Can You Have A Roth 401K And A Traditional 401K? 
Yes , if your company offers both you can have both , however the total contribution for both accounts combined can not exceed the IRS contribution limits between the two accounts . The value in having both is for tax diversification in the future . The traditional 401K will require taxes to be paid on distributions in the future , and is subject to RMD , where the Roth is not . 