Using a stages of change approach to explore opportunities for increasing bicycle commuting

Given the potential benefits of bicycling to the environment, the economy, and public health, many U.S. cities have set ambitious goals for increasing the bicycle share of commute trips. The Transtheoretical Model of Behavior Change, which seeks to describe how positive and permanent change can be fostered in individuals, may shed light on how cities can most effectively increase bicycle commuting. We use the model’s “stages of change” framework to explore the potential for increased bicycle commuting to the UC Davis campus in Davis, California. Our analysis uses data from the 2012 to 2013 UC Davis Campus Travel Survey, an annual online survey that is randomly administered to students and employees at UC Davis. Based on their responses to questions about current commute mode and contemplation of bicycle commuting, respondents are divided into five stages of change: Pre-contemplation, Contemplation, Preparation, Action, and Maintenance. We construct a Bayesian multilevel ordinal logistic regression model to understand how differences in socio-demographic characteristics, travel attributes, and travel attitudes between individuals explain their membership in different stages of change. In addition, we use this model to explore the potential of various intervention strategies to move individuals through the stages of change toward becoming regular bicycle commuters. Our results indicate that travel attitudes matter more to progression toward regular commute bicycling than travel attributes, tentatively supporting the efficacy of “soft” policies focused on changing travel attitudes.     

Determining the role of bicycle sharing system infrastructure installation decision on usage: Case study of montreal BIXI system

The traditional quantitative approach to studying Bicycle Sharing System (BSS) usage involves examining the influence of BSS infrastructure (such as number of BSS stations and capacity), transportation network infrastructure, land use and urban form, meteorological data, and temporal characteristics. These studies, as expected, conclude that BSS infrastructure (number of stations and capacity) have substantial influence on BSS usage. The earlier studies consider usage as a dependent variable and employ BSS infrastructure as an independent variable. Thus, in the models developed, the unobserved factors influencing the measured dependent variable (BSS usage) also strongly influence one of the independent variables (BSS infrastructure). This is a classic violation of the most basic assumption in econometric modeling i.e. the error component in the model is not correlated with any of the exogenous variables. The model estimates obtained with this erroneous assumption are likely to over-estimate the impact of BSS infrastructure. Our research effort proposes an econometric framework that remedies this drawback. We propose a measurement equation to account for the installation process and relate it to the usage equations thus correcting for the bias introduced in earlier research efforts by formulating a multi-level joint econometric framework. The econometric models developed have been estimated using data compiled from April 2012 to August 2012 for the BIXI system in Montreal. The model estimates support our hypothesis and clearly show over-estimation of BSS infrastructure impacts in models that neglect the installation process. An elasticity analysis to highlight the advantages of the proposed econometric model is also conducted.     

Capacity of Dual-Right-Turn Lanes at Signalized Intersections under Mixed Traffic Conditions

To explore the potential capacity of dual-right-turn lanes at signalized intersections under mixed traffic conditions, we defined two conflict zones between right turn vehicles and through bicycle corresponding to different right turn flows from dual-right-turn lanes. Relationships between the arrival rate of bicycle group at each conflict zone and the saturation flow rate of right turn movement were investigated. A model based on gap acceptance theory was adopted to estimate the capacity of dual-right-turn lanes under mixed traffic conditions. An analysis was carried out using the collected data from three four-leg signalized intersections in Beijing, China, where the dual-right-turn lanes were used. In addition, we also discussed the patterns of bicycle lane in the urban area of Beijing, and classified it based on its characteristics in use. It is concluded that the two lanes of dual-right-turn lanes produce different capacities under mixed traffic conditions, and the analysis on scenarios of dual-right-turn movement traversing bicycle traffic plays a key role in explaining the different capacity performance of the two right turn lanes. Error analysis of the model indicated that the model was rational.     

Safety-based path finding in urban areas for older drivers and bicyclists

This paper presents a safety-based path finding methodology for older drivers and bicyclists in an urban area. The paths are estimated based on costs consisting of both safety and travel time. Safety is evaluated against potential risk of a crash involving an older driver (or a bicyclist) with other vehicles present on the road. To accomplish this, simple formulations are developed for safety indicators of streets and intersections, which are actually generic irrespective of the type of road user. Traffic attributes such as speed and density, driver attributes such as perception-reaction time and street attributes of length and tire-to-road friction coefficient are taken into account in building the safety indicators. Thus, the safety indicators do not necessarily require historical crash data which may or may not be available during path finding. Subsequently, a multi-objective shortest path algorithm is presented that identifies the best path (the non-inferior path) from amongst a set of selected safest paths with due considerations to travel time incurred on each. A simple application example of the proposed methodology is demonstrated on an existing street network system from the City of College Station, Texas. The contributions of this research are twofold – first, the safety indicators can be used by planners in determining high crash potential sites – streets and/or intersections – and second, the safety-based path finding methodology developed in this paper can be integrated with modern day route planning devices and tools in guiding older drivers and bicyclists within an Intelligent Transportation Systems framework.     

