Its not entirely clear, but it can be seen that traffic is worse when you have 20 traffic lights for crossroads in a row... Or at least its logical. The cities that grew over time with circular planing have better capacity even on thinner roads, meanwhile grid cities have up to 8 lane roads (4 in 4 out) very often as their main road.
Its not 100% clear but its pretty likely that its one of the factors. Another one is public transport.
The city that's the least linear. Charlotte is a constant log jam because for major metropolis cities you do actually want a directional grid specifically for making the city easy to navigate with multiple outlets for traffic to flow in the event of a conflict (break down, accident, road work, etc). A city that doesn't prioritize navigability will be filled with culs-de-sac which are horrible for traffic and navigability
São Paulo city is a messy case. It started out roughly circular, then that circle was distorted into a grid plan, then that grid plan was tied to a bunch of mismatching grids. Picture related:
As such it's hard to reach any conclusion taking its general layout into account.