i havent done this before mate but seen it being done.
car park lining. the guy was basicaly using chalk lines etc to mark out the ground.
pedro may know more about this, so maybe he can elaborate but.. i think you can buy the line paint sealed in a thin plastic sleeve.. it comes in on a roll and you lay it on the ground were you want it.. this can be cut up with scissors in bits to form words, bike images, pedestrians etc.. once you have everything sitting in place you basicaly go over it all with a large blowtorch and it melts the sleeve and paint basicaly sticks to the ground.
gives you plenty time to mess around and get things right before its permanant 🙄 😉