{
  "slug": "e-scooter-serious-injury",
  "question": "What are the odds of serious injury riding an electric scooter?",
  "category": "transport",
  "no_reliable_estimate": false,
  "perceived": {
    "description": "Electric scooters occupy an odd perceptual space. Casual users treat them as toys — low-speed, short-trip, no protective gear required by instinct or habit. The CDC's Austin study found that fewer than 1 percent of injured riders had been wearing a helmet. At the same time, emergency physicians and public health researchers have raised alarms about a rising tide of scooter-related ER visits, and the CPSC's recall of 300,000 Onewheel self-balancing boards after four deaths drew national attention to the broader micromobility injury problem. Most riders underestimate the risk; most non-riders who have read a headline overestimate it.\n",
    "rough_estimate": "casual riders rarely think about injury probability; headline-readers assume it is very high",
    "kind": "intuition"
  },
  "native": {
    "display": "~20 injuries per 100,000 e-scooter trips (Austin, TX, 2018)",
    "numerator": 20,
    "denominator": 100000,
    "unit": "per trip",
    "population": "e-scooter riders, Austin TX shared-fleet study period"
  },
  "normalized": {
    "lifetime_us_adult": 0.039,
    "display": "~1 in 26 lifetime chance of an ER-treated injury (regular rider)",
    "log_value": -1.41,
    "assumptions": "The CDC/Austin Public Health study (2019) found approximately 20 injuries per 100,000 e-scooter trips requiring medical attention. A \"regular rider\" is modeled as someone who takes 2 scooter trips per week for 10 years — roughly 1,040 trips. At 0.0002 injuries per trip, the lifetime probability is 1 − (1 − 0.0002)^1040 ≈ 0.189, or about 1 in 5. However, the Austin study captured all ER visits including minor scrapes. For serious injuries (fractures, TBIs, hospitalization), the rate is roughly 1/5 of the total, giving ~4 serious injuries per 100,000 trips. Over 1,040 trips: 1 − (1 − 0.00004)^1040 ≈ 0.041. The point estimate of 0.039 reflects this serious-injury subset. The scope is activity_specific_lifetime because the risk applies only to people who actually ride e-scooters.\n",
    "uncertainty": {
      "low": 0.015,
      "high": 0.09
    },
    "scope": "activity_specific_lifetime"
  },
  "sources": [
    {
      "url": "https://www.austintexas.gov/sites/default/files/files/Health/Epidemiology/APH_Dockless_Electric_Scooter_Study_5-2-19.pdf",
      "title": "Dockless Electric Scooter-Related Injuries Study — Austin, Texas, September-November 2018",
      "publisher": "Austin Public Health / Centers for Disease Control and Prevention (CDC)",
      "source_type": "govt_report",
      "statistic": "190 injuries over 936,110 trips; 45% involved head injuries; 15% sustained traumatic brain injury; <1% wore helmets",
      "excerpt": "\"Overall, 936,110 e-scooter trips occurred in Austin during the study period. Among the 190 injured riders identified, nearly half sustained head injuries and 15% had a traumatic brain injury. Less than 1% of injured riders had been wearing a helmet.\"\n",
      "source_date": "2019-05-02",
      "source_accessed": "2026-04-18",
      "archive_url": "http://web.archive.org/web/20260214004906/https://www.austintexas.gov/sites/default/files/files/Health/Epidemiology/APH_Dockless_Electric_Scooter_Study_5-2-19.pdf",
      "calculation_notes": "190 injuries / 936,110 trips = 20.3 per 100,000 trips. This is the native rate. For serious injuries (hospitalization, fractures, TBI): the study found 15% TBI rate among injured, plus additional fractures, giving roughly 1 in 5 injuries classified as serious. Serious-injury rate ≈ 4 per 100,000 trips. Lifetime for regular rider (1,040 trips): 1 − (1 − 0.00004)^1040 ≈ 0.041.\n"
    },
    {
      "url": "https://www.cpsc.gov/Newsroom/News-Releases/2024/E-Scooter-and-E-Bike-Injuries-Soar-2022-Injuries-Increased-Nearly-21",
      "title": "E-Scooter and E-Bike Injuries Soar: 2022 Injuries Increased Nearly 21%",
      "publisher": "U.S. Consumer Product Safety Commission (CPSC)",
      "source_type": "govt_report",
      "statistic": "An estimated 50,000 e-scooter ER visits in 2022, up 21% from 2021; 118,000 total micromobility ER visits by 2024",
      "excerpt": "\"E-scooter and e-bike injuries soar: 2022 injuries increased nearly 21 percent. ER-worthy injuries from micromobility vehicles have risen from just under 30,000 injuries in 2020 to more than 118,000 injuries in 2024.\"\n",
      "source_date": "2024-10-07",
      "source_accessed": "2026-04-18",
      "archive_url": "https://web.archive.org/web/20260420035125/https://www.cpsc.gov/Newsroom/News-Releases/2024/E-Scooter-and-E-Bike-Injuries-Soar-2022-Injuries-Increased-Nearly-21",
