Companies are increasingly being held accountable for the life‐cycle impact of their products and services. Transportation is frequently a major component of this life‐cycle impact. Hence, to reduce total environmental impact, logistics managers will have to become more sophisticated in their understanding of how they can reduce the environmental impact of their transportation operations, without negatively affecting the cost or effectiveness of these operations. In line with this mandate, we quantify the dynamic impact of road vehicles on the environment. In most emission models, a constant speed is used depending only on the specific road type. Using such a model will lead to an underestimation of the effective emissions. It turns out that the differences with a more realistic dynamic assessment model are significant. The analysis here suggests that the policy consequences of these differences for both public sector managers and private companies are potentially quite important.