European Transport / Trasporti Europei (2012) 52

Traffic congestion on urban roads has become a serious concern, particularly, at intersections. The performance of an intersection controls the performance of urban roads meeting at that intersection. The paper presents the effect of addition of turning lane in the middle of approach road at busy signalized at-grade intersection, narrowing the width of all lanes to keep total road width the same, in heterogeneous traffic. The traffic at intersection comprises both of vehicles and pedestrians. Their interactions along with signal cycle decide the efficiency of an intersection. A microscopic simulation tool VISSIM, has been used to model the heterogeneous (mixed) traffic under constraints of roadway geometry, vehicle characteristics, driving behaviour and traffic controls. The effect is investigated with different random seeds to obtain reasonable results for analysis. The performance evaluation is done in terms of vehicle throughput, average queue length, maximum queue length, average delay time per vehicle, average speed and emission of Carbon monoxide CO, mono-nitrogen oxides NOx, Volatile organic compounds (VOC) etc. It has been observed that on adding turning lane in the middle, of approach road the average queue length, maximum queue length, average delay time per vehicle and emission per vehicle get considerably reduced, while there is an increase in vehicle throughput and average speed of all the vehicles. The results reported in this paper clearly shows that addition of turning lane in existing intersection can reduce congestion considerably, enhancing performance of intersections and network.

Developing countries like India need to have proper Level of Service (LOS) criteria for various traffic facilities as this helps in planning, design of transportation projects and also allocating resources to the competing projects. The LOS analysis for urban street followed in India is an adaptation of HCM-2000 methodology but the methodology is relevant for developed countries having homogenous traffic flow. In this research an attempt has been made to establish a framework to define LOS criteria of urban street in Indian context keeping in mind the geometric and surrounding environmental characteristics. Defining LOS criteria is basically a classification problem for which cluster analysis is a suitable technique can be applied. In this research a hybrid algorithm comprising of Genetic Algorithm (GA) and Fuzzy C-mean is utilized. As input to the clustering algorithm GA-Fuzzy a lot of speed data is required. From literature review GPS is found to be a suitable tool for collecting second by second speed data and GIS is suitable in handling large amount of speed data. The clustering algorithm is used twice in this study. First the GA-Fuzzy algorithm was used to classify Free Flow Speed (FFS) data into number of classes in order to get the FFS ranges of different urban street classes. To determine the optimal number of cluster using FFS data five cluster validation parameters are considered. After getting the FFS ranges for different urban street classes the same GA-Fuzzy algorithm is used on average travel speed data collected during both peak and off-peak hours to determine the speed ranges of different LOS categories. From this analysis the free flow speed ranges for different urban street classes and the speed ranges for different LOS categories are defined and the values are found to be lower than that suggested by HCM-2000. The coherence of the clustering result in classification of urban streets into four classes and speed values into six LOS categories is agreed with the physical and surrounding environmental characteristics of road segments under the study area. From this analysis it is also found that good LOS can’t be expected from urban street segment for which physical and surrounding environmental characteristics are not good.

Purpose: Study of the basic traffic flow characteristics and clear understanding of vehicular interactions are the pre-requisites for highway capacity analysis and to formulate effective traffic management and control measures. The road traffic in India is highly heterogeneous comprising vehicles of wide ranging physical dimensions, weight, power and dynamic characteristics. The problem of measuring volume of such heterogeneous traffic has been addressed by converting the different types of vehicles into equivalent passenger cars and expressing the volume as Passenger Car Unit per hour (PCU/h). Methods: Computer simulation has emerged as an effective technique for modeling traffic flow due to its capability to account for the randomness related to traffic. This paper is concerned with application of a simulation model of heterogeneous traffic flow, named HETEROSIM, to quantify the vehicular interaction, in terms of PCU, for the different categories of vehicles, by considering the traffic flow of representative composition, on upgrades of different magnitudes on intercity roads in India. Results and Conclusions: The PCU estimates, made through microscopic simulation, for the different types of vehicles of heterogeneous traffic, for a wide range of grades and traffic volume, indicate that the PCU value of a vehicle significantly changes with change in traffic volume, magnitude of upgrade and its length. It is found that, the change in PCU value of vehicles is not significant beyond a length of 1600 m on grades. Also, it has been found that the PCU estimates are accurate at 5% level of significance.

