It's funny that it's both visible and wrong

change my view.

Me and the Sullivan twins would like to have a conversation with you and a few baseball bats in the alley out back if you're seriously arguing that Boston isn't a metropolis... and don't you dare fucking insult the Red Sox, Dunkin' or the Bruins (actually, we care more if you bad mouth our college hockey teams) unless you'd like to qualify for Medicare early.

In Amsterdam the mode share for all trips is like 30% for biking and for walking and like 20% for driving and for transit

Ok! As per the marriam-webster definition of a metropolis:

the chief or capital city of a country, state, or region,

the city or state of origin of a colony (as of ancient Greece),

a city regarded as a center of a specified activity,

a large important city.

As per Cambridge:

a very large city, often the most important city in a large area or country.

Collins:

A metropolis is the largest, busiest, and most important city in a country or region.

Britannica:

a very large or important city — usually singular

Oxford:

A very large urban settlement usually with accompanying suburbs. No precise parameters of size or population density have been established. The structural, functional, and hierarchical evolution of global metropolises is rooted as much in the past as in the present: modern information and communications technology may be more advanced than the 19th-century telegraph, but the processes and outcomes are much the same (Daniels (2002) PHG 26). ‘[Berlin's] wealth of facilities, as well as their scatter across the metropolis, can be understood only in the light of the city's history and, paradoxically, its troubles.

Longman:

a very large city that is the most important city in a country or area

You:

NYC but only if half the people use public transit

Because motorcycles take up way less space than a car

One, they are much better on gas use. So less energy in general to move them.

Two, they are much lighter, which as we are discovering with electric vehicles, matters a great deal in how horrible the tire wear is (and remember that 28% of microplastics in the environment come from car tire degradation alone!).

Three, for traffic purposes, they are much, much better. They are smaller, so recall that picture that floats around of how much space 100 passengers takes up. They aren't near the train/bus level, but are closer to the bicycle portion of the picture than the cars. It becomes even better if they are scooters compared to motorcycles (scooters are generally even lighter and have smaller engines with better gas usage). I always hear the stat thrown around that if 25% of individuals switched to motorcycles, modern traffic jams in cities (in America, I guess, where I hear it uttered) would nearly disappear.

Climate impact is significantly less for motorcycle riders, that's the only mitigation I can think of.