Originally Posted by
FBinNY
Cities grow and develop haphazardly, based on happenstance. A popular, successful business might attract more causing a quiet area to become not so quiet. Streets can become busier and one city may want to widen them, or modify intersections, while another has other budget priorities.
Cities often grow around arterials, so if the paths are maintained along the arterials, it will help a lot, but certainly the merging of two previously independent urban centers can be haphazard.
Waterways are often unique areas. Somehow Eugene was able to acquire/annex a huge amount of parkland along the Willamette river, which has grown into a good bike path network along the river. And, since the river divided Eugene and Springfield, and various outlying communities, the riverfront network has been a bonus for cyclists going between the cities.