How to handle vehicles dragging trailer or being heavily loaded?

[Sam Baughn]

Say you want to carry more equipment than your vehicle's Load statistic allows for. The obvious solution is to simply treat the extra weight as encumbrance.

But (assuming it's a wheeled vehicle) should you use the rules for pulling a load on wheels? They seem rather generous; it looks like an ordinary car could pull twice it's weight behind it without suffering any encumbrance penalty at all!