Universal vehicular communication promises many improvements in terms of ac- dent avoidance and mitigation, better utilization of roads and resources such as time and fuel, and new opportunities for infotainment applications. However, before widespread acceptance, vehicular communication must meet challenges comparable to the trouble and disbelief that accompanied the introduction of traf c lights back then. The rst traf c light was installed in 1868 in London to signal railway, but only later, in 1912, was invented the rst red-green electric traf c light. And roughly 50 years after the rst...