City logistics refers to the process of total optimisation of the logistics and transport activities in urban areas while considering economic, environmental, social and safety aspects. This paper considers a collaborative scenario for the urban goods transport planning and management as a way to reduce transport costs, congestion and environmental impact of this activity. An approach from the Operations Management field, using mathematical modelling, for tactical and operational decision-making is proposed to discuss and compare both collaborative and non-collaborative scenarios. This approach is validated using real data taken from the city of Bogotá, Colombia. Results put in evidence the quantitative benefits that can be achieved when collaborative logistics operations are implemented, represented in both transportation costs and environmental impacts. Although these results might not be surprising (like in the field of supply chain management), the contribution of this paper is centred in the fact that the impacts of collaboration in city logistics have not yet been quantified until now. This allows an 'ex ante' evaluation of the benefits of collaborative goods transport in cities.