This paper describes two newly developed low-cost thermoelectric infrared imaging sensors, having a 48 × 32 element thermoelectric focal plane array (FPA) and a 120 × 90 element thermoelectric FPA, respectively, and two experimental vehicle systems. The FPAs provide high responsivity of 2.100 V/W and 3.900 V/W, respectively. The FPAs are basically fabricated with a conventional IC process and micromachining technologies and have a low cost potential. One experimental system incorporated in the Nissan ASV-2 is a blind spot pedestrian warning system that employs four infrared imaging sensors. This system helps alert the driver to the presence of a pedestrian in a blind spot by detecting the infrared radiation emitted from the person’s body. The system can also prevent the vehicle from moving in the direction of the pedestrian. The other is a rearview camera system with an infrared detection function. This system consists of a visible camera and infrared sensors, and it helps alert the driver to the presence of a pedestrian in a rear blind spot. The sensor performance is suitable for use in various safety and occupant comfort systems.