As the new light-rail lines that run from downtown to the airport in Seattle and Vancouver mark their one-year anniversaries this summer, the differences between the two are as striking as the similarities.

Both were built after years of public wrangling, cost staggering amounts of money, and had to grapple with challenging construction. But one has four times as many riders as the other.

Both are seen as triumphs for rapid transit. But for one city, the new line is just a first step in a journey to creating a modern-day rapid-transit system. For the other, it’s an addition that pulls the whole system together.

As a result, both the Canada Line in Vancouver and the Central Link in Seattle are case studies, examined intently by planners, transit experts and regular citizens anxious about the future of urban life.

Cities from Shanghai to Paris are scrambling to create rapid-transit networks or expand what they have, as the health of metropolitan economies becomes dependent on efficient ways to move large numbers of people around. Even Los Angeles, long viewed as the city of freeways, now has 130 kilometres of rail lines and ambitious plans to build much more.

So as the sister cities on the West Coast celebrate the first birthday of their shiny new lines, it is also a celebration of a year-long experiment, revealing exactly what has worked, and where they missed the mark. For many transportation experts, Vancouver has emerged the winner.

“Both lines are really important. Both are part of what are going to be incredibly successful systems. But Vancouver is out in front,” says Jarrett Walker, an Australia-based international consultant in public-transit network design.

“It’s because their system is driverless. The reason I talk about Vancouver all over the world is that it’s a system you turn on in the morning and it can go all day without costing any more.”