[Ma8ee]

One suggestion I like a lot is making walls with solar panels along highways. They'd reduce sound pollution, hinders wild animals to run into the road while at the same time producing electricity in a space not used for anything else.

[e_y_]

It wouldn't be particularly efficient, given that most of the day less than half the panels would be receiving direct sunlight.

I think a more practical option would be to put the solar panels above the road, such as https://www.theguardian.com/environment/2011/jun/06/tunnel-s... or https://renewsable.net/2017/06/28/south-korean-bike-highway-...

[Ma8ee]

Why do you think that less than half the panels will receive sunlight? Also, panels are very cheap today, so their placement doesn’t mean to be optimal. I believe the cost per kWh will be cheaper with panels mounted vertically off the ground than building a roof to place them on.