城市公共交通系统中低碳出行合理路径算法

应对公共自行车发展的趋势,针对城市多模式组合网络路径算法研究中对路径合理性和用户偏好关注的不足,提出一种新的出行路径寻优算法。根据居民出行的一般规律分析了一般路径的构成特征,并充分考虑了居民出行策略的个性化。根据＂低碳出行＂路径选择问题的描述,引入＂多元标号＂的概念,提出了基于经典Dijkstra算法改进的分层标号算法。给出了算法的详细求解步骤,而且通过算例对新算法的适应性和有效性进行了验证。     

正交试验设计在交通意向调查中的应用

为了在保证意向调查精度的基础上精简方案数量,采用正交的方法进行方案设计。文中简要介绍了正交设计的原理,利用因素间的正交特点进行多因素多水平的方案组合,并比较了应用正交设计前后的效果。该方法降低了组合次数,也有利于提高后期数据处理的工作效率。在调查实例中,运用正交设计的停车行为意向调查问卷取得了较好的效果。     

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探讨了乘客在实时换乘信息提示下,结合自身偏好进行线路选择的行为.由于实时提示等车信息不完全准确,通过引入不确定分布予以描述,并针对实时信息提示的等车时间建立了基于实时-时变结合策略的更新机制,据此对乘客的线路初始偏好值进行修正,并建立了能综合反映实时提示信息和乘客个体偏好对线路选择行为影响的线路选择概率模型.最后,通过数值仿真验证了该模型的可行性和有效性,并分析了等车时间和乘车时间的权重对乘客线路选择行为的影响.结果表明,实时提示信息会改变乘客对线路初始偏好,进而改变乘客的线路选择行为.     

Assessing carbon reduction effects toward the mode shift of green transportation system

Plans are underway to introduce green transportation systems at Taiwan's famous scenic spot, Sun Moon Lake, to reduce carbon emissions. Carbon reduction effects after changing the current lake tour modes are assessed using a nested logit model with a stated preference survey, which investigated tourists' choice preferences. The empirical results reveal that the modes of electric bus, electric vehicle sharing, and bike are clustered in the same competitive group. Travel cost, in‐vehicle travel time, and out‐vehicle travel time are found to be statistically significant with the expected negative effects. In particular, the attribute of carbon reduction is only significant for green tourists, who are willing to pay US$ 3.5/kg of carbon saved. The result indicates that more efficient carbon reduction is possible by restricting the usage of gasoline vehicles rather than improving the service levels of low‐carbon modes. Notably, the effect of parking charges on emission reduction is equal to the amount of carbon dioxide absorbed by 4511 trees per day. Copyright © 2016 John Wiley & Sons, Ltd.     

Estimation of Travel Time Values for Urban Public Transport Passengers Based on SP Survey

Quantitative study on the travel costs of urban transit passengers has great significance for scientifically evaluating social benefits of public transportation system. Analysis of travel time values is one of the most important parts of traveler's travel cost estimation. According to the stated preference (SP) survey data for Beijing residents, factors that influence public transport values of travel time are analyzed and a Logit-based model is used. An improved SP survey based model is proposed, in which traveler's income is introduced as a variable. The parameters estimating the travel time values under the trip purposes of work/business and leisure are calibrated. Then the values of travel time under different conditions in Beijing are obtained (i.e. different trip purposes and with/without transferring). The results indicate that the travel time values for work are generally higher than those for leisure. The waiting time values are higher than transferring time values and in-vehicle time values under any circumstances, and the waiting time values are higher with transferring than those without transferring.