How to Design a Better Bus Transit Map

Evan Landman writes a post explain the importance of quality mapping to illustrate the frequent service routes in a bus system. To do so, Landman focuses on the city of Portland:

"Portland's agency TriMet has traditionally been a best practice example here, given their extensive Frequent Network branding down to the individual stop level, but curiously, their system map has not embraced this idea so wholeheartedly. Today, TriMet's new system map [pdf] changes that, introducing a cleaner, more readable map, which does a much better job of highlighting the agency's premier bus services." 

The post goes on to describe how the design details have changed between the old map and the new. To summarize the key success of the new map: "This is a map that truly focuses on communicating the usefulness of the transit routes. The most important factor for usefulness is frequency, which is obscured when every line on the map is the same color, or a different color, or colored by a less important attribute, like which corner of the city it serves. "