In Garry's Mod, is there any way to stand on a moving object?

Solution 1:

Actually, there's now a new tool called the gravity hull stool I think. It makes a localized physics field so you can move around on any surface even if its spinning or moving at light speed and you won't be affected by the outside world. Extremely useful for moving spaceships and vehicles.

Solution 2:

Actually standing on a moving object doesn't really work because Source isn't suitable for it. There are a number of things you can try. You can try spawning a seat, welding it to the vehicle and use it, for example. Alternatively, you can use this Player Weld STOOL to weld yourself to it, causing you to move along with it.