Civilization – Do Automated Workers build roads/railways

There are two basic reasons to connect your cities by roads: for Trade Route income, and for Unit movement

Connecting for Trade Routes

Warning! These calculations are now suspect because of new info found about how road maintenance works. I will update this with any changes needed once we have verified numbers for road maintenance costs.

Summary: only build trade routes to cities with 6 population or more. If you care for the math, then continue reading...

Now that Oak has solved the Trade Route formula for us, we know that normal trade income is very close to 1.25 * population of the connected city. (not the capital)

So, suppose you have your capital and one city, they are separated by 6 hexes. You'll be paying to maintain each of those roads, costing you 6g. So, at a population of 3, you would make 3.75g, be spending 6g, and be losing money overall. Your worker time is EASILY spent doing something else. Of course, if your cities are closer together, the calculations look better. Finally, I believe that Harbors cost 2g to maintain. Realizing that you only pay for your capital harbor once, sea routes effectively only cost 2g to maintain.

Population | Income | Net Income with...| Harbor/ |
           |        | 6 Roads | 4 Roads | 2 Roads |
3          |  3.75g |  -2.25g |   -.25g |   1.75g |
4          |  5.00g |  -1.00g |   1.00g |   3.00g |
5          |  6.25g |   0.25g |   2.25g |   4.25g |
6          |  7.50g |   1.50g |   3.50g |   5.50g |

I would like to propose a rule of thumb. You can pick whichever population number seems best to you, but I believe my worker can do better than even a 4g improvement by working other tiles in the time it would have taken him to build that road. Thus:

Only build trade routes to cities with 6 population or more.

If you follow this rule of thumb, you will, at the least, never lose money on a trade route. Further, if you start working on the trade route when the city is size 6 already, there's a good chance it will have grown to 7 at least by the time you finish, and you can actually start making enough money for that worker time to be worth it.

Final note on trade routes: Arabia gets a flat +1 to trade route income. (AFTER the multiplier, so simply add 1 to every gold number on the chart.) So feel free connect Arabian cities at population 5 or more, if you like.

Connecting for Unit Movement

We don't have nearly as good of data on this, but from my Civilization experiences, roads are VERY worth building if you are producing units and sending them to war. You get your best units at the front for longer before they are obsolete, and you'll have more units at the front at any given time.

If you're not moving units for war, roads may also be worth building to quickly move defenders in the event of being attacked, by barbarians or another Civ. I think you can just ask yourself:

• Am I likely to be attacked in that city?
• Is the attack likely to beat the city?
• Do you HAVE units that could get there by the road to defend?

If any of those it no, the road is not worth it, cause it won't help.

And if you're not at war, and not defending, I doubt you want to build roads just to move units, because you don't sound like you're moving units around much at all!

No. I haven't found the advisors to be particularly good at choosing buildings. Most buildings are much more situational now due to the maintenance costs, so you shouldn't build them unless they seem like a good match with what you're planning for that city.