A system and method are provided for detecting use of RF transmit devices
(e.g., cellular phones) in a vehicle. The system includes a first RF
antenna for detecting signal strength of an RF signals transmit device at
a first location in a vehicle and a power first detector for generating a
first output signal indicative thereof. The system also includes a second
antenna for detecting signal strength of the RF signals at a second
location in the vehicle and a second power detector for generating a
second output signal indicative thereof. The system further includes a
signal processor for processing the first and second output signals to
determine the presence of an RF transmit device in use in the vehicle and
to further determine the location of the RF transmit device to determine
if a driver is using the device.