Every summer in Paris, the city closes an almost two-mile stretch of road along the Right Bank of the Seine and turns it into a beach, complete with sand, beach huts, deckchairs, and parasols. This year, Paris decided not to re-open the road at all, turning the riverside into a permanently pedestrianized area.

The first traffic figures for the “non-re-opening” are in, with detailed numbers for the amount of cars displaced onto nearby roads. And while the traffic on these roads has jumped quite alarmingly during the morning rush-hour, the figures are way lower than Paris’ mayor Anne Hidalgo expected. Better still, evening rush-hour traffic has seen little to no effect. It’s as if those cars just disappeared. In fact, many of them have.

On this stretch of the river there are two roads running parallel, one high and one low. With the closure of the low road, big increases in traffic on the upper road were expected, as well as spillover onto the nearby Boulevard Saint Germain. And this did happen. The upper road saw a morning increase in traffic of 73%, and 13% in the evening. On the Boulevard Saint Germain, traffic increased 41% in the morning and just 4% in the evening.

[Photo: Flickr user Monscter

That doesn’t look good, but even these numbers were far less than predicted by traffic studies. What’s more, those studies estimated the situation after six months, not three weeks.

If we look at the numbers another way, you’ll see that overall traffic has actually been reduced. Before the closure (measured in September 2015), 2,600 vehicles per hour passed on the low road. But after the closure, only 1,301 extra cars are being seen on the Boulevard Saint Germain and the high river road combined. That is, half of the cars that used to use the now-closed road have disappeared.

Some of these cars will have found alternate routes on other roads, but many of those passengers and drivers will now be using alternative forms of transport to get to and from work.

Paris seems to be the European capital most serious about cleaning up its air and getting rid of urban congestion. It has had car-free days, redesigned major intersections to make them more pedestrian-friendly, and even changed the laws to allow bikes to run red lights. But this closure of a major traffic artery could have its biggest impact outside of Paris. Conventional wisdom says that closing roads will choke surrounding roads, but that turns out not to be true, especially when you have plenty of alternative transport systems already in place.