Each weekday 6,500 London buses carry 5.1 million passengers
More buses are being introduced on four routes in London after services received a further investment of £3.5m.
Passengers in Hounslow, Hillingdon, Richmond and Kingston should see more frequent and more reliable buses from this weekend.
The Mayor of London, Ken Livingstone, has been pouring money into London's buses and said they are "getting better right across" the city.
Each weekday 6,500 London buses carry 5.1 million passengers on more than 700 different routes.
"Brand new routes are being introduced and we're putting more buses on existing routes to boost capacity, comfort and reliability," said Mr Livingstone.
"This is part of an enormous package of bus improvements that will make a real difference for bus passengers, new and old."
The latest routes to benefit are 111, U2, U3 and U4.