Transport policy loves photogenic objects: interchanges, metro lines, bridges. But a city’s real behaviour changes not on opening day but years later — when a habit shifts. The tool to measure this is the modal split: the share of trips made on foot, by bike, by transit and by car.
What moved over fourteen years
Two stacked horizontal bars: how trips are distributed across modes in two snapshots.
The picture is typical of a city that invested steadily in transit and cycling. The car’s share fell noticeably — but it neither vanished nor collapsed. That is the key lesson: modal shifts are measured in percentage points per decade, not per year. Anyone promising to “get the city off cars” in a single term either never looked at the data, or looked and decided not to see it.
Congestion is a surface, not a number
Average traffic speed is a poor metric: it blends an empty night and a gridlocked evening into one meaningless value. It is far more useful to see congestion as a surface over two axes — hour of day and day of week.
Heatmap: the brighter the cell, the higher the congestion at that hour and day.
The map reads at a glance: two weekday peaks — morning and evening — a stretched midday activity at weekends, and near-empty overnight hours. It is from a surface like this, not from a single average, that a planner sees where a bottleneck appears on schedule and where time-targeted measures help: peak-hour bus lanes, flexible working hours, hour-dependent pricing.
The takeaway
A good transport report shows not a record (“the new line carried X passengers”) but a shift in habit — and it does so on a long series. If a deck contains only an average speed and not a single breakdown by time, you are looking at a press release, not analysis.
