Used Car Safety: Why a Coin Test Isn't Enough, Says DGT Expert 2026

When buying a used car, many shoppers rely on a quick coin test to check tire tread or a visual once-over, but according to Francisco Javier Páez Ayuso, a doctor in industrial engineering and director of the University Institute for Automobile Research (INSIA-UPM), that's not enough. He insists that buyers should demand the full DGT report to uncover a vehicle's true history and ensure safety.

Páez, who has dedicated over 30 years to road safety and accident reconstruction, knows firsthand how hidden damage can compromise a car's structural integrity. In a recent interview, he emphasized that the advances in active and passive safety over the past two decades have been extraordinary, but they only work if the vehicle is in proper condition.

The Coin Test: A False Sense of Security

The coin test—placing a coin in the tread of a tire to check its depth—is a common trick among used car buyers. While it can give a rough idea of tire wear, it says nothing about the car's accident history, frame damage, or electronic safety systems.Páez warns that many used cars have been repaired after serious collisions, and without a proper inspection, buyers may unknowingly purchase a vehicle that won't protect them in a crash. "The coin test is not sufficient," he says. "You need the complete DGT report."

What the DGT Report Reveals

The DGT (Directorate-General for Traffic) report is an official document that compiles a vehicle's history, including previous owners, mileage records, and any reported accidents or inspections. It can reveal if a car has been declared a total loss, if it has outstanding fines, or if its odometer has been tampered with.For Páez, this report is a crucial tool for anyone buying a used car. It provides transparency and helps buyers make informed decisions. Without it, you're taking a gamble on a machine that could have hidden flaws affecting its safety.

Active and Passive Safety: Progress and Pitfalls

Over the last 20 years, automotive safety has advanced significantly. Passive safety features like crumple zones and airbags have become more effective at reducing injuries in a crash. Active safety systems, such as electronic stability control and automatic emergency braking, help prevent accidents altogether.

However, these systems are only as good as their maintenance. A car that has been poorly repaired after an accident may have compromised structural integrity or malfunctioning sensors. That's why a thorough inspection and a DGT report are essential.

Key Takeaways for Used Car Buyers

• Don't rely on the coin test alone—it only checks tire tread and ignores other critical safety aspects.
• Request the full DGT report to uncover accident history, mileage discrepancies, and legal issues.
• Have a professional inspection done by a certified mechanic to assess structural and electronic systems.
• Check for recalls and ensure all safety updates have been performed.
• Consider the vehicle's maintenance records to gauge how well it has been cared for.

How to Obtain the DGT Report

In Spain, the DGT report can be requested online or at a DGT office. You'll need the vehicle's license plate or VIN. The report includes details such as the car's registration history, technical inspections (ITV), and any incidents recorded. It's a small investment that can save you from costly surprises. The longer history behind the story is traced in Used Car Safety: Why a Coin Test Isn't Enough, Says DGT Expert.

Páez also recommends checking the vehicle's ITV (technical inspection) history to ensure it has passed safety and emissions tests. A car with a lapsed or failed ITV may have underlying problems that could affect its roadworthiness. The background to this story is set out in Car: latest articles. A related thread runs through France Bans New Drivers from High-Power Cars Under New Law. Earlier coverage in LED Headlights Too Bright: A Growing Road Safety Concern shows how the argument developed.

The Role of Advanced Driver Assistance Systems (ADAS)

Modern cars often come equipped with ADAS features like lane-keeping assist and adaptive cruise control. While these can enhance safety, they also require proper calibration after repairs. If a car has been in an accident and the ADAS sensors weren't recalibrated, the systems may not function correctly. A closer look at the same subject appears in Japan's Senior Driver 'L' Mark: Mandatory Safety Sticker for Elderly. Anyone following the wider picture can start with What Makes a Vehicle a Lemon in Nevada: 5 Rules Most Owners Miss. The same theme surfaces in Invisible Car Technology That Keeps You Cool in Summer Traffic, which takes a different angle.

Páez's work with UPM Racing, where students apply engineering principles to build race cars, underscores the importance of precision and safety. The same rigor should apply to used car purchases. Context on how this played out before sits in DGT Chief Pere Navarro: Speeding Fines Target 'Idiots' Not Revenue. A companion piece, Why Drivers Keep Old Cars: DGT Environmental Labels Explained, approaches the same subject from another angle.

FAQ

When it comes to buying a used car, safety should never be compromised. Páez's advice is clear: go beyond the coin test and demand the full DGT report. It's a simple step that can make all the difference in finding a reliable and safe vehicle.