Interesting tech, but why not (also) broadcast this information to displays to the side of the road or above it? Much like some other warnings are already displ

Interesting tech, but why not (also) broadcast this information to displays to the side of the road or above it? Much like some other warnings are already displayed on highway signs about black ice, accidents and a whole variety of other hazardous conditions. Focusing on "smart" cars does come at the detriment of drivers and passengers of older cars who do not receive these warnings, and means that only the drivers and passengers of modern vehicles benefit from these alerts. Even putting aside from the obvious fairness issue of such a system, what good is it if only a fraction of drivers can be reached? Public safety alerts should not be limited to a limited group of people who could afford the latest tech.