基于浮动车数据调查方法的交叉口延误计算

针对目前城市中现有的GPS浮动车研究城市交叉口延误估计方法,为了摆脱传统计算方法,提出一套利用浮动车数据估计延误的新方法。在分析了车辆经过交叉口的受阻过程,界定了交叉口范围以及车辆经过交叉口的畅行速度的基础上,确定了交叉口延误的计算流程以及计算公式,并且对此方法进行了验证。     

基于GPS车辆定位信息的交叉口延误计算方法

为得到车辆在城市道路信号控制交叉口的瞬时延误,根据车辆在交叉口的运行特征,利用GPS车辆定位信息,提出了交叉口车辆延误3种指标的计算方法。为确定加速度临界点,探讨了两种车辆延误的计算方法：加速度临界值过滤法和非线性拟合～局部最优解法。这两种方法能够很好地描述车辆加速和减速等运动过程,并有效地寻找交通流特征曲线的拐点,从而计算车辆在信号控制交叉口的延误。最后,通过实际数据对两种算法进行了验证。通过比较分析,从算法的简便性、有效性和准确性层面分别得出结论,结果表明,非线性拟合一局部最优解法比加速度临界值过滤法平稳,精度相对较高。     

车辆 GPS 监控导航系统研究

综合分析了GPS车辆监控导航管理系统的研究背景以及国内外GPS车辆监控导航管理系统的研究现状.在此基础之上,以MapInfo为研究平台,选用VC++作为系统的开发工具,研制了符合我国国情的车辆导航系统.文中重点阐述了GPS车辆监控导航管理系统的设计方法,进而拟定了系统软件开发框架和各组成部分的性质功能.并以武汉市一环线为案例进行了模拟研究,结果表明所研制的GPS车辆监控导航管理系统能够有效的实施车辆的跟踪导航.     

Hypothetical bias in Stated Choice Experiments: Is it a problem? And if so,how do we deal with it?

The extent to which Stated Choice (SC) experiments suffer from hypothetical bias continues to be a controversial topic in the literature. This research provides further evidence in this debate by examining the existence of hypothetical bias in a transport-related SC experiment. Data for this research were sourced from a University of Sydney study exploring the effect of exposure-based charging on motorist behaviour. The sample included 148 Sydney motorists who were recruited to take part in the 10-week GPS driving field study (Revealed Preference/RP data). In addition, participants were also required to complete an SC survey which was designed to mimic the RP decision context in order to capture what participants indicated they would do as opposed to what participants actually did in reaction to the charging regime.The current state of practice for measuring hypothetical bias in the literature is to compare aggregate differences in model outcomes using SC and RP data sources. Aggregate analysis is limited in its scope and does not allow for the calculation of the prevalence of hypothetical bias (i.e., how many participants are affected by hypothetical bias). This research is uniquely structured to allow for individual categorisation of hypothetical bias by comparing SC and RP data from the same sample for the direct purpose of investigating the prevalence of hypothetical bias. Furthermore, the extent to which mitigation techniques (cheap talk and certainty scales) influence hypothetical bias is also explored. The findings from this research show that the SC model estimates are prone to hypothetical bias and that the mitigation techniques have potential to compensate for this inherent bias.     

The vehicle emissions and performance monitoring system: analysis of tailpipe emissions and vehicle performance

This paper describes tailpipe emission results generated by the Vehicle Performance and Emissions Monitoring system (VPEMS). VPEMS integrates on‐board emissions and vehicle/driver performance measurements with positioning and communications technologies, to transmit a coherent spatio‐temporally referenced dataset to a central base station in near real time. These results focus on relationships between tailpipe emissions of CO, CO₂, NO_x and speed and acceleration. Emissions produced by different driving modes are also presented. Results are generally as one would expect, showing variation between vehicle speed, vehicle acceleration and emissions. Data is based upon a test run in central London on urban streets with speeds not exceeding about 65 km/h. The results presented demonstrate the capabilities of the system. Various issues remain with regard to validation of the data and expansion of the system capability to obtain additional vehicle performance data.     

移动定位系统在高速公路管理中的应用

移动定位系统的应用对规范通行费用拆分方式、提高拆分透明度和公平性具有重要意义。文章分析了目前广西高速公路管理中存在的问题,同时结合移动定位定义、系统的构成及基本原理,介绍移动定位系统在高速公路管理中的具体应用情况及达到的效果。     

A bus route evaluation model based on GIS and super-efficient data envelopment analysis

When compared to large cities in developed countries, the shares of public transportation in most Chinese cities are low. Increasing the competitiveness of urban public transportation remains an urgent problem. A capable evaluation method for public transportation is required to assist the development of urban transit systems. This paper focuses on the bus system. Being devoid of standard criteria, it is difficult to determine the efficiency of a transit system or any bus line using a single evaluation index. This paper proposes a comparative analysis to evaluate bus lines so as to filter out candidates for further optimization. From the viewpoints of transit planning, operation and quality of service, this paper establishes 10 subordinate evaluation indices and then uses geographical information system tools, global positioning system data and smart card data to assist the index definition and calculation. Super-efficient data envelopment analysis (DEA) method is adopted for the proposed single factor and comprehensive evaluation models. Finally, the bus system in Shenzhen, China is used as a case study. The comparable significant results validate the capability of the proposed model.     

Estimating the most likely space–time paths,dwell times and path uncertainties from vehicle trajectory data: A time geographic method

Global Positioning System and other location-based services record vehicles’ spatial locations at discrete time stamps. Considering these recorded locations in space with given specific time stamps, this paper proposes a novel time-dependent graph model to estimate their likely space–time paths and their uncertainties within a transportation network. The proposed model adopts theories in time geography and produces the feasible network–time paths, the expected link travel times and dwell times at possible intermediate stops. A dynamic programming algorithm implements the model for both offline and real-time applications. To estimate the uncertainty, this paper also develops a method based on the potential path area for all feasible network–time paths. This paper uses a set of real-world trajectory data to illustrate the proposed model, prove the accuracy of estimated results and demonstrate the computational efficiency of the estimation algorithm.     

卫星定位系统在汽车防盗中的应用

介绍了卫星定位系统的功能、应用范围,国内卫星定位系统的应用情况及其普及应用应解决的问题。     

Map-matching poor-quality GPS data in urban environments: the pgMapMatch package

Global Positioning System (GPS) data have become ubiquitous in many areas of transportation planning and research. The usefulness of GPS data often depends on the points being matched to the true sequence of edges on the underlying street network – a process known as ‘map matching.’ This paper presents a new map-matching algorithm that is designed for use with poor-quality GPS traces in urban environments, where drivers may circle for parking and GPS quality may be affected by underground parking and tall buildings. The paper is accompanied by open-source Python code that is designed to work with a PostGIS spatial database. In a test dataset that includes many poor-quality traces, our new algorithm accurately matches about one-third more traces than a widely available alternative. Our algorithm also provides a ‘match score’ that evaluates the likelihood that the match for an individual trace is correct, reducing the need for manual inspection.