A man in a place with bad public transit gets the call that his mother has been in a car accident and is being rushed to the hospital at 8AM. Since it’s rush hour, he spends the next two hours stuck in gridlock traffic (bad traffic today, something about a big car accident…). He doesn’t make it in time for her last goodbyes.
In contrast:
A man in a city with a good public transport goes to work easily and there is minimal traffic. His mom doesn’t get hospitalized because there are fewer cars on the road and the streets are designed for pedestrian safety.
or
His mom gets to the hospital more quickly because there is less traffic. She survives.
or
He runs (or bikes) to the hospital within 20 minutes because he lives close to it in a dense neighborhood without endless sprawl caused by parking lots and cars.
or
He gets to the hospital quickly via an efficient transit route since there are many routes going to a hospital because… it’s a hospital!
or
He calls a taxi that arrives quickly and gets him to the hospital in 1 hour because there is less traffic.
Also, in all these scenarios everyone in the society is wealthier and healthier due to spending less money on their cars and breathing less pollution. They all get to work quicker because of less traffic congestion.