Research: Effects of Roads

[therother]

frogbeastegg has asked for a thread to investigate the possible effects of roads, specifically to do with trade (post 1.2 patch) and movement rates, although any other feature is also relevant.

For those interested, the effect of roads on trade before the 1.2 patch is detailed in the following Guides & Ludus Magna threads. AFAIK, these figures are still to be confirmed for 1.2.

[frogbeastegg]

Thanks for opening this thread

I'll keep this very brief; I haven’t got much time just now and I’m pretty exhausted to boot, and therefore probably not too coherent. This is both research for the beginner's guide and an attempt to satisfy my own curiosity.

In 1.1 roads and trade worked like this:

Land trading is automatically established, via the road system, between neighbouring settlements. For trade to occur between settlements, they must have a common land border. Improving these routes past normal roads will increase income.

• The first level of roads adds nothing to land trade.
• Paved roads always doubles land trade,
• Highway increases it by a further 50%

So if you have a land trade route worth 100 Denarii with no roads, with will be worth:

Dirt	Roads	Paved	High
100	100	200	300

I want to know if this is still true in 1.2. I'm dyslexic and the kind of maths that gets these results is beyond me, so I'm asking for help. Actually about all I can do is take the results and copy them to the beginner's guide with credit given :embarrassed:



Part 2 of this topic deals with roads and movement for units and armies. I want to know how much of a boost each road type gives, and if all units receive the same boost. I suspect all army unit types (infantry, cavalry, artillery) will gain the same, and I expect agents will gain the same boosts as armies but you never know. Cavalry, for instance, has a larger base movement stat than artillery and if roads if a percentage based bonus then cavalry will gain more from them than slower units.

This part I can and will be working on myself, although quite how I am going to research it I have not yet decided. The campaign map does not obviously display its squares, so measuring is going to be tough.

[zhuge]

One minor issue here on the economics part. Quoting Quietus's economic guide (https://forums.totalwar.org/vb/showthread.php?t=40072):

"Highways: 50% land trade boost from Paved Road in originating city only. In my test, only 3 of 5 got the increase, the two lowest values didn’t increase. There maybe a) a distance limit how far a highway upgrade is effective (the two farthers didn’t get a boost) or b) only a fraction of the land trades get a boost (3 of the 5 were the highest values). Neither sea exports nor imports were affected by the upgrade. Currently, I’m leaning towards choice a)."


I made 1 check BEFORE patch 1.2 and it seemed to be true. IIRC, 3 out of 5 possible provinces adjacent to Patavium got the boost. Rather risky to make conclusions based on 1 observation though.
However since Quietus and I have essentially observed the same odd phenomenon, I would think that it is worth looking into. They might have 'corrected' it for the patch or perhaps it's still the way it is.

[therother]

Ah yes, I'd forgotten about that effect. IIRC, it's due to the other provinces not having a comparable level of roads. So to get the bonus from paved roads, the neighbouring provinces need at least basic roads. Similarly, to get the bonus from Highways, the neighbouring provinces need paved roads. As with zhuge, I haven't had time to check in 1.2 though. (*)

IIRC, there are also a few other trade income idiosyncrasies to do with Governor's buildings, but that's off this particular topic.

(*) Edit: Just did a very cursorily check with 1.2, using a 1.1 game, and it does seem to still be the case. Also, based on this quick check, the effect of roads on trade income does seem to be unchanged, although I recommend more testing. I do not currently have the time, I'm afraid.

[therother]

The campaign map does not obviously display its squares, so measuring is going to be tough.

There are two ways that I know of to count the tiles. The first is probably the best, especially over long distances, and certainly the most reliable. Place your cursor on the spot you want to get info on, and then enter the command show_cursorstat into RomeShell. The output should be something like this (cursor is over Tarentum):

pos 114,63 region id 63 (Apulia)

This means that the tile your cursor is over is 114 from the left and 63 from the bottom of the screen. You can measure distances this way. Also, the show_cursorstat can be used as many times as you like, unlike show other RomeShell commands.

The 2nd method is a little fiddlier. If you click and hold the right mouse button on an unoccupied map tile, an information box will pop up. It should show the type of terrain, the region name, and the region owner (via faction symbol and colour). Now if you move the cursor a little, with the mouse button still held down, the info box should move. Everytime the box moves symbolises a transition between tiles. Using this, you can count the number of squares. Note: this will only work on land, which shouldn't be a problem for your purposes.

[frogbeastegg]

The second method sounds like the safest one for a dyslexic frog, so I shall try that on a part of the map with a relatively straight stretch of road. The test will probably have to wait until the weekend though.

[therother]

I did a quick bit of research on your second topic. There seems to be some complications, but hopefully this will help you nonetheless:

Distance in tiles for different road types

This is the data from one test. I tested the distance each type of unit could travel along the vertical road from Bostra to its port.

I know, because I quickly checked, that there is some variance here, as I got 17 tiles for Calvary on Paved roads at some positions. I didn't find any difference between 1.1 and 1.2, although I only checked quickly. Also, I didn't notice any differences between the terrain types, although again I didn't check very thoroughly.

I don't see any obvious pattern:

% Increase from dirt

Progressive increase

Anyway, hope that is of some use...

[frogbeastegg]

Hmmm, thanks. Most interesting. My own tests were delayed until today (I haven't done highways yet though) but my findings for no roads, simple roads and paved roads mostly match yours, except my set is not nearly so neat looking. The discrepancy comes with paved roads; I found they offered a slightly larger boost than simple roads; 4 tiles instead of your 3. I suspect this may be down to the variance effect you yourself mentioned, and I would trust your set of results over mine simply because I know how poor at this kind of thing I am.

So ... highways are useful, but not really worth crying over if you are playing a non-Roman faction. They certainly aren't such a high priority item as the first two road types, as they cost a significant amount but the increase they provide is not so dramatic. Paved roads and simple roads deserve to be high priority items, IMO, but highways are now slipping down to a mid level priority, depending on location, trade income and the need for fast moving armies.

[frogbeastegg]

Highways have now been tested, and again we have a concordance between our findings. So I suppose that is it, job done. I do wonder what causes the variance in movement though, but I have no real ideas on how to investiagte that further. It's also not beginner's guide material, or at least not for the main 1.2 update, and the guide update has to be my main RTW priority now. Maybe in the future I will be able to come back to this.

Anyway, thanks for your help

[therother]

I was going to research a complementary area, that of the effect of terrain on movement, but it quickly became apparent to me that there was little or no effect. My plan was then to bring this data together with the data for the effect of roads, to see if a desert road allowed the same level of movement as a road through hills. I've still to check what effect height has on movement - it could be responsible for the variance. Hopefully I can get some time soon.

So ... highways are useful, but not really worth crying over if you are playing a non-Roman faction. They certainly aren't such a high priority item as the first two road types, as they cost a significant amount but the increase they provide is not so dramatic. Paved roads and simple roads deserve to be high priority items, IMO, but highways are now slipping down to a mid level priority, depending on location, trade income and the need for fast moving armies.

Good analysis - I agree with your conclusions.