I've already fitted clusters of white LED's as replacements for sidelight and reversing light bulbs on my 3-wheeler motorcycle - the location was plagued by vibration and I had to constantly replace filament bulbs. The LED's have proven fine, even surviving a low-speed bump that saw the plastic cover knocked off and would have lost me the bulb if I hadn't changed.

I'm also trialling red LED clusters as stop/tail lights to cut down on the amperage in that circuit - when I towed a trailer it would blow the 10A fuse. I fitted a 20A but wan't happy that that was a safe solution, so I'm working through replacing the bulbs with LED's - they even come with a standard automotive bayonet mounting.

When enough are changed over, I'll replace the 10A fuse...

These are special examples, of course, but the LED's are so good that they will replace many light fittings on vehicles in the next few years. Many late-model trucks and buses already have LED arrays instead of turn and tail lights, since they fail gracefully rather than totally.