What's the deal with traderoutes?

[AkwaticDudeCity]

We all know the golden rule; the farther away and the bigger the demanding city is, the more gold the caravan will collect. But does the same go for the amount of 'trade-arrows' in the respective cities?
I thought it did, until i actually tested it in a scenario (Joel André's Crusades). I had a traderoute open from Caïro (size 18) to Constantinople (size 16), which is 25 squares away. That generates 18 'trade-arrows'. Then i discovered Iceland. For testing i put a new city on the island and edited it to size 25. That city was 63 squares away from Caïro, and yes, the caravan generated more gold than the caravan to Constantinople, but the 'trade-arrows' amount was a measly 8 ... AAARRGH!!! The distance was 63! squares for crying out loud. And it had nothing to do with the city being mine, in fact i let it be captured by the Holy Roman Empire and tried again to no avail.
Then i figured maybe it was because the traderoute was brand new and maybe extra 'trade-arrows' get added every so many turns. So i built another city near Caïro, edited it to size 25 and tried again... AAARRGH! It generated just 2! fooking 'trade-arrows' with the city in Iceland and 6 with Constantinople.
Please can anyone explain me what the KruD is going on here? ...please anyone

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ugh crud, why won't they fall prey to my Machiavellian schemes?
<font size=1 face=Arial color=444444>[This message has been edited by AkwaticDudeCity (edited March 14, 2000).]</font>

[Sieve Too]

Per-turn trade from a route and the bonus for establishing the route are not functions of exactly the same variables. IIRC the per-turn trade is a function of the total trade being generated in the two cities, whether the cities belong to the same civ and whether you have Superhighways.

The trade route bonus is a function of all the above variables plus several other variables: distance, whether on same continent, whether cities road connected, Caravan vs. Freight, whether Airports in both cities, which commodity, whether commodity is demanded, whether Railroad discovered yet, whether Flight discovered yet, probably more...

All the additional variables make it difficult to correlate the bonus with the per-turn value of the route. But do note that things like distance, different continents and such do not matter at all in determining the per-turn value of the route.

[Sten Sture]

Supposedly the per-turn trade benefit of a route is:

Route = ((raw trade arrows of City A) + (raw trade arrows of City B)+ 4)*modifiers)/8

Both cities are yours -50%
Airports in both cities +50%
Superhighways in home city +50%
*Cities connected by road +50%
Cities connected by rail +50%
**Freight instead of caravan +50%
**Cities on different continents +100%

* - I think this is just the individual square benefit

** - I think these are actually applied just to the one time bonus.


(this might belong on the strategy forum... )

[Sieve Too]

Thanks Sten! I vaguely remember somebody testing all this in the somewhat distance past and IIRC the part about road and rail connections doesn't matter.