Can I somehow prevent the construction of connecting roads to new industries?

[fhaag]

I am trying to add transportation of all kinds to a large sandbox map.

I have recently upgraded from Simutrans-Extended 120 to 123 (specific new version see below). One change I noticed is that newly built industries (both those explicitly built and those added by means of the "Increase industry density" feature) now automatically get a connecting road.

Unfortunately, that road can be quite extensive and leads just anywhere ... no matter what is in the way. This entirely sabotages any attempt of mine to build a network of access-controlled highways (with one road per direction), as the auto-generated road will mercilessly lead across those lanes, connecting them in the process.

While I have not closely observed the effect, I fear the same may be happening when new industries emerge on their own, as they occasionally do.

Is there any way to prevent this auto-generation of connecting roads?

Simutrans verison: Simutrans 123.2 Extended nightly 14.23
Pak128.Britain-Ex (v 123.7, e 14)

[209CATrus]

First of all, check simuconf.tab, i believe there should be a setting for that. Secondly, you have an option. Let's start with public road system bit **** (sorry, Isaac, but this is how things are there, in Extended) up regarding what is considered a building required being connected (for example some of your own buildings are), but i hope you'll get through that. Secondly, THIS IS REALISM GAMEPLAY, this ain't Stone Age era gameplay, where buildings are built in the middle of nowhere with no road connection required (at least public ones).

The option is that you provide an alternate way to the public road system. That means you pick a piece of public RoW road, place a detour next to it, cut it out, repeat for as long as you need it. Given 2 posts out of 2 of yours are fixated on road building, you must understand that the public road system, while it's clunky, works ALMOST as supposed. The people of SimuEx might be dumb, but surely are smart enough to understand that they NEED to have option to get from A to B on their own. They won't build it themselves, but they will keep it once they found a way. So you VVILL build an access to your highway

The PRoW system has it's benefits in multiplayer, although not perfect. It somewhat disallows players to secure (through less dirtier means than potentially available, i'm looking at you, multiplayer enjoyers) exclusive rights to access a public building

[Isaac Eiland-Hall]

Different players certainly can have different opinions on how things should work. The nice thing about Simutrans is how many options there are to allow for differing styles of gameplay. The way I play is different from the way many people play.

Sometimes, there aren't options - like for so many years, roads in cities had forced speed limits. That's just how the game worked.

So it can be a good idea to come up with ways of dealing with problems that the game throws you.

As a fan of building multi-tile–wide freeways, I'd suggest protecting them with fences. The paks that include fences typically keep them cheap, but it might require making a custom pak for the purpose.

[fhaag]

First of all, check simuconf.tab, i believe there should be a setting for that.

True that, maybe setting auto_connect_industries_and_attractions_by_road to 0 will help.

The option is that you provide an alternate way to the public road system.

Oh, I do that, I want to do that. I'd just like to skip the extra effort of cleaning things like this up:

Or this:

Or this:

As a fan of building multi-tile–wide freeways, I'd suggest protecting them with fences.

Thank you, I'm looking at some posts that imply there are some fences available that can be somehow integrated into existing paksets. Anyway, this makes me wonder whether having one-way roads and the like makes any sense at all without fences, because the auto-generated public roads can always grow into them.

[Isaac Eiland-Hall]

I play on standard, where it's only an issue around city limits, so I only protect close to cities (larger than city limits so when the city grows...)

Seems like here fences would make more sense.

but in fairness to Simutrans, multi-tile roads are pushing the engine a bit, since the original scale was 1km² per tile, that means freeways are two kilometers wide.

[fhaag]

For what it's worth, I don't want a multi-tile road. It's just that apparently, that's the only way to have roads on which vehicles can overtake each other, and where they cannot turn around just anywhere, but the directions are actually separated.

[Isaac Eiland-Hall]

Unless extended is different from standard, vehicles can overtake on single-tile roads, it's just a matter of having straight sections and no oncoming traffic as well as being fast enough to overtake. But I admit that I don't pay as much attention to that in my games.

[Octavius]

it's just a matter of having straight sections and no oncoming traffic

Which practically means that overtaking is highly exceptional. This isn't really unrealistic though. In my country (Netherlands), overtaking is allowed on most roads, but usually practically impossible if there's just one lane per direction. Only when traffic is very sparse (like middle of the night) it's possible, but then you're unlikely to encounter anyone you might want to overtake. It's a side effect of having junctions close together.

Real life also suggests a solution to the problem discussed in the original post. We have (in my country, in the modern day) three classes of roads, all of which come in a rural and an urban version. I think I posted a similar table before.

class	version	speed limit (km/h)	vehicle access	building access
first	rural	100–130	limited, >50km/h	no
first	urban	80–100	limited, >50km/h	no
second	rural	80	open to all, but bicycles discouraged	some large factories and ports
second	urban	50–70	open to all, but bicycles discouraged	some large factories and ports
third	rural	60–80	open to all	all buildings can connect directly
third	urban	30–50	open to all	all buildings can connect directly

First class roads cannot connect directly to third class roads, but only via second class roads. Many older roads don't fully conform to these standards. 'Bicycles discouraged' means that road owners are encouraged to provide a separate bikepath.

What does this mean for Simutrans?
The roads built automatically to connect one city to another are all 2nd class. These are only built during map creation (afaik), so they won't interfere with player-built motorways. Diversions added to a 2nd class public right of way are 2nd class too. Maybe city buildings can be build along a 2nd class road, maybe not (it would be more likely in early days than in modern days), but in any case there can be 3rd class side streets and city buildings would be allowed in the corners.
Automatically built city streets and automatic access roads to rural industries would all be 3rd class. These will never connect to 1st class roads.
Motorways (and some single-carriageway express roads) are 1st class roads. They are not (or less) affected by city speed limits. They don't get publicly owned when absorbed by a city. Until Simutrans gets a way to build motorways automatically, no 1st class roads are generated automatically. The 1st class road doesn't forbid city buildings, but it's ignored by the city building placing algorithm and any personal cars spawning from the city building would be put on a 3rd class road also adjacent to the building.
Naturally, players can assign the class of the roads they own.
This simultaneously solves 4 issues:
- Automatically built roads to rural industries no longer break motorways.
- Automatically built city streets no longer connect to motorways, without requiring space-consuming fences.
- Motorways no longer suffer from the automatic city speed limit.
- City speed limits varying with road class will guide city traffic to preferred routes.
Now I suppose you all expect me to code this myself...

[Combuijs]

"Now I suppose you all expect me to code this myself..."

Yes, of course :-) . And apart from programming skills the first problem you will encounter is that there is no concept of a road (as in leading from A to B) in Simutrans. There are only tiles which you can pave with a road piece, telling which of the four tile sides is connected to which of the remaining three tile sides. So, it's not possible now to give a road a classification. That's a major obstacle to your concept.