## 3 Materials and Methods  
### Crowdsourcing  
In recent years, citizen participation has been increasingly used in various software applications such as advertising and marketing, disaster response, transportation and management, taking advantage of new universal and ubiquitous technologies. In 2007, [PERSON] introduced the name \"voluntary geographic information\" (VGI), a term used for geospatial data collected by citizens [25]. Nowadays, in the age of information abundance, traditional methods of traffic monitoring and control are facing great challenges. Therefore, several studies on traffic monitoring using wireless sensor networks have been conducted in the last decade. Most of them focused on tracking and detecting mobile vehicles equipped with sensors and mobile sensing devices [26]. In 2008, the University of California at Berkeley launched a pilot traffic monitoring project called Mobile Century. The follow-up project is known as Mobile Millennium and was designed to collect traffic data based on GPS embedded in mobile phones. They found that only 2-5% of the points provided by sensors in mobile devices are sufficient to provide the data needed for traffic monitoring and control [26, 27]. With the increasing need for real-time, up-to-date, location-based data, a new method of real-time data collection has emerged: \"crowdsourcing\" [28]. Crowdsourcing a map means collecting information and geospatial data from a large group of people in order to visualize relationships through their spatial representation. The collection of geospatial data can be done by users voluntarily answering a series of questions or by receiving real-time data from digital devices such as mobile phones [29]. Unlike traditional data collection methods, which often require experts in various fields, crowdsourcing data collection provides real-time results at low cost. That is why crowdsourcing has become a common condition for leveraging GIS and improving data resources [28]. One of the advantages of using crowdsourcing technology on a GIS platform is that the user's geolocation is recorded at the same time as the information is collected. Because smartphones are equipped with global positioning systems, the data sent is geographically located, which increases the value of the information, especially in the case of natural disasters and subsequent crisis management [30]. In this context, an increasing number of studies have analyzed the usage of crowdsourcing technologies to provide the geospatial data needed for traffic monitoring. It should be noted that most of the platforms have been classified as open-source applications, with a focus on providing voluntary geospatial data, mobile crowdsourcing and participatory discovery. Thus, crowdsourcing methods provide voluntary geospatial information for traffic prevention and planning and have the potential to enable a multitude of citizens to build and store asynchronously knowledge of many issues and actively participate in decision making by engaging in the collection of digital data [21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33]. If in the past, traffic assessment required sensors to detect and count vehicles, today we have information on human mobility patterns from mobile phones. Therefore, crowdsourcing in GIS-based applications allows any user to represent a vehicle or pedestrian and voluntarily contribute to traffic analysis [34]. All crowdsourcing applications rely on the friendliness of participants. Routing apps like Waze or Google Maps provide real-time maps, routing solutions, and traffic updates but are also attractive for sharing any traffic event, accident, construction, or other situations that may cause traffic problems. In addition to the information voluntarily shared by users, the application collects the location of all users/traffic participants.