The physical layout of suburbs encourages more driving and less walking than cities with a lot of intersections.

Do suburbs encourage biking? Or not really?

not really. some of the top newer suburbs place a lot of focus on being able to walk to a town center and then running/biking trails around the neighborhood. 

Sounds like the newer suburbs are more like cities. 

Dense cities promote walking and biking, so the push for healthier cities fits with the vogue push for active lifestyles—as opposed to gym routines smattered across an indolent existence. Physical activity is not just concerted exercise time and deliberate recreation. It’s about ways of life. For some people, that’s best accomplished by making things inevitably more difficult on themselves in everyday life.