What is Route Network Definition File (RNDF) for Self Driving Car

One of the 4 core parts of a self Driving Car Software stack is Planning. And RNDF or Route Network Definition File is the first thing PLANNING uses.

An RNDF is a tab-delimited ASCII file. It basically defines the Roadsegments and Zones.

The typical format of an RNDF file looks like the following.

RNDF_name filename (string)

num_segments number_of_segments (integer>0)

num_zones number_of_zones (integer≥ 0)

format_version format_version (string)

creation_date creation_date (string)

<segment 1>

.

.

<segment M>

<zone M+1>

.

.

<zone M+N>

end_file

Just looking at the format, we can clearly see that the RNDF file contains details about segments and zones. Here is an example of the road segment

Fig 1: A road segment (Segment M) comprised of two lanes. Lanes do not necessarily have the same number of waypoints. (https://www.grandchallenge.org/grandchallenge/docs/RNDF_MDF_Formats_031407.pdf)

Now let’s look at the format of each segment. It should start making sense now

segment segment_id (integer>0)

num_lanes number_of_lanes (integer>0)

segment_name segment_name (string)

<lane 1>

.

.

<lane n>

end_segment

But it is not complete Just looking at Figure 1, we see that more information need to be defined. Like the lane_width provides the width of the lane in feet. We also need to define the number of waypoints and their location. We need checkpoint which indicates that the waypoint is a named checkpoint. The keyword stop indicates a waypoint associated with a stop sign. The keyword exit is followed by the name of the exit_waypoint and related entry_waypoint or entry_perimeterpoint associated with the lane. A lane may have multiple checkpoints, stop signs, entry waypoints, entry perimeter points, or exit waypoints. Here you go:

lane lane_id (x.y; x,y∈ integer>0)

num_waypoints number_of_waypoints (integer>0)