The majority of streets in American cities are massive. Single lane streets are generally slower traffic so separated cycle lanes aren't necessary...just some markings to remind drivers that cyclists might use this part of the road. Paris has a lot of those.
The bike lanes in the east coast cities I've been to aren't safe for cyclists and do nothing but take up breathing room for drivers. It's not uncommon to see a bike lane disappear after 50 feet because there was no space to continue it.