国外城市自行车发展模式分析及对我国城市自行车发展的启示

在我国城市自行车交通出行比例有所下降,但保有量依然很大的背景下,探索自行车交通的发展出路.通过分析哥本哈根、东京两个城市中不同的自行车交通发展模式,从中得到我国城市自行车交通发展出路的一点启示.并将东京与上海市的城市结构、交通特性进行比较,得出上海市的人口密度、交通结构以及交通发展政策与东京相似,东京的自行车交通发展对...     

武汉市主城区自行车停车设施规划与管理模式研究

自行车停车设施规划是自行车交通系统规划的重要内容。国内大多城市对自行车停车设施规划与建设不够重视,出现自行车停车难的尴尬局面。结合武汉市主城区自行车发展概况,探索自行车停车设施规划方法与管理措施,提出了分类分块、重点布设的原则以及停车设施分级规划思路,从自行车停车需求预测、停车场布局方法、停车管理措施等方面进行了探讨,以期完善自行车系统规划,提高自行车的吸引率。     

城市信号交叉口自行车及行人到达与释放规律

在我国城市交通管理中,对城市信号交叉口处机动车、自行车和行人的混合交通流的有效组织是交通通畅运行的关键。在交通调查的基础上,利用数理统计方法分析城市信号交叉口自行车及行人的到达与释放规律,提出城市信号交叉口自行车及行人的到达分布模型,对城市信号交叉口自行车流的释放饱和流率、释放速度和行人步速进行标定,并对信号交叉口自行车流及行人的交通特性形成原因进行分析。研究结果可应用于城市信号交叉口混合交通控制及管理。     

Modeling cyclists' facility choice and its application in bike lane usage forecasting

In some circumstances on streets equipped with new bike facilities, cyclists are not interested in using them. Instead, they continue to use shared spaces with pedestrians or motor vehicles. Thus, simply adding a bike facility does not guarantee that cyclists will switch to using it. Owing to the considerable development of bike facilities, the investigation of facility preference, particularly focusing on facility choice forecast, has become increasingly important. This study developed a model for predicting the facility choice of cyclists between on-street facilities (curb, traffic lane, and bike lane (BL)) and off-street facilities (sidewalks). Initially, the optimal model was selected using Bayesian Model Averaging method. Then, it was validated by both internal and external validations. Apart from the aforementioned factors, several other exogenous variables were also found to be significant predictors of bike facility choice, including the width of traffic lanes, existence of real-time stopping vehicle, type of bike, bus stop existence, and in-group cycling. Analysis of the relative importance of predictors indicated that bus stop existence, effective sidewalk width, and type of bike were the potential predictors. A framework for predicting BL usage, if it is present, was also developed. A test for the predictive performance of the application at a real site was carried out. By comparing predicted and actual BL usage figures, the analysis showed good predictive performance. The results of this study can help developers, planners, and designers to adopt reasonable investment decisions as well as better designs in developing new bike facilities.     

基于TOPSIS法的自行车停车场布局应用研究——南京鼓楼地铁站实例分析

现代交通设施布局选址过程中,越来越多的面临着多属性多方案优先级排序、在多备选方案中选取最优方案等问题。本文将多目标决策分析法-TOPSIS法应用到自行车停车场布局选址研究中,采用熵权系数法进行决策指标权重的计算,避免了传统方法中主观性强等弊端;并且针对南京鼓楼地铁站确定合理的自行车停车场选址决策指标,基于TOPSIs法完成鼓楼站自行车停车场选址的理论研究;最后通过对鼓楼地铁站的实地调研,进行了详尽分析,对理论上获得的自行车停车场选址结果进行分析检验,验证了该方法的有效性和实用性。     

西安市客运交通结构调查与分析

城市客运交通结构调查与研究是合理规划交通出行方式、提高城市交通效率和制定交通政策的重要环节。首先采用发放调查问卷的形式进行出行调查,通过数据处理与分析得出西安市出行方式结构比例,与2000年居民出行调查结果进行对比,分析了交通结构比例的变化和影响变化的因素。根据客运交通结构的实际,结合西安的城市建设、交通现状及道路条件,提出以TOD模式为主导,以轨道交通为骨干,积极发展自行车交通的建议,合理分布客运交通结构。尤其是通过设立公共自行车以及自行车与公共交通设施的衔接,充分发挥自行车交通的功能,带动整个城市交通的良性发展。