The Alternate Retirement Program, or ARP, is a retirement savings program that certain state employees are automatically enrolled in from 8/11/04 to 6/30/13 for two years from their initial hire date (or when they qualified for CalPERS membership.)
It's an "alternate" retirement program because it provides two years of retirement savings in lieu of two years of retirement service credit under CalPERS. Even though you don't earn retirement service credit with CalPERS during this period, you're still a CalPERS member.
Savings Plus (part of the California Department of Human Resources) administers the ARP.
For more information about ARP, including forms and publications, visit SavingsPlusNow.com. You may also contact your HR Office if you have questions.