Vehicles: Mr. Crayfish's Vehicles, there are probably others I don't know about.
People: custom NPCs (you have to make them all yourself, however), Tektopia (their building creation system is flexible enough to allow for custom builds or builds taken from other mods)
Buildings: Lost Cities, Tektopia (you build your own buildings)
Maps have all your looking for in one but mods have cars/vehicles, NPCs you can create to suit the city theme but not all in a natural way, maps with commands and/or mods are what make it more natural.
The ones listed above are good options but if you want some like roads there is a few like:
Um hello I am looking for a mod that adds a city look like real life With Car Driving Around and people mobs walking around
There's really no such mod as that.
Vehicles: Mr. Crayfish's Vehicles, there are probably others I don't know about.
People: custom NPCs (you have to make them all yourself, however), Tektopia (their building creation system is flexible enough to allow for custom builds or builds taken from other mods)
Buildings: Lost Cities, Tektopia (you build your own buildings)
Maps have all your looking for in one but mods have cars/vehicles, NPCs you can create to suit the city theme but not all in a natural way, maps with commands and/or mods are what make it more natural.
The ones listed above are good options but if you want some like roads there is a few like:
-Road Runner 1.12.2 and prior
https://www.curseforge.com/minecraft/mc-mods/road-runner
-RC Roads 1.11.2/1.12,2
https://www.curseforge.com/minecraft/mc-mods/rc-roads
-Road Stuff 1.14.4 and prior
https://www.curseforge.com/minecraft/mc-mods/road-stuff
and more:
https://www.curseforge.com/minecraft/mc-mods/search?search=road
Or there is mods with custom structures but many don't add skyscrapers or modern like buildings, there more player built (at least I haven't found many and don't remember which might) like these for example: https://www.curseforge.com/minecraft/mc-mods/useful-structures or https://www.curseforge.com/minecraft/mc-mods/instahouses
Depends on what your looking for really.
Niche Community Content Finder, Youtuber, Modpack/Map Maker, Duck
Forum Thread Maintainer for APortingCore, Liteloader Download HUB, Asphodel Meadows, Fabric Project, Legacy Fabric/Cursed Fabric, Power API, Rift/Fabric/Forge 1.13 to 1.17.
Wikis I Maintain: https://modwiki.miraheze.org/wiki/User:SuntannedDuck2
Thanks Its Useful