The best replacement for barriers is obstacles.

The best alternatives to barriers are rated as following:
★★★★★  obstacles
★★  bridges
★  vapor barriers
★  free trade
★  entry
★  postzygotic
★  non tariff barriers
  tariff
  postzygotic barriers
  social barriers
  boundaries
  prezygotic barriers
  constraints

Your alternative for barriers is not listed? Suggest!
Speaking about barriers, one probably shouldn't forget about joel barish.

Other search terms related to barriers and their ratings are:
★★★★★ joel barish
★ books
You have in mind a companion for barriers and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of barriers in all years. Click on graph for more.
barriers
obstacles
bridges