# Use of Wireless Sensor Networks for Area-Based Speed Control and Traffic Monitoring
## 2 State of the Art  
Modern technologies have been supporting efforts to improve road traffic safety for years [9; 10; 11; 12]. The most obvious and popular examples include speedometers, originally radar-based and later laser-based as the technology advanced. Solutions such as video cameras and drones also provide additional support. The development and application of new solutions necessitate the adoption of new data transmission standards and technologies, such as Bluetooth [13]. Increasing user requirements and expectations have led to the implementation of ICT solutions that enable the creation of vast wireless networks supporting a variety of devices and sensors. These include a wide range of possibilities and specific process solutions offered by LPWAN (Low Power Wide Area Network), a type of wireless network designed for long-distance, low-power-consumption communication. It is an ideal solution for the Internet of Things (IoT), where devices often need to operate on batteries for extended periods and may be distributed over vast areas, including both urban and rural environments. LPWANs thus present an alternative to hard-wired solutions based on fiber optic cables [14]. The main features of LPWAN include the following:  
* Low energy consumption: Devices can run on batteries for years without the need for replacement or recharging. * Long range: LPWANs can cover an area with a radius of up to several dozen kilometers. * Low throughput: LPWANs are optimized to transfer small data volumes, typical of many IoT applications. * High capacity: The networks can handle a large number of devices within their range. LPWAN technologies include the following solutions:
* LoRaWAN (Long Range Wide Area Network): This technology uses LoRa modulation to achieve long range and penetration in harsh environments [15; 16; 17; 18]. * Sigfox: This technology employs Ultra Narrowband (UNB) radio technology to achieve a long range with very low power consumption [19; 20; 21]. * NB-IoT (Narrowband IoT): A communication standard developed by 3 GPP that uses narrowband LTE radio communication [22; 23; 24]. * LTE-M (LTE Cat-M1): A version of LTE adapted for IoT purposes, offering balanced coverage, power consumption, and throughput parameters [25; 26]. Road transport LPWAN applications that are particularly important in the context of road traffic safety include solutions designed for real-time traffic monitoring, as reviewed in [27; 28], or even those that detect undesirable events such as traffic accidents [29]. The LoRaWAN wireless data transmission technology is increasingly being employed in various branches of the economy [30; 31; 32]. Its benefits, such as long-distance data transmission and low power consumption, are driving its use in the fields of smart cities [33; 34; 35] and intelligent transport systems [36; 37; 38; 39; 40]. The particular significance of the potential application of LoRaWAN technology in road transport stems, among other factors, from the search for new solutions aimed at increasing the safety level of both drivers and pedestrians. Efforts in this regard cannot be undertaken on a local scale through stationary vehicle speed control but instead require the implementation of area-based solutions. One such option is employing LoRaWAN technology in combination with V2X (Vehicle to Everything) communication [41]. Test results demonstrated in [42] confirm the viability of deploying such solutions. Another potential application of LoRaWAN technology aimed at increasing traffic safety is a wireless motion detection system. The authors of [43] developed such a system and conducted tests focused on determining when traffic intensity decreases or is suspended, which is particularly important on expressways, as it increases the risk of traffic accidents. The conducted tests led to the conclusion that it is possible to determine vehicle speed using this system. LoRaWAN technology has also been applied in managing parking spots [44; 45; 46] for motor vehicles and bike-sharing systems [47; 48].