Streetcars run on rails, share the road with cars, make frequent stops, and largely serve downtown areas (as opposed to light rails that are separate from the road, have less frequent stops, and connect suburban areas to city cores.)
Phased out in favor of busses. This is popularly attributed to meddling by car companies, but it was probably just helped along by them.
Streetcar companies, in order to operate as a monopoly, had to agree to things like keeping fares 5 cents and maintaining the pavement around their tracks.
This was fine until WW1. Once 10% of the population had cars, the street cars no longer operated as a monopoly. They had to maintain the pavement around their tracks, which served cars, and they couldn't raise fares to reflect actual costs. Gridlock meant that they couldn't run on time.
Oh, and inflation meant that 5 cents was worthless at that point.
Only in cities where they maintained right-of-way did they survive.
Problem: they cost way more than busses, but aren’t nearly as fast as light rails. In the long term they can be cheaper than busses.
Tourists and first-time users are more likely to use them than busses
Encourage more growth in an area because the lines are permanent
Microtransit: like Uber, but specifically for work commutes
Routes are partially predetermined, but alter themselves on the fly based on demand
It’s kind of the dream of overall efficiency: using data on overall demand to only send vehicles where they are needed, and reducing travel time when compared to rigid transit routes
Private companies running these companies will likely encounter legal hurdles like Uber has
Problem: in the short term, they could be bad for public transit, because they attract higher-income passengers
“The fear is that by creating a segregated, two-tiered transport system, we'd be allowing for fast, comfortable service for those who can afford it — and slower, less frequent service for those who can't.”
Okay, but right now we essentially have that situation; it’s just that the higher tier is owning your own car
The best end-game scenario is that municipal transit systems will provide these, possibly as last-mile services