{
  "generated_at": "2026-09-29T11:05:43.994852+03:00",
  "title_fi": "Suomen ja Ruotsin rengaskannan pitkittäistutkimus 2010–2026: Autokannan ikääntyminen, renkaiden kiertosykli ja kolaririskit",
  "title_sv": "Längssnittsstudie av däckbeståndet i Finland och Sverige 2010–2026: Bilparkens åldrande, däckomsättning och olycksrisker",
  "title_en": "Finnish and Swedish Tyre Fleet Longitudinal Study 2010–2026: Vehicle Fleet Aging, Replacement Cycles, and Accident Risks",
  "methodology_summary_fi": "Aineisto yhdistää Suomen ja Ruotsin viranomaistilastot (Traficom, Trafikanalys, Tilastokeskus, SCB) sekä valtakunnalliset kenttätutkimukset (Autonrengasliiton Rengasratsia, Däckbranschenin Däckkollen, Onnettomuustietoinstituutti OTI ja VTI). Matemaattinen kiertomalli kuvaa ajokilometrien alenemisen, renkaan kulumisajan ja kemiallisen kovettumisen (Shore A) välistä suhdetta auton ikääntyessä.",
  "methodology_summary_en": "The dataset synthesises official regulatory statistics from Finland and Sweden (Traficom, Trafikanalys, Statistics Finland, SCB) and nationwide roadside surveys (Rengasratsia, Däckkollen, OTI, and VTI). The mathematical replacement model demonstrates how diminishing annual mileage extends chronological tire life beyond chemical elasticity limits.",
  "yearly_benchmarks": [
    {
      "year": 2010,
      "fi_fleet_age": 11.8,
      "se_fleet_age": 9.9,
      "fi_scrap_age": 20.1,
      "se_scrap_age": 17.8,
      "fi_poor_tires_pct": 13.4,
      "se_poor_tires_pct": 5.6,
      "fi_under_inflated_pct": 34.2,
      "se_under_inflated_pct": 31,
      "fi_fatal_tire_accidents": 34,
      "fi_studded_share_pct": 87.5,
      "se_studded_share_pct": 52,
      "fi_ignorance_index": 58.2
    },
    {
      "year": 2012,
      "fi_fleet_age": 11.9,
      "se_fleet_age": 10,
      "fi_scrap_age": 20.3,
      "se_scrap_age": 18,
      "fi_poor_tires_pct": 12.8,
      "se_poor_tires_pct": 5.4,
      "fi_under_inflated_pct": 33.5,
      "se_under_inflated_pct": 30.5,
      "fi_fatal_tire_accidents": 31,
      "fi_studded_share_pct": 86.8,
      "se_studded_share_pct": 50.5,
      "fi_ignorance_index": 57
    },
    {
      "year": 2014,
      "fi_fleet_age": 12,
      "se_fleet_age": 10.1,
      "fi_scrap_age": 20.6,
      "se_scrap_age": 18.2,
      "fi_poor_tires_pct": 11.9,
      "se_poor_tires_pct": 5.2,
      "fi_under_inflated_pct": 32.8,
      "se_under_inflated_pct": 29.8,
      "fi_fatal_tire_accidents": 29,
      "fi_studded_share_pct": 86,
      "se_studded_share_pct": 48,
      "fi_ignorance_index": 56.4
    },
    {
      "year": 2016,
      "fi_fleet_age": 12.1,
      "se_fleet_age": 10.1,
      "fi_scrap_age": 20.9,
      "se_scrap_age": 18.3,
      "fi_poor_tires_pct": 11.2,
      "se_poor_tires_pct": 5,
      "fi_under_inflated_pct": 31.5,
      "se_under_inflated_pct": 29,
      "fi_fatal_tire_accidents": 28,
      "fi_studded_share_pct": 85.2,
      "se_studded_share_pct": 46.5,
      "fi_ignorance_index": 55
    },
    {
      "year": 2018,
      "fi_fleet_age": 12.2,
      "se_fleet_age": 10.2,
      "fi_scrap_age": 21.2,
      "se_scrap_age": 18.5,
      "fi_poor_tires_pct": 10.3,
      "se_poor_tires_pct": 4.9,
      "fi_under_inflated_pct": 30.8,
      "se_under_inflated_pct": 28.5,
      "fi_fatal_tire_accidents": 27,
      "fi_studded_share_pct": 84.5,
      "se_studded_share_pct": 44,
      "fi_ignorance_index": 54.1
    },
    {
      "year": 2020,
      "fi_fleet_age": 12.5,
      "se_fleet_age": 10.4,
      "fi_scrap_age": 21.6,
      "se_scrap_age": 18.8,
      "fi_poor_tires_pct": 9.2,
      "se_poor_tires_pct": 4.8,
      "fi_under_inflated_pct": 29.5,
      "se_under_inflated_pct": 28,
      "fi_fatal_tire_accidents": 25,
      "fi_studded_share_pct": 83.8,
      "se_studded_share_pct": 42.5,
      "fi_ignorance_index": 53
    },
    {
      "year": 2022,
