Model and algorithm of optimizing alternate traffic restriction scheme in urban traffic network

An optimization model and its solution algorithm for alternate traffic restriction(ATR) schemes were introduced in terms of both the restriction districts and the proportion of restricted automobiles. A bi-level programming model was proposed to model the ATR scheme optimization problem by aiming at consumer surplus maximization and overload flow minimization at the upper-level model. At the lower-level model, elastic demand, mode choice and multi-class user equilibrium assignment were synthetically optimized. A genetic algorithm involving prolonging codes was constructed, demonstrating high computing efficiency in that it dynamically includes newly-appearing overload links in the codes so as to reduce the subsequent searching range. Moreover,practical processing approaches were suggested, which may improve the operability of the model-based solutions.

Long-range correlation analysis of urban traffic data

This paper investigates urban traffic data by analysing the long-range correlation with detrended fluctuation analysis. Through a large number of real data collected by the travel time detection system in Beijing, the variation of flow in different time periods and intersections is studied. According to the long-range correlation in different time scales, it mainly discuss the effect of intersection location in road net, people activity customs and special traffic controls on urban traffic flow. As demonstrated by obtained results, the urban traffic flow represents three-phase characters similar to highway traffic. Moreover, compared by the two groups of data obtained before and after the special traffic restrictions （vehicles with special numbered plates only run in a special workday） enforcement, it indicates that the rules not only reduce the flow but also avoid irregular fluctuation.

机动车限行对西安市空气质量的影响及其模型分析

近年来,空气污染已成为限制西安城市人居环境质量提升的重要因素之一。当地政府采取了一系列的措施进行空气污染治理,其中机动车限行政策以其可实施性强、公共投入较少、简单易行等特点而最受青睐。在分析2016―2020年间西安市空气质量变化趋势的基础上,运用R语言针对相关影响因子(限行政策、平均风速、相对湿度和平均温度)与空气质量之间的关系建立了广义相加模型,并进行了拟合分析和相关性检验,结果表明机动车限行政策与西安市空气质量改善具有较明显的相关性。

考虑引航员拖轮调配的船舶交通组织优化

为解决限制性双向航道的船舶交通组织问题,提高港口通航效率,从应用需求出发,综合考虑了引航员、拖轮、潮汐、安全距离以及单双向航道中的交通冲突因素,以船舶总等待时间最小为优化目标,建立了混合整数规划模型。考虑到模型的特征,提出了改进差分进化算法(improved differential evolution,IDE)来解决该问题。经过不同规模算例的试验,将所得到的船舶调度结果与先到先服务和其他算法结果进行比较验证,模型和算法可以有效地为限制性双向航道提供船舶交通组织方案。

精细化治理背景下的交通限行区分级管控合理性评估与优化——以杭州市为例

合理地划定限行区域,辅之以差异化的交通需求管理政策能够有效缓解城市拥堵、精准提升城市交通治理水平。以实时交通拥堵指数、OSM路网数据、公交线路和站点数据为研究数据,识别杭州市分级限行区内的拥堵区分布,分析拥堵区交通供给特征,在此基础上划分拥堵区类型并提出分类管控优化策略。研究发现,杭州市限行区分级较为合理,对浙A及区域号牌限行的拥堵区路网密度及其等级配置合理,公共交通供给略有错位与不足;对外地车辆限行的拥堵区路网供给不足,公交供给水平相对较高,但在精细尺度上存在交通供给要素的错位与替代性公共交通不足的问题;根据交通供给特征及限行政策将拥堵区划分为片区式、飞地式和节点式拥堵区,分别提出实施拥堵收费、优化路网结构、提高微循环能力、增设公交线路串点成线及引导公交出行等策略,以期为大城市交通精细化治理提供借鉴。

长隧道路段货车限道措施的数值模拟——以甬莞高速角洞岙隧道路段为例

基于实际交通录像分析得出的边界条件和货车影响距离,提出了含有长隧道的双车道元胞自动机交通流模型.模拟结果与实际交通数据对比,吻合较好,表明模型能够准确反映实际交通流的特性.数值模拟显示,货车的存在增加了隧道路段交通拥堵的发生概率,且这种影响随货车比增加而增强.为降低货车对隧道交通的影响,提出了货车限道措施,并开展数值模拟,结果表明,货车限道措施能显著提升左车道的车速,在大进车率时也能提升右车道的车速,在高货车比时流量提升效果显著.

