Battle Nations - Roads

You'll notice that there is a "Decoration" category in Battle Nations with stuff to make your outpost look pretty.  Some of these are functional.  Roads, specifically:

• Dirt Roads
• Cost: 6,500 gold, 100 stone, 0 seconds
• Return: +1% XP to agriculture, max of +5%
• Cobblestone Road
• Cost: 1 nanopod, 0 seconds
• Return: +2% XP to housing, max of +10%
• Blacktop Road:
• Cost: 28,000 gold, 250 concrete, 100 oil, 0 seconds
• Return: +2% XP to shops, max of +10%

The simple ROI is easy.  What's REALLY cool about roads though, is that they can increase Hauler efficiency at your Resources Depots.  Note here in the picture that I've just placed two Dirt Roads in the path of my Hauler, and efficiency increased so much that I only need 1 Hauler for two resources (Stone and Iron).