Swift Foot -- Page 11.
Just would like it worded a little better. Is it a bonus to her "base" speed? I believe that there are still some magic items or spells that might double the speed which would affect this. I'm assuming that it would increase their run speed as well appropriately (x4) and so on. Also, I'm not sure why you have a limit on the bonus to the speed. Is there really that much of an issue if they get +50 to their speed for 15 rage points? You might want to consider limiting the bonus based on the level of the barbarian rather than just saying no more than +30 feet.