Can anyone have code for emergency message dissemination.

I want to construct a network having intersecting roads and multiple vehicles and a road side unit. Road side unit send warning message to vehicles. Can someone help me in this?

[Rik]

This is a really large question with hardly any context given. Have a read here and here. It will greatly improve your chances of getting an answer. One of the tips is to keep your question as on point as possible. Try to split your question into solvable parts.