As this Age Explainer article details, all cities have traffic congestion. But better public transport (and walking and cycling) helps people avoid it.
Read more: https://archive.md/Brgk4
RE: https://mastodon.social/@ptua/115770748055199188
But sadly no matter how much you invest in public transport if you're not also investing in reducing the number of cars on the road the public transport won't be good enough.
If you're pro-public-transport then you need to also be anti-car because these are opposing forces.