Jacek Kosiński advised the company Gϋlermak and PBDiM in the public procurement procedure for the construction of the Southern Ring Road of Warsaw and represented the consortium in the proceedings before the National Appeals Chamber, initiated by other offerors. All the resolutions of the Chamber were advantageous to the consortium of the firms Gϋlermak and the Road and Bridge Construction Company (PBDiM). The section constructed by Gϋlermak and PBDiM covers 6.45 km, from the interchange Przyczółkowa to the interchange Wał Miedzeszyński, including erection of the southern bridge.