Bicycle is very convinient means of transportation especially in big cities as Warsaw.
It is nice to see some set up cycling paths in city with adequate roads signs. That is not I see in my region. Later I find touristic broshures that promote bicycle tours. I am very interesting to explore that opption on my next visit to Warsaw.
Air pollution in 90% of Europe's cities does not meet the World Health Organisation's standards. This shocking statistic published by the EEA is something Polish people are well aware of with cities like Warsaw and Krakow also experiencing emissions issues. However, I have lived in Warsaw for 2 years, during which I have witnessed a dramatic change in 'bicycle friendliness'. The city now has 400km of dedicated bicycle lanes and plans to increase this to around 600 within the next few years. Having also lived in Holland my benchmark is high and I can honestly say getting around using the current network of bicycle lanes has become extremely convenient.
Moreover, Next Bike has managed steady growth of its multiple-rider scheme in the capital with other cities seeing similar schemes being introduced. In April Warsaw will see another development with a company Rowery Studenckie (Student Bikes in Polish) starting a program of giving bicycles to students for free.
So, as you can see...the wheel of change are turning in Poland.
I don't think, it's easy to rent a bike in Warsaw as it's far too easy to lose it (read: have it stolen).
Bike lanes are well-marked, although there are too little of them.