[Tactician_mark]

Here's an infographic from Sustainable Prosperity: https://i.imgur.com/2rgkaOZ.jpeg

That's just one area in Halifax, but the idea is that higher population densities require less infrastructure per person. Less road, power line, water/sewer pipe, etc. However, low density houses usually pay less in property taxes per unit area than high density, meaning that increased infrastructure cost is coupled with a considerable tax break.