I have been running LED bulbs in one of my bikes for 2 years. They work well, but there are issues.....
I use them for brake lights and turn signals, and running lights (I was trying to reduce the standing load on the alternator so I could run other stuff.....like a heated vest
). They can be really bright if the bulb is facing the direction you are looking, but they do not utilize the reflector in the light housing as well as the incandescent bulbs. The LED's are directional bulbs, not omnidirectional like the incandescent bulbs. They are also sensitive to heat, if you mix an LED and an incandescent in the same housing face, expect the LED to burn out quick because of the heat from the incandescent bulb.
As is stated earlier in this thread, on my bike I used a solid state flasher relay to have the correct flash rate for the turn signals. I am not sure how our trucks work with the turn signal and hazard flashers.