Progress bars use some of the same button and alert classes for consistent styles.

40% Complete (success)
20% Complete
60% Complete (warning)
80% Complete (danger)
<div class="progress">
  <div class="progress-bar progress-bar-success" role="progressbar" aria-valuenow="40" aria-valuemin="0" aria-valuemax="100" style="width: 40%">
    <span class="sr-only">40% Complete (success)</span>
  </div>
</div>
<div class="progress">
  <div class="progress-bar progress-bar-info" role="progressbar" aria-valuenow="20" aria-valuemin="0" aria-valuemax="100" style="width: 20%">
    <span class="sr-only">20% Complete</span>
  </div>
</div>
<div class="progress">
  <div class="progress-bar progress-bar-warning" role="progressbar" aria-valuenow="60" aria-valuemin="0" aria-valuemax="100" style="width: 60%">
    <span class="sr-only">60% Complete (warning)</span>
  </div>
</div>
<div class="progress">
  <div class="progress-bar progress-bar-danger" role="progressbar" aria-valuenow="80" aria-valuemin="0" aria-valuemax="100" style="width: 80%">
    <span class="sr-only">80% Complete (danger)</span>
  </div>
</div>

Related classes: