In 2015, the Ministère des Transports du Québec entrusted me with carrying out a pre-feasibility study on a third road link east of Québec. Since then, the debate has evolved and the options have multiplied. This letter presents an analysis of the file from the angle of its feasibility, but also of its necessity.
Posted at 1:00 p.m.
As time does its work, it will eventually be necessary to consider major repairs to the two existing bridges. The creation of an additional road link should therefore not be ruled out, especially in a context where the prolonged closure of one of the existing structures would have disastrous economic and environmental repercussions.
High risks of budget overruns
Several options have been considered so far. The proposal currently under consideration is among the most risky. Tunnel projects indeed come with a high level of uncertainty mainly due to the nature of the soils, which are partly unknown. It is not uncommon for this type of project to see its schedule extended and generate significant cost overruns.
With a diameter of almost 20 m, the planned tunnel project is at the limit of what is technically feasible.
Very few construction companies in the world are currently able to carry out such work and none will venture into such a project without having the guarantee that the owner will absorb the budget overruns associated with unforeseen events.
Safety standards to be respected
Tunnels are structures where the safety of users must be ensured. In the event of a fire, users must have access to emergency exits leading to protected and ventilated corridors. Emergency services must also be able to quickly access the accident site. Such conditions will be difficult to implement for a tunnel with six traffic lanes on two levels. A double tunnel with regular interconnections would probably be preferable.
Constraints and impacts of the current project
The current route connects Autoroute 20 to the south with the Laurentienne Autoroute to the north. The slopes and curves of the route will ensure that heavy transport will travel at reduced speed while it will not be possible to transport hazardous materials. It is therefore difficult to conceive that such an infrastructure will improve the circulation of road users. It could be beneficial for the east of Lévis, but it is unlikely to be useful for the people of the national capital. In fact, they are the ones who will suffer the repercussions during the construction and the influx of traffic at the already very congested intersection of the Capital and Laurentian highways, without deriving any tangible benefits. The current proposal is a choice that should be questioned.
Split the project to reduce costs and better serve users
To better serve the population, one option to consider would be to split the project in two, by creating a public transit-type link between downtown Quebec and Lévis and by adding a third road link where it would be the most advantageous. Each of the links would thus meet different needs. The road link could take different forms, but a bridge would be the optimal choice from a cost and schedule perspective. Three sites are possible: near the existing bridges, west of Cap-Rouge and east of Lauzon.
It is highly likely that two separate projects, well integrated with the public transport and road transport networks, would ultimately cost the state less and could be completed more quickly than the project currently under consideration.
Rethinking the project collectively
My intervention is essentially limited to technical issues and challenges. Questions of economic development, environmental protection, town planning and others must be included in the debate. I leave it to the experts in these fields to shed light on these points.
There is certainly no simple choice, but the option currently considered deserves very seriously to be reconsidered, collectively. This is an exercise that must be undertaken calmly and without political partisanship, for the benefit of future generations.
* The author of this text is a full professor in the Department of Civil, Geological and Mining Engineering at Polytechnique Montréal. The comments reflect his personal and professional opinion only, and should in no way be interpreted as an official position of Polytechnique Montréal.