How to generate a self-designed road network structure?

[cjybupt]

Hi, I am interested in your simulator for road graph. After reading the Waymax documentation in https://waymo-research.github.io/waymax/docs/autoapi/waymax/datatypes/roadgraph/index.html, I have known that your simulator supports loading data from Waymo Open Motion Dataset ,loading data from local disk and streaming data remotely via Google Cloud. However, I am wondering how to build my own map like the example format in https://waymo.com/open/data/motion/tfexample. Are there any simple methods to generate a map in this format? Is there a third-party software could help me build efficiently? plz help me,Thx!