Toll tax is not any kind of tax, actually, it is a Value charge for service like, mobile service, decoration etc. for which rendered money falls in GST.
If Toll charge is Rs 100 then It will be Base Price + GST.
The main concern of Toll charges is to get money back by Road, Bridge building agencies, Government as per profit sharing, maintenance of road according to contract for years to operate. In so many cases few roads, bridges charges abolish after the recovery or payback period of that asset.