Topic: Overtaking very slow vehicles, bikes in traffic jams, etc...

[Vladki]

Just a few random ideas sparked about the "know your horses" thread.

Problems:
1. A mail bike in modern city cases traffic jams (even if the town is not jammed anyway), or gets caught in jam which in real world would not be a problem for a bike.
2. Game without timeline spawns private horse carriages, causing jams too.
3. It is impossible to build a roadside bay stop, where a bus would pull aside to load/unload, while other traffic can pass in both directions.

Solution.
1. We have a few road vehicles, that are mostly narrow (and slow): bikes, horse riders, livestock drover, maybe others (e.g. pizza delivery motorised scooter). These could be overtaken even if there is traffic in opposite direction. They also could overtake standing (jammed) vehicles. Allowing this would add nice use to mail bike in modern times - priority mail delivery in jammed city...  However this would require a new dat option (is_narrow = can_overtake_anywhere = can_be_overtaken_anywhere), similar to flag for double decker buses.

2. The roads in simutrans are quite wide - there is an extra lane in the middle for trams to pass. One tile of rad is 125 m which is quite a lot for overtaking a slow vehicle. Would it be possible to relax the overtaking rules, if the speed of overtaking vehicle is 2x-3x higher than of the one being overtaken? Perhaps with additional check that there are no tram tracks - to make it appear as the overtaking car is using the tram lane. This could apply to overtaking with narrow vehicles too.

3. We have an overtaking mode allowing overtaking "only loading convoi".  What would be imho more appropriate is to relax rules for overtaking loading convoy, in similar way as 2. Or to make it a new explicit overtaking mode, perhaps even with some costs (for building the bay).

[dannyliux]

For 1. I was thinking, since we are able to build tram tracks on top of roads, would it be possible to have a new waytype for pedestrian pathways that can also be built on top of roads? It could act as a dedicated path for pedestrian type ‘vehicles’ such as the mail boy and post bike, and could be auto generated by the city. Players can place it on top of their own roads or countryside roads that were generated without sidewalks. This way bikes and runners won’t interfere with road traffic. Just a thought.

[Vladki]

I wouldn't say so. Bikes and horses should not use pedestrian sidewalk. And "mail boy" or "post boy" is not pedestrian but a horse rider.

[freddyhayward]

Some of these problems are actually bugs that I'm working on: simutrans.com/index.php/topic,20049.0.html
As of the latest patch, player vehicles can now overtake each other on two-way roads except when there is another vehicle or intersection in front of them. For reasons I don't understand, private car overtaking on two-way roads doesn't work.

[Ranran]

I wondered if pedestrians like carts and mailmen could have the attribute is_pedestrian=1 and ignore tile occupancy like ships, but I don't know how difficult it is.

[Ves]

One of the real big limitations to road vehicles is that there can only be one convoy at each tile. This is problematic especially in high density cities, where there might only be 2-3 tiles between intersections, allowing only 2-3 small tiny winy postmans to be there as well.
Allowing road vehicles to wait directly after one another would help greatly on the density of a city, making it more realistic, and I believe will help solve some of the other issues as well:

Overtaking - The overtaking convoy has potentially a much smaller distance to cover when overtaking
Road/"pedestrian" convoys -  As this is typically very small vehicles (read short vehicles), these will also be much easier to overtake, thus much more frequently done so. Although it would not elimitate/solve the raized issues completely.


Other than that, I agree that it would be nice to have a dat-file parameter like the one Ranran suggests, although I wonder if the word "pedestrian" is the correct term. Perhaps "narrow" is better as that is more universal.

[Ranran]

Yes, another expression may be better.
It's the difference between a roadway and a sidewalk.
In many cases, the thing that goes through the sidewalk is not a vehicle, but there may be an example like a bicycle.

[jamespetts]

It would certainly be a good idea to have a more nuanced representation of road traffic, including
(1) multiple vehicles in the same direction on the same tile (the number allowable being based on the vehicle length in proportion to the tile length);
(2) vehicles that can be overtaken at any time, such as bicycles;
(3) player vehicles being able to be overtaken at any time when servicing stops, e.g. 'buses; and
(4) terminal road vehicle stops with a capacity of four simultaneous vehicles rather than the current type with a capacity of only one (worse than non-terminal stops, which have a capacity of two, being one in each direction).

Adding these features would take a substantial amount of work, however, and I cannot prioritise these above balance critical features. If anyone else would like to work on these, this would be most welcome.