This paper documents an analysis of fatal work zone crash data on US roadways for calendar years 2012 through 2014 in order to better understand when and where large trucks tend to be most overrepresented in those fatal work zone crashes. Odds ratios were used to assess the time periods for key functional roadway classifications where large truck involvement was significantly overrepresented. It was found that large truck involvement in fatal work zone crashes on rural principal arterials is significantly overrepresented during the midday and PM peak time periods; for urban principal arterials, large truck overrepresentation occurs during the nighttime and midday time periods. Although the principal arterials experience the greatest percentage of large truck-involved fatal work zone crashes, the magnitude of overrepresentation tends to be highest on collectors and local roads. Even so, more than 50 percent of fatal work zone crashes on rural principal arterials involve a large truck.