Ten rules for a better bus map.

A bus map is a small public promise. It says where service goes, how often it comes, and how a person can get from one line to another. The map should not require a planner standing beside it to explain what the symbols mean. Here are ten rules I return to whenever a network needs to be drawn clearly.

• Show frequency with line weight. A thicker line can make frequent service visible at a glance, as long as the legend explains the distinction and the underlying service actually supports it.
• Straighten geography only as much as helps. Simplification makes a map legible, but bends and landmarks still matter when they help someone recognize where the bus goes.
• Label where routes go, not just their numbers. Major destinations and neighborhoods tell a rider more than a route number alone; use names people know and can find on the street.
• Show the frequent network first. Make the routes that come often easy to find, while keeping the full network available for trips that need less frequent service.
• Mark accessible stations and stops accurately. Use a clear symbol and explain whether accessibility applies to the whole station and the path a rider needs.
• Make transfer points unmistakable. Show where lines meet, how to move between them, and whether the connection requires crossing a street or changing levels.
• Design for print and phone. Text must remain readable on a small screen and the whole map must still work when printed or viewed without color.
• Include the walk. A route is only useful if people can reach the stop; show key pedestrian links and do not make a short transfer look like a teleportation device.
• Test with real riders. Ask people who do not already know the network to plan a trip, then watch where they hesitate and revise the map accordingly.
• Keep it updated. Put a date on the map, assign responsibility for revisions, and remove obsolete versions from the places riders are likely to find them.

A map cannot make an infrequent bus frequent or a difficult transfer comfortable. It can make the network’s promises honest and understandable. If a rider can find their route, recognize the places it serves, and see how often it runs, the map has done its first job.

There is a useful test: give the map to someone unfamiliar with the system and ask them to find a trip they might actually take. Do not explain the colors or point to the transfer. Notice where they pause, which names they search for, and whether the map helps them understand when service runs. Then make the map answer those questions. A beautiful map that leaves a rider uncertain is still unfinished.

And remember that maps age. A route changes, a station closes, a new frequent corridor appears. If the agency updates the website but leaves old printed maps at stops, riders can receive two different answers. Put a revision date where people can find it and make updating the map part of the service change itself.

— Ines