首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   212篇
  免费   0篇
公路运输   13篇
综合类   9篇
水路运输   84篇
铁路运输   3篇
综合运输   103篇
  2020年   1篇
  2019年   6篇
  2018年   2篇
  2017年   1篇
  2016年   5篇
  2015年   1篇
  2014年   1篇
  2013年   67篇
  2012年   2篇
  2011年   7篇
  2010年   7篇
  2009年   8篇
  2008年   4篇
  2007年   8篇
  2006年   8篇
  2005年   2篇
  2004年   3篇
  2003年   2篇
  2002年   5篇
  2001年   2篇
  2000年   4篇
  1999年   4篇
  1998年   2篇
  1997年   1篇
  1996年   2篇
  1995年   3篇
  1994年   1篇
  1993年   1篇
  1992年   4篇
  1991年   2篇
  1990年   2篇
  1989年   2篇
  1988年   2篇
  1987年   1篇
  1985年   2篇
  1983年   4篇
  1982年   2篇
  1981年   5篇
  1980年   6篇
  1979年   4篇
  1978年   1篇
  1977年   3篇
  1976年   3篇
  1975年   2篇
  1974年   5篇
  1973年   2篇
排序方式: 共有212条查询结果,搜索用时 15 毫秒
1.
Major highway reconstruction can cause significant disruptions to existing travel patterns and economic activity. Reducing these impacts on travelers, shippers, businesses and residents requires that innovative and effective transportation management actions be developed and implemented. This paper reports the major findings and recommendations of a research study on managing transportation during highway, reconstruction. The primary objectives of the study were
–  to investigate and document the critical interrelationships among state-of-the-art reconstruction and scheduling techniques, traffic accommodation strategies, construction quality control measures, and project planning and evaluation processes, and
–  to formulate and recommend a corridor transportation management process that can be used to develop, implement and evaluate a transportation management plan of strategies to mitigate the corridor-wide impacts of major highway reconstruction.
The recommended process consists of five chronological phases, each composed of many tasks having related focuses within the overall process. Each task is designed to contribute to the common objective of seeing that an effective transportation management plan for mitigating travel impacts throughout the project corridor is successfully realized. This process was formulated on the basis of information collected on 25 highway reconstruction projects throughout the United States by way of site visits, direct meetings with project personnel, requests for documentation, and phone interviews.  相似文献   
2.
Habitual travel behaviour: Evidence from a six-week travel diary   总被引:1,自引:0,他引:1  
This paper introduces different methods to measure similarity of travel behaviour addressing the question of how repetitious travel behaviour actually is. It compares empirical results of the different methods based on the data from a six-week travel diary. In general, the results show that the day-to-day behaviour is more variable if measured with trip-based methods instead of methods based on time budgets. Furthermore, it is confirmed that the similarity declines if the method captures more of the complexity of the travel pattern. It is also shown that travel behaviour is neither totally repetitious nor totally variable. Even for the whole observation period, it is demonstrated that two days always have some common elements. Additionally, it is found that the different methods yield the same pattern of variability for different types of day. Travel behaviour is clearly more stable on work days. Similar results for all methods are also obtained concerning the question of how long the minimum period of observation should be. All measures show that the period should not be less than two weeks if one aims at measuring variability.  相似文献   
3.
Carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NO) emission factors (EFs) are measured with a commercial vehicle emissions remote sensing system (VERSS) during a large-scale vehicle exhaust emissions study in Las Vegas. Particulate matter (PM) EFs are simultaneously measured for individual vehicles with a newly developed PM-VERSS based on ultraviolet backscatter light detection and ranging (Lidar). The effectiveness of CO and HC EFs as proxy for NO and PM EFs for spark-ignition vehicles is evaluated. Poor correlations were found between EFs for pollutants on an individual vehicle basis indicating that high EFs for one or more pollutants cannot be used as a predictor of high EFs for other pollutants. Stronger functional relationships became evident after averaging the EF data in bins based on rank-order of a single pollutant EF. Low overlap between the highest 10% emitters for CO, HC, NO, and PM was found. These results imply that for an effective reduction of the four pollutants, inspection and maintenance (I/M) programs, including clean screening, should measure all four pollutants individually. Fleet average CO and HC concentrations determined by gaseous VERSS were compared with fleet average CO and HC concentrations measured at low-idle and at high-idle during local I/M tests for spark-ignition vehicles. The fleet average CO concentrations measured by I/M tests at either idle were about half of those measured by remote sensing. The fleet average high-idle HC concentration measured by I/M tests was about half of that measured by VERSS while low-idle I/M and VERSS HC average concentrations were in better agreement. For a typical vehicle trip, most of the fuel is burned during non-idle conditions. I/M measurements collected during idling conditions may not be a good indicator of a vehicle’s potential to be a high emitter. VERSS measurements, when the vehicle is under a load, should more effectively identify high emitting vehicles that have a large contribution to the mobile emissions inventory.  相似文献   
4.
This article reviews the history of esthetics and its role in the development of outdoor recreation policy. Current research is also reviewed, demonstrating the broad scope and complexity of esthetics as a focus for research. Finally, in the absence of sufficient research for formulating coastal recreation planning and management decisions, the ethics of coastal recreation “development”; is considered.  相似文献   
5.
Abstract