限行政策下兰州市空气质量影响因素分析

机动车尾气排放是空气污染物的主要来源之一。为了解机动车限行政策下兰州市空气质量的影响因素,首先对2016—2019年兰州市空气质量数据进行统计分析,其次利用逐步回归分析法建立空气质量指数(Air Quality Index,AQI)与空气污染物浓度的多元线性回归模型,最后对气象因素和空气污染物浓度进行相关性分析。结果表明,限行政策有助于改善空气质量,AQI与空气污染物浓度有明显相关性,气象因素与空气污染物浓度也有明显相关性。

博弈模型下小汽车尾号限行方案优化

为揭示不同尾号限行方案在实施过程中的效果,得到令政府和小汽车拥有者都满意的限行方案,研究基于效用函数和博弈论模型的尾号限行方案制定方法。首先,在分析政府和小汽车拥有者的动态博弈过程基础上,分别定义政府和小汽车拥有者的效用函数;然后,构建小汽车尾号限行方案的非合作动态Stackelberg博弈模型;最后,设计基于种群多样性控制策略的遗传算法,并利用Python对所建模型编码求解。以兰州市为例进行模型验证,研究表明,优化尾号限行方案下小汽车拥有者的平均出行成本基本没变化,政府的平均社会效用值提高1.062×10^(7)。因此,依靠理论模型制定的小汽车尾号限行方案,不仅具有充分的理论依据,还能更好发挥限行方案功效。

Effect of traffic restriction on atmospheric particle concentrations and their size distributions in urban Lanzhou, Northwestern China

During the 2012 Lanzhou International Marathon, the local government made a significant effort to improve traffic conditions and air quality by implementing traffic restriction measures. To evaluate the direct effect of these measures on urban air quality, especially particle concentrations and their size distributions, atmospheric particle size distributions （0.5-20μm） obtained using an aerodynamic particle sizer （model 3321, TSI, USA） in June 2012 were analyzed. It was found that the particle number, surface area and volume concentrations for size range 0.5-10 μm were （15.0±2.1） cm-3, （11.8±2.6） μm2/cm3 and （1.9±0.6） μm2/cm3, respectively, on the traffic-restricted day （Sunday）, which is 63.2%, 53.0% and 47.2% lower than those on a normal Sunday. For number and surface area concentrations, the most affected size range was 0.5-0.7 and 0.5-0.8 μm, respectively, while for volume concentration, the most affected size ranges were 0.5-0.8, 1.7-2.0 and 5.0-5.4 μm. Number and volume concentrations of particles in size range 0.5-1.0μm correlated well with the number of non-CNG （Compressed Natural Gas） powered vehicles, while their correlation with the number of CNG-powered vehicles was very low, suggesting that reasonable urban traffic controls along with vehicle technology improvements could play an important role in improving urban air quality.

Effects of odd-even traffic restriction on travel speed and traffic volume:Evidence from Beijing Olympic Games

This paper reports the effects of using an ＂odd and even＂ traffic restriction policy in Beijing during the 2008 Olympic Games. Based on data from 529 traffic detectors on the expressway network and some main arterials in Beijing, China, a comparative analysis has been carried out on the following parameters： the total traffic volume within the expressway network, the total traffic volume on different ring expressways, the traffic volume and speed of a freeway segment, and an arterial street before and after the implementation of the traffic restriction policy. The results show that during the traffic restriction period, although more than 50% of vehicles were forbidden to travel in Beijing, the traffic volume was only reduced by 20%-40% while the travel speed had been increased by 10%-20%. This suggests that such traffic restriction policy may be an effective shortterm management measure in dealing with increased transportation demand and congestion during major events, such as the Olympic Games. Results also indicate that vehicle travel demand does not decrease with the same proportion as the total vehicles forbidden, at least for the expressway and main arterials in a city.

