Sudden Acceleration Dispute & Proof Diagnosis Calculator

What is the Sudden Acceleration Dispute & Proof Diagnosis Tool?

Sudden unintended acceleration (SUA) refers to a suspected accident in which a vehicle accelerates on its own even as the driver presses the brake.
In Korea, however, most lawsuits filed against manufacturers over sudden acceleration have ended in defeat for consumers.
The reason is not the size of the damages, but the burden of proof: the consumer must prove that a defect existed and caused the harm.

This tool is not a damages calculator. Instead, it diagnoses whether you can realistically pursue a claim, along three axes.
First, an evidence-readiness score (0–100); second, the three requirements of the defect presumption under Article 3-2 of the Product Liability Act; and third, expected litigation costs and the practical value of a dispute.
Check your evidence and run the self-assessment to see your odds and your next steps at a glance.

This calculator is based on Korean law (2026 rules): the Product Liability Act and the Motor Vehicle Management Act.
It is for reference only, has no legal force, and does not replace advice from a Korean attorney or loss adjuster.

Who is this for?

• Drivers weighing whether to dispute a suspected SUA accident with a manufacturer
• Victims and families who want to gauge odds and cost before litigating
• Anyone unsure which evidence (EDR, dashcam, appraisal) to secure
• People who want to understand the Product Liability Act defect presumption
• Those deciding whether mediation or negotiation beats a lawsuit

Why is sudden acceleration so hard to prove?

The electronic control unit (ECU) defect blamed for sudden acceleration is extremely hard to reproduce or observe after an accident.
Software errors that control the engine and transmission often leave no trace, and repairing or scrapping the vehicle erases even that.
As a result, the same accident can be winnable or hopeless depending entirely on how much evidence you have secured.

The evidence that carries the most weight

• EDR (event data recorder): records pre- and post-crash speed, accelerator and brake pedal input, and engine RPM — decisive data.
• Pedal cam / cabin dashcam: shows whether the driver actually pressed the brake, rebutting a misoperation defense.
• Front/rear dashcam: supports the sequence of events — acceleration noise, speed change, surroundings.
• Official appraisal: results from the National Forensic Service or the Korea Transportation Safety Authority greatly raise credibility.
• Same-model defect history: SUA reports or recalls for the same model support the presumption requirements.

The tool’s evidence-readiness score weights each item by importance and sums them.
Direct evidence scores highest — EDR 20 points, pedal cam 16, official appraisal 12.
A score of 70+ is rated strong and 85+ is rated very strong.

Product Liability Act defect presumption (Article 3-2)

Article 3-2 of the Product Liability Act, effective 19 April 2018, eases the consumer’s burden of proof.
If the victim proves the following three facts, the product is presumed to have had a defect and to have caused the harm.
In other words, meeting the three requirements shifts the burden so you need not prove the defect and causation item by item.

The three requirements for the presumption

① Normal use: the harm occurred while the vehicle was being used in a normal manner.
② Maker’s sphere of control: the harm arose from a cause within the manufacturer’s substantial sphere of control.
③ Would not ordinarily occur: such harm does not ordinarily occur in the absence of a defect in the product.

However, the presumption is rebutted if the manufacturer proves the harm arose from a cause other than a defect.
For example, if the maker proves driver pedal misoperation, the presumption falls away.
That is why evidence like a pedal cam, which rebuts misoperation, is so important.

💡 If you mark all three requirements as “met” in the self-assessment and your evidence score is 70+, the overall verdict shows “actively consider litigation.”
If the requirements are hard to meet and evidence is thin, it guides you to “strengthen evidence first.”

How to use the tool

Step 1: Check the evidence you have

Select the items you actually secured — EDR, pedal cam, dashcam, appraisal, witnesses.
The evidence-readiness score updates in real time as you select.

Step 2: Self-assess the three requirements

Rate normal use, sphere of control, and ordinary occurrence as met, partial, or not met.
Meeting all three marks the presumption as arguable.

