The paper outlines as follows: Section 2 consists a literature review on methods for emission estimations based on sensors measurements. Section 3 provides a description of the methodology of estimating emissions from cross-sectional data by either using AADT estimation techniques or more sophisticated traffic estimators. Section 4 presents the case study that is a part of the E4 motorway in Stockholm, and provides details about the data collection. The results are presented in Section 5 and finally Section 6 concludes the study and discusses future work.