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Case Study #249 — 300 Software Failure Case Studies

US 'Cash for Clunkers' CARS.gov website overload

The US government's popular 'Cash for Clunkers' car-trade-in rebate program's website and processing system was overwhelmed within days, leaving car dealers unable to submit rebate applications and get paid.

2009-07
When it happened
Government
Sector
#249 of 300
Ranked by documented impact
01 — What Happened

The damage was public. The root cause was preventable.

The US government's popular 'Cash for Clunkers' car-trade-in rebate program's website and processing system was overwhelmed within days, leaving car dealers unable to submit rebate applications and get paid.

Government
Sector affected
2009-07
Date of the event
#249
Rank in the 300 Software Failure Case Studies
1
Distinct root-cause clause identified below
02 — The Root Cause

What the software actually got wrong

The CARS.gov application system had not been built or tested to handle the volume of simultaneous dealer submissions the popular program generated, causing the site to crash repeatedly and creating a backlog of unprocessed rebate applications that took the government weeks to work through.

01Root Cause

The CARS.gov application system had not been built or...

What Happened

The CARS.gov application system had not been built or tested to handle the volume of simultaneous dealer submissions the popular program generated, causing the site to crash repeatedly and creating a backlog of unprocessed rebate applications that took the government weeks to work through.

How Requs AI Catches This

Requs AI Edge Case flags this exact pattern at the requirements and architecture stage — before a single line of code implementing it exists — so the assumption behind it gets challenged while it is still cheap to fix.

03 — How This Gets Caught Before It Happens

Beyond code coverage and "shall" testing

Root causes like this one rarely show up in code coverage or requirements-compliance testing, because nobody wrote a requirement anticipating the specific edge case that broke. Requs AI Edge Case and Requs AI Software FMEA are built to surface exactly this class of overlooked failure mode — before the software is written.

Requs AI Edge Case

Surfaces this before code exists

Identifies edge cases like this one at requirements and architecture time, using the Common Defect Enumeration to catalog failure patterns seen across hundreds of real-world software failures — including this one.

Requs AI Software FMEA

Connects the failure mode to the hazard

Traces this class of root cause directly to the system-level hazard it can produce, so a defect pattern like this one gets flagged during design review instead of after it ships.

Find the overlooked root causes before they ship.

Schedule a demonstration, or explore how Requs AI Edge Case and Software FMEA use the Common Defect Enumeration.