考虑交叉口使用数量的救援交通优化研究

为科学规划局域突发灾害下救援车辆对道路的占用,通过考虑救援车辆在路网上通行时使用的交叉口数量,以救援车辆尽快到达受灾区域为目标,建立救援交通优化的混合整数线性规划模型。针对救援车辆使用的交叉口数量的约束值上限为未知参数且无约束进行限制的特点,设计两阶段算法,分析救援车辆在路网上通行时对交叉口的使用情况及其对路径选择与通行效率的影响,提出救援车辆路径选择的建议。结果表明:通过限制救援车辆在路网上通过的交叉口数量,能够在不延误救援车辆到达受灾区域的情况下,获得不同的最优救援路径并减少占用的道路。因此,调整救援车辆在路网上通过的交叉口数量可以用于优化路网资源配置。

Effect of short-term regional traffic restriction on urban submicron particulate pollution

During the 2013 and 2015 Lanzhou International Marathon Events （LIME1 and LIME2）, the local government made a significant effort to improve traffic conditions and air quality by implementing traffic restriction measures. To fill the gap in information on the effect of short-period {several hours） traffic control on urban air quality, submicron particle size distributions and meteorological data were measured simultaneously during June 2013 and June 2015 in urban Lanzhou. The number and surface area concentrations of particles in the 100-200 nm range declined by 67.2% and 6B.0% for LIME1 due to traffic control, while they decreased by 39.2% and 37.1% for LIME2. The impact of traffic restriction on air pollution near the sampling site lagged behind the traffic control period for LIME2. In addition, the effect of traffic restriction on air pollution near the sampling site was dependent on the distance between the relative orientation of the sampling site and traffic-restricted zones, as well as meteorological conditions such as wind direction. The influence of traffic restrictions on the particle concentrations differed for different particle sizes. The size range most affected by traffic restriction was 60-200 and 60-300 nm for number and surface area concentrations in the urban environment, respectively, while for the particle volume concentration it was the 100-600 nm range. This study will provide a basis for implementation of future urban traffic-induced particulate pollution control measures.

成都市低排放区限行措施方案研究

在人口分布密集的大城市中心区对高污染排放机动车进行管控,不仅有利于缓解城市拥堵,还有利于改善大气环境。成都作为全国汽车保有量第一的大型城市,若能实施低排区限行管控,将对改善大气污染和交通缓堵产生重要影响。本文在分析成都市大气污染物排放与机动车管控现状的基础上,借鉴国内外先进城市经验,设计了成都市低排放区限行方案,并对实施效果进行定性和定量预判。最后分析该政策实施的合法性,提出政策推广所必要的配套保障条件,以期为下一步的政府决策提供相关参考依据。

限行政策对外地牌照车主出行选择行为的影响研究——以深圳市为例

根据国内典型限行政策的内容,分析了外地牌照车主在限行政策下的应对行为,在此基础上研究了他们在限行时段的出行决策过程。以深圳市外地牌照车主为调查对象,进行出行选择行为问卷调查。基于随机效用理论,建立外地牌照车主出行选择行为的两阶段Logit模型,同时对外地牌照车主的“改变出行方式”与“改变出行时间”的选择行为进行分析,结合个体社会经济属性、出行属性分析两阶段出行行为选择的影响因素。模型可为限行政策效果的评估及优化提供依据和参考。

改进的区域道路交通安全广义DEA评价模型

为了科学评价区域道路交通安全水平,为制定更符合实际的道路交通安全发展战略和管理策略提供依据,利用复相关分析建立了区域道路交通安全评价指标体系;基于数据包络分析原理,在BC2基本模型的基础上,引入偏好信息,建立了面向面板数据、只有非期望输出、权重受限的道路交通安全广义DEA评价模型,并对中国等9个国家2000—2012年的道路交通安全水平进行了评价.研究显示,2000年以来,中国道路交通安全形势逐渐转好,但距国际先进水平还有一定差距,而且改善幅度逐渐放缓,应继续加强道路交通安全工作.通过与不同方法的对比,本文所建立模型的评价结果与实际符合性更好.

