My idea for a U-Lock with an Alarm system
It'll be like a standard u-lock. Push in the U metal part into the main part of the lock then turn the key to lock. But here's the difference in my idea. The U-Metal part houses a wire that, where, once the lock is closed, a circuit is completed. Turning the key both locks the lock and turns on the alarm system. This alarm system will activate when the circuit is broken before the lock is unlocked with a key. This means that the U metal part is cut and therefore the wire and circuit is broken. If the alarm sounds, people will notice and if they see a guy running off with a bike, they'll suspect him of being the thief and hopefully give chase.
There is also an alarm that is attached directly to the bike and not only to the lock. It'll be strong enough to take a banging if the thief tries to break it off without using the key.
How does this part work? When the circuit of the lock is broken, a wireless signal is sent to the alarm attached to the bike so if the thief runs of with the bike, he or she would also be running with teh alarm attached to the bike. The alarm won't stop unless the lock's key is used.
Future high end bikes could even have that alarm module built into the bike's frame to make it harder to stop by a thief.
If there are any engineers here, please make this.