After a lot of searching I have failed to come up with a definitive statement on the actual resolution provided by the Cadillac de Ville camera beyond the statement that it uses a 320 x 240 pixel BST sensor.
I even found a General Motors paper on the system and attach a small extract, describing the camera, here.
It states that the camera uses a 320 x 240 pixel sensor but that is as detailed as it gets on the resolution front. There was also some interesting comment on the playoff between wide angle lenses and telephoto lenses when it comes to depth of field which is important in vehicle borne pedestrian safety systems.
The system was designed for distance observation beyond the coverage of the vehicles headlamps so a relatively narrow 11 Degrees HFOV by 4 Degrees VFOV was presented to the driver.
Fraser