important: how to create routable roads for car navigation system

I am an expert in gis (arcinfo :netwoek dataset for street ) and gps programmes ,mapsource< cgpsmap routable, mapedit and lots,
I have created roads map in arcinfo ,converted to mp then img for garmin , but I have free cgpsmap not routable >>>
but I want professional method to convert road maps to routable ones >>
I thing cgpsmap routable is stupid , bcz WE create all road network for our country…

repeat: how to make routable maps for navegation system in car ,which in cd or dvd
and what is the more much famous format in map cd of navegation system

I don’t know what GPS systems you are using, but if they are Garmin then you can use mkgmap to create routable maps from OSM data (it also works with MP, but most development effort is on OSM so some things may not work quite so well with MP formatted input data).