Not doing necessary bridge maintenance work costs nearly 9 times more than doing it, study finds

Road bridges in figures

• Between 200.000 and 250.000 road bridges in France
  • 12.000 belong to the non-concessionary state network
  • 12.000 belong to the concessioned state network
  • 100 to 120.000 bridges belong to the departments
  • 80 to 100.000 bridges belong to the communal block.
• 40.000 bridges are in very poor condition in France.
• 1 bridge every 30 km shows significant structural deterioration...

On average, not doing necessary bridge maintenance work costs almost 9 times more than doing it.

The Project

At a time when public money is scarce and local authorities tend to postpone work, STRRES – the civil engineering repairers' union – wanted to quantify the impact of postponing work on these everyday infrastructures that are bridges.

To do this, he commissioned the independent research firm Citizing, which studied 10 bridges of different sizes, techniques and geographies, which had recently undergone work. He quantified how much it would have cost if the work had not been carried out, both financially, but also socially, and from an environmental point of view. In other words, he calculated the collective cost of inaction.

Methodology implemented: socio-economic analysis of infrastructure projects

This is a recognized, standardized and mandatory method for State investments of more than €20 million.

It consists of balancing the positive and negative impacts of projects, in all their dimensions (economic, social and environmental). These impacts can concern all stakeholders (users, local residents, public authorities, etc.) and occur in the short and long term.

This method has 2 specificities:

• The situation of carrying out the work is compared to a situation of inaction (no work is undertaken)
• The impacts are translated into euros, according to the State's recommendations. For example, 1 hour lost for a detour is equivalent to a loss of €25 // 1 tonne of carbon = €170.

By making it possible to verify that the positive impacts outweigh the negative impacts, this method serves two objectives: ensuring that public money is mobilized for projects that create collective value and strengthening the acceptability of the work among citizens.

What STTRES discovered

On average, not doing necessary bridge maintenance work costs almost 9 times more than doing it.

Indeed, a bridge that is not monitored deteriorates invisibly. If it is allowed to deteriorate, the problems grow exponentially, as do the repair costs and the socio-economic and environmental costs.

This result is the result of a study carried out on 10 works. The value according to which not acting or acting late costs 9 times more than acting is an average that imperfectly reflects the unique situations of each work. However, if the figures can be significantly different from one project to another, it should be noted that the Return on Investment is positive in 100% of cases.

2 types of effects of inaction are cumulative:

• For the community budget. It is more economical to do the work quickly rather than wait: the more we let the situation deteriorate, the more important the work will be, and the more it will weigh on the community budget. On average, we must count on an investment multiplied by 3 if we postpone the bridge work for a decade. This additional cost is not linked to inflation, but to the additional work that will have to be undertaken due to the increased deterioration of the structure.
• The impacts on citizens and businesses. Not doing the work means assuming that there will be complete, lengthy and sometimes permanent closures of the bridges in order to ensure the safety of users. However, a bridge closure creates detours, which in turn generate:
  • Waste of time
  • With these, vehicle usage costs, which represent losses of purchasing power for motorists
  • Probability of additional road accidents
  • CO2 and air pollutant emissions
  • Operating losses for traders in the affected areas

A conversion into euros (monetization) was carried out for all of these impacts, based on the State's benchmarks, on the traffic data for each bridge and on the estimate of the distances to be covered in the event of the bridge being closed and a detour being required. On average, the extra-budgetary impact is almost 6 times higher than the cost of the necessary maintenance work. In other words, citizens and the planet are the big losers from the postponements of work.

Thus, postponing the work is on average 3 times more expensive in budgetary terms and 6 times more expensive in socio-environmental terms. Overall, over 10 years, it is therefore 9 times more expensive not to do the work rather than to carry it out, despite the amount of work that may at first sight put off some short-term public decision-makers.

Especially since the proposed figures are conservative. Indeed, certain dramatic effects linked to the closure of bridges in landlocked territories have not been quantified, such as isolation, loss of links and economic losses.

For Lionel Llobet, president of STRRES – Repairers of civil engineering works: "TIME IS MONEY" The study shows that postponing maintenance work means spending a lot more! At a time when budgets are increasingly tight and optimizing public funds is more than necessary, it is proven that postponing maintenance work on civil engineering structures means wasting public money unnecessarily and increasing the carbon impact. It also means imposing unfair costs on citizens that reduce their purchasing power today and will increase their children's taxes tomorrow. What are we going to leave our children??? Debts and a planet in pitiful condition. There is still time to react. Quickly."

For Julie de Brux, founder of Citizing: "At Citizing, our specialty is the method, not the objects to which we apply it. So, we never know before we start what results we are going to come across. As we progressed in studying these bridges and modeling the impacts of inaction, we were impressed by what we found. Who would think that a small bridge with a traffic of less than 500 vehicles per day could generate, in the event of closure, up to several million kilometers of detours per year of closure? Furthermore, throughout this work, we have endeavored to question professionals in civil engineering structures and to derive prudent hypotheses for modeling the economic, social and environmental impacts. The figures presented here are really minimum estimates."

The 10 cases studied

The socio-economic assessment method was adopted for 10 recently rehabilitated works, selected for their variety in terms of:

• Geography, with most regions represented, including rural, urban and semi-urban areas
• Work size
• Typology of project owner, with works owned by municipalities, departments and the State
• Types of structure (masonry, concrete, metal)

Thus, we find both the Pont du Bonheur in the Gard, for which the renovation cost was around €200, and which records a daily traffic of just over a hundred vehicles per day; and on the other hand, the Groléjac bridge which spans the Dordogne, which required more than €10 million of investment and records a traffic of around 4500 vehicles and 250 heavy goods vehicles per day.

In all the case studies, the highlighting of the additional distances to be covered in the event of closure (of a more or less long duration depending on the scale of the work required) is striking: + 5 km to bypass the Tilleul bridge, + 12 km for the Doubs bridge, + 13,5 km for the Andelys bridge, + 20 km for the Port qui Tremble bridge, + 25 km for the Groléjac bridge, etc.

Multiplied by the attendance data, these additional distances per journey result in additional distances per year of closure that are counted in hundreds of thousands of kilometers, or even millions of kilometers. The aptly named Pont du Bonheur, with its daily attendance of around 110 vehicles per day and its necessary detours of 3 km in the event of closure (which would have lasted 3 years if the work had been postponed, while simple alternating traffic was sufficient during the 2023 work), generates nearly 120.000 km of detours per year of closure.

The societal cost of these detours is therefore colossal.

Illustrative image of the article via Depositphotos.com.