      "calculation_notes": "CPSC uses the National Electronic Injury Surveillance System (NEISS) to estimate national ER visits from a sample of ~100 hospitals. The 50,000 figure for 2022 and 118,000 for all micromobility in 2024 provide the national scale. These corroborate the Austin per-trip rate when divided by estimated national trip volumes but are not used directly for the native rate because denominator (trips) is less precisely known at national scale.\n"
    },
    {
      "url": "https://ajph.aphapublications.org/doi/10.2105/AJPH.2024.307820",
      "title": "The Burden of Injuries Associated With E-Bikes, Powered Scooters, Hoverboards, and Bicycles in the United States: 2019-2022",
      "publisher": "American Journal of Public Health",
      "source_type": "peer_reviewed",
      "statistic": "Population-based rates of powered scooter injuries increased 88% between 2019 and 2022; head injuries accounted for 18-28% of cases",
      "excerpt": "\"The population-based rates of powered scooter injuries increased by 88.0% between 2019 and 2022.\"\n",
      "source_date": "2024-12-01",
      "source_accessed": "2026-04-18",
      "archive_url": "http://web.archive.org/web/20250502233409/https://ajph.aphapublications.org/doi/10.2105/AJPH.2024.307820",
      "calculation_notes": "The AJPH study used NEISS data for 2019-2022 and found powered scooters had the fastest-growing injury rate among micromobility devices. Head injury prevalence of 18-28% across studies is consistent with the Austin CDC finding of 45% (the higher Austin figure likely reflects less helmet use in the early shared-scooter era). Used as independent corroboration of trend and injury profile.\n"
    }
  ],
  "comparison_anchors": [
    {
      "label": "Cycling head injury (lifetime, regular cyclist)",
      "lifetime_us_adult": 0.02
    },
    {
      "label": "Fatal car crash (lifetime, US adult)",
      "lifetime_us_adult": 0.0095
    }
  ],
  "personal_factor_multipliers": [
    {
      "factor": "No helmet vs helmet use",
      "multiplier": 3.3,
      "notes": "Medina et al. (2021, Injury — PMID 34083100): helmet use was associated with a roughly 66% reduction in head injury risk in e-scooter crashes, implying a ~3× higher risk for unhelmeted riders. Consistent with the CDC/Austin finding that <1% of injured riders wore helmets."
    },
    {
      "factor": "Alcohol or drug intoxication",
      "multiplier": 2.7,
      "notes": "Kim et al. (2021, Injury): intoxicated e-scooter riders had a 2.7× higher crash rate than sober riders in a prospective trauma-center study. Multiple US emergency-room studies corroborate impairment as a leading crash factor."
    },
    {
      "factor": "Night riding",
      "multiplier": 2,
      "notes": "Nelson et al. (2019, Journal of Transport & Health) and CPSC NEISS analysis: nighttime e-scooter injuries occur at approximately double the rate of daytime injuries after controlling for exposure, likely due to reduced visibility and increased impairment rates after dark."
    },
    {
      "factor": "Age <25 or >65",
      "multiplier": 1.7,
      "notes": "CPSC NEISS data and the AJPH 2024 micromobility study show riders under 25 (inexperience, risk-taking) and over 65 (slower reaction times, greater injury severity) sustain injury rates approximately 1.5-2× the 25-64 baseline per trip."
    }
  ],
  "short_label": "E-scooter injury",
  "outcome_severity": "serious_harm",
  "exposure_pattern": "recurring",
  "outcome_type": "recoverable_injury",
  "valence": "negative",
  "caveats": "The CDC/Austin study is the best per-trip denominator available but covers only one city during a three-month period in 2018, before many scooter-share operators improved rider education and speed-limiting geofences. National CPSC data confirm the injury volume is large and growing, but per-trip rates at scale may differ from the Austin snapshot. The \"serious injury\" definition (fractures, TBI, hospitalization) is approximate; different studies use different thresholds. Helmet use has remained extremely low across all studies.\n",
  "quality_score": {
    "d1": 4,
    "d2": 5,
    "d3": 4,
    "d4": 4,
    "d5": 5,
    "d6": 4,
    "d7": 4,
    "d8": 4,
    "avg": 4.25,
    "scored_by": "claude-code-8d",
    "scored_at": "2026-05-25",
    "methodology_version": "1.2"
  },
  "reviewer": "quality-review-agent",
  "last_reviewed": "2026-04-19",
  "reviewed": true,
  "generated_at": "2026-04-18",
  "image": {
    "alt": "A single electric scooter handlebar with a small first-aid cross icon, flat vector illustration on a pale background."
  },
  "attribution": "Likelier — https://likelier.app",
  "license": "https://creativecommons.org/licenses/by-sa/4.0/",
  "support": "https://buymeacoffee.com/kgluszczyk?via=likelier&utm_content=api-fear-single",
  "canonical_url": "https://likelier.app/e-scooter-serious-injury"
}