城市支路在设计中的常见问题分析

城市支路在设计中常见的问题有：道路横断面因规划红线宽度限制如何选取;道路纵坡因桥梁、地块、交叉口等标高制约如何系统协调;道路沿线出入口及交叉口等重要节点处交通组织设计等。因此,依托《杭州市下城区长木、草庵、沈家三村连片综合改造工程项目》中24条新建城市支路的系统分析,为城市支路中道路横断面、道路纵坡、交叉口交通组织等要点的设计提供参考。     

华南地区城市快速公路植物设计实践

1项目概况佛山一环全长99.2公里,共42个出入口。途经佛山市的4个区,11个镇街,并与境内多条高速公路、国道和交通干线连接,是市干线路网中最为重要的骨干道路,是沟通佛山各区以及密切佛山与广州的联系的重要通道。一环规划控制红线宽114-120米,行车道宽度79米;全线采用一级公路兼城市道路标准设计,双向14车道。其中,主路为双向8车道,设计速度为100 km/h;辅路为双向6车道,与地方路网衔接,为普通城市道路,设计速度为50 km/h。     

道路运输

西安:规划建设渭北大横线10月23日,西安市政府常务会议确定规划建设东接国道310、西连西铜一级公路的渭北大横线。据了解,国道310西安过境公路(渭北大横线)起于临潼区零口镇与西咸北环线高速公路渭南高新立交连接线相接,向西上跨西咸北环线高速公路,经临潼现代工业组团、高陵装备工业组团,终点与西铜一级公路相接。全线按一级公路标准规划建设,起点至新阎路段红线控制宽度不低于60米,路基宽度33.5米,双向六车道,新阎路至终点段按照红线控制宽度不低于80米,路基宽度33.5米,双向六车道,同步规划辅道和市政配套设施。     

城市核心区地下道路设计关键问题研究

随着城市的发展，地下空间由单点式开发向成片联动开发转变，其中城市地下道路（以下称地下道路）是重要的联系纽带。地下道路作为城市地下空间和路网系统的重要组成部分，是解决城市核心区停车问题、分流地面交通以及提高城市品质的重要手段。本文总结国内外相关研究及案例，着重从地下道路的组成、功能、形式、规模（长度和横断面）、出入口（外部出入口和车库出入口）、所在层数等进行系统分析，以期对地下道路的规划和建设有一定借鉴作用。     

上海西藏南路南段改拓建工程方案概述

结合上海西藏南路南段（复兴东路一中山南路）改拓建工程，介绍了在规划红线宽度受限、周边建设条件受制约的情况下，对该路段建设规模的论证及平面线形优化的方法，并对拓建方案进行了比选。     

市政道路快速化改造工程的设计思路探讨

文章分析了快速路设计理论的发展,总结了设计思路与基本方法,并结合合肥市包公大道快速路改造工程实例,从周边用地性质、道路红线宽度、沿线路网情况、工程投资等方面进行综合比较,合理确定快速路的型式、立交节点及立交型式,对市政道路快速化改造工程具有一定的借鉴意义。     

路内停车需求快捷估算方法研究

合理设置路内机动车停车规模一直是城市静态交通管理面临的重要挑战。为研究路内停车需求规模，以福建省晋江市经济开发区为例，首先通过对经济开发区路内停车现场数量调查、宏观经济用地数据采集以及兴趣点数据进行相关性分析，发现路内停车的需求规模与规划人口毛密度、临街餐饮店数量两组参数具有极高的相关性。最后，通过对规划人口毛密度以及临街餐饮店数与路内停车数量进行曲面函数拟合，多项式函数中的二重傅里叶级数对于预测路内停车数量拟合精度较高，可以作为工程应用中路内停车需求快速预测的方法。同时研究认为，合理布置餐饮店位置，控制餐饮店数量规模，是有效减少路内停车，提高路内静态交通管理水平的重要手段。     

城市道路交通布局及规划设计研究

现阶段我国城市发展中,城市交通问题已经是影响社会发展的重要关键点,我国各个城市中为了可以更好的缓解交通压力问题,均投入大量的资金与人力,来对城市道路的整体规划与布局等方面进行优化,同时形成了各种科学合理的流程与标准。稳定城市经济发展的重点便是科学合理的规划城市交通设计与布局,基于此,本文主要对城市交通布局与规划进行分析总结,探讨了城市交通道路合理规划与布局的对策,希望可以为我国城市交通道路建设提供可行性参考意见。     

