Some Other Road Types Definition

SORTD; a new definition proposal for Road Types.

Currently, there are two "layers" of road; road, and tram. The second layer will be dispensed with and only one road type (and one road owner) per tile will be allowed.

13 bits are in use;

4 bits for road type (16 road types)
5 owner bits (m1 4-0)
4 road bits (m5 3-0)

Building, Crossing and Converting

Road types will be built like railtypes, with a drop-down menu for selecting different road types.

When a road is built across an existing road and the two are of different road types, and the road type with the highest rating supports all the powered and compatible roadtypes of the other, the junction tile will be the road type with the highest road rating property. It will remain owned by the original builder, even if the road type changes. If the higher rated road type does not support the compatible and powered roadtypes of the other, the junction building will fail, in a similar way to the current railtype implementation.

For example if a dirt road (rating 10) is built across a tarmac road (rating 80), the junction tile will be tarmac. If a highway (rating A0) is built across a tarmac road, the junction tile will become highway. If a highway (rating A0) is built across a tarmac road with tram track (rating 90), the building will fail because the highway cannot power or carry tram vehicles.

A conversion tool will be provided, as with railtypes. Roads owned by the company doing the converting will remain owned by the company. Roads owned by no player will become the property of the converter. Roads owned by another company will be converted only if the road rating of the new type is higher than that of the old type, and if all compatible and powered road types of the old type are supported by the new type. Ownership will remain with the original owner.

In all cases, ownership of road tiles remains with the original owner, unless there is no original owner. While this is arguably open to griefing (for example, a player could upgrade all of their opponents' dirt roads to highways, greatly increasing their property maintenance costs; or a player could remove the tram tracks another player built on their roads), this is not significantly worse than the current situation (players can already remove their own roads or tramtracks even if they are used by other players, or block roads with level crossings). Making the game ungriefable would be difficult to achieve and would mean sacrificing a lot of features.

Road Type Properties

Road types share the current properties with the rail types currently available.

Number	Size	Description
08	4*B	Road type label
09	W	StringID: Build road toolbar caption
0A	W	StringID: road construction dropdown text
0B	W	StringID: Build vehicle window caption
0C	W	StringID: Autoreplace text
0D	W	StringID: New engine text
0E	B n*D	Compatible road type list
0F	B n*D	Powered road type list
10	B	Road type flags
13	W	Construction costs
14	W	Speed limit
16	B	Minimap colour
17	D	Introduction date
18	B n*D	Introduction required road type list
19	B n*D	Introduced road type list
1A	B	Sort order
1B	W	StringID: road type name
1C	W	Infrastructure maintenance cost factor
1D	B n*D	Alternate road type labels that shall be "redirected" to this road type

Property 10 road type flags has the following bits;

Bit	Value	Meaning
0	1	Draw catenary for this road
1	2	Disallow level crossings for this road
2	4	Disallow building drive-in vehicle stops
3	8	Disallow building drive-through vehicle stops
4	10	Disallow vehicles of this type making U-turns and overtaking (eg, trams).
5	20	Road type cannot be built as one-way road
6	40	Road type can only be built as one-way road
7	80	Towns will use this road type when expanding or replacing road

Bits 5 and 6 should not both be set.

And introduce the following new properties;

Number	Size	Description
11	B	Minimum speed limit
15	B	Tractive effort multiplier
1E	B	Road rating

The minimum speed limit property is for high-speed roads such as highways. Vehicles which cannot achieve the desired speed will attempt to avoid these roads.

The Tractive effort multiplier has a base value of 0x80, and will reduce or increase the tractive effort of vehicles on these roads, to simulate loose surfaces etc. For example, you may set this to 0x40 (50%) for a gravel road, or 0x88 (110%) for a high-speed grooved highway.

The Road Rating property is used to decide which roadtype to use when building junctions, to allow overbuilding by other companies, and for towns when selecting a road to expand with. It is suggested that average tarmac roads be given a value around 0x80, with lower values for earlier and cheaper road types, and higher for more high-tech.

Road Type Variables

The variables for road types will be mostly the same as for rail types. Town zone (var 44) will be available for all tiles.

Additional variables;

Number	Size	Description
45	B	Road tile layout. bit 0 (1): NW piece bit 1 (2): SW piece bit 2 (4): SE piece bit 3 (8): NE piece.
46	4*B	Road type IDs of surrounding tiles; NE SE SW NW. 80 = no road.

See the talk page for an example of how these vars may be used for pretty tram track junctions.

Action 3

The following "cargo types" are accessed from Action 3.

This is quickly bashed together and subject to change. :)

'Cargo' Type	Sprite Type	#Sprites	Useage
00	Icons and cursors	12	2 road directions, autoroad, depot, tunnel and convert road. First all icons, then all cursors.
01	One-way markers	8	4 flat and 4 slope.
02	Road	17	13 flat and 4 slope. No landscape should be drawn (except, eg, pavement for in towns).
03	Tunnel	4	1 sprite for each direction. Sprite is overlay for road in existing tunnel graphics. The original ground sprite is drawn, then the overlay, then possibly an RV and the original tunnel head is drawn over the top. This keeps compatibility with different landscape types. Sprite order: SW, NW, NE, SE. If type 0A is defined as well, this sprite is used slightly different, see Tunnel portal overlay (0A).
04	Catenary wire	?	?
05	Catenary pylons	?	?
06	Bridge surfaces	6	10 sprites if we ever include diagonal bridges.
07	Level crossing overlay	2	2 road underlays
08	Depots	6	2 sprites for each southish, 1 sprite for each northish. Follows the original layout for depot sprites.
09	Street furniture	4	Trees and streetlights, or whatever else you want to put beside your roads.
0A	Tunnel portal overlay	4	1 sprite for each direction, order is SW, NW, NE, SE.
0B	Loading bays/stations	26	2 icons, 12 (4 ground tiles, 4 rear and 4 front tiles) for bus stations, 4 (2 rear 2 front) for bus drive-through stations, and 12 and 4 for lorry loading bays. Can use var 43 (Depot construction date).