Ciclovía keeps cars off the streets in the Colombian capital and brings rich and poor together - if only for a day

It's a bright Bogotá morning and I'm sprinting, standing up out of the saddle pushing hard on the pedals to cross La Septima (7th Ave) and 19th street, normally one of the most nightmarish junctions in this traffic-swamped, car-crazy town. But I'm doing it for a laugh, not to escape quickly, as today's a Ciclovía.

Ciclovía is a weekly, city-wide, car-free day in Bogotá that puts 76 miles of roads, including La Septima – the city's main commercial centre – off-limits to cars. It's been running since 1974, and offers a brilliantly bonkers insight into this wild Andean capital.

More than 2 million people come out every week to cycle, hang out, flirt, pose and eat on the street. It's transport policy in a Critical Mass dreamworld, and the weekly event makes Boris Johnson's once-a-year cycling ambitions for London look like the lily-livered, business-loving, small-thinking, can't-do claptrap they truly are.

Three out of four lanes in La Septima (7th Ave) are closed and today are filled with elderly strollers in superfly shades carrying massive radios listening to tango, children scrambling round on toy bikes, punks on skates, stern-faced Lycra warriors on $5,000 Treks, moody goth skateboarders and, fabulously, one man and his pitbull in matching leather harnesses, panting in unison.

And all along the sidewalk, you can buy mangoes, coconut juice, salpicon (a delicious fruit slurry) as the guys selling mystery-meats-on-a-stick fan their embers with their baseball caps. In public parks there are free yoga and aerobics classes, known as the Recrovia. Today in the National Park, there was what looked suspicously like a vast and riotously good-humoured three-legged race.

Ciclovía's impact has spread far and wide, with similar events all over Latin America, but here it's had an unintended but very welcome consequence: social integration.

"Ciclovía is one of the few places where Colombians of different classes mix," says Mike Ceaser, who owns a bike rental business, Bogota Bike Tours. "You've got a lot of poor people and very few rich, here. Rich and poor only meet as workers and employees in Colombia - janitor and bank manager, maid and home-owner. But the Ciclovía is democratic. Here, everyone's on a bicycle, mixing, meeting on an equal level," says Ceaser, a former journalist who set up his bike shop here last year when the US newspaper industry started cutbacks.

In Latin American cities, class and wealth define everything, with galaxy-sized gaps between the dirt poor and the astronomically wealthy, and here it's no different. Bogota's income division is north-south. The rich live in the north, and the poor in the south, but people switch territories during Ciclovia. Cycling in Bogotá does not carry the eco/health/lifestyle cachet it does in the UK – if anything, it's seen as a poor man's way to save money on bus fares. Wealthy Colombians won't commute to work as they think it makes them look poor. But everyone loves the Ciclovía.

Any cyclist wanting a good look round Bogotá should stop by Ceaser's shop in the old colonial heart of Bogotá, La Candelaria, where he has around 40 bikes and helmets for hire and expert tour guides on call. It's a fantastic way to see the city - safe, easy and affordable. Today, I covered 10 times the ground on two wheels as I would have done by foot, or taxi, or bus. As I pedal, smiling Colombians laugh at the tall gringo in the biggest, yellowest helmet they've ever seen, panting and purple-faced as the altitude takes its toll: Bogotá is the world's third-highest capital city, at 2,640m above sea level.

Don't worry if you hit a spot of bother on your bike, though. The route is attended by hundreds of paid guardians carrying medical kits and bike tools. (When the call first went out for the guardians, just 20 CVs were received. When the city authorities rebranded the job as Bikewatch guards, after Baywatch, asking for athletic and active people to apply, they got 1,500 CVs, says former city official Enrique Peñalosa in this great film).

Be aware though - bike theft is rife, and bike parking spots are few and far between - and even when they look official, you may not be able to lock and leave, as Ceaser recalls on his blog.

The city also has a vast network of bike lanes - though they are in a pretty poor state and are often used by sidewalk vendors to sell anything from scavenged mobile phone parts to barbecued corn on the cob. And the Ciclovía's main route is under threat: the mass transit bus service, Transmilenio, may expand into some of the roads where the cyclists currently reign.

But it seems to have luck, albeit of a grim variety, on its side. A few years back a Bogotá senator, Fernando Castro, tried to move the hours of Ciclovía to run it from 5am to 12 noon, cutting back the most popular hours with the public. During the senate hearing arguing for the move, in a scene straight out of a magic realist novel, the car-loving, chain-smoking senator keeled over at the dispatch box and died later that day.

If a city as busy and poor as Bogotá can close its roads every Sunday of the year, and every one of the dozens of holidays enjoyed here, why can't London, or Manchester, or Liverpool, or Glasgow or Cardiff or Newcastle? Is it so radical a concept to promote healthy, non-polluting, silent forms of transport that bring people together, rather than locking them behind airbags and safety glass, for just half a day a week? Must we measure everything so drearily in pounds lost to business?

I guess revolutions are best left to the Latin Americans.