Segments and Nodes
Types of segments (Highways)
Highways
In the US we can find diferent types of highways, we set the segment according to the road size.
A freeway is a highway with separated lanes, and without traffic lights or stop signs.
Only interchanges (ramps) and other types of highwats are used for entering or exiting a freeway.
Roads such as streets, primary streets etc. can't be connected.
Major highways have two one way roads, their access and exits could be a ramp or a junction.
In the picture you can see a combination of both: some of the turns are controlled by traffic lights and some are by ramps.
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A minor highway is a narrow intercity road, has only junctions. usually has one lane on each direction, and is not separated.
Highways usually have intersections but there are certain cases in which highways have traffic lights.
Ramps are used to exit or enter a freeway or a major highway.
Streets
Also in a city we can find different types of streets:
A primary street is usually a two ways road with more than one lane to each direction, it doesn't have a separation wall. In order to enter or exit that kind of road we use junctions.
Street is a small one or two ways road, small junctions are used to enter or exit from it.
Service roads are separated slow-speeds drivable roads, parallel to freeways/highways used as access points to buildings (usually used to reach gas stations).