Device, system and method, in a vehicle communication system, of transmitting a risk value in a message, wherein the risk value identifies quantitatively a risk of vehicle collision. Embodiments determine risk value by combining sub-risk values wherein sub-risks comprise: (i) vehicle behavior; (ii) weather and road conditions; (iii) current traffic; and (iv) location history. Embodiments include driver warnings responsive to the risk value in a received message. Embodiments include a collision type in a message. Embodiments include unique features of: risk is applicable to receiving vehicles; risk is applicable to a geographical region; computation and storage of location histories; messages free of IP and MAC addresses; haptic devices used for driver warning.