Transport is one of the fastest-growing sources of greenhouse gas emissions, and in cities around the world it is also one of the biggest daily frustrations. Congestion, pollution and long journeys to work affect millions of people every day.

In this episode of The Climate Question, Jordan Dunbar explores how cities can move large numbers of people more quickly, cheaply and with fewer emissions. With most urban journeys still dominated by private cars, the challenge is how to shift people towards more efficient forms of transport.

He speaks to Dario Hidalgo, a transport expert based in Bogotá, where a system known as Bus Rapid Transit has helped transform how millions of people travel. By giving buses dedicated lanes, larger vehicles and faster boarding systems, cities can move more people using fewer vehicles, cutting both congestion and emissions. Variations of the model are now being used in cities around the world.

Jordan also hears from Sarah Kaufman, Director of the NYU Rudin Center for Transportation in New York, about why similar systems can be harder to implement in dense cities, and how measures like congestion charging are helping to reduce traffic and fund improvements to public transport.

While electric cars are often seen as part of the solution, both experts say reducing the number of cars on the road altogether is key. From buses to bikes, they explore how cities might redesign transport systems to be cleaner, faster and more efficient.

Guests: Dario Hidalgo – Professor of Transport and Logistics, Pontificia Universidad Javeriana, Bogotá Sarah Kaufman – Director, NYU Rudin Center for Transportation, New York

Got a question or comment? email us at theclimatequestion@bbc.com

Production team: Grace Braddock, Diane Richardson, Nik Sindle Sound Engineer: Tom Brignell and Mike Regaard Production Coordinator: Brenda Brown Editor: Melanie Stewart-Smith

Image: Guillermo Legaria/AFP via Getty Images