F36 Safety and Security Engineering in Transport ORIGINAL RESEARCH ARTICLE © 2022 UNIVERSITY OF ZILINA COMMUNICATIONS 24 (2) F36-F45 APPLICATION OF DATA MINING ALGORITHM TO INVESTIGATE THE EFFECT OF INTELLIGENT TRANSPORTATION SYSTEMS ON ROAD ACCIDENTS REDUCTION BY DECISION TREE Mohammad Mehdi Khabiri *, Matin Ghahfarokhi, Sara Sarfaraz, Hasan Mohammadi Anaie Geotechnic and Road Departement, Faculty of Civil Engineering, Yazd University, Yazd, Iran *E-mail of corresponding author: mkhabiri@yazd.ac.ir Resume Due to the large amount of available data in this study, authors have utilized data mining algorithms, especially the decision tree, to process these data and obtain the information, which would result in increasing road safety, determining the causes affecting it and patterns leading to traffc accidents. The effective use of this tool and its role in controlling the number of driving accidents is the subject of this study with the help of data mining algorithms. The results show that the increase in the number of roadside assistances to more than 41; number of driving accidents (fatally injured) is not signifcantly different, hence one of the proposed strategies for intelligent relay stations and its organization with the intelligent transportation tool is available. The intelligent transportation system utilities comprise of monitoring, guidance and enforcement tools, plus service tools such as rescue, driver assistant and road improvement. Article info Received 1 March 2021 Accepted 23 November 2021 Online 4 March 2022 Keywords: data mining algorithm, intelligent transportation systems (ITS), driving accidents, road safety, decision tree Available online: https://doi.org/10.26552/com.C.2022.2.F36-F45 ISSN 1335-4205 (print version) ISSN 2585-7878 (online version) with fast informing and without human errors could reduce approximately 40 % of the road casualties and accidents. The statistics and offcial information of the country have demonstrated that using the intelligent transportation system technologies, such as controlling cameras, speed and message boards and other facilities, such as the creation of databases and establishing telecommunication and computer communication networks, from 2009 to 2012 have increased 5 times on average [3-9]. A vast database with huge information is informing and developing by expanding the data collection tools and it can be used in many felds of knowledge and experiments. The main and widely used algorithms in knowledge exploration and data mining include categorization, anticipation, clustering, recognition of redundant information and obtaining association rules and analyzing the time series. One of the main advantages of the decision tree is the fact that knowledge in the form of if-then classifcation laws, can be extracted and displayed [2-10] ITS are not only safety-related but primarily are applied for other purposes like traffc fow and mobility improvements. Therefore, by considering the importance of the intelligent transportation system in this context, for more perception and gathering this subject, it is tried to classify the performed researches in a concise way and it is asserted in a case study and analyzed. For 1 Introduction Annually more than twenty thousand people die on the roads of Iran because of car accidents. This issue is a social health problem not only for Iran but for other countries, as well. For example, more than 40000 people die on European roads annually. Every year, road accidents impose 200 million euros expenses in the European economy [1]. Expenses of road accidents in Iran are unprecedented in their kind and they account for about 7 % of the country’s GDP [2-6]. Presence and monitoring by police at mostly accident hotspots, modifying the geometric scheme of these places, using warning signs, increasing vehicle safety and using seat belts are some of the solutions that can reduce road casualties. Besides these solutions, applying intelligent transportation systems is another method that the majority of developed countries and many developing countries have followed that today and by applying this system they have been able to increase the road safety level [4-9]. Currently, the road conditions in Iran are such that, in spite of the implemented efforts by relevant organizations and bodies over the past few years, this country is still considered one of the most unsafe countries in terms of the traffc problems. Despite the new telecommunication and communication technologies, the intelligent transportation system