绿色公路理念在漳武高速公路设计中的思考与实践

随着我国高速公路网基本形成,目前新增高速公路建设项目多位于山区腹地及偏远地区,这些地方往往基本农田资源稀缺、陆域、水域生态、自然保护地分布多、范围广,生态环境保护要求高,因此对于绿色公路理念的贯彻和落实显得尤为重要。本文从集约通道资源、保护土地资源、生态选线、多元化服务区设计等方面详细阐述了绿色公路理念在漳武高速项目勘察设计中的应用情况,实践表明绿色公路设计对于控制资源占用、减少能源消耗、降低污染排放、保护生态环境、拓展公路功能、提升服务水平方面起到了极大的提升作用。     

基于状态空间采样的高速公路智能网联车辆轨迹动态规划

为实现智能网联车辆在高速公路动态行车环境下的轨迹实时规划，提出一种基于状态空间采样的轨迹动态规划方法。首先，以安全性为原则选取主车当前行驶的理想车道。基于Frenet坐标与笛卡尔坐标的转换关系，建立车辆运动横、纵向解耦的独立积分系统。将高速公路常见的行驶状态分为车道保持与定速巡航、变道以及前车跟随3类，预测主车行驶车道并针对3类行驶状态分别设计轨迹终端的目标配置方法。然后，利用多项式函数生成连接初始配置和目标配置的多条待选轨迹。构建考虑轨迹偏离理想车道程度、始末速度变化、规划周期和轨迹舒适性的综合损失函数，结合速度、加速度、曲率检查来评价各条待选轨迹的成本并进行排序。最后，预测车辆的横、纵向运动轨迹并构建一种胶囊形的车辆虚拟安全边界，通过碰撞检测，确定主车的最优轨迹，设置动态规划触发条件及时更新最优轨迹并避免过度规划浪费资源。研究结果表明：提出的算法能满足高速公路场景的动态规划需求；通过对轨迹规划周期、虚拟安全边界、动态规划时间间隔等关键参数的分析与优化，主车的横摆角速度范围稳定在-0.1~0.15 (°)·s^-1，横向加速度范围稳定在-0.16~0.32 m·s^-2，跟踪参考轨迹的最大误差不超过0.022 m，提出的算法能规划出具有高安全性、稳定性和舒适性的轨迹。     

ICT Adoption among Logistics Companies in ASEAN Countries

In this era of globalization, adoption of information and communication technology (ICT) is one of the critical determinants of logistics companies' competitiveness and growth. This is especially so for the ASEAN countries as they pursue the vision of regional economic development and integration. Existing empirical studies on ICT adoption by logistics companies in developing countries are, however, scarce and have limited theoretical support and so far no comparative analysis of ICT adoption among ASEAN logistics companies and its determinants has been undertaken. This paper investigates the level of ICT adoption among ASEAN logistics companies and also develops an investment-based model to explain it. The model is evaluated with logistic regression using firm-level data collected from interviews with a sample of ASEAN logistics companies. The study finds that ICT adoption level varies significantly among the ASEAN countries and provides an empirical support for an investment-based view of ICT adoption. It also finds no further evidence for the relevance of the institutional theory to the ASEAN logistics industry. These findings have important strategic and policy implications for the ASEAN policy-makers and logistics industry.     

A Review of Pseudo Panel Data Approach in Estimating Short-run and Long-run Public Transport Demand Elasticities

Abstract

The distinctions between short-run and long-run public transport demand elasticities have been highlighted in the literature, but the identification of long-run travel demand has been constrained by existing research methodology and the unavailability of longitudinal travel survey data. The pseudo panel data approach using repeated cross-sectional data has been suggested as an alternative to conducting a longitudinal travel demand analysis when genuine panel data are not available. This paper comprehensively reviews the background and the current practices of pseudo panel data research, and introduces the challenges in applied research that need further investigation, particularly for public transport. A case study using the Sydney Household Travel Survey data is presented to demonstrate pseudo panel data construction and to identify the short-run and long-run public transport demand elasticities using a pseudo panel data approach. The research findings suggest that the public transport demand elasticity of price in Sydney is ?0.22 in the short run and ?0.29 in the long run.     

Investigating the effect of travel time variability on drivers' route choice decisions in Shanghai,China

Abstract

This paper investigates the effect of travel time variability on drivers' route choice behavior in the context of Shanghai, China. A stated preference survey is conducted to collect drivers' hypothetical choice between two alternative routes with designated unequal travel time and travel time variability. A binary choice model is developed to quantify trade-offs between travel time and travel time variability across various types of drivers. In the model, travel time and travel time variability are, respectively, measured by expectation and standard deviation of random travel time. The model shows that travel time and travel time variability on a route exert similarly negative effects on drivers' route choice behavior. In particular, it is found that middle-age drivers are more sensitive to travel time variability and less likely to choose a route with travel time uncertainty than younger and elder drivers. In addition, it is shown that taxi drivers are more sensitive to travel time and more inclined to choose a route with less travel time. Drivers with rich driving experience are less likely to choose a route with travel time uncertainty.     

Expansion of a Controlled Parking Zone (CPZ) and its Influence on Modal Split: The Case of Edinburgh

Abstract

This article considers the inter-relationship between on-street parking and choice of mode for journeys to work in the Scottish city of Edinburgh. This city is typical of many in that its centre has significant on-street parking controls but, beyond a radius of 1 to 1 1/2 miles (1.5 to 2.5?km) from the centre, there are no controls and commuter parking on-street is commonplace. The article reviews the relevant literature, and then considers the results of a survey undertaken of Edinburgh city centre employees in order to ascertain their parking habits and likely response to the extension of existing on-street parking controls. The article concludes that the results are transferable to other cities but that the scale of the impacts in each will be related to site specific factors, particularly the demand for residential parking space on-street in areas close to the city centre.     

高校校园停车设施调查与分析

随着高等教育事业和小汽车产业的不断发展,高校校园规模不断扩大,小汽车保有量不断增加,高校校园的交通方式发生了重大改变,校园停车问题日益突出。鉴于此,以浙江师范大学为例,对校园停车设施进行了系统的调查和分析,并提出了相应的改进措施。     

规划新城区交通量预测分析

交通量预测是进行交通状态评价、综合分析建设项目必要性和可行性的前提和基础。预测的交通量数据是确定公路建设项目建设规模、技术标准的主要依据之一。通过对临夏市经济园区的用地性质、经济以及人员、车辆出行预测的分析,运用四阶段法对该地区的交通量进行预测,预测结果合理、准确。     

一种基于手机定位数据的出行行程识别方法

提出并实现了一种基于手机定位轨迹数据的出行行程识别方法.通过速度对轨迹点进行划分,将低于一定速度阈值以下的轨迹点合并为候选停留位置,再利用距离阈值和时间阈值对候选停留位置进行合并,从而确定出真正的停留点,继而自动统计出行次数和出行时间.该方法解决了手机定位数据的定位漂移和抖动的问题,行程识别精度高,识别结果可为交通规划工作提供相关数据,并具有比传统交通调查方法更低的成本和更短的数据更新周期.     

基于SP/RP调查的停车设施规划及收费政策研究

针对目前许多城市的停车乱、停车难、路边路外停车设施利用不均等问题,以独山子地区作为案例,研究合理可行的停车设施规划方案及停车政策,以调节路边路外停车比例、规范停车行为.同时,通过RP、SP调查,了解居民停车的影响因素,构建离散选择模型,并确定不同因素对停车选择的影响程度.基于分析结果,提出相应的停车规划及政策建议.