Depends a bit on the city, where in the city, etc. Once you go outside of the inner city things usually tend to be better, but not always. Capitals are probably worse than average. "Tube" implies London and London is definitely worse than average.

When I lived in Bristol (England), it wasn't so bad for the most part (not that I had a car). Some smaller cities can still be pretty bad though; e.g. inner city traffic in Cork (Ireland) is just horrible. I was quite a bit faster cycling to the city centre from work than some coworkers were with cars, especially if you take parking in to account.