In 2015, the Quebec Ministry of Transport entrusted me with carrying out a pre-feasibility study on a third road link east of Quebec. Since then, the debate has evolved and the options have multiplied. This letter presents an analysis of the dossier from the point of view of its feasibility, but also of its necessity.
As time is working, 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 one of the most risky. The tunnel projects indeed come with a high level of uncertainty mainly due to the nature of the soils, in part unknown. It is not uncommon for this type of project to see its schedule extended and generate significant cost overruns.
With a diameter of nearly 20 m, the proposed 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 a work and none will venture into such a project without having the guarantee that the owner will absorb the budget overruns associated with the unforeseen.
Safety standards to be respected
Tunnels are structures where user safety 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 set up for a six-lane two-level tunnel. A double tunnel with regular interconnections would probably be preferable.
Constraints and impacts of the current project
The current route links Highway 20 in the south to the Laurentian Highway in 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 thus 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 that it will be useful for the people of the national capital. In fact, they are the ones who will suffer the repercussions during construction and the influx of traffic at the already very congested crossroads 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 transport type link between the city centers of 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 timing perspective. Three sites are possible: near the current bridges, west of Cap-Rouge and east of Lauzon.
It is very likely that two separate projects, well integrated into the public transport and road transport networks, would ultimately cost the State less and could be carried out more quickly than the project currently under consideration.
Rethink 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 being considered deserves 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 Montreal. The comments reflect his personal and professional opinion only, and should in no way be interpreted as an official position taken by Polytechnique Montréal.