Projects

Heat-Protection Trams: Bordeaux is innovating for thermal comfort

To make life more comfortable during summer heat waves, the TBMouv! Lab at Keolis Bordeaux Métropole Mobilités has been testing a heat-protection system aboard trams in the Bordeaux network. The project aims to improve the thermal comfort of passengers and drivers by installing solar films on windows and applying reflective paint on air conditioner hoods.

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Posted

DEC. 1, 2025

Adapting transportation to the effects of global warming

Growing more intense every summer, heat waves can make the Bordeaux tram network uncomfortable. High temperatures not only impact passengers but also working conditions for drivers and the operation of air conditioning systems.

For this reason, the TBMouv! Lab, Keolis’s innovation lab in Bordeaux, has explored cooling solutions that are effective and easy to roll out. In 2024, a test was launched to improve thermal comfort on the Bordeaux tram network.

In 2024, eight tram cars were equipped with solar films on their windows and reflective paint on their hoods.

Solar films and reflective paint: solutions tested in real-life conditions

The test led by the TBMouv! Lab took part in two steps. In 2024, ten tram cars in Bordeaux underwent three months of testing. Eight were equipped with solar films on their windows and reflective paint on their hoods, while two control tram cars did not receive any modifications. Sensors installed throughout the inside of the vehicles recorded a drop in temperature between 0.83°C and 2.13°C in the tram cars equipped with the system, compared with the control tram cars.

tram cars in test phase 1 (2024)

tram cars in test phase 2 (2025)

⬇️ 0,83 to 2,13°C

A drop in temperature recorded between 0.83°C and 2.13°C (2024)

Sensors were installed at various points inside each vehicle to measure temperatures.

These promising initial results led to the second test phase, in 2025. This time, 12 tram cars took part: three control cars with no alterations, three equipped only with reflective paint, three with just solar films and three combining both solutions. Six sensors were installed at various points inside each vehicle to measure temperatures.

Although the results are still under analysis, teams have already observed that the combination of both solutions had a positive impact on temperatures aboard the most recent tram cars, especially at external temperatures above 30°C.

Margot Quantin

Innovation Project Manager with the TBMouv! Lab and innovation lead for the Heat-Protection Trams project

"Every TBMouv! Lab project starts with a concrete need or an everyday annoyance, to which we try to find the simplest and most cost-effective solution to put in place. For Heat-Protection Trams, we chose to test external protection solutions that are easy and fast to apply."

A collaborative approach that boosts efficiency

The benefits range from improving user comfort to demonstrating the efficiency of a collaborative method. Alongside the TBMouv! Lab, the project mobilized business teams from Keolis Bordeaux Métropole Mobilités – notably Anthony Audebert, Manager of Industrial Quality with the maintenance division – external partners (Solar Paint supplied the reflective paint and Sip World supplied the solar films) and Bordeaux Métropole. The iterative approach, based on feedback, made it possible to optimize solutions before planning their deployment. For example, Solar Paint tested the resistance of its reflective paint on bodywork parts supplied by Keolis.

The project has demonstrated the efficiency of a collaborative method.

Towards a rapid deployment of the solution

A full analysis of the results from this exploration phase is still ongoing, and all feedback will be presented at Bordeaux Métropole in early 2026.

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