E-scooter riders three times more likely than cyclists to end up in hospital, study shows

A team of researchers conducted a cohort analysis of scooter and bicycle injuries and found that young, helmetless and often intoxicated e-scooter riders were seen in Helsinki's emergency services at much higher rates than cyclists, highlighting a critical safety gap in urban mobility.

In a study published in the journal Scientific Reports, researchers quantified and compared the incidence, severity, and risk factors of injuries between e-scooters and bicycles.

Prerequisites

Picture a Friday night in the city centre: neon lights flash, taxis queue up, and the sounds of wheels carry on the traffic. Micromobility brings life to the streets, but previous studies estimated that about 10 riders per 100,000 end up in the emergency room after riding an e-scooter, while in Helsinki the rate was 7.8 per 100,000 trips – about three times higher than for cyclists. Unlike cars, these platforms have no crumple zone; the rider is the only “bumper”.

Young adults, night riding, alcohol and no helmets make for a dangerous combination. Knowing how scooter accidents differ from bicycle accidents will help inform speed limits, safety campaigns and bike lanes. Further research should confirm which measures actually reduce injuries.

About research methods

Small wheels, big falls: Having your feet closer to the road may allow scooter riders to let go of the handlebars more quickly, which may explain the lower number of broken arms compared to cyclists, who often try to brace themselves with their arms.

The team conducted a cohort analysis of injuries sustained while riding a stand-up e-scooter and bicycle in three emergency departments from 1 January 2022 to 31 December 2023. Anonymised cases were retrieved through keyword searches of hospital databases and records were checked for evidence of a crash. Age, gender, time of day, helmet use, alcohol testing and injury details were recorded. The most severe injury was coded using the AIS and the composite injury severity score was coded using the NISS.

Usage denominators: Vianova Cityscope ride logs for shared scooters and bike ride survey data. Injury rates per 100,000 rides and relative risks (RR) with 95% confidence intervals (CI) were calculated.

Continuous variables with normal distribution are described as mean ± SD; proportions are given as number and percentage. Fisher's exact test, χ², or Student's t-test were used for statistical comparisons at a significance level of 0.05. Analyses were performed in SPSS 29, taking into account STROBE recommendations. The Hospital Research Committee approved the protocol and waived informed consent; all procedures were in accordance with local regulations.

Research results

• Alcohol intoxication and traumatic brain injury: Among drunk riders, traumatic brain injury was 76% for e-scooter users and 63% for cyclists, demonstrating a sharp increase in crash severity under the influence of alcohol.
• Over two years, emergency departments treated 677 e-scooter and 1,889 cyclist victims. The average age was 33 ± 13 years versus 47 ± 17 years; men accounted for 64% and 59%, respectively. Helmets were worn by only 29 (4%) scooter riders and 522 (28%) cyclists. Alcohol was detected in 29% of scooter riders and 8% of cyclists.
• Based on 8.06 million shared scooter trips, the injury rate was 7.8 per 100,000 trips, while for 82.98 million bicycle trips, the passenger injury rate was 2.2 per 100,000 trips. The relative risk for scooters was 3.6 (95% CI: 3.3–3.9).
• Head and neck injuries occurred in 46% of scooter crashes and 31% of bicycle crashes. Cyclists had more frequent upper limb (45%) and trunk (11%) injuries. Craniofacial fractures were common in scooters (12%) and wrist and hand fractures in bicycles (9%). The distribution of AIS was similar, but scooter users had slightly more serious injuries (10% vs. 8%). The only critical case in scooter users was diffuse axonal injury; cyclists had one multiple intracerebral hemorrhage.
• In the intensive care unit (ICU) there were 8 (1.2%) scooter riders (7 with TBI, 6 intoxicated) and 12 (0.6%) cyclists. Surgical treatment was required more often by cyclists (13%) versus 8% by scooter riders, mainly orthopedic interventions for fractures of the wrists, collarbones and ribs. Inpatient hospitalization was low, but cyclists again outperformed scooter riders (9.8% versus 8.1%).
• By time of day, 69% of bicycle accidents occurred between 8:00 and 22:00, while 60% of scooter accidents occurred during this period, and 40% at night. Half of night scooter accidents were accompanied by alcohol, compared to 20% of night bicycle accidents. Helmets were rarely worn by drunk riders. Despite the 15 km/h night speed limit introduced in 2021, warm evenings still give rise to clusters of alcohol-related TBIs among city commuters - a trend that is consistent across all seasons and clinics.

Conclusions

More than half of the injuries in both groups were minor (abrasions or strains, AIS 1), although scooter users had a slightly higher proportion of serious injuries.

Thus, stand-up e-scooter travel carries a higher injury burden than traditional cycling. Scooter riders are younger, more often drunk and without helmets, and are particularly vulnerable to head injuries, while cyclists mostly injured their arms and torso, but were more likely to require surgery.

Even with the speed limit, the RR remains 3.6, indicating that behavior is the culprit, not technology. Municipalities should prioritize helmet use campaigns, include alcohol checks in rental apps, and consider additional restrictions on nighttime use.

Future prospective studies should test whether such measures, along with cycle lane redesigns, can reduce emergency department and intensive care unit visits. As with all retrospective observational studies, caution should be exercised in drawing causal conclusions, and incomplete or missing data may bias the results.