The Defeat Device (i.e. software that VW installed to detect whether the vehicle was in a test lab or on the road) involved major software effort that detected which of the following:

The correct option is All of the above.
The Volkswagen "defeat device" software was designed to detect conditions specific to laboratory emissions tests versus real-world driving. It monitored multiple parameters to identify when a vehicle was undergoing a test cycle. These parameters included:

• Ambient temperature: Lab tests are conducted within a narrow, controlled temperature range.
• Sequence of speeds: The software could recognize the specific, repeatable driving patterns of official test cycles.
• Steering wheel motion: During a dynamometer test, the steering wheel typically remains stationary, unlike real-world driving.
• Rotational speeds of front and rear tires: For front-wheel-drive vehicles on a two-wheel dynamometer, only the front wheels would rotate, while the rear wheels would be stationary. This difference is a clear indicator of a test environment.