However, if an engineer unit is created, I think the first and foremost problem that will arise is road spamming. The AI (and the player) need to be able to realize that roads should only be placed where they are needed (or in the players case, wanted with consequence).

Roads should cost upkeep. That would mean that roads should be faction specific so that the faction that built the road, pays the upkeep. That also means that if another faction takes over ZofC of some roads, that the upkeep of those roads is transferred over aswell.

Now, in order to encourage meaningful roads there needs to be incentive. Earlier (perhaps it was even in another thread) I proposed that whenever a road connects two cities that you control, you gain a trade bonus of 1gp/turn. IF road upkeep were 0.1gp/turn, than you could have a city 10 tiles away and break even. In theory this would balance empire growth since expanding too far would generate too much expense.

I like this approach.  Give us the choice.   AI factions could still have the autobuild.

There are several ways manual road building could be implemented.

1) Commanders or pioneers get it as an initial trait.

2) Engineers

3) a trait for designed units

4) An Earth spell

Whatever is done have a toggle on the unit to build a road whenever it moves.  It's very tedious to have to click "Road" after each move.

If we do go down the Engineers path (which I approve), it might also be good allow them to upgrade outposts, too. Engineers could also double as spies/scouts, too, which would only add to their usefulness.

Yeah, the only good solution is to be able to build your own roads. You don't necesarily need an engineer unit. We could let the pioneers be able to build roads as well. This would add to the strategy of their use.

To prevent road spam there of course has to be an upkeep cost. This could also be combined with a one time cost every time a pioneer builds a road on a tile.

It's not tedious to build your own roads. This is a strategy game, and road building can add alot of hard choices for the player.

Examples:

1. (If the pioneer is the unit that builds roads) Do you build that city first, or start to build the road to the city spot first? Perhaps you ar better of getting acces to some ressources first via an outpost? Hmmmm......

2. Do I build the road arround a spooky monster lair, or do I prioritize to take this monster lair out first, to be able to build a straighter road? (we should also be able to raize roads and rebuild the road network more efficiently later on).

3. You have to plan ahead regarding what threats the road builders can come out for. Do you prioritize troops for this task, or will you rather take the gamble?

4. What is the best route to take when you plan the road that shall Connect city A and B. Just the straightes line, or another route that will make the total amount of road tiles as small as possible later when city C and B is also built?

Each road section should require 1 lumber and 1 brick...

(Catan reference)

I recommend the road cost be free.

Instead, have roads associated with faction ownership and cost upkeep to maintain. (example: 0.1gp/tile)

Then, encourage smart roadbuilding by gifting a trade bonus to a section of road that connects two cities you control. (example 1gp/connection)

Now you have a system where you don't want to build too many useless or duplicate roads between or away from your cities or else your economy will tank.

I had a game tonight that did the same thing- ran right through a monster lair. A banshee, no less, so I couldn't really clear it out until much later.

Even if these other changes can't happen soon, could the algorithm be modified to go around monster lairs?

Roads should be upgradable: Path - Road - Hiway

If roads are going to be insta-built then at least limit their establishment within territorial borders.

How about this:

+ Roads can only be established within friendly territory
+ Each settlement can support one connected road per settlement level.
+ Each settlement's road can only extend up to twice its current border strength
+ Each settlement has a button to "link a road" to either a valid (friendly territory + range limits) settlement or outpost.
+ Each outpost can support two connected roads, more with outpost upgrades or tech research
+ Each outpost's road can extend only up to its current border strength

My objective is to make roads obtainable in a meaningful way to balance their incredible benefit to a faction. Also, I want to counter "insta-pop" roads when you throw a settlement 50 tiles away from your borders and you are awarded a road into the heart of the frontier without much effort at all.

This would promote the idea that far off settlements without a string of supporting outpost roads will be isolated from quick reinforcements and highly vulnerable.

One problem then is how do trade routes between factions get established. How about, trade routes act as they do now but instead of a regular road, they create a graphically smaller and thinner road. Only small units would get a travel bonus on these roads (heroes, unit groups 3 or less, small-medium in size, ie no Juggernauts/Ogres/Slaags getting speed boosts) that are low maintenance and designed for small trade caravans. These roads would also immediately disappear when trade is stopped for whatever reason (war, broken trade treaty, etc).

*Edited to flesh out the idea some

This is how it works in Total War series (Medieval2 at least probably others).  You pay to build a "Road" improvement in a city, which when constructed auto connects a road to all adjacent cities.  Would need more smarts in LH because there is no real concept of an adjacent city.

There's like 3 levels of roads and each provides increased trade revenue.

That would work great here.... basic roads provide x2 movement and some basic revenue from trade (caravans), and building better roads would improve movement and income.

I know that the autobuilt maps are quirky as heck, but I don't mind them. I like the idea of the engineer unit doing upgrades or for building short roads. Upkeep for those roads though sounds like a nightmare. It isn't as if we can build lots of cities any more.

Sorry double post

This is why a game option has been suggested.   Auto-build for you that like it.  Manual build for those of us that hate the squirrely auto-built roads.