Driver monitoring is a vital topic nowadays due to the high number of traffic accidents on public roads around the world. Because self-driving cars are not yet available everywhere, research and development in the field of intelligent transportation systems concentrates on driver monitoring. This Special Issue covers smartphone sensor utilization for the purpose of driver monitoring, as well as security aspects for when a driver tries to fool the app while in a dangerous state. The smartphone’s front-facing camera tracks the driver’s face and computer vision algorithms are used to detect dangerous situations. In addition to the front-facing camera, the rear camera detects dangerous situations on the road. Dangerous situations are defined by the driver’s behavior. Other sensors, such as GPS, accelerometer, gyroscope, and magnetometer, are used for context situation detection interpretation. This Special Issue also covers mobile application integration with vehicle infotainment systems via Android Auto and Apple CarPlay. Both review articles and original research papers are welcome. There is particular interest in papers concerning new applications and innovative approaches to driver monitoring. The Guest Editors: Dr. Alexey Kashevnik, Prof. Andrei Gurtov, and Prof. Sara Ferreira.