I just want those people that want children to have them, and those that don't now. We don't need a global or national policy on how much population we want.
In fact, we are currently subsiding families. I tend to oppose that, but not because of fear of overpopulation.
Most roads are already not used often, its really just a few roads that are to full. And in those cases its really a density problem that we are not gone solve by having slightly less children.
For the rest I don't think population is the issue. The issue is with how those markets are organized. More people means you can have more teachers, not just more children. Currently the ratio is going down already, so I this is happening automatically anyway.
But we must also get over the idea that we need mass immigration into the West.
The most environmentally friendly thing to do is accept a slow decline in absolute population numbers.
This will mean roads are not as busy, hospitals not full to bursting and the chance to improve the kids to teacher ratio.