Climate change is making heatwaves more frequent and severe. In June, at least 1,300 people died because of heat during the annual Hajj pilgrimage in Saudi Arabia, marking a higher toll than in previous years. People living in the tropics experience the worst effects of heat. But by 2100, three-quarters of the world’s population could be exposed to climatic conditions that exceed a lethal threshold of temperature and humidity, compared with just under one-third in 2000¹.

Transport systems, too, are adversely affected. Extreme heat buckles rails, melts wires and road surfaces and bursts tyres. This year, traffic in India has been disrupted by melting road surfaces. And last summer, bus passengers in Houston, Texas, had to wait in bus shelters hot enough to make people ill. During the 2022 heatwave in the United Kingdom, scores of flights were disrupted by melting runways and trains were delayed by warped rails.

Such problems will grow as the world warms. For example, by 2050, Spain could face up to 500 cases of rail buckling each year, compared with 20 expected in 2025². By 2100, pavements in New Hampshire might need to be replaced every 4 years, compared with every 16 years today³. Also by the end of the century, annual costs of road and rail operation and maintenance in the European Union and United Kingdom are projected to increase by €0.9 billion (US$1 billion) compared with 2016 if there is 1.5 °C of global warming above pre-industrial levels, and by €4.8 billion for 4 °C of warming⁴.

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The effects will be felt unevenly, with disadvantaged communities hit the hardest. For example, in Oregon, between 2012 and 2017, the number of people taking the bus on very hot days (30 °C or more) dropped by 1.6% in lower-income neighbourhoods, by 1% in middle-income ones, and hardly at all in high-income areas⁵. Governments, bus and rail operators and cities should urgently prepare transport systems for a warmer future. But efforts so far have been inadequate. Just over 160 countries mention ‘transport’ in their policies for adapting to extreme heat. Yet, few have progressed from planning to implementation, owing to lack of funding, prioritization, coordination, technical expertise and capacity, as well as uncertainty over what the future holds.

A comprehensive, strategic approach is needed. Existing frameworks for coping with extreme heat either focus only on disaster response or single out physical transport infrastructure without considering the people who use it. A wider range of climate-change hazards, vulnerabilities, risks and infrastructure conditions needs to be factored in.

Here we propose a road map to strengthen transport systems’ heat resilience. In the short and medium term, transport operators should assess climate risks and the feasibility of various solutions and implement some ‘low regret’ options to improve resilience to extreme weather. In the longer term, strategies need to be designed to improve the resilience of transport steadily as conditions change. This road map reflects deliberations of an expert panel on transport infrastructure and extreme heat, convened with funding from the Global Facility for Disaster Reduction and Recovery.

Set up a governance framework

The first step is to establish what immediate risks extreme heat poses to local, regional and national transport networks and users. Municipalities and other areas should set up a transport task force of researchers, agencies, citizens, policymakers and governments. The task force should consider climate projections and impact assessments from the Intergovernmental Panel on Climate Change and the annual United Nations Framework Convention on Climate Change Conference of the Parties. Mitigation or adaptation strategies already in place for heatwaves should be identified. All modes of transport need to be represented, including by air, water, rail and roads.

Governance should be put in place — heat policies remain scarce worldwide. Ideally, a regional chief heat officer would coordinate efforts across sectors. As well as protecting human health, policies should consider the resilience of transport infrastructure to heat, how best to guide investments and how to avoid failures of crucial systems. First responders, utility companies and transport-concession firms should be involved in shaping policies.

Transport should be embedded in all heatwave-related efforts. Impacts on movement of people and goods should be included, as is the case in the US National Integrated Heat Health Information System (NIHHIS), created by the National Oceanic and Atmospheric Administration and Centers for Disease Control and Prevention. The NIHHIS compiles and shares information about extreme heat with the public and with decision makers.

International collaboration is crucial. This includes in capacity building, finance to support adaptation to heat and sharing tools and data for assessing risks. The Global Heat Health Information Network, run by the World Health Organization and the World Meteorological Organization, is one such forum.

Best practices can be borrowed from other sectors. For example, flood risk governance has specific objectives, such as preventing a once-every-100-years flood. Heat governance needs equivalent targets for planning.

Deploy sensors and monitoring

Temperature sensors and monitoring systems should be installed along transport networks, especially around the most vulnerable parts, such as exposed sections of railway track and underground infrastructure with poor ventilation⁶. Combining temperature sensors with Internet of Things technologies can enable real-time monitoring of conditions. This would allow improved planning for maintenance as well as better-informed, local, dynamic responses to changing weather conditions — for instance, imposing speed restrictions to improve safety.

Start feasibility studies

Practical assessments should start as soon as possible to test existing heat-adaptation strategies in various geographical contexts. Tempe in Arizona, Abu Dhabi and Singapore are increasing the amount of shade provided for pedestrians, cyclists, passengers and transport workers, such as bus drivers and maintenance staff⁷. Phoenix, Arizona, has installed ‘cool pavements’, by applying coatings that reflect solar radiation. Spain is using heat sensors on rail tracks to provide early warnings, as well as heat-reflective coatings and paints to limit rail temperature increases. The United Kingdom sets speed limits during heatwaves to prevent rail buckling and reduce the risk of accidents.

Cost–benefit analyses are needed to prioritize strategies, resources and investments. In Seoul, for example, transforming roads into green corridors has been a cost-effective way to reduce heatwave impacts for pedestrians, cyclists and public-transport users.

Develop tools for adaptation

Given uncertainty about the extent and impacts of climate change, governments and cities need to develop ‘resilience toolkits’ for keeping the transport sector running in extreme conditions. Such tools range from simple rules of thumb for local practitioners to ‘digital twins’ of transport systems for monitoring and planning. Current toolkits tend to focus only on local climate risks (see go.nature.com/3sazyuk) or on public health (the NIHHIS, for example).

To inform these toolkits, transport managers need to gather meteorological data, predict future climate patterns, assess the heat resilience of infrastructure components and monitor user exposure to heat.