Car-following behaviour is well studied and analyzed in the last fifty years for homogeneous traffic. However in the mixed traffic, following behaviour is found to vary based on type of lead and following vehicles. In this study, a neural network based model is proposed to predict the following behaviour for different lead and following vehicle-type combinations. Performance of the model is studied using data collected for six vehicle-type combinations. A multi-layer feed-forward back propagation network is used to predict vehicle-type dependent following behaviour by incorporating the vehicle- type as input into the model. The neural network model is then integrated into a simulation program to study the macroscopic behaviour of the model. Performance of the proposed neural network model is compared with the conventional Gipps‟ model at microscopic and macroscopic level. This study prompts the need for considering vehicle-type dependent following behaviour and ability of neural networks to model this behaviour in mixed traffic conditions.

This paper analyzes a profit-maximizing private airport with market power in providing aeronautical services. Our model implies that airports with ample capacity may voluntarily abstain from abusing their market power if non-aeronautical revenues are airports’ main source of income. In this case, a price regulation that is confined to the aviation business will be unnecessary from a welfare point of view.

This paper outlines the EU regulatory framework and analyses current practice in four European countries in respect of public procurement and tendering of ferry services. Tender management for major ferry services resides with national government agencies, while tenders for smaller volume regional and/or inter-isles services are generally managed by local authorities and/or regional transport authorities. Operator selection criteria increasingly emphasises service quality aspects, and environmental impacts, as well as price (i.e. amount of subsidy required). There is a continued trend towards privately-owned operators providing and investing in essential ferry services, with an increasing role played by larger international integrated transport organisations. For transport authorities, ferry service procurement involves a continuous evolutionary process of specifying, offering, selecting, monitoring and reviewing services supplied. Based on the information collected and analysed, the authors have developed a ‘tender route map’ which explains the different stages and key issues concerning public procurement of ferry services.

Rail intermodal services are an alternative to all-road services if the average transport time offered by these services is at least comparable. One of the determinants of transport time is how well actors in the transport chain cooperate. In this paper it is shown that substantial improvements in rail transport time are possible if these actors improve their cooperation substantially. This goes along with relatively moderate investments (a few million Euros per case). Such investments may then be regarded as a cost-effective alternative for (multi-billion) investments in rail infrastructure. This is particularly relevant in an era where budgets for rail infrastructure are either limited or create an additional burden for already debt-ridden countries.

The purpose of this paper is to explore the impact of differentiated control on the performance of a Foliated Transportation Network (FTN). The network models are evaluated through discrete event simulation. Empirical input data and parameters have been drawn from a case company. The study shows that moderately increased levels of differentiation improve the network performance. However diminishing returns with regards to increased levels of differentiation suggest that the necessary effort to account for the real time dynamics of the network is likely infeasible. Satisfactory results can be achieved utilizing a static approximation of the network dynamics. Substantial efficiency improvements are feasible to achieve using FTN logic which may be implemented with relatively small modification to existing systems and without the immediate need for extensive investments in new technology.

Cities and towns play a vital role in promoting economic growth and prosperity. Although less than one-third of India’s people live in cities and towns, these areas generate over two-third of the country’s income and account for 90% of government revenues. In the coming years, as India becomes more and more urbanized, urban areas will play a critical role in sustaining high rates of economic growth. But, economic growth momentum can be sustained if and only if cities function efficiently - that their resources are used to maximize the cities’ contribution to national income. City efficiency largely depends upon the effectiveness of its transport systems, that is, efficacy with which people and goods are moved throughout the city. Poor transport systems stifle economic growth and development, and the net effect may be a loss of competitiveness in both domestic as well as international markets. Although Indian cities have lower vehicle ownership rate, number of vehicles per capita, than their counterparts in developed countries, they suffer from worse congestion, delay, pollution, and accidents than cities in the industrialized world. This paper provides an overview of urban transport issues and challenges in India. Rather than covering every aspect of urban transportation, it primarily focuses on those areas that are important from policy point of view. The paper first reviews the trends of vehicular growth and availability of transport infrastructure in Indian cities. This is followed by a discussion on the nature and magnitude of urban transport problems such as congestion, pollution and road accidents. Building on this background, the paper proposes policy measures to improve urban transportation in India.