Do I need Space Age?
No. Everything works in the base game except the V3 Launcher, which needs Space Age.

Why does it install Heavy Trucks: Autopilot too?
The Autopilot gives the trucks their window, schedules and truck stops, so it's a required dependency and installs by itself. The trucks can still be driven by hand like any car.

What is Heavy Trucks: HD graphics?
Optional. Heavy Trucks ships with standard-resolution graphics to keep the download small; install the HD mods if you want the trucks at twice the resolution. Nothing else changes.

Fuel ends up in my cargo. Why?
That's how the base game works with cars: inserters fill the fuel slots first and, once they're full, put the extra fuel in the trunk. To stop it, filter the cargo slots: middle-click a slot in the truck window, like on a cargo wagon. Filtered slots only take that item, so the fuel stays in the fuel slots.

Can I choose what goes into each slot?
Yes: middle-click a slot to filter it to the item on your cursor (or, with an empty hand, to the item in it). Middle-click again to remove the filter.

Can I limit the trunk like a chest?
Yes: the red button next to "Trunk" in the truck window, then click the first slot to close. Closed slots take nothing in. Right-click the button to remove the limit. (Vehicles can't have the chests' red bar in the base game, so this does the same job.)

How do I fill or empty the Tanker Truck?
Park it next to an ordinary pump: the pump's arm reaches the tank valve, like with a fluid wagon. Pump towards the truck to fill it, away from it to empty it. It has two separate tanks, so it can carry two different fluids.

How do I use the Artillery Truck / V3 Launcher / Radar Truck?
Stop, then deploy it (button in its window or Shift + G). Deployed, it can't be driven; fold it the same way. The Artillery Truck and the V3 fire in a cone ahead of them: aim by hand with the targeting tool, or turn on automatic fire in the window, with target priorities like a turret's.

Can I add it to an existing save?
Yes. Research the trucks as usual.

Will it work with Factorio 2.1?
Yes, it will be updated when 2.1 is out as stable. Until then, stay on 2.0 for this mod.

I found a bug / I have an idea.
Please post it in the Discussion tab, with the error message or a screenshot if there is one. Thanks!