The most common objections — and our straight answers.

In reality, a tunnel boring machine digs through practically any ground. Some terrain makes progress slower and more costly, but it doesn't stop it. And the geology of the Québec City region is nothing extreme: we are in rather soft rock of the St. Lawrence Lowlands, not the Canadian Shield — except for the northern part of the city.

This type of sedimentary rock resembles formations (like the limestone of the Nashville region) where digging goes well, and where The Boring Company's Prufrock machines have shown they progress without major difficulty. As a precaution, we nonetheless apply a markup factor for our type of ground — already built into our calculations. See the Geology page.

Absolutely — and that’s exactly what the project plans for. Nobody claims you can bore 150 km without investigating the subsurface: a drilling campaign and a geotechnical study are essential, and they are already in the budget. They appear in the “BAPE, geotechnics, permits, consultations” line of the realistic scenario, on the Construction costs page. So it is not a forgotten item that would “blow up” the bill: it is planned and provisioned.

More importantly, a proper investigation isn’t done all at once — it proceeds in stages, as on any major tunnel:

1. Reconnaissance and corridor selection. A first set of boreholes (rock abrasivity and strength tests) surveys the ground and rules out difficult zones before the route is fixed. This is an advantage unique to a network: unlike a tunnel under a river, which must cross one specific point, our route can be adjusted if a borehole reveals a bad zone.

2. Design campaign. Once the corridor is chosen, a denser investigation (closely spaced boreholes and geophysics between them) refines each segment for construction.

3. Continuous probe drilling, ahead of the boring machine, during excavation — so there are never any surprises.

Set against the project’s ~12.6 G$, this investigation remains a small item: it is never what decides financial feasibility. The geological detail is on the Geology page.

No — and that’s precisely a question of depth. All these networks live in the first few metres below the surface, whereas the tunnel passes well beneath them, at about 10 m. We don’t dig into them: we pass underneath.

The figures confirm it. In Québec City, the municipal bylaw (R.V.Q. 25) requires a water service to be buried at least 1.5 m deep to protect it from frost, and at least 2 m when it shares its trench with a sewer. Electrical and telecom cables sit higher still, around 0.6 to 1 m.

The most telling benchmark is the provincial standard BNQ 1809-300, which governs the installation of the drinking-water and sewer mains of every municipality in Québec: it applies to works whose invert is at most 7 metres deep. In other words, the entire municipal network — sewers, water, telecom, electricity — fits within the first 7 metres. Our tunnel, at ~10 m, runs beneath that whole layer, with several metres of rock as a margin above it.

The only places where we actually cross that congested layer are the launch shafts and the station entrances — discrete points, known in advance, where we pull the utility plans (via Info-Excavation) and adjust the route as needed. It isn’t a diffuse problem spread over 150 km, but a few dozen localized, planned points. The subsurface detail is on the Geology page.

That's fair — and we took it into account. We did not adopt their most optimistic scenario: we even modelled a scenario with no improvement at all in cost or productivity.

And even in that unfavourable case, our project remains cheaper than all the other modes considered. The detail is on the Construction costs page.

Above all, there is now a real project to validate these figures. Since February 2026, a Boring Company tunnel boring machine has been digging under Nashville, in soft rock of the same geological age as Québec's, at a price per mile that already comes in below our projections. In other words, the only comparable project that exists today confirms our approach — and our estimate still remains more prudent than that real-world price. We break down the comparison in our blog article “Nashville puts a price on rock tunnelling” (in French).

No — and we have quantified it. The Boring Company is our reference assumption because it offers the best cost per kilometre, but the project does not rely on it. Tunnel boring is not a proprietary technology: conventional hard-rock machines — gripper, single- or double-shield — have been used around the world for decades. It is an older and more proven technology than The Boring Company’s, not less.

So we modelled the full scenario in which a level of government rules out The Boring Company, for whatever reason. The result: the cost rises from ~12.6 G$ to a range of 16.5 to 22.4 G$. That is more expensive in capital — but even at its worst, the project stays cheaper per user than a car, and than the RTC, and in a class of its own against the region’s other megaprojects.

One last point in our favour: a competitive tender among several bidders, rather than a single supplier, fits Québec’s public procurement rules better. The full scenario, quantified and compared, is on the Without The Boring Company page.

False. With electric-assist bikes and a route with no stops at all, riding becomes child's play — even for someone who isn't fit. And anyone who, on the contrary, wants to get back in shape can still choose a classic bike.

Better still: teenagers without a driver's licence will be able to get to school safely, without a parent having to drive them.

Teenagers, for their part, gain autonomy thanks to the network. For younger children, a parent can use an electric-assist bike fitted with a child trailer at the back.

We own it: this isn't suited to every family. But the goal was never to bring 100% of the population into the network — only about 10%.