What was the worst decade for traffic in NYC?

Nowadays NYC is very pedestrian and public transport friendly (by US standards) so there aren't many cars clogging its roads these days. But I'm sure there was a time where NYC roads were jam packed full of cars and traffic was atrocious. As recently as the 1980s (by comparison) in Western European and... show more Nowadays NYC is very pedestrian and public transport friendly (by US standards) so there aren't many cars clogging its roads these days.
But I'm sure there was a time where NYC roads were jam packed full of cars and traffic was atrocious.
As recently as the 1980s (by comparison) in Western European and Canadian cities there was plenty of breathing space on the roads as not many families owned 2 cars or more. In NYC on the other the hand the pollution was horrendous in the 1980s (probably due to the insane amount of cars New Yorkers owned then).

Even when I look at pictures of NYC as far back as the 1920s the streets were proper FULL of cars!
So when was the last time NYC had quiet roads (not full of vehicles) and which was the worst decade for traffic/pollution?

Thanks!
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