Will a driving restriction policy reduce car trips?—The case study of Beijing,China

A driving restriction policy, as one of the control-and-command rationing measures, is a politically acceptable policy tool to address traffic congestion and air pollution in some countries and cities in the world. Beijing is the first city in China to implement this policy. A one-day-a-week driving restriction scheme was expected to take 20% of cars off the road every week day. Using household survey and travel diary data, we analyze the short-term effect of this driving restriction policy on individual travel mode choice. The data also allow us to identify which demographic groups are more likely to break the restriction rule. The estimates reveal that the restriction policy in Beijing does not have significant influence on individuals’ decisions to drive, as compared with the policy’s influence on public transit. The rule-breaking behavior is constant and pervasive. We found that 47.8% of the regulated car owners didn’t follow the restriction rules, and drove “illegally” to their destination places. On average, car owners who traveled during peak hours and/or for work trips, and whose destinations were farther away from the city center or subway stations, were more likely to break the driving restriction rules. Therefore, Beijing is probably in need of more comprehensive and palatable policy instruments (e.g., a combination of congestion tolls, parking fees, fuel taxes, and high-speed transit facilities) to effectively alleviate traffic congestion and air pollution.     

浅谈公路环评解译工作中遥感影像的选择

对目前公路环评解译工作中常用的TM、SPOT5、QUICK BIRD等影像在分辨率、波谱特征和经济性等方面进行了对比,得知TM影像在分辨率、波谱特性、价格方面均满足公路环评工作的需要,是适合公路环评工作的卫星影像。并以神池至河曲高速公路所在地区的TM影像为例,运用Chavezetal提出的最佳指数法得到了该区域解译的最优波段组合。     

Port privatization under Cournot vs. Bertrand competition: a third-market approach

By incorporating port competition into a third-market model consisting of two exporting firms and one importing country, we demonstrate the endogenous choice of port structures (i.e. privatization or public ownership) under either Bertrand or Cournot competition. In contrast to previous studies on port competition, we analyze the port strategy in view of all trading countries (i.e. importing country and exporting countries). We find that regardless of transport cost, the port ownership strategy alters according to exporting firm’s competition mode. Under Bertrand competition, the choice of port ownership structure depends on the degree of imperfect substitutability. However, under Cournot competition, all trading countries choose same ownership structures of each port. By comparing equilibrium of each competition mode, we show that welfare of exporting country under Cournot competition is higher than under Bertrand competition if goods are sufficiently substitutes. In contrast, importing country prefers Bertrand competition to Cournot competition when the competitive pressure is sufficiently high.     

重载运输车侧向调平控制系统研究

结合虚拟样机技术和控制系统仿真技术对自行式重载运输车的自动调平系统进行了设计研究,建立了运输车横向半车多刚体动力学模型,并针对该模型设计了模糊控制器。联合仿真研究结果表明,模糊控制策略能对车架横向倾斜有很好的控制效果。调平精度达到0.17°,调节时间约为1.6s,能够满足调平系统高精度和快速度的要求。     

ATR技术在杭州湾跨海大桥跨海三角高程测量中的应用

跨海高程控制测量是现代大型桥梁工程测量的难点,结合杭州湾跨海大桥施工高程测量控制网的建立,以ATR技术为硬件基础,介绍ATR三角高程测量的具体实施方法。经实测数据分析,采用ATR三角高程测量,在多项精度指标上均达到了国家三等水准测量的要求。     

润扬大桥悬索桥全站仪法挠度变形观测

为科学评价桥梁结构体系的实际使用性能,大型桥梁竣工验收时必须进行静载试验。针对润扬大桥悬索桥静载试验工程项目,研究了利用全站仪进行桥梁挠度变形观测的方法。论文介绍了全站仪法测量桥梁挠度的原理和计算公式,并对全站仪法观测桥梁挠度变形值的测量精度进行了分析。通过到润扬大桥实地踏勘,制订了全站仪法挠度变形观测的具体方案。通过对全站仪实测数据和理论计算数据的比较和分析,证明了全站仪法大型桥梁挠度变形测量结果可靠,观测效率高。     

Analysing Demand for Suburban Trips: A Mixed RP/SP Model with Latent Variables and Interaction Effects

We analyse mode choice behaviour for suburban trips in the Grand Canary island using mixed revealed preference (RP)/stated preference (SP) information. The SP choice experiment allowed for interactions among the main policy variables: travel cost, travel time and frequency, and also to test the influence of latent variables such as comfort. It also led to discuss additional requirements on the size and sign of the estimated model parameters, to assess model quality when interactions are present. The RP survey produced data on actual trip behaviour and was used to adapt the SP choice experiment. During the specification searches we detected the presence of income effect and were able to derive willingness-to-pay measures, such as the subjective value of time, which varied among individuals. We also studied the systematic heterogeneity in individual tastes through the specification of models allowing for interactions between level-of-service and socio-economic variables. We concluded examining the sensitivity of travellers’ behaviour to various policy scenarios. In particular, it seems that contrary to political opinion, in a crowded island policies penalising the use of the private car seem to have a far greater impact in terms of bus patronage than policies implying direct improvements to the public transport service.     

The Impact of Travel Time Information on Travelers’ Learning under Uncertainty

In this work, laboratory experiment was conducted in order to evaluate the effect of feedback on decision-making under uncertainty, with and without provided information about travel times. We discuss the prediction of travelers’ response to uncertainty in two route–choice situations. In the first situation travelers are faced with a route–choice problem in which travel times are uncertain but some external information about routes’ travel times is provided. The second situation takes place in a more uncertain environment in which external information about travel times is not provided, and the travelers’ only source of information is their own experience. Experimental results are in conflict with the paradigm about traveler information systems: As a consequence of information, the propensity of travelers to minimize expected travel time is not necessarily increased. Providing travelers with static information about expected travel times reveals an increase in the heterogeneity of travelers’ choices and reduces the maximization rate.     

Mixed Logit模型及其在交通方式分担中的应用研究

离散选择模型的典型代表Logit模型简洁易用的特点使其在经济、交通等领域得到了广泛的应用，但同时Logit模型的两个重要缺陷限制了其应用范围。在分析了Logit模型固有的两个缺陷和Mixed Logit模型的良好性质后，比较了Logit模型与Mixed Logit模型的差异，对Mixed Logit模型的算法进行了研究，并借助SAS统计软件提供的仿真算法给出了详细的工程实践应用范例。结果表明，Mixed Logit模型有着更丰富的物理含义，对个人出行交通方式选择行为的描述更符合实际。     

RSS,一种全新的摊铺机自动找平系统

通过与沥青摊铺机传统自动找平方式的比较 ,介绍了一种全新的摊铺机非接触式激光扫描自动找平系统的原理 ,安装方式 ,性能特点和技术参数