I know you prefer to not have drivers post hazards, but most do. I would have less hazard options and make them 1 click only. For example when you are marking down that there is a cop. You make us 1) choose hazard 2) select police officer 3) select hidden or visible 4) Post it.

Why not just have a button on the mail screen that says COP. People slow down no matter what. Having too many steps increases chances of car crashes.