Step 3: Enter dispute value and costs

Enter the expected claim amount (suit value), the appraisal fee, and whether you file electronically.
The tool sums the stamp duty, service fee, appraisal fee, and attorney fee into an expected total.

Step 4: Read the verdict and action plan

The overall verdict appears with the missing evidence listed in order of weight.
You immediately see which evidence to prioritize to improve your odds.

How are litigation costs estimated?

SUA lawsuits carry a heavy cost burden because engineering appraisal fees are large.
The tool shows an approximate cost based on the Stamp Duty Act for civil litigation and common practice.

Cost components

• Stamp duty: for a suit value of KRW 10M–100M it is value × 0.45% + KRW 5,000, with a 10% reduction for e-filing.
• Service fee: a deposit reflecting the number of parties and mailings (about KRW 156,000 for two parties).
• Engineering / EDR appraisal: typically KRW 3M–8M, a large share of SUA litigation cost.
• Attorney retainer: varies by difficulty and suit value; the success fee is separate.

The expected total is a rough figure for first-instance filing and excludes appeal costs and success fees.
Note that if you lose, you may bear part of the opposing party’s litigation costs.
So it is important to weigh cost against the probability of winning.

What to do the moment you suspect sudden acceleration

Brake hard, once: press firmly with both feet if needed; do not pump, which weakens braking.
Shift to neutral (N): cutting power stops the acceleration. Do not switch off the ignition carelessly (risk of losing steering and braking).
Apply the parking brake gently: pull the electronic or mechanical brake smoothly to shed speed.
Preserve the vehicle: re-appraisal and parts analysis are only possible before repair or scrapping.
Demand the EDR: under Article 29-3 of the Motor Vehicle Management Act you can request the records and analysis report in writing.
Back up video and the scene: immediately secure dashcam memory, skid-mark photos, witness contacts, and the 112 report.

Use scenarios

Pre-litigation self-check

Checking your evidence and requirements before meeting a lawyer makes the consultation far more efficient.
Securing missing evidence first saves both time and money.

Choosing an alternative path

If the diagnosis shows proof is difficult, you can prioritize Korea Consumer Agency mediation or negotiation with the maker instead of a lawsuit.
It helps you avoid losing money on an unwinnable case.

An evidence roadmap

Securing the missing evidence from the action plan in order of weight raises your odds systematically.
The EDR, pedal cam, and official appraisal are the highest priorities.

Frequently asked questions (FAQ)

Q. Is an SUA lawsuit really hard to win?

A. Korean courts have strictly required the consumer’s burden of proof in SUA product-liability suits, so plaintiff wins have been rare.
Still, with direct evidence like an EDR and pedal cam plus the three presumption requirements, your chances improve.

Q. How do I obtain the EDR data?

A. Under Article 29-3 of the Motor Vehicle Management Act, an owner can require the maker to provide the EDR records and analysis report.
Request it in writing where possible and keep the reply.

Q. Can I repair the accident vehicle?

A. Repairing or scrapping it makes re-appraisal and parts analysis impossible, destroying key evidence.
If you are considering a dispute, preserve the vehicle as-is.

Q. Is there a time limit to file a claim?

A. Under Article 7 of the Product Liability Act, you must claim within 3 years of learning of the harm and the liable party, and within 10 years of the product’s supply.
Missing the deadline can extinguish the claim by prescription.

Q. Can I use this result as legal grounds?

A. No — this tool is for reference only and has no legal force.
Decide your actual litigation strategy in consultation with an attorney or loss adjuster.

Diagnose your sudden acceleration dispute odds now

Check your evidence and self-assess the presumption requirements to see your odds and expected cost right away.

Based on the 2026 Product Liability Act and Motor Vehicle Management Act. Missing evidence is highlighted in the action plan.

Auto and mobility scenario inputs

Related calculators