Driving/Data

Baseline rates (verbatim; used directly in models)

The following U.S. national rates are taken verbatim from authoritative sources and are **not** converted here. Conversions to per-miles exposure are performed only inside the RiskModel calculations below.

• Fatalities: **1.26 deaths per 100 million vehicle miles traveled (VMT)** in 2023 (national estimate).

 * NHTSA 2023 Traffic Fatalities Estimates  
 * IIHS: Fatality statistics

• Injuries: **75 injuries per 100 million VMT** in 2022 (police-reported injuries, national estimate).

 * NHTSA: Traffic Safety Facts 2022

Distance Options

Distance choice	Miles
100 miles	100
1,000 miles	1000
100,000 miles	100000

These rows provide user-friendly exposure choices. The RiskModels convert the per-100M-VMT base rates into expected counts for the chosen miles.

Time of Day (modifier)

Time of day	Fatality risk multiplier	Injury risk multiplier
Day	1.0	1.0
Night	3.56	1.47

Per-mile risk is higher at night: in 2022, ~53.9% of fatalities and ~32.9% of injury crashes occurred during roughly ~25% of VMT (nighttime). Using exposure-adjusted ratios yields ≈3.56× (fatalities) and ≈1.47× (injuries).

• Night/day crash distribution and injuries: NHTSA 2022
• Background on time-of-day involvement: NHTSA
• Exposure assumption (≈25% of VMT at night): FHWA Lighting Guidance
• Supplemental analysis: University of Michigan per-mile risk

Seat-belt Usage (modifier)

Seat-belt usage	Fatality risk multiplier	Injury risk multiplier
Worn (car)	1.0	1.0
Not worn (car)	1.82	2.0
Worn (SUV/van/truck)	1.0	1.0
Not worn (SUV/van/truck)	2.5	2.857

Seat belts reduce fatal injury risk by ~45% in cars and ~60% in light trucks; moderate-to-critical injury by ~50% in cars and ~65% in light trucks. The multipliers above are the inverse of those reductions (i.e., increased risk when not wearing a belt).

• Effectiveness summary: IIHS: Seat belts
• Technical background: NHTSA: Seat belt effectiveness

---

  RiskModel: Driving/Data:fatality_model
Calculation: (1.26 / 100000000 * distance_miles) * time_fatality_multiplier * belt_fatality_multiplier
    Content: 
Your estimated chance of being in a fatal crash is {{One_In_X|{result}}}.

  RiskModel: Driving/Data:injury_model
Calculation: (75 / 100000000 * distance_miles) * time_injury_multiplier * belt_injury_multiplier
    Content: 
Your estimated chance of being injured in a crash is {{One_In_X|{result}}}.

---

Note on uncertainty: These are national averages and approximate modifiers. Actual risks vary by state, roadway type (urban/rural), weather, vehicle, driver demographics, and year-to-year changes. Modifiers are population-level and not individual predictions.

Mostly generated by GPT-5 Thinking