Yes, you can maintain both types of IRAs at the same time. You can even make contributions to both types of IRAs in the same year. But your contributions to both Roth and traditional IRAs cannot exceed the maximum contribution limit for all IRAs.
There are limits on the amount of income one can make during a given year—and the limits change from year to year. Please visit the IRS website for details.
Note: The IRS maintains a page that provides additional information about Roth IRAs. You can find that page here http://www.irs.gov/Retirement-Plans/Roth-IRAs and you will want to link on a regular basis. The IRS might update its site and change the location of the information.
Another option is for your credit union to update the answer to this question yearly.
A Roth IRA is an individual retirement account created by the Taxpayer Relief Act of 1997. Roth IRA accounts are traditionally used as retirement savings accounts. They allow limited contributions to be made throughout the tax year and can be withdrawn within 5 years after establishing the account provided you are aged 59 1/2 or older.
Those who work for a living can contribute to a Roth IRA account. The income must be derived from actual work efforts and compensation in the form of wages, tips, salaries, bonuses and professional fees.