“…In a more dense traffic scenario the vehicles could experience even a lower performance, for instance if they were forced to decreased to 5 km per liter, for the same distance, the resulting emissions would increment to 5.38 kg CO 2 e. Now, considering a portion of the General Cañas highway, where Herrera-Murillo et al (2013) [23] reported a transit of 90 thousand vehicles on a day in 2011. Applying the above considerations for a 10 km distance with high congestion, where 20% of the vehicles could have a performance of 5 km per liter instead of 10 km per liter, where 19% of the fleet are light freight trucks, and from which 88% use diesel (Villegas and Camacho, 2005) [29] , the total emissions of this kind of trucks could have been 16.2 ton of CO 2 e per day rather than 8.1 ton of CO 2 e if they would have been able to travel at the desired speed and performance.…”