The subway that runs on roads

In the 1970s, Curitiba, a fast-growing city in the south of Brazil, had a problem that many Vietnamese cities know well: too much traffic and not enough space. Building a subway would have taken years and cost an arm and a leg. So the city's young mayor, an architect called Jaime Lerner, decided to think outside the box.

Rather than digging tunnels, Curitiba gave buses their own lanes in the middle of the main roads. Cars could not use these lanes, so the buses rarely got stuck in traffic. In other words, the city built a kind of subway, but above the ground. Later, it added tube-shaped glass stations where passengers paid before the bus arrived. Thanks to this, people could get on and off quickly, and buses spent much less time at each stop.

The new system changed daily life. Workers who lived far from the centre could now get to work much faster. On top of that, the city allowed tall buildings, shops and offices along the bus routes, so more people lived and worked close to a station. Over time, many residents began to take the bus instead of driving.

However, the story is not perfect. As Curitiba kept growing, the buses became more and more crowded, and many passengers complained about long waits at busy times. Today, the city still has plenty of traffic jams. Despite this, the idea took off around the world, and cities from Bogota to Jakarta have built their own versions.

Curitiba shows that a city does not always need the most expensive solution. Sometimes a simple idea, planned carefully, can make a big difference. For cities like Hanoi and Ho Chi Minh City, where millions of motorbikes fill the streets every day, that lesson is worth remembering.