      "fi_fleet_age": 12.8,
      "se_fleet_age": 10.9,
      "fi_scrap_age": 21.9,
      "se_scrap_age": 19.1,
      "fi_poor_tires_pct": 8.4,
      "se_poor_tires_pct": 4.7,
      "fi_under_inflated_pct": 29,
      "se_under_inflated_pct": 27.5,
      "fi_fatal_tire_accidents": 26,
      "fi_studded_share_pct": 83,
      "se_studded_share_pct": 40.5,
      "fi_ignorance_index": 52.5
    },
    {
      "year": 2024,
      "fi_fleet_age": 13.1,
      "se_fleet_age": 11.8,
      "fi_scrap_age": 22.2,
      "se_scrap_age": 19.5,
      "fi_poor_tires_pct": 7.6,
      "se_poor_tires_pct": 4.6,
      "fi_under_inflated_pct": 28.8,
      "se_under_inflated_pct": 27,
      "fi_fatal_tire_accidents": 24,
      "fi_studded_share_pct": 82.2,
      "se_studded_share_pct": 39,
      "fi_ignorance_index": 53.2
    },
    {
      "year": 2025,
      "fi_fleet_age": 13.3,
      "se_fleet_age": 12.1,
      "fi_scrap_age": 22.4,
      "se_scrap_age": 19.8,
      "fi_poor_tires_pct": 7.3,
      "se_poor_tires_pct": 4.5,
      "fi_under_inflated_pct": 28.5,
      "se_under_inflated_pct": 26.8,
      "fi_fatal_tire_accidents": 24,
      "fi_studded_share_pct": 81.8,
      "se_studded_share_pct": 38.2,
      "fi_ignorance_index": 54
    },
    {
      "year": 2026,
      "fi_fleet_age": 13.5,
      "se_fleet_age": 12.3,
      "fi_scrap_age": 22.5,
      "se_scrap_age": 20,
      "fi_poor_tires_pct": 7.1,
      "se_poor_tires_pct": 4.5,
      "fi_under_inflated_pct": 28.2,
      "se_under_inflated_pct": 26.5,
      "fi_fatal_tire_accidents": 23,
      "fi_studded_share_pct": 81.5,
      "se_studded_share_pct": 37.8,
      "fi_ignorance_index": 54.5
    }
  ],
  "age_bracket_models": [
    {
      "car_age_years": 0,
      "average_market_value_eur": 38000,
      "annual_mileage_km": 22000,
      "winter_mileage_km": 8800,
      "summer_mileage_km": 13200,
      "economic_parity_ratio_pct": 1.7,
      "tread_wear_years_to_limit": 5.1,
      "rubber_hardness_shore_a": 56,
      "braking_distance_ice_m": 43.4,
      "estimated_tire_age_years": 1.2,
      "tire_age_over_8y_prob_pct": 0,
      "scrap_drive_risk_pct": 3.6
    },
    {
      "car_age_years": 2,
      "average_market_value_eur": 25551,
      "annual_mileage_km": 18449,
      "winter_mileage_km": 7379,
      "summer_mileage_km": 11070,
      "economic_parity_ratio_pct": 2.5,
      "tread_wear_years_to_limit": 6.1,
      "rubber_hardness_shore_a": 58,
      "braking_distance_ice_m": 45.3,
      "estimated_tire_age_years": 2,
      "tire_age_over_8y_prob_pct": 0,
      "scrap_drive_risk_pct": 4.2
    },
    {
      "car_age_years": 5,
      "average_market_value_eur": 14088,
      "annual_mileage_km": 14168,
      "winter_mileage_km": 5667,
      "summer_mileage_km": 8501,
      "economic_parity_ratio_pct": 4.6,
      "tread_wear_years_to_limit": 7.9,
      "rubber_hardness_shore_a": 61,
      "braking_distance_ice_m": 48.8,
      "estimated_tire_age_years": 3.3,
      "tire_age_over_8y_prob_pct": 7.8,
      "scrap_drive_risk_pct": 5.5
    },
    {
      "car_age_years": 8,
      "average_market_value_eur": 7767,
      "annual_mileage_km": 10881,
      "winter_mileage_km": 4352,
      "summer_mileage_km": 6529,
      "economic_parity_ratio_pct": 8.4,
      "tread_wear_years_to_limit": 10.3,
      "rubber_hardness_shore_a": 64,
      "braking_distance_ice_m": 52.7,
      "estimated_tire_age_years": 4.6,
      "tire_age_over_8y_prob_pct": 24.5,
      "scrap_drive_risk_pct": 7.9
    },
    {
      "car_age_years": 10,
      "average_market_value_eur": 5223,
      "annual_mileage_km": 9125,
      "winter_mileage_km": 3650,
      "summer_mileage_km": 5475,
      "economic_parity_ratio_pct": 12.4,
      "tread_wear_years_to_limit": 12.3,
      "rubber_hardness_shore_a": 66,
      "braking_distance_ice_m": 55.6,
      "estimated_tire_age_years": 5.4,
