Project ZomboidGuideFour settings on your dashboard decide how kind the roads are: Car Spawn Rate, Starting Gas in Cars, Car Condition, and Easy Vehicle Use. Changing them is…
Four settings on your dashboard decide how kind the roads are: Car Spawn Rate, Starting Gas in Cars, Car Condition, and Easy Vehicle Use. Changing them is safe and never removes vehicles your players already own or parked. The new values show up in areas nobody has visited yet, and they apply on the next restart after you save.
Open your server's settings and look for these four. A fresh server starts with spawn rate, gas, and condition all on Low, which is why early tickets often read "there are no cars anywhere".
Car Spawn Rate (None, Very Low, Low, or Normal): how many vehicles the world places on streets and in parking lots. Normal is the highest choice on the dial.
Starting Gas in Cars (Very Low, Low, Normal, High, or Very High): how much fuel is in the tank of a found vehicle.
Car Condition (Very Low, Low, Normal, or High): what shape found vehicles are in (battery, engine, tires).
Easy Vehicle Use (on or off): when on, vehicles are always unlocked and already hotwired. No key hunt and no Electrical skill needed to drive off.
Set the dials, hit Save, then restart the server.
Casual driving-friendly server: Normal spawn rate, Very High gas, High condition, Easy Vehicle Use on. Walking simulator with trophies: None or Very Low spawn rate, Very Low gas and condition, Easy Vehicle Use off.

The game decides a street's vehicles the first time a player gets near it, and that result is saved into the world. Changing these settings affects streets and parking lots your group has not discovered yet. So if you just turned spawns up, drive somewhere new; the old neighborhood was already rolled.
"No cars are spawning" tickets usually turn out to be Car Spawn Rate sitting on None or Very Low, combined with an already-explored starting town. Check the dial first, then explore outward.
Restarting over and over to refill explored streets. Restarts apply settings; they do not re-roll areas that are already part of the save.
Easy Vehicle Use to repair wrecks. It unlocks doors and removes the key requirement; it does not change vehicle condition. That is Car Condition, and it also applies to newly discovered vehicles only.
Restarting without saving. Settings apply on restart, but only after you hit Save.
Ping us on Discord or open a ticket and tell us how central you want cars to be; we will suggest the exact four values.
How thirsty engines are (gas consumption) is not one of the four dials, but you can reach it through the Sandbox Overrides box: Change Any Sandbox Setting
Scarcity of items in general is its own set of settings: Make Loot More (or Less) Common