It seems facial recognition of a driver behind a wheel is becoming a reality, we should see commercial systems soon.
http://www.springerlink.com/content/y4164k783008rg15/ "...Our experimental results indicated that the algorithm is robust for driver authentication inside the vehicle and is also reasonably fast for real-time processing....."
As an added measure place a dome camera on the roof which will send snapshots to the base via an embedded pc/GPRS combination. Install an IR and/or Ultrasonic distance measurement(UDM) device that is used in robotics on the roof/door junction. The UDM can accurately determine the distance of a close range object up to a centimeter. Thus as people walk past the car say 1meter away, no images will be sent, only if somebody is within 50cm of the door will a snapshot be sent.
Now imagine if you can prove to a would be hijacker with a logo on the door pointing to a website that you really, really do have such a face authentication system and that his face will be sent via GPRS to a PC, he won't hijack the car to begin with in the first place - just like no Eskom and Telkom bakkies are hijacked anymore since the crooks are convinced they won't get away.
Lets recap: 1) Camera dome on roof that automatically turns in the direction of UDM trigger and sends snapshot to base. 2) Bonnet lock device. 3) Ultrasonic(UDM) and IR distance measurement sensors on roof and inside car. 4) GPRS/GPS system linked to embedded pc in car. 5) Embedded PC gets power from a DC-DC converter(http://tinyurl.com/6n3qa6) 6)GPS signals aren't always available such as in city centers. Measure the distance and speed a vehicle travels from the gearbox sensor. A Propeller RateGyro2 and digital compass determines the turns a vehicle makes. Allows an approximate GPS position to be established from the moment of GPS signal loss. 7) On spectrum jamming attempt using http://www.phonejammer.com the panic button is activated on the Netstar radio transponder back-up system. Netstar gets SMS from your PC saying that it has lost GPRS contact and provides last GPS coordinates. Netstar sends out the marines. 8) Place a GunShotDetector device in your car - http://tinyurl.com/6gpwn4. 9) A Propeller RateGyro2 - http://tinyurl.com/5aojhv - measures the incline a vehicle makes and alerts the Gprs system. If a car is being towed it will make an incline. The "propeller" IMU uses Kalman filtering. 10)When Netstar gets the radio panic alert they will FTP all the images triggered by the UDM the dome camera sent to your PC via GPRS to theirs to see what happened right before your door was opened. 11) Infrared module detects wether a white, colored or black person is behind the wheel. http://citeseer.ist.psu.edu/676368.html 12) Each chair has a weight sensor. 13) Vibration and ambient light detection circuit inside dashboard and bonnet to detect forced entry - http://www.ewcop.com 14) Ultra-violet detector detects actual flames - http://www.bomarc.org/catalogs/Catal.../DETECTION.txt 13) Advertise all these measures - don't bluff, prove it - hijacker will go somewhere else.
Bomarc provides reverse engineered schematics of commercial electronic and security products. http://www.bomarc.org/catalogs/Catal.../DETECTION.txt