It&#x27;s the biggest fallacy in armchair transit planning: Misunderstanding what induced demand means. If the system is at capacity everywhere, but you build to the point where a modality(any modality) is no longer congested, new demand will shift towards that modality. Thus, you can have a city where all the trains are packed, or one where it&#x27;s the highways. Presumably, if you invested enough in them, bikes and buses could go the same way.<p>But what you can&#x27;t do is create an &quot;all-around&quot; city where every transit option has equally low congestion. People will show a preference for whichever mode they got used to, and fill the others only as they hit their tolerance limits - not because one is faster, or cheaper, unless it&#x27;s substantially so(and then congestion will arise to even the odds). This typically manifests today in a city crowding the highways but leaving the buses empty. New construction will mostly be used by newcomers unless there is some disincentive to drive, like downtown congestion charges, reduction of parking, smaller roads, etc.<p>The bus lane capacity thought experiment equates velocity to throughput. This is obviously wrong; while a bus interferes with some traffic, it also pulls more people into less space. Multiply that along the whole route, at high frequency, and you end up with geometric efficiency. A bus may go at a third of the speed, but it carries easily 10x as much as a four-seater, and bigger buses could hold even more. At the peak hours, congestion and slow speeds are assumed and vehicle capacity starts to matter for delivering the most commuters home in a timely fashion.<p>Then consider the network benefits of running more routes and connections at higher frequencies. Public transit has to hit a certain critical mass of densities and destinations before it really takes off; most of the US today, being heavily suburbanized in the mid-century fashion, does not enjoy this. But the New York City region got there, and several other metros are showing signs of moving in this direction. Access to transit is implicitly improving now that we&#x27;re in the era of electric rideable vehicles and people making their first&#x2F;last-mile connection can go at 10-15 MPH on whatever weird gadget they want without breaking a sweat or having to find lockup space. Capacity becomes a complicated equation with all these factors.