On the wiki page for the London charge they suggest that ten years after the introduction of the congestion charge, traffic levels have been reduced by 10% (ten).
So yes technically less traffic, but not really enough to make any meaningful difference IMO. It is still noisy, it is still congested, it is still polluted, it is still hard to cross roads, it is still hard to get anywhere on a bus in a predictable time, it is still very frightening to be a cyclist (and indeed it is still common for cyclists to get killed or badly injured), and it is still better to get the tube.
I view it more as a toll now really, rather than an attempt to dissuade people from driving in. If they were really serious about trying to stop people driving in, the price would not be £15/day but it would be £500/day or more.
As it stands at the moment, even on the weekend (yes, it runs on the weekend even though there is not much congestion e.g. on a sunday afternoon) if I want to go to central London with the family I will drive. It costs £15, but the price of a return tube ticket is £6, so x2 for me and the wife and it is already £12, then add in £1.75 for the bus tickets to-and-from the tube station (so £3.50 per adult return = £7), and you are already at £19 to use public transport, vs £15 for the congestion charge.
So it is approx 20% cheaper to drive, AND it is more convenient, AND it is quicker, AND it is more comfortable.
Like I said, if they were serious about it being a deterrent they'd price it way, way higher than £15. But actually they want to make cheap enough so that people pay it, and they get money for me using my own private transport and fuel to travel around, and don't have to pay for the running costs of more tubes/buses etc.
So yes technically less traffic, but not really enough to make any meaningful difference IMO. It is still noisy, it is still congested, it is still polluted, it is still hard to cross roads, it is still hard to get anywhere on a bus in a predictable time, it is still very frightening to be a cyclist (and indeed it is still common for cyclists to get killed or badly injured), and it is still better to get the tube.
I view it more as a toll now really, rather than an attempt to dissuade people from driving in. If they were really serious about trying to stop people driving in, the price would not be £15/day but it would be £500/day or more.
As it stands at the moment, even on the weekend (yes, it runs on the weekend even though there is not much congestion e.g. on a sunday afternoon) if I want to go to central London with the family I will drive. It costs £15, but the price of a return tube ticket is £6, so x2 for me and the wife and it is already £12, then add in £1.75 for the bus tickets to-and-from the tube station (so £3.50 per adult return = £7), and you are already at £19 to use public transport, vs £15 for the congestion charge.
So it is approx 20% cheaper to drive, AND it is more convenient, AND it is quicker, AND it is more comfortable.
Like I said, if they were serious about it being a deterrent they'd price it way, way higher than £15. But actually they want to make cheap enough so that people pay it, and they get money for me using my own private transport and fuel to travel around, and don't have to pay for the running costs of more tubes/buses etc.