Lloyd, Rodgers and Roberts M – METRO MAP COLOUR-CODING 2018

Description

This study tested how three colour-coding schemes—route, trunk and shaded—affect usability for route tracing on a diagrammatic New York City subway map. Using modified Weekender maps, 285 US Mechanical Turk participants completed 17 origin–destination tasks designed to expose common navigational hazards (route slippage types, branch jumps, and a phantom transfer). Overall, route colouring produced significantly higher accuracy (71.9%) than trunk (66.8%) or shaded (65.7%) colouring; time differences were not significant. Subset analyses showed that route colouring strongly improved accuracy for slippage hazards (flipping, joining, and combined flip/underpass), while trunk colouring outperformed route colouring for one branch-jump type (Jump R). Some hazards (parallel running, underpassing) showed no colour effect. Route colouring sometimes improved speed but only in limited cases. The authors conclude that optimal colour schemes depend on the prevalence of specific local hazards and task type (route tracing versus journey planning), and recommend design fixes (avoid flips, clarify joins, avoid splitting routes, align transfer symbols) and consideration of hazards in automated map design.