Observation of a handful of transit platform sign styles from around the world on their clarity and usefulness.
Eric Jaffe compares transit platform signs and their usefulness and limitations as viewed by "novice riders." Jaffe points out that "..urban way finding in general is a bit more art than science--and evidently there's no universal practice, either." Most of his observations show that "each [transit system] adopts its own particular platform style." However, this particular approach leaves room for confusion. As Jaffe notes, the use of "Uptown" and "Downtown" in New York City subway signs or "Inbound" or "Outbound" in Boston's transit system signs require certain knowledge of the local geography.
Jaffe praises a more simplified signage system such as the Tokyo Metro, which "pairs a letter representing the line with a number representing a station. That makes finding a destination a simple matter of counting...[This sign style] effectively eliminate[s] memorization from the entire process."