Vote: Widening the A1 motorway would congest Geneva and Nyon

Is widening the A1 the miracle solution to improve traffic flow or a nightmare that will lead to congestion in cities? This question, inherent to the vote of November 24, is at the heart of an independent study commissioned by the ATE. Twenty-seven pages that we were able to consult and whose conclusion is clear.

“By inducing a significant volume of additional traffic, the extension of the A1 between Nyon and Le Vengeron will unbalance a coherent whole in Lake Geneva mobility,” writes the author of the study, Yves Delacrétaz, professor at the Haute École specialized in Yverdon. For him, the impact will be particularly negative for Geneva and around the junctions of Nyon and Coppet (VD).

To achieve this result, the study breaks down preconceived ideas on this route widely used by commuters. An overloaded highway? False, according to the author. “The maximum capacity of the A1 is 4,000 vehicles per hour per direction. However, this value is rarely reached, according to federal counts. Obviously, the closer we get to saturation, the more a one-off event – ​​accident or construction site – can cause traffic jams.”

No traffic reporting

However, he notes a black spot, the Vengeron’s bottleneck at the entrance to Geneva. “With 3,800 vehicles per hour in the morning and evening from Lausanne, traffic jams form there because of the configuration of the interchange, which forces vehicles to change lanes. This reduces capacity locally.” It also refutes the argument of a transfer of traffic from the motorway to cantonal roads. “It only happens in one-off events. The figures from the canton of Vaud show that road traffic on these sections is decreasing.

For Yves Delacretaz, widening the highway is therefore nonsense. “The figures, both for Vaud and Geneva, show that automobile flows have not increased for around ten years, despite strong demographic growth.” He thus challenges the forecasts of the Federal Roads Office, which would be based “on the perpetuation of old, not updated trends”.

Like a game of dominoes

If widening the A1 is not essential, its completion would have a damaging effect. Because such an infrastructure will “self-generate its own traffic” (the famous induced traffic) and because of a “reverse” modal shift, namely commuters who leave the train to take the car. “Going against the grain of climate objectives,” specifies the author.

Like a game of dominoes, this additional traffic would pose other problems, particularly in Geneva. “While the Canton wants to reduce traffic on its territory by 40% and widen its bypass highway to make it an efficient ring road and thus prevent vehicles from entering the city, this additional flow from the Canton of Vaud would ruin the efforts made. by saturating this axis again.” In contradiction with the vision of public authorities.

The draft caused by widening the A1 would finally have consequences for the municipalities located near the junctions of Coppet – where cross-border traffic from Divonne arrives – and Nyon, where the road begins (and ends). 3^e lane, because the access roads will have to be adapted to absorb this additional traffic. “To limit nuisance, it would undoubtedly be necessary to build new infrastructures which would in turn generate more traffic,” fears Yves Delacrétaz.

For the no camp, “this expertise confirms that this vote will not solve the traffic jam problems, on the contrary it will aggravate them”, reacts Brenda Tuosto (PS/VD). She recalls that “federal funds are not extensible, just like the territory. Competition between road and rail will be inevitable in the Lake Geneva region, thus hampering the development of rail in French-speaking Switzerland. At a time when budgetary and climate challenges are undermining our society, politicians must be able to prioritize investments over pragmatic and sustainable solutions.”

“It’s urgent”

On the other hand, this report does not shake the yes camp. “The problem with these studies is that they are based on projections,” reacts Mauro Poggia (MCG/GE). However, no one knows what modes of transport and mobility will be like tomorrow. Between teleworking, autonomous vehicles and the use of highways by public transport, a lot can change. Not to mention the possible reservation of a lane for carpooling during rush hours. On the other hand, there are facts, namely that the Lausanne-Geneva axis is overloaded. Knowing that rail will not be able to solve these fluidity problems before 2060, it is right to focus on widening the motorway where it is urgent.

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Florent Quiquerez has been a journalist in the Switzerland section since 2015. Specializing in politics, he primarily covers federal news. Previously, he worked as a parliamentary correspondent for Radios Régionales Romandes.More info

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