Static space. In the real world people exist in both space and time. Ten people who complete a journey at 100mph take up the same time-space (ie road) as one person at 10mph. Someone at 1mph takes up as much road as 100 people on the same journey at 100mph.

If the question is how many people can we shove through a pipe/tunnel/travel network, speed is as much a factor as physical size. Bikes and cars both take up massively more time-space than trains or busses. But pro-buslane voices are rare these days.

I'm not a fan of that example - the cars photo is more zoomed in than the others.

To paraphrase Sartre: "Traffic is other people."