The private courier company that provides transport for NHS Blood & Transplant (NHSBT) have predicted that blood deliveries during the 2012 Olympics could be at risk if their vans get stuck in traffic. 

There is an obvious solution to this — Blood Bikes! A number of charities have been delivering blood across the UK since the 1960s. The reason we use bikes is that they are perfect for cutting through heavy traffic. So medical staff and patients can rest assured — if London and other Olympic locations grind to a halt, the blood deliveries will still get through as two wheels triumph over four.

Reference: "Blood delay fears" Michael Hurst, BBC News, January 2012