A new campaign is urging Londoners to ditch their cars for short journeys and walk instead.
Launched by Transport for London, the poster and radio adverts focus on the school run and the commute to work and ask the question "Why not walk it?".
It is TfL's first advertising campaign to promote walking.
On Thursday, the first ever Walk to Work Day in London is being held. The aim is to show workers the benefits of being more active on their commute.
Research has shown that half of all car journeys in outer London are less than two kilometres and take an average walking time of 25 minutes.
Ken Livingstone, Mayor of London, said: ''London is a great city for walking and we are investing to make it even easier and safer.
"This Transport for London campaign encourages people to think twice before using the car for short journeys.
"Walking offers a great way to travel as it is good for your health and helps reduce carbon emissions as we all try to prevent catastrophic climate change."
Adrian Bell, from Transport for London, said people often overestimate how long it takes to walk a short distance.
"Walking can be a great way to make short journeys and this advertising campaign highlights that," he said.
"It's also great exercise, environmentally friendly, and a brilliant way to start or finish your day."
On Walk to Work Day, commuters dressed in Dolly Parton wigs to highlight the day's message "Walking 9 to 5" will lead a parade across Tower Bridge before the official campaign launch in City Hall.
The campaign - Walking Works - is run by the national charity Living Streets and funded with £150,000 over three years by TfL.
During the next three years, £126m will be invested by TfL to improve conditions for Londoners on foot including new pedestrian crossings, lowered curbs and improved signage.