Here is about 70 people on a freeway. It was running at more-or-less full speed, though on the verge of getting congested. It was a Saturday, so vehicle occupancies were probably higher than average.
And here’s about 70 people in a single train carriage. It wasn’t crowded, though certainly getting there. (The same number would fit into a conventional bus or small tram.)
Note the space taken by each. A four lane freeway has a capacity of about 10,000 people per hour (assuming a level of car occupancy well above what’s normal). A conventional railway has a capacity of at least double that (triple if you assume good signalling, and trains reasonably full).
Of course it’s not a simple thing to get people to switch from one to the other.
For the highest capacity public transport mode — rail — you first need to get people to the station before they’ll get onto a train — and it needs to be easy for them to get where they’re going at the other end.
On the carrot side that’s a mix of good urban planning (for instance homes and destinations both close to stations) and good feeder services (bus or tram or bicycle or an easy walk to the station — preferably not park and ride, as it’s very expensive and space-inefficient). On the stick side, regular congestion and expensive or hard-to-find parking (all by-products of a growing city) contribute too.
But ultimately we need to decide what we prioritise — continuing to encourage (and even force, through lack of real choice) car travel, or more efficient modes.
- Note: the numbers were estimates. I zoomed up the photos to count as accurately as possible, but it was hard to see any people in the back seats of cars — however I erred on the high side. The train carriage number is based on doubling the number in the half of the carriage you can easily see.