After crossing the Vaal River, the N1 continues towards Johannesburg, bypassing Vanderbijlpark and featuring another toll plaza at Grasmere. At the southern outskirts of Johannesburg, the N12 once again meets the N1, and they are co-signed northwards for a few kilometers (bypassing Soweto) before the N12 splits off to become the Southern Bypass portion of the Johannesburg Ring Road. From just north of the Vaal River the N1 changes from being a tarred road to a concrete road, until just after the N12. The R553 Road off-ramp in between the two N12 interchanges marks the beginning of the N1 being an e-toll highway (with open road tolling).