'People still cannot cycle safely'
UK towns and cities should become more like the Colombian capital of Bogota, at least in their transport policies, according to Professor Martin Wiseman, medical and scientific adviser at the World Cancer Research Fund.
In this week's Scrubbing Up health column, he says following the South American city's example would help prevent cancer.
When he became mayor of Bogota in Colombia in 1998, Enrique Peñalosa made it one of his priorities to make life easier for pedestrians and cyclists.
Eleven years later, the city has expanded cycle paths and pedestrian zones and improved parks.
Every Sunday and public holiday, over 120km of streets are closed to motor vehicles from 7am to 2pm and are used for walking, skating and cycling.
These are the kind of changes that make a city a nicer place to be, but it is about much more than that.
One of the major challenges we face as a country - and indeed all round the world - is that people are becoming less and less active.
This is obviously bad news for our health generally, but what is less well known is that being physically active also reduces risk of cancer.
'Not about the gym'
According to a recent YouGov survey, over half of us do not know about the link between physical activity and cancer prevention.
But the stark fact is that the decline in physical activity levels across the world is one of the reasons scientists are projecting a doubling in global cancer rates over the next 40 years.
This needs to be addressed.
This does not mean we should all join a gym tomorrow.
In fact, it is the smaller changes that fit into our existing routines, such as walking or cycling to work rather than driving that can make a difference and we are also more likely to stick to them in the long run.
But it is no good people like me recommending that you trade in your car for a bike if the roads around where you live seem too dangerous to cycle safely.
This is why when it comes to our attitude towards our public spaces, we in the UK need to become a bit more like Bogota.
We at the World Cancer Research Fund want to see widespread safe walking and cycling routes throughout the country.
To be fair, the UK is not doing badly at the moment.
According to Transport for London, there has been a 66% increase in cycling in central London between 2002 and 2007.
A man cycling through Bogota on a car-free day last year
Also, three "sustainable travel demonstration towns" have been created that, within two years, led to an increase in walking of about 20% and in cycling of about 50%.
So there is no doubt we are moving in the right direction.
But have we got to the point where all of us can safely cycle to wherever we want to go?
The answer is "no" and that is why there is still a lot more work to do.
You could argue that it would be too expensive to make these sorts of changes, particularly in the current economic climate, but this is an investment in the health of the population.
Making these changes would help prevent many thousands of cases of cancer.
In fact, scientists estimate about a third of the most common cancers could be prevented if people ate healthily, maintained a healthy weight and were regularly physically active.
This is how high the stakes are, and this is why places like Bogota, with all the problems that exist there, are grasping the nettle and prioritising these kinds of changes.
And while they may cost a significant amount of money, the cost of doing nothing and sleepwalking our way towards a public health catastrophe is surely too high to bear thinking about.