Problem: In many countries, a new road user group, e-scooter riders, share the existing cycling infrastructure. The study aimed to investigate if an individual's status as a cyclist or e-scooter rider affects their social identity and whether it results in ingroup favoritism or outgroup discrimination. Method: An online experiment involving 179 cyclists and 64 e–scooter riders was conducted, where they rated the behavior of ingroup or outgroup members in six traffic scenarios. Results: Participants rated dispositional attributions as more causally relevant than situational ones across all traffic scenarios. Cyclists and e–scooter riders were inclined to judge ingroup members' rule violations more harshly than those of outgroup members in terms of dispositional attribution ratings and punishment severity. For situational attributions, few indications of ingroup favoritism were observed for the e–scooter rider group. Summary: Findings suggest initial indications of considerate coexistence, from the perspective of social identity theory, between the two modes of transport, supporting current regulations on the use of cycling infrastructure by e–scooter riders. Indications of ingroup discrimination, however, suggest that safety campaigning may target to promote courtesy within the cyclist and e-scooter rider groups.