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Showing 4 results for Level of Service

R. Prasanna Kumar, G. Dhinakaran,
Volume 11, Issue 1 (3-2013)

Delay is one of the principal measures of performance used to determine the Level of Service (LOS) at signalized intersections and several methods have been widely used to estimate vehicular delay. Very few studies only have been carried out to estimate delay at signalized intersections under mixed traffic conditions prevailing in developing countries like India. In the present study, various problems associated with delay estimation under mixed traffic conditions in a developing country (India) and the methods to over come them were discussed and an attempt was made to improve the accuracy estimating the same. Five isolated signalized intersections from a fast developing industrial city located in TamilNadu, India were chosen for the study. Site specific PCU values were developed considering the static and dynamic characteristics of vehicles. Saturation flow was also directly measured in the field for the prevailing roadway, traffic and signalized conditions and expressed in PCU/h. Control delay was also measured following HCM 2000 guidelines. Later, this was compared with that estimated from the theoretical delay model. Even after taking several measures, good correlation between observed and predicted delay could not be obtained. Therefore, in the present scenario field measured control delay was taken into account to define LOS. A new criteria for Indian cities recently published in the literature was used to assign LOS grades of study intersections and found to be better reflecting the field conditions.
S. Soudmand, M. Ghatee, S. M. Hashemi,
Volume 11, Issue 4 (12-2013)

This paper proposes a new hybrid method namely SA-IP including simulated annealing and interior point algorithms to find the optimal toll prices based on level of service (LOS) in order to maximize the mobility in urban network. By considering six fuzzy LOS for flows, the tolls of congested links can be derived by a bi-level fuzzy programming problem. The objective function of the upper level problem is to minimize the difference between current LOS and desired LOS of links. In this level, to find optimal toll, a simulated annealing algorithm is used. The lower level problem is a fuzzy flow estimator model with fuzzy link costs. Applying a famous defuzzification function, a real-valued multi-commodity flow problem can be obtained. Then a polynomial time interior point algorithm is proposed to find the optimal solution regarding to the estimated flows. In pricing process, by imposing cost on some links with LOS F or E, users incline to use other links with better LOS and less cost. During the iteration of SA algorithm, the LOS of a lot of links gradually closes to their desired values and so the algorithm decreases the number of links with LOS worse than desirable LOS. Sioux Falls network is considered to illustrate the performance of SA-IP method on congestion pricing based on different LOS. In this pilot, after toll pricing, the number of links with LOS D, E and F are reduced and LOS of a great number of links becomes C. Also the value of objective function improves 65.97% after toll pricing process. It is shown optimal toll for considerable network is 5 dollar and by imposing higher toll, objective function will be worse.
Ilker Erkan, Hasan Hastemoglu,
Volume 14, Issue 8 (12-2016)

In this study, the usage of the Level of Service (LOS) concept, which was developed specifically for pedestrian satisfaction and safety, was critically analyzed. The focuses of this investigation were the Fruin and Highway Capacity Manual (HCM) LOS values, which were evaluated and compared in terms of their anthropometric dimensions. In this paper, new LOS values are proposed on the basis of the critical evaluation of the HCM and Fruin LOS values revealing the inconsistencies between the LOS values and the analysis. The importance of emptiness area in calculating human comfort and satisfaction in terms of the anthropometric dimensions and LOS value is also discussed. A software program called Laborer Image Analysis Software (LIAS) was developed to evaluate and compare the impacts of different body dimensions on the LOS values and on the space requirements for pedestrians. LIAS is presented as a facilitation tool for calculating more concise and effective emptiness areas and LOS values. The comfort area concept is also presented and discussed. This discussion is used to reveal the contrasts and inconsistencies in the existing usage of the LOS concept and to highlight the importance of the emptiness area approach. The paper presents a different perspective and discussion on the existing utilization of LOS levels, particularly for pedestrians in different structures. The research contributes to the LOS analysis discussion in terms of the anthropometric scale according to changing user profiles and develops facilitator(s) for analyzing and applying amendments to pedestrian needs, which can be used in transportation buildings.

Dr. Prasanta Bhuyan, Mr. Amit Das,
Volume 15, Issue 7 (10-2017)

The present study aims at the divination of the speed ranges of Level of Service (LOS) categories of urban traffic facilities. Free flow speed (FFS), congested travel speed, geometric and surrounding environmental conditions are considered to define LOS criteria for urban street in Indian context. Cluster analysis is found to be a powerful tool to delineate LOS criteria. Hard Competitive Learning (hardcl) method is used to classify large number of speed data obtained using Global Positioning System (GPS). Six cluster validation parameters are used to classify the urban streets as well as the LOS categories. It can be confirmed from the above research work that the LOS categories for different urban street class are lower than that of the values proposed by HCM 2000 and the average travel speed of LOS categories expressed in percentage of the free flow speed are lower than the values mentioned in HCM 2010.

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