广州市轨道交通站点交通衔接功能分级体系探讨

制定轨道交通站点交通衔接功能分级体系,明确站点交通衔接功能定位,是实现轨道交通与其它交通方式高效衔接的基础。本文针对当前国内轨道交通站点衔接功能分级体系不统一,分级指标和标准不明确的情况,结合广州市的实际,对轨道交通站点衔接功能等级划分、分级指标选取、指标标准的确定等方面进行了探讨。     

城市客运交通结构的影响因素研究

在分析交通结构组成和基本模式的基础上,归纳总结了城市客运交通结构存在的问题。对影响城市客运交通结构的主要因素进行了定性研究,为城市客运交通结构向合理化方向发展提供借鉴。     

城市交通拥挤的社会成本分析初探

交通拥挤的社会成本可分为生产成本、使用成本、时间耗费成本及外部成本,本文在定性分析的基础上,对使用成本和时间耗费成本做了定量分析,给出了计算公式,并通过对大连市西南路某路段在拥挤时段的调查,计算出了居民出行时间成本的损失和城市交通使用成本的损失,这一结果可以推广到整条道路或区域路网,从而为城市交通的良性发展和减少经济损失等方面提供了有效的理论依据。     

The principles of calibrating traffic microsimulation models

Traffic microsimulation models normally include a large number of parameters that must be calibrated before the model can be used as a tool for prediction. A wave of methodologies for calibrating such models has been recently proposed in the literature, but there have been no attempts to identify general calibration principles based on their collective experience. The current paper attempts to guide traffic analysts through the basic requirements of the calibration of microsimulation models. Among the issues discussed here are underlying assumptions of the calibration process, the scope of the calibration problem, formulation and automation, measuring goodness-of-fit, and the need for repeated model runs.

Adaptive cruise control design for active congestion avoidance

We present an adaptive cruise control (ACC) strategy where the acceleration characteristics, that is, the driving style automatically adapts to different traffic situations. The three components of the concept are the ACC itself, implemented in the form of a car-following model, an algorithm for the automatic real-time detection of the traffic situation based on local information, and a strategy matrix to adapt the driving characteristics (that is, the parameters of the ACC controller) to the traffic conditions. Optionally, inter-vehicle and infrastructure-to-car communication can be used to improve the accuracy of determining the traffic states. Within a microscopic simulation framework, we have simulated the complete concept on a road section with an on-ramp bottleneck, using empirical loop-detector data for an afternoon rush-hour as input for the upstream boundary. We found that the ACC vehicles improve the traffic stability and the dynamic road capacity. While traffic congestion in the reference scenario was completely eliminated when simulating a proportion of 25% ACC vehicles, travel times were already significantly reduced for much lower penetration rates. The efficiency of the proposed driving strategy even for low market penetrations is a promising result for a successful application in future driver assistance systems.     

基于节点重要度与交通区位的公路运输枢纽布局研究

从区域社会经济、公路运量及交通区位三方面出发,基于节点重要度与交通区位综合分析,建立了运输枢纽节点重要度与交通区位相结合的评价指标体系。由于各指标在比较时具有一定模糊性,因此文章运用模糊层次分析法确定了各指标的权重,通过引入重要度综合指数,对区域内各运输枢纽节点的重要度综合指数进行了分析。通过对山东省区域公路运输枢纽布局重要度综合指数的实例分析,验证了该方法的合理性和可行性,为公路运输枢纽总体布局研究提供了主要理论依据。     

国省道两侧建设项目出入口规划设计

为降低建设项目对国省道的影响,文章从国省道两侧建设项目特点和所处交通环境的分析入手,借鉴国内外城市项目出入口管理技术,提出了6种出入口交通组织方式.以312国道昆山市境内的某一项目为例,分析其所处交通环境,对近远期出入口交通设计方式提出建议,为国省道两侧建设项目的出入口设计提供参考.     

交通冲突技术在桂林市交叉口安全评价中的应用

文章通过引入交通冲突的概念,以早高峰、晚高峰、平峰三时段的交通冲突量与混合交通当量比值作为交通安全评价的指标,利用灰色理论对桂林市九个典型交叉口进行安全程度的评价。     

An intersection control strategy for a short‐headway P.R.T. network

Much PRT development and research is currently being undertaken assuming quasi‐synchronous longitudinal control of guideway vehicles. This method of control has the characteristic that intersection performance has a substantial influence on the efficiency of trip demand processing. An algorithm for the control of a PRT intersection is discussed here, which would appear to have significant advantages over all other known existing stratagems. The stratagem is not only efficient but its flexibility facilitates tailoring to diverse local conditions; furthermore, the algorithm does not require intractable computations or excessive computer memory requirements. The algorithm is described and simulation results are presented. A comparative study is also made between this algorithm and its fore‐runner.     

Individual versus mass transportation: feasibility of substitution

This paper is addressed to the question of social costs and social benefits (primarily environmental) which might derive from a large‐scale substitution of so‐called mass‐transit for the present, largely private, system of automotive transportation. Energy consumption and emissions are compared for the two basic alternatives and several variants. Varying degrees of physiological tolerance to pollutants are taken into account, in an attempt to develop comparable weight‐factors for different types of emissions. It is suggested that if automobiles succeed in meeting the 1975/76 emission standards set by the Clean Air Act of 1970, rail rapid transit will probably offer no advantage (in environmental terms) unless electric power is available from virtually non‐polluting sources (e.g., natural gas or nuclear plants). Economic implications of large‐scale substitution are examined, and it is noted that such substitution would involve major restructuring of our society as a whole. However, more intensive use of mass transit in central cities, possibly in conjunction with various measures to discourage the use of private automobiles in very congested areas is feasible and likely.