C.R.S. § 31-31.5-409

The board may establish by rule a deferred retirement option plan for vested members who have attained age fifty. The purpose of the DROP is to allow an eligible member to elect, in lieu of immediate termination of employment and receipt of a lifetime retirement benefit, to continue employment for a specified period of time of up to five years and to have the member’s otherwise deductible employee contribution and retirement benefits paid into the member’s individual account created by section 31-31.5-503 until the end of the specified period of the member’s participation, at which time employment ceases.