There is limited information about the behavior and movement of people in case of fireevacuation in smoke-filled environments, and there is limited guidance on how peoples’walking speed in smoke can and should be represented in the fire safety design process.In this report, a literature review within this area, and a subsequent recommendation onhow to represent walking speed in both smoke-free and smoke-filled environments ispresented. The recommendation includes three different methods to represent the peoples’walking speed in a life safety verification, depending on how the treatment ofuncertainties is done on an overall level within the analysis. Finally, in the end of thereport, a direction for future research in order to reduce the current uncertainties ispresented.