This time can be rightly called the time of data. The paradigm that describes modern society was created in 2006 when the British mathematician Clive Hamby exclaimed from the roof of a building: "Data is the new oil." With the development of information technologies, the Internet and social networks, the amount of information has been growing from year to year at high speed. It is estimated that 2.7 zettabytes of data had been collected by 2013, while it is assumed that in 2025 that number will be 175 zettabytes (Daley, 2022). Data processing has become both a challenge and a necessity in order to make quality business and life decisions. The new era characterized by ubiquitous computing, big data, the use of sensors, the Internet of Things, artificial intelligence, blockchain and a number of other technologies is called the Fourth Industrial Revolution (Industry 4.0) (Krivokapić at al, 2019). Industry 4.0 would not be possible without the use of large amounts of data in business. The European Union (EU) recognizes the importance of data as a resource for economic development, creation of new jobs, competitiveness, innovation and social progress. One of the pillars of the development of the EU economy is the construction of the data economy, the total share of which in 2016 was 300 billion euros (1.99% of European social income) with a tendency to grow in the following years (Krivokapić at al, 2019).

Open data is data that is publicly available to everyone and can be used for any purpose in any way, without copyright or other restrictions (Dymora at al, 2018). Most often, this term refers to data obtained from public institutions of society, but the term is also used for other types of data (medical data and the like). The open data initiative was created in 2007 when Lessing and his collaborators started the initiative to open the data of Government institutions in the United States of America (USA) in order to achieve transparency and introduce control at work (Ayre & Craner, 2017). In 2013, in the USA, then-President Obama signed an executive order on open data. The decree opens an open data portal, states that openness in government strengthens democracy, promotes the delivery of efficient and effective services to the public and contributes to economic growth. The advantage of open government is the facilitation of information resources, finding, availability and usability of data (Ayre & Craner, 2017).

Proper use of open data can help achieve the following goals (Terzić & Majstorivić, 2019):

- Open data helps governments and citizens to make better decisions based on the availability of more data.

- Users can combine different datasets.

- The openness of data allows researchers to explore trends as well as uncover social and economic problems.

- Open data helps the public sector and institutions to achieve better results in areas such as health, education, public safety, ecology, natural disasters and the like.

- Open data contributes to economic development and helps in business operations.

- It improves the flow of information in the government, improves intersectoral cooperation and contributes to greater transparency.

- The openness of economic data helps to control the spending of public money.

- Government openness accelerates institutional reactions, reduces corruption and helps build new democratic spaces for citizens (Keserű & Kin-Sing Chan, 2015).

Open data is usually created by public institutions. Before being published, data must go through an anonymization process (Dymora at al, 2018). One of the basic requirements that open data must meet is to ensure privacy. Data that is not allowed to be shared is called closed data. The term closed data usually means personal data. Some data may be processed by a limited number of users for the purpose of various research. Such data is called shared data.

Open data must be in a format that allows easy machine processing. Open data formats must enable processing in at least one open format software (opendata portal).

The use and processing of open data creates favorable conditions for the discovery of new knowledge in order to provide answers to important social problems. One of the major problems around the world are traffic accidents that claim more and more lives and cause great material damage. With high-quality data analytics, conclusions can be drawn that could reduce harmful consequences in the future. Saxena & Robila (2021) describes the use of open data in the field of traffic and presents a tool for the analysis of traffic accidents in the territory of the city of New York based on open data analytics. The tool analyzes all the factors that have influenced traffic accidents, visually represents the locations where accidents have occurred, and provides insight into the details in order to draw conclusions with the aim of reducing the number of accidents in the future. Gladivić and Deretić describes the analysis of traffic accidents in the territory of the City of Belgrade (Gladović & Deretić, 2018). At the very beginning, the authors describe a set of open data, and then provide an analysis of the data in Excel. The hypothesis of increased traffic safety in the territory of the City of Belgrade in 2016 compared to 2015 was examined.

Visualization means translating information into a visual context to make it easier to understand. Visualization can be used to create high-quality graphical representations of data, but also to perform exploratory data analysis, EDA. In the paper (Volpi at al, 2014), the authors presented the visual platform Roma Crash Map, which visually presents open data on traffic accidents in 19 municipalities of the city of Rome. A similar project in Serbia was developed by the Observatory of Social Innovation (ODI) through an interactive map based on open data on traffic accidents from 2015 to 2019 sorted by various categories (Opservatorija društvenih inovacija, 2023).

The practical application of the application for research purposes refers to the analysis of traffic accidents on the territory of the Užice Police Department (Užice PD). The primary goal of the research is to test the hypothesis about whether the analysis of open data on traffic accidents for previous years, and preventive actions, has led to an increase in traffic safety in the territory of the Užice PD. The data was obtained by using the application and selecting the appropriate filters available on it.

A total of 664 traffic accidents were recorded on the territory of the Užice police department in 2021, namely 349 accidents with material damage, 297 traffic accidents with injured persons and 18 accidents with killed persons. Regarding the time interval when the traffic accident occurred, 219 traffic accidents occurred from midnight to 12:00 and 445 from 12:00 to midnight. The most serious forms of traffic accidents are those in which there are injured or killed participants. Traffic accidents with injured persons in 2021 occurred more often after 12:00 (201) than before 12:00 (96). In the period from midnight to 12:00, there were 5 fatal traffic accidents, while in the period from 12:00 to midnight that number was 13. Through graphic interpretation and visualization, it is possible to identify potentially dangerous road routes on the territory of the selected PD. The graphic representation of the geolocations of the accidents with injured persons for the year 2021 on the territory of the Užice PD is shown in Figure 6.

Figure 6

Рис. 6 – Географические координаты дорожно-транспортных происшествий с пострадавшими в 2021 году (Gavrilović, 2023)

Слика 6 – Локације саобраћајних несрећа са повређеним лицима у 2021. години (Gavrilović, 2023)

This work shows the possibility of using the Streamlit framework for creating an application for processing open data. The work begins with a short introduction, then the concept of open data is explained and the previous works based on open data on traffic accidents are presented. The main part of the paper is a description of the web application for the analysis of traffic accidents in the Republic of Serbia and its practical application to the analysis of traffic accidents in the territory of the Užice PD. The aim of the work is to get acquainted with open data and the functional possibilities of the Streamlit development environment through the analysis of the application operation. Using the application enables a review of data on traffic accidents according to various criteria, which facilitates the review by researchers and services in charge of traffic safety. The analysis of the data for the Užice Police Department showed that there was an increase in the general level of traffic safety in 2022 compared to 2021. The visualization identified road routes where there were the most accidents with injured and dead persons and where preventive control measures should potentially be strengthened. The application presented in the paper has room for upgrading in the future, by introducing additional functionalities, in order to make the work even easier for professionals for whom it is intended.