"I can't really see the reasoning behind this, it would be far easier, more efficient, quicker and cost effective to put panels along the roadsides, "
Needs permits since it's above ground, hides the views of rich people and gives everybody living there a right to object, on the roads they can do whatever they want. 1 owner, no permits.
"Until they can lay solar panels like they do pavement for virtually the same cost as pavement ..."
You mean waiting until the money making pavements is as cheap as the dead not-money-making kind?