Nedal T. Ratrout

Review of the Fuzzy Logic Based Approach in Traffic Signal Control : Prospects in Saudi Arabia

Abstract The first implementation of fuzzy logic controller in the literature appeared in 1977, which shows better performance compared to vehicle actuated controller for a very simplified intersection having two one-way streets based on a simple green time extension principle. After that, further development is taking place by adopting fuzzy logic based traffic signal control for two-way single intersection without turning vehicles, single intersection with all possible movements, multiple intersections, phase sequence and time determination, congested intersection and network, etc. Research in fuzzy logic based traffic signal control is getting inspired by the results which indicate better performance compared to traditional traffic signal controls, specifically during heavy and uneven traffic volume conditions. It can be expected that the fuzzy logic approach will not only contribute in the advancement of adaptive traffic signal control but will also contribute significantly in the future approach of transportation management system (TMS) by improving the performance of the adaptive controller and the overall decision making process of the TMS. However, there are only a few examples of this kind of traffic signal control or TMS in real life. Researchers in rapidly developing countries like Saudi Arabia should investigate the potential of the fuzzy logic based traffic signal control or TMS under the unique local conditions to curb the loss incurred due to congestion.

THE EXTENT OF ILLEGAL OVERTAKING IN THE EASTERN PROVINCE OF SAUDI ARABIA

Illegal overtaking is a major contributor to traffic accidents in the Kingdom of Saudi Arabia. It is the second most frequent cause of traffic accidents after speeding, and responsible for 10% of all traffic accidents in the year 2001. This paper evaluates the extent of illegal overtaking in the study area and examines the effect of time and alignment on its frequency. The study took place in the eastern part of the Kingdom of Saudi Arabia and covered tangent sections and horizontal curves during off-peak, peak, and night-time periods. It was concluded that overtaking violations in the study area were statistically influenced by alignment and traffic volume. Overtaking along tangent sections was statistically more than that on horizontal curves. The number of overtaking vehicles in a given direction was found to proportionally increase with the traffic volume in the same direction and decrease with the traffic volume in the opposite direction. On average, the overtaking violations constituted 2.1% of the observed traffic volume (in both directions) during 98 hours of data collection in the study area.

Factors Affecting Performance of Parametric and Non-parametric Models for Daily Traffic Forecasting

Traffic forecasts are used for a wide variety of purposes from the planning to the design and operational stages of the highway network. The forecasting models need the historical traffic data and some supporting variables that are relevant to the traffic demand. Apart from that, choice of an appropriate model or technique is also an important consideration. This paper gives an overview of the traffic forecasting process and the models that are used for this purpose with emphasis on the use of different types of Artificial Neural Networks (ANNs). In this research, two types of Artificial Neural Networks (ANNs) are being compared with the traditional parametric technique of linear regression analysis for daily traffic forecasting on King Fahd causeway, which provides a link between Saudi Arabia and Bahrain. It was observed from the estimated error values that ANNs have better accuracy than linear regression technique for predicting daily traffic. However; increasing the size of dataset and restructuring of the dataset showed the greatest effect on predictive accuracy of the models instead of the configuration of the model or type of technique. In fact, it was also observed that providing large number of classified data samples can make the accuracy of the regression analysis comparable to ANNs.

Comparison of Optimal Signal Plans by Synchro & TRANSYT-7F Using PARAMICS – A Case Study☆

Abstract TRANSYT-7F and Synchro are two of the most extensively used signal timing optimization softwares in Saudi Arabia. Each of them has its inbuilt objective function to optimize signal plan for intersections, which is different from each other. In this paper, the performance of the optimal signal timing plans developed by TRANSYT-7F and Synchro is compared using the microsimulation software PARAMICS. An urban arterial with three intersections and moderately high traffic in Dhahran, Saudi Arabia is studied. Comparison of the optimized plans is done on the basis of queue length and average delay from the simulated results of PARAMICS. The study showed that the optimized plan by TRANSYT-7F gave better results than the plan by Synchro in terms of queue length and average delay. The study also showed a trend of better optimized signal performance when the timing plans are simulated in their respective simulation model.

