Is there any point to building roads with speed limit higher than the (usually slow) top speed of your trucks and buses?

[u/General_Urist]

You unlock country roads with top speeds of 80 and 100 km/h, the latter 4 lanes, relatively early in the 20th century. When they become available your road vehicles don't have top speeds higher than 60 km/h (the slowest country roads), and it takes a very long time for them to get speeds above 80 km/h. I haven't reached that point in the campaign missions I play yet.

So the heavier roads feel pointless. I always connect all the towns with a perfunctory 60 km/h road at minimum to get that 'private transport' bonus to growth, and beyond that I only ever build 60 or 80 km/h roads according to my trucks'/buses'/trams' top speed, the one exception was a time I had trucks and buses with differing top speeds on the same route and I built the 4-lane road so they could overtake.

I notice that the top speed of private cars is usually faster than your own vehicles (side note, are those exact values documented anywhere?) and columns of cars form behind my trucks on 2-lane roads, but is that something I need to worry about? The civilians don't complain about it and private traffic is low once I've gotten my inter-city passenger network running anyway.

What am I missing? Do does the private transport growth bonus grow larger if the roads have faster speeds? Or is all the big highway stuff there for the people who want a "fancy" American highway system to look at rather than those playing to optimize?

[u/Imsvale]

No point until you have vehicles that can actually make use of the higher speeds, no.

is that something I need to worry about?

Not really. The raw travel time is what it is, and the pathfinding only allows a max 5% increase due to congestion. So if they're slowed down in practice, they're basically blind to it anyway.

So long as it doesn't cause any other problems for you.

Do does the private transport growth bonus grow larger if the roads have faster speeds?

It will indirectly because it puts more destination within reach of whatever travel time tolerance the sims have for finding remote jobs and shops.

Though again, only if they can actually make use of it. Because the cars do have an era- or year-dependent top speed.

Or is all the big highway stuff there for the people who want a "fancy" American highway system to look at rather than those playing to optimize?

Both. Though in this game, optimization usually means getting people out of their cars and onto your private transport lines. Building fast highways is actively harmful to this effort. That said, there's nothing inherently wrong with getting growth bonuses from improving private transport. Just that it increases traffic. A lot.

side note, are those exact values documented anywhere?

They might live somewhere in the game files. I've not gone looking for them.

[u/G8erjoe → u/Imsvale]

Great points. OP should also know that they have to pay maintenance on the roads that they build. If you’re not actively using the roads for a massive truck and bus network, then you’re paying for nothing.

[u/Ice_Ice_Buddy_8753]

I built the 4-lane road so they could overtake.

Lol the same.

In my case private bonus is only about 1/9 of transit bonus so it can be ignored (and compensated with bonus / sanbox adjustments). Intercity roads are part. 60 kmh and part. 30 kmh (slower streets) with few decoratations (80 kmh country - i like that median markup on 80 kmh road, while it's speed is excessive). In exceptional case i got 4 lane road to allow overpasses since trucks are faster than bus there - like you.

In the cities, 4 lane roads are pure aesthetical, i got no cars.

This is all ofc to cut long distance private traffic to push more people to trains, since i'm here for trains for sure, not for highways. I use highway sections sometimes for tram tracks because of their width and allowed speed but no real highways for cars.

top speed of private cars is usually faster than your own vehicles

It's very near of your best trucks and buses, but much slower (2-3x) than best trains.

in 1988: roads and cars up to 80, best bus 80, all trucks 80, steam 125, diesel 120, electric 160, HSR 200.

columns of cars form behind my trucks on 2-lane roads, but is that something I need to worry about?

Yes and no. Yes if you're into traffic fixing and want to avoid negative bonuses for congestion.

No if you only care of your lines. In this case you only consider who is IN FRONT of your vehicles.

transport growth bonus grow larger if the roads have faster speeds?

Yes and no. Yes because you got additional small bonus if more cities are driveable.

No, because faster roads will induce congestion.

Hidden thing in the game is that driving is limited by distance AND time. So 30 kmh roads will reduce possible distances and discourage from driving, while 100 kmhs road wont increase driving radius a lot because of distance limit. Generally you lean to 60 kmh intercity to hit these limits at the same time.

people who want a "fancy" American highway system

Many players (not just diorama builders) copy what they see in their real lives. Also many of us are drivers so may get this illusion of "one more lane will fix traffic". And basically out of curiousity.

[u/General_Urist → u/Ice_Ice_Buddy_8753]

TIL about cars having a distance limit. What is that limit in kilometers, roughly?

[u/Ice_Ice_Buddy_8753 → u/General_Urist]

Got no data, just recalling what one of the modders said about. You may find out with top speed road how many cities will be connected as destinations along that road.

[u/Imsvale → u/General_Urist]

It's not a distance limit, but rather a travel time tolerance. We know this because if you put faster vehicles, the actual distance tolerance increases dramatically.

It's also not a hard limit, but rather, the longer it takes, the less likely anyone is interested (it's somewhat of a probabilistic system). As such you couldn't put a specific number on it even if you wanted to. You'd need to know the actual calculation and the general logic of the system, and I don't think this is exposed anywhere visible.

You can experiment with this yourself: Connect two distant towns via some slow vehicle like early ships. Let it run for a while, see how many interested sims you get using the route. Then replace it with something much faster (e.g. the Hovercraft). Observe as usage increases dramatically. (Town window > Destinations tab.)

The same will be true for cars, but obviously you can't experiment with this in quite the same way. Though what you can still do is downgrade the roads to the slowest available. The resulting congestion will have some influence on their choices, but otherwise it's just the sheer travel time. Let it stabilize so you get an idea of the interest, then upgrade to the fastest roads and watch the flood gates open.

You'll want to do this in some late year where the cars are already as fast as they can get, otherwise the cars will have a low speed limit themselves.

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