| Barriers and problems | Number of studies | Facilitators and benefits | Number of studies |
| Fear related to safety/accidents | 10 | Opportunity for sociability | 10 |
| Lack of sociability | 8 | Improved safety/reduced accidents | 7 |
| Cultural factors | 7 | Accompanied travel | 5 |
| Crime | 7 | School/local authority influence | 4 |
| Time pressure | 6 | Time pressure | 3 |
| Quality of surroundings | 6 | Training | 3 |
| Gender differences | 5 | Quality of surroundings | 3 |
| Peer pressure | 5 | Gender differences | 2 |
| Travelling alone | 4 | Peer pressure/status | 2 |
| School influence | 3 |