How to calculate proj-string when convert from CR to lanelet2?

Scenario Designer
1

I create a common road(CR) map by converting an OSM file to CR format, by the following command:

crdesigner map-convert-osm -i 250_550_1.osm -o cr.xml

Then I want to convert the CR map to lanelet2 format, by the following command:

crdesigner map-convert-lanelet -i cr.xml -o cr.osm -c --proj xxxx

How can I specify what proj-string I should use?
I tried not using the --proj option, but the result lanelet2 map seems a little distorted.

2

You can try this website to find a projection string.
However, it could also be caused by the quality of the OpenStreetMap data.
The converted CommonRoad map looks okay?