Effect of public transportation in reducing passenger car trips to schools in Al-Khobar–Dhahran metropolitan area, Saudi Arabia

Abstract School trips comprise a major portion of daily vehicular demand on urban road networks. Dependence on cars for school trips can induce congestion on a routine basis. In this study, use of sustainable transport strategy in the form of public transport has been analyzed using mode choice models. The objective of this study was to develop mode choice models for public boys’ schools in Al-Khobar and Dhahran metropolitan cities in Saudi Arabia. These schools do not have any public transport service. Mode choice modeling was done using logit models for the present modes as well as for future modes with a hypothetical bus service. From the mode choice models, it was found that family income is one of the significant factors for mode choice decisions, with or without bus service. Sensitivity analysis was also performed to find the market share of bus for different scenarios, which showed that bus service will become the dominant mode.

Effects of potential modes on mode choice behaviour for travel between Saudi Arabia and Bahrain

A new transport mode or service is bound to change the travellers’ behaviour and may induce new demand for the route. The situation becomes more complex if more than one potential mode is compared for border transport. Consideration also has to be given on the induced demand because of higher level of service or different characteristics of the new mode or service. This study reviews the present trends in border mode choice decisions of travellers between Dammam-Khobar metropolitan area of the Kingdom of Saudi Arabia (KSA) and the Kingdom of Bahrain. The changes in mode choice behaviour of travellers because of the potential future train and ferry services and their induced demand are also presented. Logit models have been used to study the travellers’ behaviour on this route. The study indicated that either one of these future modes might reduce the market share of car by a considerable amount. Sensitivity analysis was also performed to determine the optimum fare values for car and ferry services. It was found that the fares at which train and ferry service have higher probability to be chosen than car, are SAR 52 (

Effects of using average annual daily traffic (AADT) with exogenous factors to predict daily traffic

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Relationship between Chauffeurs’ Demographics, and Knowledge of Traffic Signs in the Kingdom of Saudi Arabia

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A review of mode choice modelling techniques for intra-city and border transport

Traffic demand can be highly correlated to the exogenous factors that exist outside the road system under study. Factors like day of week, presence of vacation or salary disbursement or economic parameters are readily available and may affect traffic flow between two countries. Collection of traffic data on a consistent basis is a cumbersome process in terms of time and resources. Considering these two factors in mind, this paper investigated the feasibility of using exogenous factors with Average Annual Daily Traffic (AADT). It was found that inclusion of AADT for traffic prediction is beneficial and further analysis will be done in the future with detailed traffic data.

A COMPARATIVE ANALYSIS OF CURRENTLY USED MICROSCOPIC AND MACROSCOPIC TRAFFIC SIMULATION SOFTWARE

Abstract Authorities in the Kingdom of Saudi Arabia (KSA) are investing heavily on developing Intelligent Transport Systems, which includes installations of Variable Message Signs (VMS) for the road users. However, it is challenging to design the VMS messages since the population possess different cultural, linguistic, and social backgrounds. To aid in the process of VMS design, this paper presents results from a questionnaire survey, conducted on chauffeurs involved in crashes in the Kingdom to understand their knowledge of traffic signs. A sample of around 800 chauffeurs, who were involved in crashes, was collected by conducting personal interviews. The relationship between chauffeurs’ demographic characteristics, such as nationality, age group, language skills, and knowledge of traffic signs were assessed. The chauffeurs’ language skills were assessed for Arabic, English, and native language. Chauffeurs’ knowledge of five traffic signs namely speed limit, no entry, no overtaking, stop sign, and roundabout were tested. The results from descriptive analysis indicated that more than 60% drivers were able to understand traffic signs written in Arabic and English language. The least understood sign was no entry and the most understood sign was stop sign. Nationality of chauffeur was related to the knowledge of traffic signs and language skills. These results suggest that more research should be undertaken before designing VMS especially in a heterogeneous driver population like that of the Kingdom of Saudi Arabia.