Solar Roadways has been around since 2006 and has consumed vast piles of crowdfunding and public dollars without producing real results. Now they understand how impractical roads made of solar panels really are so they've moved roads to the end of their list of things to solarize. (even though it's in their name)
In my part of the country, there will NEVER be solar roads. There can be 100 F heat in the summer and -40 F in the winter. Every year the roads buckle, heave, crack and come apart taking months of maintenance work. It can dump 2-3 feet of snow overnight and the kilocalories to melt that snow in time for morning traffic would be way more than any system could generate. Now, imagine a snow plow spraying road salt tearing across the surface of solar cells lining this buckling heaving road pocked with small sinkholes.
There are parts of North America with long stretches of open road in the desert where the concept could be made to work (at great expense.) However, those road usually pass right by large swaths of open land that could be used for solar farms that are cheaper and more efficient.
This doesn't mean we shouldn't pursue the technology. Photovoltaic tar or paint would be a game changer that could be right around the corner. But, Solar Roads was just another crowdfunding fail.