基于Matlab优化算法的物流中心选址

应用Matlab优化函数求解带时效性约束的物流中心选址问题。分析选址问题的时效性约束条件,构造带时效性约束的物流中心选址模型,利用Matlab优化工具箱中的“fmincon”函数,设计选址模型的精确算法,并给出具体算例,验证模型和算法的可行性。研究结果表明,基于Matlab函数的优化算法编程简单,运算速度快,既能够求解带时效性约束的选址模型,又能够求解不带时效性约束的重心选址模型,是一种比传统算法更有效的求解物流中心选址问题的算法。

考虑换道约束空间的车辆换道模型研究

为进一步提高换道安全性,根据不同换道需求给出四种换道情形。针对不同类型司机在不同换道情形下对安全距离的敏感度不同,提出了一种新的基于不同速度及不同司机类型的最小安全距离模型———动态椭圆最小安全距离模型。在此基础上,运用车辆运动学理论,生成换道约束空间。通过Matlab仿真对比发现,该模型较之传统最小安全距离模型在相应情形下的约束空间具有更高的安全性和灵活性。然后利用摄像机标定方法对北京市朝阳区西大望路的实际换道拍摄的图像进行处理,获取了双车道、低速情况下实际换道轨迹。并在换道约束空间下,以更加适合双车道、低速换道环境的圆弧换道轨迹为基础生成换道轨迹,最后采用回旋曲线解决了圆弧换道模型的侧向加速度过大,曲率不连续等问题。

基于蒙特卡洛方法的受限航道船舶交通拥塞仿真

在分析受限航道船舶交通物理过程的基础上,提出受限水域船舶交通拥塞状态的若干表征参数。利用离散事件仿真思想,构建以"船舶到达-通过航道-船舶离开"为主要逻辑单元的受限航道船舶交通仿真模型,着重研究船舶在航道中航行时船舶间的速度干扰关系。基于蒙特卡洛的思想对受限航道船舶拥塞状态的演化过程进行仿真研究,探讨船舶交通拥塞状态与船舶航行特征之间的内在关联。

交通限行对细颗粒物浓度及其谱分布的影响

采用电迁移率粒径谱仪SMPS 3936对颗粒物数浓度及其谱分布进行了实时监测,对2013年兰州市国际马拉松赛交通管制期间细颗粒物浓度及其谱分布特征开展研究,并通过多元对数正态分布拟合和主成分分析方法分别对数浓度谱特征及其影响因素进行了分析,以阐明2013年兰州国际马拉松赛期间交通管制对细颗粒物浓度及其谱特征的影响。气象条件相似的交通限行期间,交通限行日50~100 nm,100~200 nm和200~500 nm粒径段颗粒物数浓度均较正常周六有所降低,特别是50~200nm粒径段颗粒物表现最为显著,在此期间,交通限行日50~100 nm和100~200 nm粒径段平均颗粒物数浓度分别为2567.5±807.4 cm-3和1567.8±193.8 cm-3,分别较正常周六相应时段低60.2%和67.2%。交通限行对颗粒物数浓度的影响主要集中在107 nm为峰值粒径的积聚模态附近,而气象条件对10~300 nm粒径段颗粒物数浓度均有较显著的影响,最大影响在80 nm附近。

地面等待策略数学模型分析

地面等待是空中交通管理中普遍应用的一种方法.系统地分析了单机场和多机场地面等待策略GDP(Ground-Delay Policy)经典模型.在这些模型的基础上,研究了确定容量条件下的多元受限地面等待问题,建立数学模型.通过对成都机场流量的仿真计算,验证了模型的可行性.