IR and electrochemical gas detectors for CO, CO₂, NO, NO2. Both technologies are reliable and accurate. They allow to monitor the level of toxic gases along the tunnel and trigger alarms and appropriate actions when some thresholds are exceeded. The gas concentration parameter can be used for ventilation system control and the data can be stored for viewing and statistical purposes. Quality gas detectors are essential in tunnel instrumentation due to their countless benefits. These devices ensure safety by identifying hazardous gases, thus preventing potential disasters and protecting workers and the general public. In addition, modern detectors offer accurate and fast detection, allowing for immediate response in case of an emergency. Their ability to monitor various toxic and combustible gases ensures a healthy work environment and reduces the risk of explosions. In short, these detectors not only save lives, but also optimize operational efficiency in tunnels, creating safe and productive environments.