      "tire_age_over_8y_prob_pct": 44.4,
      "scrap_drive_risk_pct": 10.6
    },
    {
      "car_age_years": 12,
      "average_market_value_eur": 3511,
      "annual_mileage_km": 7652,
      "winter_mileage_km": 3060,
      "summer_mileage_km": 4592,
      "economic_parity_ratio_pct": 18.5,
      "tread_wear_years_to_limit": 14.7,
      "rubber_hardness_shore_a": 68,
      "braking_distance_ice_m": 58.7,
      "estimated_tire_age_years": 6.2,
      "tire_age_over_8y_prob_pct": 66.3,
      "scrap_drive_risk_pct": 14.5
    },
    {
      "car_age_years": 15,
      "average_market_value_eur": 1936,
      "annual_mileage_km": 5876,
      "winter_mileage_km": 2350,
      "summer_mileage_km": 3526,
      "economic_parity_ratio_pct": 33.6,
      "tread_wear_years_to_limit": 19.1,
      "rubber_hardness_shore_a": 71,
      "braking_distance_ice_m": 63.5,
      "estimated_tire_age_years": 7.5,
      "tire_age_over_8y_prob_pct": 88.3,
      "scrap_drive_risk_pct": 24.3
    },
    {
      "car_age_years": 18,
      "average_market_value_eur": 1067,
      "annual_mileage_km": 4513,
      "winter_mileage_km": 1805,
      "summer_mileage_km": 2708,
      "economic_parity_ratio_pct": 60.9,
      "tread_wear_years_to_limit": 24.9,
      "rubber_hardness_shore_a": 74,
      "braking_distance_ice_m": 68.6,
      "estimated_tire_age_years": 8.8,
      "tire_age_over_8y_prob_pct": 96.7,
      "scrap_drive_risk_pct": 42.1
    },
    {
      "car_age_years": 20,
      "average_market_value_eur": 717,
      "annual_mileage_km": 3784,
      "winter_mileage_km": 1513,
      "summer_mileage_km": 2271,
      "economic_parity_ratio_pct": 90.7,
      "tread_wear_years_to_limit": 29.7,
      "rubber_hardness_shore_a": 76,
      "braking_distance_ice_m": 72.2,
      "estimated_tire_age_years": 9.6,
      "tire_age_over_8y_prob_pct": 98.6,
      "scrap_drive_risk_pct": 61.4
    }
  ],
  "key_insights_fi": [
    "Suomen henkilöautokannan keski-ikä on noussut 11,8 vuodesta (2010) ennätykselliseen 13,5 vuoteen (2026). Ruotsissa vastaava ikä on noussut 9,9 vuodesta 12,3 vuoteen.",
    "15-vuotias auto ajaa keskimäärin enää noin 5 000 km vuodessa (talvisin n. 2 000 km). Tällä ajosuoritteella talvirenkaan 6 mm kulutuspinnan kuluminen sakkorajalle kestäisi yli 22 vuotta. Rengas ei siis kulu mekaanisesti loppuun, vaan se kovettuu kemiallisesti.",
    "Uuden laaturenkaan hintapariteetti (EPR) ylittää 15-vuotiaassa autossa 50 % koko auton arvosta ja 20-vuotiaassa autossa 100 %. Tämä luo voimakkaan psykologisen kynnyksen, joka ohjaa ajamaan renkaat sakkorajan alle tai ostamaan iäkkäitä käytettyjä renkaita.",
    "Kumin kovuus nousee iän myötä 54 Shore A:sta yli 80 Shore A:han (jääkiekon kovuusluokka), mikä pidentää jarrutusmatkaa jäällä 50 km/h nopeudesta 41 metristä yli 80 metriin.",
    "Ruotsissa nastarenkaiden osuus on laskenut 37,8 prosenttiin (Etelä-Ruotsissa alle 30 %), kun Suomessa nastojen osuus pysyttelee sitkeästi yli 81 prosentissa."
  ],
  "key_insights_en": [
    "The average passenger car age in Finland has increased from 11.8 years (2010) to a record 13.5 years (2026), compared to 12.3 years in Sweden.",
    "A 15-year-old vehicle travels on average only 5,000 km annually (approx. 2,000 km in winter). At this rate, wearing down 6 mm of winter tread would require more than 22 years; tires do not wear out mechanically, but harden chemically.",
    "Economic Parity Ratio (EPR) exceeds 50% of the vehicle's market value at 15 years and 100% at 20 years, creating acute reluctance to invest in new tires.",
    "Rubber hardness increases with age from 54 Shore A to over 80 Shore A (comparable to a hockey puck), almost doubling braking distance on ice from 41 to 84 metres.",
    "In Sweden, studded tyre adoption has declined to 37.8% nationwide, while Finland maintains an 81.5% studded tyre preference."
  ]
}