You can manually increase the number of people seen walking in cities by editing the g_traffic and pedestrian settings in your game's config file. How to Install and Manage These Mods
. While SCS Software has not natively added hitchhiking, the community has developed several ways to simulate this experience. Top Hitchhiker & Passenger Mods Passenger Mod for Buses (v1.56+) ets2 hitchhiker mod top