Radar obstacle detection can be a tricky thing--it's easy to get false positives, to be tricked into seeing something that's not there because of the shape or movement of the car's surroundings. That's where the Brooklyn Bridge came into play.
Heavy traffic volume and the bridge's intricate metal design itself provided a sort of torture test for the system, where the engineers worked to weed out the false information while holding onto the sensor data necessary to keep the car--and its occupants--safe.
“We have to try and anticipate every scenario, especially those that really challenge the technology,” said Jim Nickolaou, Cadillac's lead engineer for sensor fusion. “We tune the systems to discern actual obstacles from other things in the vicinity that should not cause a warning or braking action.”
Cadillac's 'Sensor Fusion' ties in various inputs to provide a wider range of safety assists
Radar also ties into the "sensor fusion" concept through the alert system, part of which includes the Safety Alert Seat, which vibrates to let the driver know there's a potential hazard on the road.