The main cities of the world face traffic congestion as one of their biggest problems for their operation and development; it is increasingly difficult to move from one place to another. The aim is to determine the degree of future improvement in mobility in an area of high traffic congestion for any city. The research provides a methodology to determine the variation of the Level of Service (LS) from the speed of circulation of vehicles on urban roads in a congested area with the implementation of a congestion fee and was applied to the downtown area of the city of Medellin. The results obtained indicated for the hypothetical charging scenario a 15% increase in the average speed of circulation in the internal roads and a 5% decrease in the average speed for the surrounding ring roads; regarding the NS of the roads, in the internal zone approximately 2.5 km (14%) of roads improve the NS going from a less favorable level of service to a more favorable one, despite this variation, 40% of roads (7.4 km) continue in unfavorable NS (D, E and F).