One fear everybody with a roof rack has is forgetting about the bike when pulling into the garage...
HeadsUP Systems has developed a sensor to help warn you before you pull into the garage with your bike still strapped to the roof.
How it works is simple. A sensor is mounted on the bike, and one in the garage. When you pull in and the garage sensor sees the bike sensor, a sign flashes and an in car buzzer alerts you to stop.
It's pricey at $169 USD, but I suppose it's cheaper than a new frame :)
See more here,