I have a few ideas on transportation:
Roads/streets that are places right next to a building a sidewalk appears. These sidewalks should have a capacity, like roads/streets. When too many people use them it's time to make them broader - they need more space.
Another thing is rooms for bikes along the road. This is also like the broader sidewalks somethat that you must add yourself - again they need more space.
If you have a good system of bikepaths it'll promote the use of bikes meaning less cars on the road.
In Copenhagen (And probably also other large cities) you can grab a bike for free at some special stations around town where you have to return them again - this could further boost the use of bikes.
Sidewalks with a lot of traffic on them will attract shops. If you zone for shops in an area with hardly any pedestrians these lots won't be as attractive as the ones with more traffic on them.