This is my main Minecraft project.
It was the first ever world I started in Minecraft, back in May 2011.
I build a highway network consisting of varying road classes.
In the future, I plan to build cities. I am not a very skilled builder however, so this will take several years.

Classification:
M roads are motorways with at least 4 lane (2 in each direction).
A roads are main routes with at least 2 lanes and usually with a median fence.
B roads are minor roads.

Road numbering:
Odd numbers: north/south bound
Even numbers: west/east bound
(With exceptions)

Road surface and materials:
All new roads: Grey concrete powder (252:7). Looks the most like asphalt in my opinion
Older roads: Andesite (1:5). Looks like worn asphalt
One section on M1S: Light grey concrete powder (252:8). Looks like concrete road surfacing.
Lane lines: White concrete (251)
Left shoulder line/direction separator: Yellow concrete (251:4)
Traffic barrier: Acacia Fence (192). Looks the most like rusty traffic barriers (used in Norway)

Built so far:
M1: North/south main corridor. 6 lane motorway. Most of this has been deleted, as I'm replacing it.
M2/A2/B2: West/East main corridor. 6 lane motorway. Features an unfinished rest area just west of new M1 (will be rebuilt by new M2 later)
M1 and M2 are connected in the middle of the map with a roundaboout.
M1N to M2E slip lanes: 2 motorway lanes going from M1 northbound to M2 eastbound, bypassing the roundabout. Also has exit towards my house.
A3: North/south corridor. 2+1 divided highway with grade separated intersection (currectly only 1 with A9)
M5: North/south corridor in the west of the map. 4 lane motorway. Begins where M2 turns into A2 in the west.
B7: North/south corridor in the far west. 2 lane road. Completely straight, and cuts through the terrain. Will probably be rebuilt sometime.
A9: NW/SE corridor. 2 lane road with median fence. Starts at M1/M2 roundabout, Ends at A3.
B09: old "A9". Runs along A9. Currently only connected to new A9 at one end. Also is connected to a village.
B11: 2 lane road. Stars where A9 ends. Goes north-east.

Under construction:
new M1: will be a 8 lane motorway with dedicated truck lanes (in each direction: 3 car lanes, 1 truck lane)
most other roads: They will either be terminated at other roads or end at "end of map"

New M1 and M2:
Will replace old M1 and M2.
Will be built as 8 lane motorways (in each direction: 3 car lanes, 1 truck lane), featuring grade separated interchanges, and separate carriageways. They will diverge in some places and rejoin (ie. one direction going on one side of a mountain)

Tools used:
WorldEdit
Creative mode
JourneyMap
Photoshop (Curvature pen tool)