It is gaining great importance to develop and integrate physiological sensors into daily healthcare. Especially, electrocardiogram (ECG) is useful for the disease diagnosis and daily health monitoring, also for the driver's cognitive state monitoring. Capacitive ECG monitoring system, which enables to collect ECG with indirect skin contact, is implemented in this study. Signal attenuation and noise contamination is considered by installing flexible electrode, neutralization circuit, AC coupling circuit, Driven right leg (DRL), and DSP board in the configuration. The system is evaluated with 5 subjects with a car in situations of engine off and on. R-wave Detection Sensitivity (Se) and Positive Predictivity (P+) of 99.8% and 100% were obtained during the engine on.