龙腾路提升改造工程（罗龙路-金鸡路）设计分析

为进一步解决高峰期汽车交通拥堵的问题。针对现状道路两侧已街道化、无法拓宽的情况,如何利用既有道路红线范围内进行提升改造,解决交通拥堵问题,并对现状水泥道路美化改造、提升城市整体形象等成为当务之急。结合工程案例龙腾路提升改造工程（罗龙路-金鸡路）,对现状道路进行改造设计分析。     

城市道路交通标志的视觉设计研究

城市管理设施包含了城市道路交通标志的设计和规划管理,是实现安全行车、优质服务、智能化管理的基础。城市交通标志直接为司机和行人提供了准确信息,发挥了疏散、咨询和限制交通流量的效果,并通过这样的方式来实现最大交通流量和保持道路畅通。合理的交通标志设计和布置能够有效的解决道道路拥挤的问题等。城市道路交通标志设计中色彩选择及排版对于充分发挥交通标志的作用至关重要。本文探讨了城市道路交通标记设计对色彩和排版的要求,并具体分析了城市道路交通标志设计中色彩选择和排版设计。     

Generating lane-based intersection maps from crowdsourcing big trace data

Lane-based road information plays a critical role in transportation systems, a lane-based intersection map is the most important component in a detailed road map of the transportation infrastructure. Researchers have developed various algorithms to detect the spatial layout of intersections based on sensor data such as high-definition images/videos, laser point cloud data, and GPS traces, which can recognize intersections and road segments; however, most approaches do not automatically generate Lane-based Intersection Maps (LIMs). The objective of our study is to generate LIMs automatically from crowdsourced big trace data using a multi-hierarchy feature extraction strategy. The LIM automatic generation method proposed in this paper consists of the initial recognition of road intersections, intersection layout detection, and lane-based intersection map-generation. The initial recognition process identifies intersection and non-intersection areas using spatial clustering algorithms based on the similarity of angle and distance. The intersection layout is composed of exit and entry points, obtained by combining trajectory integration algorithms and turn rules at road intersections. The LIM generation step is finally derived from the intersection layout detection results and lane-based road information, based on geometric matching algorithms. The effectiveness of our proposed LIM generation method is demonstrated using crowdsourced vehicle traces. Additional comparisons and analysis are also conducted to confirm recognition results. Experiments show that the proposed method saves time and facilitates LIM refinement from crowdsourced traces more efficiently than methods based on other types of sensor data.     

Evaluating effects of traffic and vehicle characteristics on vehicular emissions near traffic intersections

Urban air quality is generally poor at traffic intersections due to variations in vehicles’ speeds as they approach and leave. This paper examines the effect of traffic, vehicle and road characteristics on vehicular emissions with a view to understand a link between emissions and the most likely influencing and measurable characteristics. It demonstrates the relationships of traffic, vehicle and intersection characteristics with vehicular exhaust emissions and reviews the traffic flow and emission models. Most studies have found that vehicular exhaust emissions near traffic intersections are largely dependent on fleet speed, deceleration speed, queuing time in idle mode with a red signal time, acceleration speed, queue length, traffic-flow rate and ambient conditions. The vehicular composition also affects emissions. These parameters can be quantified and incorporated into the emission models. There is no validated methodology to quantify some non-measurable parameters such as driving behaviour, pedestrian activity, and road conditions     

Increase in particle number emissions from motor vehicles due to interruption of steady traffic flow

We assess the increase in particle number emissions from motor vehicles driving at steady speed when forced to stop and accelerate from rest. Considering the example of a signalized pedestrian crossing on a two-way single-lane urban road, we use a complex line source method to calculate the total emissions produced by a specific number and mix of light petrol cars and diesel passenger buses and show that the total emissions during a red light is significantly higher than during the time when the light remains green. Replacing two cars with one bus increased the emissions by over an order of magnitude.     

古亭山互通式立交方案设计比选分析

文章基于古亭山互通式立交所处的地形地质概况及其交通量情况,从立交匝道布置及左转匝道主要技术指标方面,对所提出的小环道+半定向混合型设计方案和对称苜蓿叶+半定向混合型设计方案进行了比选,最终选定小环道+半定向混合型方案为可行的立交方案。     

贵港航运枢纽二线船闸工程总体设计方案探究

文章基于贵港航运枢纽二线船闸的建设规模及工程特点,提出了合理的船闸工程总体设计方案,并详细阐述了方案的设计原则、平面布置及施工组织情况,为今后类似航运枢纽复线船闸工程设计提供借鉴。     

Optimization of horizontal alignment geometry in road design and reconstruction

This paper presents a general formulation for optimization of horizontal road alignment, composed of tangential segments and circular curves suitably connected with transition curves (clothoids). It consists of a constrained optimization problem where the objective function is given by a line integral along the layout. The integrand is a function representing the cost of the road going through each point and, by considering different costs, a wide range of problems can be included in this formulation. To show it, we apply this methodology to three different situations. The two first cases are related with the design of a new road layout and used to solve a pair of academic examples. The third problem deals with the improvement of a road adapting the old path to current legislation, and it is solved taking as case study the reconstruction project for a regional road (NA-601) in the north of Spain.     

