One of the most common safety issues at work zones is high speed variation. Nevertheless, few studies have addressed psychological variables to deepen the understanding of drivers’ speed choice in work zones. The present study examined whether work zones represent a type of situation that may trigger the expression of certain personality traits resulting in large individual differences in speed preferences. An additional aim was to study whether the expected relationship between personality traits and speed in work zones was dependent upon the presence of visible roadwork activity. Four sub-scales of the UPPS-Impulsivity scale (perseverance, premeditation, negative urgency and sensation seeking), a measure of altruism and a measure of normlessness were chosen for this purpose. A video-based experiment of real work zones was used where drivers (N = 815) stated their preferred speed in conditions with and without roadwork activity present. Afterwards, they answered an online questionnaire with the study variables. The presence of roadwork activity was the strongest predictor for speed, resulting in a relatively large reduction in preferred speed. The effect of roadwork activity was also found to moderate the relationship between normlessness and speed as well as perseverance and speed, suggesting that the presence of this contextual factor to some extent influences the relation between personality traits and preferred speed. A serial mediation model showed that sensation seeking, altruism and normlessness had weak, but statistically significant indirect effects on preferred speed in work zone through attitudes towards speeding. Negative urgency had an indirect effect on preferred speed through risk perception, but in the opposite direction as expected. The practical implications such as in planning countermeasures are discussed, as well as in interventions targeting attitudes and risk perception specific for work zones.