Drowsiness detection plays a crucial role in enhancing safety and preventing accidents in domains such as transportation and industrial operations. This work presents a data-driven approach for detecting driver drowsiness using electrocardiogram (ECG) signals from 20 sleep-deprived participants driving on a motorway in real-world driving conditions. Heart rate variability (HRV) features were extracted from ECG signals and used as sequential input to Long Short-Term Memory (LSTM) networks, which are well-suited for modeling temporal physiological patterns associated with drowsiness. The model was trained and evaluated using 10-fold cross-validation and leave-one-subject-out (LOSO) cross-validation strategies to ensure generalization across individuals. Experimental results demonstrate the model’s ability to distinguish between alert and drowsy states (10-fold accuracy = 87.8%, LOSO accuracy = 61.0%), highlighting the potential of HRV-based deep learning approaches for robust, non-intrusive drowsiness detection. This work underscores the importance of physiological signal analysis and deep learning techniques in developing reliable real-time driver monitoring systems.