Understanding Car Safety Ratings: What They Really Mean

When shopping for a new vehicle, safety ratings from organizations like the National Highway Traffic Safety Administration (NHTSA) and the Insurance Institute for Highway Safety (IIHS) often feature prominently in marketing materials. But what do these ratings actually mean, and how should they influence your car-buying decision?

How Safety Ratings Are Determined

NHTSA's 5-Star Rating System

The National Highway Traffic Safety Administration uses a 5-Star Safety Ratings system to evaluate vehicle safety performance. Here's what they test:

• Frontal Crash Tests: Vehicles are crashed into a fixed barrier at 35 mph, simulating a head-on collision between two similar vehicles.
• Side Crash Tests: Include both a side barrier test (simulating an intersection collision) and a side pole test (simulating a vehicle sliding sideways into a tree or pole).
• Rollover Resistance Tests: Evaluate how top-heavy a vehicle is and its likelihood of rolling over in a single-vehicle crash.

The scores range from 1 to 5 stars, with 5 being the highest safety rating.

IIHS Testing Procedures

The Insurance Institute for Highway Safety conducts different tests:

• Moderate Overlap Front Test: 40% of the vehicle's front on the driver's side impacts a barrier at 40 mph.
• Small Overlap Front Tests: 25% of the front end on either driver or passenger side hits a barrier at 40 mph.
• Side Impact Test: A barrier designed to simulate an SUV or pickup truck strikes the driver's side at 31 mph.
• Roof Strength Test: Measures how well the roof would protect occupants in a rollover crash.
• Head Restraint Test: Evaluates how well seats and head restraints protect against whiplash in a rear-end collision.

IIHS ratings include "Good," "Acceptable," "Marginal," or "Poor." Vehicles with top performance across all tests may earn "Top Safety Pick" or "Top Safety Pick+" designations.

Interpreting Safety Ratings

What High Ratings Mean

A 5-star NHTSA rating or IIHS "Good" rating indicates:

• The vehicle provides better protection than average in the specific tested scenarios
• Crash test dummies recorded lower forces and accelerations that correlate with reduced injury risk
• The vehicle's structure maintained integrity during the test scenario

What Ratings Don't Tell You

Despite their importance, safety ratings have limitations:

• They only reflect performance in specific test scenarios, not all possible crash types and speeds
• Real-world crashes involve variables like crash angles, speeds, and other vehicles that may differ from test conditions
• Ratings don't account for driver behavior, which significantly influences crash outcomes
• Tests are designed to evaluate vehicles within their class, not across different vehicle types (e.g., comparing SUVs to sedans)

Beyond Crash Ratings: Advanced Safety Features

Modern vehicles often include advanced safety technologies that help prevent crashes altogether:

Crash Prevention Technologies

• Automatic Emergency Braking (AEB): Automatically applies brakes to prevent or mitigate frontal collisions
• Forward Collision Warning: Alerts the driver when a potential front-end collision is detected
• Lane Departure Warning/Lane Keeping Assist: Alerts drivers when unintentionally drifting out of lane or actively helps maintain lane position
• Blind Spot Detection: Warns of vehicles in adjacent lanes that might not be visible in mirrors
• Rear Cross-Traffic Alert: Detects approaching vehicles when backing out of parking spaces

IIHS and NHTSA Evaluation of Safety Technology

Both organizations now incorporate advanced safety feature evaluations:

• IIHS rates front crash prevention systems as "Superior," "Advanced," or "Basic"
• NHTSA includes information about recommended safety technologies in vehicle listings
• To achieve top IIHS safety picks, vehicles must offer effective crash prevention systems

Size and Weight Considerations

Physics plays an important role in real-world crash outcomes:

• Larger, heavier vehicles generally provide better protection for their occupants in multi-vehicle crashes
• However, larger vehicles may have handling limitations and longer stopping distances
• SUVs and trucks have higher centers of gravity, potentially increasing rollover risk
• Safety ratings should be compared within vehicle classes, not across different sizes and weights

Making Safety-Informed Decisions

How to Use Safety Ratings Effectively

Follow these guidelines to incorporate safety ratings into your car-buying process:

1. Look for vehicles with top ratings from both NHTSA (5 stars) and IIHS (Top Safety Pick+)
2. Pay attention to individual test scores rather than just overall ratings
3. Consider which types of crashes are most common in your driving environment
4. Evaluate advanced safety features that can prevent crashes entirely
5. Remember that ratings are most comparable within vehicle classes
6. Consider that newer ratings are generally more stringent than older ones

Safety Features Worth Prioritizing

Based on effectiveness research, these features provide significant safety benefits:

• Automatic Emergency Braking with Pedestrian Detection
• Blind Spot Warning
• Rear Automatic Emergency Braking
• Lane Departure Warning/Lane Keeping Assist
• Adaptive Headlights that adjust brightness and direction

Conclusion

Safety ratings provide valuable information about a vehicle's crash performance, but they tell only part of the safety story. For the most comprehensive assessment:

1. Consider both crash test ratings and crash prevention technologies
2. Recognize the inherent safety advantages of larger vehicles while balancing other factors
3. Understand that driver behavior remains the most critical factor in crash outcomes
4. Use safety comparisons within comparable vehicle classes

At CarCompare, we provide detailed safety information including crash test results, standard and optional safety features, and real-world safety statistics to help you make the most informed decision possible.