The urban port: A hidden resource for the city and the coastal zone

Abstract

This paper is concerned with the changing pattern of activity on the urban waterfront. It examines developments in marine transportation technology and in the economic structure of the central city that have influenced the function of the urban port. Drawing upon data related to the West Side of Manhattan, the impact of the changes in cargo and passenger ship operations on the urban port is described and analyzed. A twofold strategy for public agencies to identify and understand the opportunities presented by technological change and to formulate policies for the redevelopment of the urban coastal zone is discussed.     

飘来一段远古记忆

丝绸之路简称丝路,一时由张骞出使西域开辟的以长安(今西安)为起点,经甘肃、新疆,到中亚、西亚,并联结地中海各国的陆上通道。因为经这条路西运的货物中以丝绸的影响最大,故得此名……     

答疑解惑

Q 我觉得夏天开车，阳光特别刺眼，我看很多人都带着墨镜开车。这样安全吗？开车时带的墨镜有什么特别讲究吗？     

Joint optimization of a rail transit line and its feeder bus system

A model is developed for jointly optimizing the characteristics of a rail transit route and its associated feeder bus routes in an urban corridor. The corridor demand characteristics are specified with irregular discrete distributions which can realistically represent geographic variations. The total cost (supplier plus user cost) of the integrated bus and rail network is minimized with an efficient iterative method that successively substitutes variable values obtained through classical analytic optimization. The optimized variables include rail line length, rail station spacings, bus headways, bus stop spacings, and bus route spacing. Computer programs are designed for optimization and sensitivity analysis. The sensitivity of the transit service characteristics to various travel time and cost parameters is discussed. Numerical examples are presented for integrated transit systems in which the rail and bus schedules may be coordinated.     

Review of the State of Development of Advanced Vehicle Control Systems (AVCS)

This paper provides a broad review of the developments that have taken place within the past thirty years in the field now known as Advanced Vehicle Control Systems (AVCS). This long time horizon was chosen to ensure that significant findings from earlier generations of work are not overlooked today. Following a history of the international development of AVCS, several methods of classifying AVCS are introduced. The main body of the paper reviews the relevant literature in lateral, longitudinal and integrated control of road vehicles and summarizes the most significant findings from this work.     

Handling Cut-In Vehicles in Strings of Cooperative Adaptive Cruise Control Vehicles

Cooperative adaptive cruise control (CACC) systems are a candidate to improve highway capacity by shortening headways and attenuating traffic disturbances. Although encouraging results have been obtained until now, a wide range of traffic circumstances has to be investigated in order to get reliable CACC systems driving on real roads. Among them, handling both vehicle-to-vehicle (V2V) communications-equipped and unequipped vehicles merging into the string of CACC vehicles is a commonly mentioned challenge. In this article, an algorithm for managing the transitions in response to cut-ins from V2V- or non-V2V-equipped vehicles is developed and tested using a string of four CACC vehicles. A CACC controller is implemented in four production Infiniti M56s vehicles and tested in real traffic, where non-V2V-equipped vehicles can cut in. The effects of a vehicle performing a cut-out are also investigated. Then responses to cut-ins by equipped and nonequipped vehicles are simulated for longer strings of vehicles using car-following models for both the production adaptive cruise control (ACC) system and the newly developed CACC controller. Results demonstrate that the CACC system is able to handle cut-in vehicles without causing major perturbations, while also reducing significantly the impact of this maneuver on the following vehicles, improving traffic flow.