© 2018, Springer-Verlag London Ltd., part of Springer Nature. Sudden visibility reductions on highways due to foggy weather conditions often lead to a drastic increase in car crash risks. Indeed, fog formation distorts drivers’ perception and judgment of inter-vehicular distances, vehicles’ speeds, and braking distances. In order to support drivers in dealing with the impact of fog, various on-board warning systems are being deployed today. Despite their added value, these systems are still in need of efficient solutions supporting smooth vehicle’s acceleration/deceleration profiles. This is to avoid sudden braking (hence, higher car crash risks) incurred by sensor technologies restricted to line of sight measurements. To meet this goal, we advocate in this paper a Wireless Fog Warning System (WFWS) where cooperative awareness messages are disseminated and used for calculating acceleration/deceleration activities. Without loss of generality, we build on IEEE 802.11p WLAN as a basis technology. Using simulations on the open-source vehicular network simulation framework Veins, we demonstrate both the potential of such a system for increasing safety and smoothing traffic flow—as well as of computer simulation as a means of its evaluation.