林区公路设计中的合理布线方法

公路线形的选择和布设,是公路工程进入设计阶段的第一个步骤,其合理性将直接影响着后续设计过程,因此做好公路设计的布线工作尤其重要。文章结合林区公路设计现状,归纳和总结了林区公路设计中合理布线的基本步骤、原则和方法,并以大桂山林场旧路改造项目为例,介绍了林区公路合理布线的注意事项。     

Analyzing spatiotemporal traffic line source emissions based on massive didi online car-hailing service data

Nowadays, the massive car-hailing data has become a popular source for analyzing traffic operation and road congestion status, which unfortunately has seldom been extended to capture detailed on-road traffic emissions. This study aims to investigate the relationship between road traffic emissions and the related built environment factors, as well as land uses. The Computer Program to Calculate Emissions from Road Transport (COPERT) model from European Environment Agency (EEA) was introduced to estimate the 24-h NOx emission pattern of road segments with the parameters extracted from Didi massive trajectory data. Then, the temporal Fuzzy C-Means (FCM) Clustering was used to classify road segments based on the 24-h emission rates, while Geographical Detector and MORAN’s I were introduced to verify the impact of built environment on line source emissions and the similarity of emissions generated from the nearby road segments. As a result, the spatial autoregressive moving average (SARMA) regression model was incorporated to assess the impact of selected built environment factors on the road segment emission rate based on the probabilistic results from FCM. It was found that short road length, being close to city center, high density of bus stations, more ramps nearby and high proportion of residential or commercial land would substantially increase the emission rate. Finally, the 24-h atmospheric NO₂ concentrations were obtained from the environmental monitor stations, to calculate the time variational trend by comparing with the line source traffic emissions, which to some extent explains the contribution of on-road traffic to the overall atmospheric pollution. Result of this study could guide urban planning, so as to avoid transportation related built environment attributes which may contribute to serious atmospheric environment pollutions.     

Why do some motorbike riders wear a helmet and others don’t? Evidence from Delhi,India

Road traffic accident fatalities lead to important private and social costs in the metropolitan areas of most low and middle income countries. An important share of these fatalities is due to injuries to the head and the neck. Helmets can provide efficient protection, but many drivers do not use them. We focus on helmet use behavior among motorbike users in Delhi. We use a detailed data set collected for the purpose of the study. To guide our empirical analysis, we rely on a model in which drivers decide on self-protection and self-insurance. The empirical findings suggest that risk-averse drivers are more likely to wear a helmet and that this has no systematic effect on speed. Helmet use also increases with education. Drivers who show a higher awareness of road risks seem to be both more likely to wear a helmet and to speed less. Controlling for risk awareness, we observe that drivers tend to compensate between speed and helmet use. The results can provide a basis for awareness-raising policies. They also show that improvements to the road infrastructure risk leading to risk-compensating behavior.     

GHG-emission models for assessing the eco-friendliness of road and rail freight transports

Intermodal rail/road transportation is an instrument of green logistics, which may help reducing transport related greenhouse gas (GHG) emissions. In order to assess the environmental impact of road and rail transports, researchers have formulated very detailed microscopic models, which determine vehicle emissions precisely based on a vast number of parameters. They also developed macroscopic models, which estimate emissions more roughly from few parameters that are considered most influential. One of the goals of this paper is to develop mesoscopic models that combine the preciseness of micro-models while requiring only little more information than macro-models. We propose emission models designed for transport planning purposes which are simple to calibrate by transport managers. Despite their compactness, our models are able to reflect the influence of various traffic conditions on a transport’s total emissions. Furthermore, contrasting most papers considering either the road or the rail mode, we provide models on a common basis for both modes of transportation. We validate our models using popular micro- and macroscopic models and we apply them to artificial and real world transport scenarios to identify under which circumstances intermodal transports actually effect lower emissions. We find that travel speed and country-specific energy emission factors influence the eco-friendliness of intermodal transports most severely. Hence, the particular route chosen for a transnational intermodal transport is an important but so far neglected option for eco-friendly transportation.