When do shared e-scooters complement or compete with public transport? A mixed-method review and comparison with bike sharing

E-scooters are one of the latest additions to transport networks in many countries and their popularity is increasing rapidly. A range of studies have been conducted to understand the relationship between e-scooters and public transport. Some found that e-scooters complement public transport, serving as a first mile/last mile access mode, whereas others found that they compete by taking riders away from public transport. The contradictory results of studies in different contexts make it unclear whether results in one city are transferrable to another. This study aims to explore the definitions of ‘complement’ and ‘compete’ in literature and to identify the circumstances where e-scooters complement or compete with public transport using a mixed-method literature review. We combine a systematic literature review of e-scooter papers with a scoping review of bike-share studies to see if the two modes act in a similar manner. Most researchers found that e-scooters tend to complement rail but are more likely to compete with buses. Bike-share behaves in a similar manner, but the competing effect with buses is higher with bike-share than shared e-scooters. Both shared e-scooters and bike-share have a complementary relationship with public transport for commuting and longer trips. Moreover, shared e-scooters have the potential to promote public transport when deployed thoughtfully, but further investigation is needed given the novelty of the field. Further research should focus on a wider variety of cities (particularly outside of Europe and the USA), the reasons behind rider behavior and different ridership patterns and characteristics of personally owned e-scooters.