Two indices of activity space measurements using Euclidian distance measurements have been argued to be able to measure specific visited out-of-home activity locations closer to activity space definitions than other methods. However, the Euclidian distance does not consider any barriers or obstacles, such as the existence of public spaces (e.g., army bases, government offices and airports) or natural barriers (e.g., mountains, hills and agricultural fields that have no road infrastructure). Therefore, this study tries to fill the research gap by measuring the two indices using road network distance. Moreover, this study tries to determine whether the activity space of different generations, namely Generations (Gens) X, Y and Z, is significantly different, and whether some socio-demographic and activity pattern variables can help differentiate the activity space measurements. Using the 2019 Yogyakarta Metropolitan Area (YMA) dataset, this study confirms that measuring activity space using road network distance statistically gives different results from activity space measured using Euclidian distance. Moreover, this study confirms that the oldest generation had opposite activity space patterns in comparison to Gens Y and Z. Unlike the younger ones, the oldest generation visited out-of-home activity locations nearer to their home locations on weekdays but expanded to visit farther out-of-home locations on weekends. Trade-off mechanisms were found between weekdays and weekends, by which Gens X and Y significantly visited out-of-home activity locations farther from their home more often on weekends than on weekdays. However, all generations were observed to visit out-of-home activity locations near their out-of-home activity anchors every day, whereas the oldest tended more often to visit the activity locations farther from their out-of-home activity anchors than the younger generations on Fridays and Sundays. © 2022 by the authors.