# Real-Time Performance Measurement Application via Bluetooth Signals for Signalized Intersections
## 1 Introduction  
The primary purpose of traffic management is to ensure that people reach their destinations in the shortest possible time while prioritizing safety. To achieve this, parameters such as the delay, waiting time, number of stops, and average speed need to be optimized. Today, smart traffic systems are increasingly implemented or developed to enhance these parameters [1; 2; 3]. Evaluating the performance of these systems and using the results as feedback is crucial for improving their effectiveness and making informed decisions about the system. Signalized intersections cause significant traffic delays. Various signaling systems have been developed to minimize delays caused by vehicles waiting at these intersections [4; 5; 6; 7]. Measuring the performance of these systems is essential in order to refine them, increase their efficiency, and understand the impact of external factors on their performance. The delay at intersections is a critical performance indicator in traffic engineering, directly affecting efficiency and user satisfaction. Adjusting signal times and phases can significantly impact delay times, and improperly set signal timings can lead to unnecessary waiting. The delay is often evaluated using data analysis, simulation models, or field tests to assess the performance of traffic signaling systems [8; 9; 10; 11]. Fixed-time signaling systems are traffic management systems in which traffic signals operate on a predetermined schedule that does not change based on traffic volume ordensity. In these systems, traffic lights follow set intervals for red, yellow, and green lights and are generally used in areas with predictable traffic patterns [12; 13]. Such systems are effective where the traffic volume is predictable and relatively constant, such as in small towns or areas with a low traffic density. On the other hand, fully adaptive signaling systems are advanced traffic management solutions that continuously optimize and adjust traffic signal times based on real-time traffic conditions. These systems aim to maximize traffic flow and minimize congestion by instantly responding to changes in traffic. Real-time data on traffic volume, speed, vehicle type, and other variables are collected using various sensors such as magnetic loops, radars, video cameras, ultrasonic sensors, and LIDAR. Advanced software then analyzes these data and optimizes signal times using complex algorithms and models, resulting in reduced travel times, enhanced road safety, and environmental benefits due to decreased fuel consumption and emissions [14; 15; 16; 17; 18; 19]. Bluetooth technology, a radio frequency communication method, is commonly used in short-range wireless communication. Bluetooth generally operates effectively within 10 m, although some advanced versions can communicate up to 100 m. It operates in the 2.4 GHz ISM band, which is used worldwide without a license for industrial, scientific, and medical applications [20]. Bluetooth is embedded in many devices, such as headphones, speakers, smartwatches, in-car entertainment systems, and phones. This widespread use enables data collection from passengers or drivers moving in traffic via Bluetooth signals. Bluetooth sensors calculate travel times between specific points by anonymously capturing the Media Access Control (MAC) addresses of devices and tracking their movements. These sensors help determine travel times, detect traffic density, and identify congestion [21; 22; 23]. In this study, performance analysis is carried out on Bluetooth data as a novelty. A method is developed based on the data received via Bluetooth and the delay parameters of the signalized intersection are determined. The developed method is applied to a real signalized intersection. The signalized intersection is operated with a fixed-time and fully adaptive signaling system and the delay parameters in two different operations are calculated. Thus, the performances of the signalized intersection in different operating types are demonstrated.