There's an excellent article in the Standard that explains the need for car sick Westminster to have its streets totally totally jammed with cars - it's what allows them to set a low Council Tax. Lambeth by contrast has much less available parking so more people walk, cycle and use public transport.
What the article doesn't point out is how cheap it is for Westminster residents to park their car, with an annual permit for a 1200cc plus car costing a mere £115 online.
In Lambeth's congestion zone area the cost is between £136 and £247 for equivalent vehicles (you'll pay more for your V8 Range Rover than in Westminster) if you live inside the Congestion Zone, and £149 to £260 outside it.
The knock on effect to Lambeth residents of Westminster's addiction to drivers is Vauxhall gyratory and its ilk.