Heatwaves: Public Transport Facing Extreme Heat

Whilst its main highlights included the football World Cup, several blockbuster movies and a solar eclipse visible across parts of Europe, the summer of 2026 will best be remembered as a summer of extreme heat. According to the European weather service Copernicus, August 2026 was the hottest month ever recorded worldwide, tied with August 2023. The particularity about the European heatwaves of 2026 was their early onset: back in May, France, Belgium, the Netherlands, the United Kingdom and Germany recorded temperatures more than 11°C above seasonal averages. These heatwaves were therefore significant both for their geographical extent and their duration. In France, the average temperature for the entire summer (June, July and August) was 24°C, far surpassing the previous record of 23.1°C set in the summer of 2003. And July was quite simply the hottest month since records began at Météo-France in 1900. Initial reports from Santé publique France confirm that ‘excess mortality’ has been observed, but it will take several months to quantify its extent. If, as many scientists have predicted this summer, these exceptional temperatures are set to become the norm, can public transport help us cope better with such heatwaves?

“Public transport is one of the best ways to combat global warming,” says David O’Neill, Marketing and Foresight Director at the Keolis Group, “but that doesn’t mean we should ignore the issue of adaptation – quite the contrary!" This is what prompted Keolis to carry out its first study on how heatwaves affect travel choices, surveying 1,025 French people in July earlier this year. The first lesson to be learnt is that there is still a world of difference between the best long-term solution and the best ways to adapt in the short term: 77 per cent of those surveyed have air conditioning in their car, compared with 36 per cent in their homes and 38 per cent in their workplaces. This is ironic, given that private cars are the mode of everyday transport that contributes most to global warming, but it is a reality to be reckoned with. In fact, several indicators show that cars were indeed the mode of transport that ‘benefited’ most from the heatwave in France in the summer of 2026: 27 per cent of those surveyed swapped journeys on public transport for car journeys; 20 per cent of car drivers used their vehicles more often; and only 3 per cent gave up this mode of transport altogether. Was it to enjoy the air-conditioning, or to have a flexible way of escaping the heat? Individual reasons will differ, but the picture painted here is in fact not quite so bleak…

Indeed, the first effect of the heatwave observed in the survey was not so much a resurgence of interest in private cars as a decline in travel: David O’Neill reports a drop of up to 25 per cent in ticket validations on networks operated by Keolis in France on days of extreme heat. Returning to the study, whilst a mere 28 per cent of respondents said they had not changed their travel plans, 43 per cent had cancelled journeys and 40 per cent had rescheduled them to avoid the hottest parts of the day. What is interesting about this same study is to consider the types of journeys that respondents cancelled due to the heat: 78 per cent cancelled those related to leisure, sport and social outings; 73 per cent gave up trips for errands or shopping; 65 per cent gave up visits to family or friends; compared with 25 per cent who gave up medical appointments and 25 per cent who gave up journeys to work or place of study. The mental health risks that this lack of mobility may pose are easy to understand, given that so many people are giving up activities that directly contribute to their social integration within their community in particular or society in general, or activities that allow them to unwind and take their minds off things. Whilst a sedentary lifestyle and isolation are seen by many as the ills of our time, care should be taken to ensure that the heatwave does not become the bridge too far.

Whilst the hellish summer of 2026 should serve as a lesson to European countries – whether or not they were severely affected – in preparing for future heatwaves, the Keolis study sheds light on another crucial point: the tipping point, that is, the temperature at which people change their travel habits. It is entirely conceivable that this threshold will shift as the climate warms, as episodes such as this summer’s become more frequent or last longer. According to the 1,025 French people surveyed, 70 per cent of them adjust their travel choices when the temperature reaches 35°C, compared with 20 per cent who do not take the temperature into account at all when travelling. The questionnaire responses reveal several categories of French people based on their heat tolerance, ranging from the 9 per cent who give up before the temperature even reaches 30°C to the 15 per cent who only call it a day at 39°C and above. The study merely confirms what had been demonstrated by emergency patient inflows: namely that we are not all equal when it comes to heatwaves, particularly depending on age, state of health or housing conditions.

The upshot is thus clear: heatwaves may prompt people to start using their cars or return to using them, but above all they lead people to travel less, and risk creating or exacerbating inequalities in mobility. For public transport to be part of the solution to heatwaves and global warming – beyond its undeniable impact on reducing emissions – it must offer tangible solutions to the problems faced by the public when temperatures soar. Starting with air-conditioning on bus, tram, underground and train services, which would remove one of the private car’s main comparative advantages in this context, whilst also saving money: after all, a private car inevitably means an individual air-conditioning unit, along with higher fuel consumption - an argument likely to carry significant weight for a long time to come, given the almost nonstop rise in fuel prices!

But to tackle the challenges posed by the heat, public transport will also need to innovate, rather than simply providing a cooler service. The study shows that, amongst those who usually walk, 13 per cent had to give up this mode of travel during the heatwave, and 34 per walked less often than usual. Could on-demand transport solutions, such as the one introduced by the Sibra network in the Greater Annecy area, provide a viable alternative, taking users to an (air-conditioned) bus, tram or metro network? Even simpler: in July 2026, a young French engineer launched the Fraichoù app, which calculates the coolest and most shaded routes possible for pedestrians and cyclists. When will these features be rolled out in Mobility as a Service apps, enabling advocates of sustainable transport to get out and about rather than staying at home? If we are to adapt so that people can get about with confidence while (at last) putting the brakes on the infernal cycle of global warming, transport operators will have to be more creative than ever – and must be able to rely on investment commensurate with the challenges at stake, at a time when, particularly in Europe, budgetary austerity is the order of the day.

In France, the summer of 2026 was also marked by severe forest fires: the CNPF (National Centre for Forest Ownership) reports that fires were detected in the majority of French departments, with the risk of fire leaving no forest area in mainland France unscathed. A total of 42,000 hectares of forest went up in flames around Saumos, in Gironde; approximately 6,000 hectares in the Var; 5,000 in the Pyrénées-Orientales; 4,000 in the Drôme; and up to 2,000 hectares in the Forest of Fontainebleau on the outskirts of Paris. In the case of mega-fires such as the one that paralysed and traumatised the Gironde, traffic congestion becomes an additional risk factor, as residents or tourists attempting to flee in their cars risk becoming trapped in traffic jams – or in the flames. As David O’Neill put it: “Public transport is a public good, whereas private cars, by their very nature, can sometimes run counter to the public interest.” As if to corroborate this claim, teams from Keolis Santé, Keolis Gironde and Keolis Bordeaux Métropole Mobilités played an active role over the summer in evacuation operations and in assisting several thousand displaced people, among them the most vulnerable. Having dealt with the emergencies, it is now time to prepare for the future, so that the summer of 2026 remains a bad memory rather than becoming a bad omen.