This article is part of a special report on Climate Solutions.
As we now know, the Covid-19 pandemic lockdown has been a silver lining for another global crisis: climate change. Sharp decreases in traffic and better air quality have been reported around the world, and hundreds of jurisdictions from Berlin to Bogotá are reallocating space to make it easier for walkers and cyclists with permanent and emergency solutions, like “pop-up” bike routes.
“We are at a moment of change that we have not seen since World War II when cities needed to reinvent themselves,” said Claudia Adriazola-Steil, global director for the health and road safety program at the World Resources Institute’s Ross Center for Sustainable Cities. “The longtime goals of reducing the number of cars on the roads and unacceptable levels of air pollution was achieved in a few weeks. You can see the Himalayan blue skies for the first time in 25 years.”
But speed is a serious “invisible threat, a hidden enabler” undermining those efforts, Ms. Adriazola-Steil said. “If you have more people able to walk and bike, it will be a huge gain in terms of climate change, but if we want cities to be more sustainable, you have to reduce the speed of cars.”
Driving at lower speed means less fuel use, which lowers carbon emissions. It also means less crash risk. Global efforts, from lowering speed and regulating the export of “dirty” and unsafe cars to adopting smart street design, aim to reduce death on the world’s roads and improve the environment.
“Humans have a developed sense of altitude, but not speed,” Ms. Adriazola-Steil said. “It’s a perception that’s difficult to change.” For example, most people fear jumping out a second-floor window, but the injury risk is about the same as getting hit by a car at 25 m.p.h.
Globally, speed is one of the biggest causes of traffic crash deaths and serious injury, contributing to about one third of fatalities in high-income countries and up to one half in low- and middle-income countries. In the United States, speed limits have been rising since the mid-1990s.
“People just do not understand that there are huge benefits from reducing speed,” said Véronique Feypell, manager of the Road Safety Program at the International Transport Forum, a Paris-based intergovernmental organization with 60 member countries within the Organization for Economic Cooperation and Development.
Nearly all countries have reported a sharp decrease in traffic, around 70 percent. But average speeds — including very excessive speeding — have increased during the shelter-in-place period, including in the United States. “The individual benefit of going just a little slower may appear to have a small impact, but the collective benefit has a huge impact on the reduction in the number of crashes, serious injuries and deaths,” she said, adding that a 10 percent increase in speed would, on average, lead to an increase of about 40 percent in fatal crashes.
Speed reduction as an important international issue for both safety and CO2 emissions was recognized at the Global Ministerial Conference on Road Safety in February in Stockholm by the Stockholm Declaration, which called for a maximum road travel speed of 30 kilometers per hour (18 to 19 m.p.h.) in most urban areas around the world, to “have a beneficial impact on air quality and climate change as well as being vital to reduce road traffic deaths and injuries.”
“This is the most hopeful of all moments,” said Claes Tingvall, a professor at Chalmers University of Technology in Sweden and former director of traffic safety at the Swedish Transport Administration, who with colleagues wrote the recommendations that formed the basis of the Stockholm Declaration. “It puts it all together into a more holistic way of thinking.”
The Vision Zero or Safe System approach to roadway design, based largely on the understanding that humans are human and make mistakes, has been widely acknowledged and implemented in recent years for its success toward eliminating road deaths and serious injuries, but the new declaration goes several steps further, said Dr. Tingvall, known as the father and chief architect of Vision Zero.
The declaration’s recommendations, supported by the vast majority of the nearly 120 governments in attendance, also acknowledge that businesses, especially multinational corporations, “are agreeing to take responsibility for their ‘safety footprint’: how their supply chain links to traffic safety, the environment and its impact on the community, ”Dr. Tingvall said. “It’s a commitment that really hasn’t been there before.”
He and other experts say among other changes underway that show promise for improving safety and air quality, are geofencing, a kind of virtual fence that controls speed in a zone, and Intelligent Speed Assistance, which inhibits speed automatically in accordance with local limits.
Skye Duncan is director of the Global Designing Cities Initiative, a program of the National Association of City Transportation Officials. The program has worked in dozens of cities in four continents. “Current practice dedicates an outsize amount of road space to private vehicles, while other modes of transportation are often an afterthought,” she said. “Streets that are designed to make it convenient and comfortable to walk, cycle, and take transport not only make our cities safer, they make them healthier, and less polluting, too.”
“Transportation is one of the largest sources of greenhouse gas emissions in the world and is the fastest-growing,” Ms. Duncan said. “By redesigning streets, cities can quickly tackle the urgent crises of climate change and road safety at the same time. The best global solutions have immediate local impacts.”
Janette Sadik-Khan, a former commissioner of the New York City Department of Transportation and now transportation principal at Bloomberg Associates, which advises mayors around the world, noted that cities were undergoing “a street design” revolution. “There is a straight line between what happens on city roads and global climate change.”
“There are 1.3 million traffic deaths annually and another 4.2 million deaths attributed to pollution,” said Ms. Sadik-Khan, who is also chair of the Global Designing Cities Initiative. “Streets that are safe for people also support the health of the planet.”
“If your goal is to save the planet, you can start by building a bike lane,” Ms. Sadik-Khan said.
Bloomberg Associates and the Global Designing Cities Initiative work, separately and in collaboration, with cities to encourage smart street design using a mix of strategies: reducing speed limits, increasing traffic enforcement and education, constructing pedestrian plazas and traffic calming measures, investing in infrastructure and public transit (including cleaner public transit vehicles), and building and expanding protected bike lanes and bike share programs.
In Fortaleza, Brazil, fatalities dropped by 50 percent from 2010 to 2019, one of the few cities in the world to experience such a steep decline during that period, said Ms. Duncan, whose organization produced the Global Street Design Guide and often works with local artists and schoolchildren to brightly paint roadways and pedestrian areas with markings and signage. “We find the use of color helps people see their streets in an entirely different light, while building a new sense of ownership of the space,” she said. “Every time we paint a street and give people a safe place to walk, it saves lives and fights the climate crisis.”
After work in Mexico City from 2014 to 2016 on 106 intersections on 10 main corridors, some of the city’s most dangerous, pedestrian deaths dropped 24 percent and cyclist deaths dropped 77 percent. In Bogotá, Colombia, traffic deaths fell 17 percent from 2014 to 2019, reaching its lowest point in 20 years.
“If we make the roads safer, people will be able to walk and cycle, without risk,” said Etienne Krug, director of the World Health Organization’s Department of Social Determinants of Health. “If we make public transport more accessible and safe, people will use it more. Governments have to make sure we have safe sidewalks and crosswalks and bicycle lanes, and driving more slowly is something we can do as individuals.”