Seaport expansion often generates tensions between the national interest in efficient transport and local interests in water quality and habitat preservation. The governing American permitting system, however, establishes an extraordinarily cumbersome, legalistic, and costly method for balancing environmental and economic considerations. A case study of the Port of Oakland illustrates the tendency. For four years, plans to find an environmentally acceptable site for dredged material have been stymied by a sequence of inconclusive regulatory and judicial proceedings. Meanwhile, large container ships can enter and leave Oakland harbor only at high tide, and not fully loaded. Despite the absence of any authoritative determination concerning environmental risks, the port was compelled to accede to progressively more expensive disposal methods. Such “adversarial legalism”; is not unique to the Oakland harbor case, but recurs in other policy spheres. It stems from a governmental structure that fragments decision‐making power among many agencies, that constrains regulatory discretion with legal demands for scientific certainty, and that by allowing agency decisions to be challenged readily in court, encourages legalistic defensiveness and extortion rather than compromise. The article concludes with a discussion of the conditions under which regional planning bodies might overcome these centrifugal tendencies.  相似文献   
6.
Sales tax measures passed at the local level and dedicated to transportation projects have become increasingly popular in the United States. While revenues from fuel taxes stagnate, growth of local transportation sales taxes (LTSTs), most approved in local elections, has led to a gradual shift of the financial base for transportation projects away from user fees and toward broader-based taxes. In this study, the relationship between voter support and the social, political, and geographic characteristics of the voters is explored. Using precinct-level voting data and census demographic data for three local transportation sales tax elections in Sonoma County, in the San Francisco Metropolitan area of California, regression models were constructed to analyze this relationship. In addition, the relationship between the outcomes of the three measures was explored to better understand which transportation projects might have garnered more support for the successful measure. It was found that the closer voters lived to the transportation projects to be funded, the greater their support. Higher incomes were also positively related to support, controlling for other variables. Political leanings were found to affect support, with the direction of the effect dependent upon the project list in each measure’s expenditure plan. Finally, it appears that the latest measure, which passed successfully, benefited greatly from its multi-modal expenditure plan.  相似文献   
7.
The potential benefits of general aviation management at a major airport is examined in this paper. The three general aviation management techniques investigated are volume reduction, runway segregation and time restriction.

First, a methodology for analyzing these techniques is discussed. The various effects on each user group are quantified for economic comparison between each management technique attempted. A computer simulation model was used to measure the delay effects. Then, these techniques are applied to Denver Stapleton Airport to measure their effects in present and future scenarios.

The results show that the best general aviation management technique is volume restriction. The use of peak‐hour pricing mechanism provided better results than random rejection, particularly if only a small degree of diversion is desired. The construction of a new general aviation runway provided equivalent results to the best technique tested.  相似文献   
8.

This paper explores the tenuous link between speeding behavior and accident causation, one that has not been well established in the international literature to date. Taking advantage of established engineering conventions and formulae, we were able to set up an a priori hypothesis suitable for testing. Utilizing this formal scientific method (which GIS researchers have been criticised for not using) we establish a statistical link for this relationship. Our methodology can be used to support all police intervention strategies, including the controversial photo radar systems. The results from our research have been entered into a GIS in order to create a map for spatial display. This map illustrates the relative probability or risk of collision occurrence resulting from speeding at all intersections and interchanges within the scope of the study. It is suggested that this methodology could easily be maintained with periodic updates of data, thus creating a dynamic model from which to monitor traffic safety within the city. Furthermore, this model can be utilized to study specific strategies, allowing for the scrutiny of before, during and after effects. The study area is the entire city of Calgary, Alberta, Canada, and includes all traffic collisions occurring during the year of 1994.  相似文献   
9.
Commentaries     
Abstract

This paper surveys the technologies available for constructing a pervasive, national‐scale road pricing system. It defines the different types of road pricing, the methods by which a vehicle’s position can be determined, and then examines possible pricing regimes in the context of their technological requirements and implications. The issue of enforcement and the distribution of pricing policies are considered, and further complexities are outlined. An examination of the security aspects of such systems is made, focusing particularly on the need to ensure privacy using technological, rather than solely procedural, methods. The survey concludes that a pervasive, national‐scale deployment is unlikely to be technically achievable in the short‐term.  相似文献   
10.
Abstract

Artificial reefs have been used extensively in coastal waters to attract and enhance recreational fishery resources. In the United States, they have been traditionally built from “materials of opportunity”; using limited budgets. This paper explores some past planning philosophies and presents a recent artificial reef deployment case that demonstrates a lack of sensitivity to local and regional recreational demand. A systems framework is developed to guide future planning efforts in artificial reef development. The framework is intended to integrate previously fragmented knowledge and to demonstrate the interdisciplinary nature of artificial reef planning. Emphasis is given to advance planning, user dimensions, and the integral issue of reef access.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号