Under which condition can the Intoxilyzer 5000 be used for tests?

The Intoxilyzer 5000 is a breath testing device that has been phased out in favor of the Intoxilyzer 9000 for use in determining blood alcohol content (BAC) due to advancements in technology and reliability. It was permissible for use until December 31, 2015, which is why the timeframe mentioned in the correct answer fits within the operational guidelines of the device. Testing conducted on or before this date, under the accepted protocols, would yield valid results in a legal context.

Testing performed after this cutoff would not comply with current regulations as jurisdictions moved to adopt more modern and accurate devices. Therefore, the specific date mentioned captures the valid window for using the Intoxilyzer 5000 effectively.