictor of fatality rate. The results indicated that time spent on the field by highway patrol officers is the best indicator of fatality rate. It was found that although some states like Wyoming have a higher number of sworn officers, they spend less time actively enforcing highway safety. This study provides information needed for authorities to allocate more funding to the highway patrol, and for the highway patrol to spend more time on the road.     

Effects of ground vehicle inclination on underhood compartment cooling

This work reports on experiments carried out on a real passenger vehicle in a large wind tunnel to investigate the effects of car inclination on underhood cooling. The vehicle??s underhood is instrumented by thermocouples that measure the temperatures of many underhood components during different car functioning modes. Measurements are carried out for three thermal functioning points at car speeds 90, 110 and 130 km/h. In these experiments the engine was in operation and the front wheels positioned on the test facility with power-absorption-controlled rollers. Three car inclinations are investigated: flat, uphill and downhill. The results show that car inclination, even if very small, can have significant effects on underhood cooling and must be taken into consideration in numerical simulations and controlled in experimental tests. It was shown that down-hill and up-hill inclinations increase temperatures of components, air zones and engine parameters in the underhood, with higher effect for the down-hill inclination. Temperature increases in constant-speed driving phase are higher than in thermal soak phase.     

Proposed quick method for applying dynamic lane assignment at signalized intersections

Almost all researches about dynamic lane assignment were conducted to evaluate the effectiveness of applying this technique at signalized intersections. However, little attention was given to the method of identifying quickly the optimum lane group. This research suggests a quick method to find the optimum lane group for 3-lane and 4-lane approaches at junctions where each approach has green by itself in turn using the percentage of turning movements. MATLAB environment was used to build an optimization model to find the optimal lane groups at all intersection approaches for hypothetical massive traffic demand combinations using an objective function of minimizing intersection delay. This finding represents a plausible quick method to predict the optimum lane group in the field instantaneously using the percentage of turning movements at the approach without conducting massive calculations.