This study attempts to uncover the most common issue of fuel shortage faced by the oil and transportation industry worldwide. In Pakistan, petroleum is transported to the northern areas from the south coast. Currently, this is done using road tankers as a pipeline is still under construction. However, even after the pipeline becomes operative, road tankers would still be used for intra-city transport. Findings from this study can be used to determine the inter-city transport losses faced by oil companies. This study determines the hydrocarbons lost to the environment during inter-city road transport of petroleum. It takes nearly 2–3 days to complete a one-way trip with the fully loaded tank. Much work has been reported worldwide on hydrocarbon emissions, but nearly all of it has been done either for storage tanks/vessels or fuel tanks in rails/cars. The aim of this study was to investigate the actual amount of fuel lost to the environment due to the sloshing of liquid. Also, the results were expected to help in determining the extent of hazardous emissions resulting from road transport of petroleum. Hence, measures could be taken by the concerned authorities to mitigate the emissions if they exceeded the acceptable range. The sloshing was not found to contribute much in terms of vapor loss. Valve location was found to be important as no loss was obtained from the third compartment because the valve is to the right in this chamber. A negligible amount of fuel was lost from the first and second compartments per application of the brakes. Over a whole trip of 2–3 days, if the tanker braked 500 times, a total of 9–10 L would be lost to the environment.