This thesis includes the research performed to investigate how to move away from the current adversarial practices in the Dutch infrastructure sector found in the current way of contracting. Adversarial practices are defined as each party pursuing their own concerns at the other party’s expense. As a result of this, the industry is not performing to its maximum. The objective of this research is therefore to stimulate client-contractor collaboration in Dutch innercity infrastructure projects in order to move away from the adversarial practices. In the way the current UAV-GC is applied in projects, dysfunctional conflicts arise between the client and contractor. This research aims to find opportunities for improvement in the UAV-GC by means of clauses from the NEC4 ECC contract. The NEC4 ECC contract is a relational way of contracting, which is relatively new for the infrastructure sector.