Trees on both side of the Road

We must agree to this point that we all want to live close to nature where we can get fresh air to breathe. But unfortunately it is not the case for most part of the world. There are big cities where you get big buildings and have hardly any sign of trees. I also stay in a big city but whenever I get time I will escape to get some fresh air.

Recently I was going out of the city where I have seen trees on both side of the Road, which makes travel so smooth and refreshing. I was wondering, if this can be done all over the world where we can plant trees on the road side which will help the environment big time.