That's actually completely incorrect. If you are a POST certified LEO, you are a sworn Law Enforcement Officer 24/7/365, regardless of whether or not you are on duty. You are only limited by agency/department regulations as to whether or not they want you furnishing arrests or writing citations while off duty.

Many municipalities require their officers to carry their badge and firearm off-duty to be able to intercede if a felony has been committed in front of them, regardless of their duty status.

In some states, speeding 25 over the limit is considered a felony, and as such, this officer would actually have been 100% legally in the right in that area.

I'm not even arguing wether it was right to do at all...just letting you know the facts; because you're speaking with authority on something you're just factually incorrect about.