Map

OpenDRIVE

from paper ref

Individual lanes are created by specifiying a lateral distance from a reference path whose ID is 0, lanes on the right have negative decreasing IDs and have same direction as the reference path, lanes on the left have positive increasing IDs and have the opposite direction.
Reference path are constructed by concatenating clothoids (aks Euler spirals) or (polynomials).
- Arc segments and straight lines are special cases of clothoids.
- Reference path segments are seperated based on curvature types.
  - Straight linle: curvature c = 0
  - Clothoid: curvature changes linearly
  - Arc: curvature is constant
The reference path is divided into multiple sections based on the number of lanes.
- Lanes have no empty space between them, to introduce gaps, one has to create an additional lane of a special type non-road type.

from official docs ref

OpenDRIVE schema can be generated by xsd tool.
OpenDRIVE has no stop lines defined.
Lanes
- Lane ID is descending from left to right. Positive number on the left of the reference line, negative number on the right.
- Left could be missing for one way roads. Lane 0 is the reference line which has width 0.
- Same lane Id may link to another lane Id of succeeding/preceeding roads due to the change of number of lanes.
Traffic signals and traffic signs are all called signal which will be distinguished by the property dynamic.
Every element based on the reference line needs to know its relation in terms of the orientation of the reference line.
All other things like parking space, cross walk or undefined things need to be defined through object type.