Phone etiquette when in a Lyft line

When on the bus or in a taxi by myself, I feel comfortable talking on the phone. But, for some reason when riding in a Lyft line, I have a nagging feeling that I'm being rude to the other passengers. If I were riding with a friend, it wouldn't be weird for us to talk to each other. So, I'm curious why talking on the phone gives me pause since I'm making the same amount of noise.

I think this feeling stems from the ambiguity of whether a Lyft line is more like a quiet car on Amtrak or a public space like a subway. Clearly, passengers are choosing to take a quieter mode of transportation, but it's unclear how quiet a Lyft line is meant to be. In the era of ridesharing, how should we treat this confined space?