Why is there a restriction on availing Input Tax Credit ( ITC) on the driver portion of the invoices?

As per section 17(5)(b) of the CGST Act, 2017, Input Credit for rent-a-cab service is restricted and accordingly GST applicable on such services is not eligible for Input Tax Credit. Since, the services provided by the Transport Service Providers (TSP) are in the nature of rent-a-cab service and hence not eligible for input tax credit.