1,721,253 research outputs found
The GPS Data Collection and Transmission Strategy for Floating Vehicle Technology
No full textFloating vehicle equipped floating vehicle technology has been widely used to collect urban and inter-urban road network traffic data for network evaluation, traffic management and dynamic road guidance purposes. It has become one of the major technologies of Intelligent Transport Systems (ITS). Most of the commonly used floating vehicle devices receive floating vehicle data in a frequency of 1 Hz. To collect real time traffic data of the road network for the above application, floating vehicle data from floating vehicles has to be transmitted from vehicles to a traffic data management centre in short time intervals. With the increase in the numbers of floating vehicles, the cost on communication increases dramatically. This is often one of the major barriers limiting the application of floating vehicle technologies for real time traffic route guidance and many other applications. This paper proposes a floating vehicle - floating vehicle data transmission strategy, which can significantly reduce the data transmission cost with satisfied accuracy for real time traffic management and dynamic road guidance purposes
Bus priority using pre-signals
No full textThe need to provide efficient public transport services in urban areas has led to the implementation of bus priority measures in many congested cities. Much interest has recently centred on priority at signal controlled junctions, including the concept of pre-signals, where traffic signals are installed at or near the end of a with-flow bus lane to provide buses with priority access to the downstream junction. Although a number of pre-signals have now been installed in the U.K., particularly in London, there has been very little published research into their design, operation and optimisation. This paper addresses these points through the development of analytical procedures which allow pre-implementation evaluation of specific categories of pre-signals. The paper initially sets out three categories of pre-signal, which have different operating characteristics, different requirements for signalling and different impacts on capacity and delay. Key issues concerning signalling arrangements for these categories are then discussed, together with a summary of the analytical approach adopted and the assumptions required. Equations are developed to allow appropriate signal timings to be calculated for pre-signalised intersections. Further equations are then developed to enable delays to priority and non-priority traffic, with and without pre-signals, to be estimated with delay being taken here as the key performance criterion. The paper concludes with three application examples illustrating how the equations are applied and the impacts of pre-signals in different situations.The analyses confirm the potential benefits of pre-signals, where these signals apply to non-priority traffic only. Where buses are also subject to a pre-signal, it i
Cyclists' path planning behavioral model at unsignalized mixed traffic intersections in China
No full textStudy on the cyclist's path planning behavior in mixed traffic flow intersection is very important. The paper presents a fuzzy logic based behavior model to describe cyclist path planning behaviors at unsignalized intersections in mixed traffic flow situations (with many conflicts among motorcars, non-motor vehicles and pedestrians). Field data have been collected for fuzzy logic modeling, model calibration and validation, and the simulation results are promising. The model can be used in mixed traffic flow simulation and path planning models for Personal Mobility Vehicles (PMVs).<br/
A study on cyclist behavior at signalized intersections
No full textA study on the cyclist behavior at a signal-controlled intersection was conducted to determine the behavioral characteristics representative. The study focused on the cyclists' behavior at signalized intersections, including the crossing speeds, crossing gap/lag acceptance behavior, and group-riding behavior. Traffic data were collected by using video cameras from a wide and complex signalized intersection. The statistical analysis of data was conducted to determine the characteristics of bicycle traffic crossing speeds, gap/lag acceptance, and group riding. Interesting group behavior of cyclists at a signal-controlled intersection was discovered and analyzed. The results are useful for understanding the performance of mixed traffic at signalized intersections and building microscopic simulation models
Simulation study of at-grade LRT at signalized intersections
No full textSIGLEAvailable from British Library Document Supply Centre- DSC:DX182210 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
Characteristics of light rail travel time: examples from France
Full text linkThe total journey time of light rail vehicles (LRVs) is made up of running time, dwell time (station stops for passenger boarding and alighting), and signal delay (delay of LRVs being stopped by the regular traffic signals). Data from operational surveys of six modern light rail systems in France has shown that LRV running time was 65-71 percent of the total journey time and dwell time was 22-27 percent, while signal delay was 7 to 8 percent of the total journey time. The average operating speed of the light rail transit (LRT) ranged from 17.7 to 22.8 km/h and has an approximate linear relationship to passenger stop frequency (stops/km). Light rail dwell time has been found to follow a log-normal distribution, although the values differed significantly between different LRT systems. The means of the dwell time distribution have the range of 16 to 31 seconds in off-peak periods and 21 to 37 seconds in peak periods. Factors that influence light rail dwell time include the number of passengers at the stops, the number of standees in the vehicles, vehicle design (number of doors, door size, low floor or high floor vehicle, etc.), fare collection system, and the location of LRT stops. The findings in this paper could be used by LRT planners and operators directly in developing and assessing operating and service changes and in providing input to long-range planning procedures. The results can also be used in microscopic simulation modeling studies of LRT in an urban network, such as the TRGMSM model.<br/
A robust scheduling method based on a multi-objective immune algorithm
No full textA robust scheduling method is proposed to solve uncertain scheduling problems. An uncertain scheduling problem is modeled by a set of workflow models, and then a scheduling scheme (solution) of the problem can be evaluated by workflow simulations executed with the workflow models in the set.A multi-objective immune algorithm is presented to find Pareto optimal robust scheduling schemes that have good performance for each model in the set. The two optimization objectives for scheduling schemes are the indices of the optimality and robustness of the scheduling results. An antibody represents a resource allocation scheme, and the methods of antibody coding and decoding are designed to deal with resource conflicts during workflow simulations. Experimental tests show that the proposed method can generate a robust scheduling scheme that is insensitive to uncertain scheduling environments.<br/
Intelligent transport systems in China
No full textThe rapid development of the Chinese economy over the past 30 years has increased demand for passenger and freight transport considerably. Although restrictions on economic development have been alleviated by a major programme of road construction, China has begun to seek more sustainable ways of supporting transport development. Intelligent transport systems (ITS) have been introduced and a series of research has been conducted to take advantage of ITS applications in traffic management and control with significant social, economic and environmental benefits. This paper reviews the current use of ITS in China and presents policies, technologies, typical applications and recent activities in ITS development. The main achievements that reflect the current level of China's ITS development are described, in particular the ITS showcase programme and preparation for the 2008 Olympic Games. Finally, the paper discusses China's future ITS plans
The socio-economic impacts assessment of advanced convoy driving on motorway
No full textThis paper presents a recent research work on socio-economic impacts of convoy driving on motorways. Two different methods have been employed for the assessment. The cost-benefit analysis method has been found to be very efficient where costs and benefits can be valued monetarily, while data envelopment analysis can deal with discretionary or intangible impacts that cannot reasonably be expressed in monetary units.
The results from both assessment methods have shown that motorway convoy driving may have significant socio-economic benefits when the convoy lane is properly fed with convoy traffic
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