This study aimed to analyze the concentration of %HSU (Heavy Smoke Unit) in the exhaust emissions of freight trucks in Manokwari Regency. It employed a quantitative research approach and utilized incidental sampling to select a total of 30 vehicles as samples. To examine the relationship between exhaust emissions and vehicle characteristics, linear regression analysis was employed. Out of the 14 vehicles (46.67%) that failed the emission test, only 2 (14.29%) were produced before 2010, while the production of the remaining 12 (85.76%) was after 2010. Simultaneously, Cylinder Capacity (X₁), Trip Length (X₂), Vehicle Age (X₃), and Vehicle Maintenance (X₄) influenced the %HSU value (Y). This was indicated by the very small p-value (0.000), where the mean differences between the groups were highly statistically significant. The results showed that the independent variables were mutually related and collectively have a significant impact on the %HSU value.