19.2 Analyzing Personal Auto Risks
Key Takeaways
Personal auto loss costs reflect claim frequency and severity, which vary by driver, vehicle, use, and territory.
Severity has been rising as vehicles add advanced driver-assistance sensors, repair labor and parts costs increase, and bodily injury litigation grows.
Telematics and usage-based insurance measure actual driving (mileage, hard braking, speed, time of day, phone use) and support more accurate pricing and safer driving.
Teen and inexperienced drivers, distracted driving, and impaired driving are major sources of frequency and severity.
Insurers manage auto risk through rating variables, underwriting rules, driver-safety programs, and claims practices, within state limits on permitted factors.
Analyzing Personal Auto Risks
Quick Answer: Personal auto results depend on frequency (how often claims occur) and severity (how much they cost). Frequency is driven mainly by driver behavior, experience, mileage, and territory. Severity is driven by vehicle repair costs, medical costs, and litigation. Vehicles with advanced driver-assistance systems (ADAS) are safer in some respects but cost more to repair. Telematics measures real driving behavior, which improves pricing and encourages safer driving.
Frequency and Severity Framework
| Loss driver | Main effect | Examples |
|---|---|---|
| Driver experience and age | Frequency | Young, inexperienced drivers crash more often |
| Driving record | Frequency | Prior violations and at-fault accidents predict future claims |
| Distraction and impairment | Frequency and severity | Phone use, alcohol, drugs |
| Annual mileage and use | Frequency | More miles means more exposure; commuting vs. pleasure use |
| Territory | Both | Traffic density, theft rates, weather, medical costs, legal climate |
| Vehicle type | Severity | Repair costs, theft rates, occupant protection, damage to others |
| Vehicle technology | Severity (and sometimes frequency) | Sensors and cameras in bumpers and windshields need calibration after repairs |
| Legal environment | Severity | Attorney involvement and large verdicts in bodily injury claims |
Coverage-Specific Considerations
- Liability (bodily injury and property damage): Driven by driver behavior, territory, and legal environment. Severity rises with medical inflation and litigation.
- Collision: Driven by driver behavior and vehicle repair costs. ADAS components and modern materials raise repair costs.
- Comprehensive (other than collision): Driven by theft, weather (hail, flood), animal collisions, and glass. Territory matters greatly.
- Uninsured and underinsured motorists: Driven by the share of uninsured drivers in the state and the insured's own limits.
- Personal injury protection and medical payments: Driven by state no-fault rules and medical cost trends.
Vehicle Trends
- Advanced driver-assistance systems such as automatic emergency braking and lane-keeping can reduce some crashes. Their sensors and cameras make repairs more expensive.
- Electric and hybrid vehicles can have high repair and battery replacement costs and specialized repair requirements.
- Theft trends shift as certain models become targets, which affects comprehensive losses in some territories.
Telematics and Usage-Based Insurance
Telematics collects driving data through smartphone apps, plug-in devices, or connected-vehicle data (with consent):
| Data element | Risk insight |
|---|---|
| Miles driven | Exposure (the basis of pay-as-you-drive pricing) |
| Hard braking and acceleration | Aggressive or inattentive driving |
| Speed | Crash severity risk |
| Time of day | Late-night driving carries higher risk |
| Phone handling | Distraction |
Usage-based insurance programs often give discounts for safe driving, and they may give feedback that changes behavior. Insurers must follow state rules on how telematics data can be used for rating, and they must handle the data with privacy safeguards.
Special Driver Situations
- Teen drivers: High frequency. Insurers use good-student and driver-training discounts, telematics, and parental monitoring programs.
- Older drivers: Lower mileage but potentially higher injury severity. Many states require or permit discounts for defensive driving courses.
- Ride-share and delivery drivers: Personal auto policies generally exclude these periods of use. Special endorsements or company-provided coverage may apply.
From Analysis to Action
- Pricing: Base rates adjusted by driver, vehicle, territory, usage, and (where allowed) credit-based insurance scores and telematics.
- Underwriting rules: Eligibility limits for serious violations; required driver disclosures; excluded drivers where state law permits.
- Loss control: Teen driver programs, telematics feedback, anti-theft discounts.
- Claims: Photo estimating, repair network management, calibration standards for ADAS, and early handling of injury claims to limit litigation.
Worked Scenario: A Rising Collision Loss Ratio
An insurer's collision severity has jumped. Analysis shows:
- Newer vehicles with windshield-mounted cameras need recalibration after glass replacement, adding cost to every glass claim.
- Repair labor rates in two metro areas rose sharply.
Actions: update vehicle rating to reflect repair costs by model, file rate changes in affected territories, negotiate repair network rates, and set calibration standards to avoid unnecessary procedures.
A Simple Loss Cost Illustration
Actuaries often break loss cost into frequency and severity:
- A book has 10,000 car-years of collision exposure and 500 collision claims averaging $6,000 each.
- Frequency = 500 ÷ 10,000 = 0.05 claims per car-year.
- Severity = $6,000 per claim.
- Pure premium (loss cost) = 0.05 × $6,000 = $300 per car-year.
Now suppose safer driving from a telematics program cuts frequency by 5%, while repair costs for sensor-equipped vehicles push severity up 10%:
- New loss cost factor = 0.95 × 1.10 = 1.045
- New pure premium = $300 × 1.045 = $313.50, a 4.5% increase
Even with fewer crashes, rising severity can raise loss costs. That is why insurers track frequency and severity separately instead of looking only at total losses.
Common Traps
- Assuming fewer crashes means lower losses: Severity trends can outweigh frequency gains.
- Treating telematics as unregulated: States regulate how driving data is used in rating and how it must be protected.
- Overlooking coverage differences: Comprehensive losses (theft, hail, animals) respond to different drivers than collision or liability.
- Using prohibited factors: Some states restrict factors such as credit or gender, so a model built on national data may not be usable everywhere.
Why can a vehicle equipped with advanced driver-assistance systems (ADAS) have higher collision severity even if it helps avoid some crashes?
ADAS vehicles are excluded from collision coverage
ADAS vehicles are always driven more miles
State law requires higher deductibles for ADAS vehicles
Sensors and cameras in bumpers and windshields are expensive to replace and must be recalibrated after repairs
A usage-based insurance program records mileage, hard braking, speed, time of day, and phone handling. What is the main underwriting benefit?
It replaces the need for liability limits
It guarantees that no claims will be filed
It allows insurers to ignore state rating laws
It measures actual driving behavior, improving risk classification and encouraging safer driving
Which factor mainly affects frequency rather than severity in personal auto?
Medical cost inflation
Repair labor rates
Annual miles driven
Jury award trends
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