"Masks Required" notice being displayed on the <a href="https://en.wikipedia.org/wiki/Destination_sign" class="extiw" title="en:Destination sign">destination sign</a> of a bus of <a href="https://en.wikipedia.org/wiki/TriMet" class="extiw" title="en:TriMet">TriMet</a> (the transit agency serving the Portland, Oregon, metropolitan area) in September 2020, during the <a href="https://en.wikipedia.org/wiki/COVID-19_pandemic_in_the_United_States" class="extiw" title="en:COVID-19 pandemic in the United States">COVID-19 pandemic</a>. TriMet began requiring all passengers to wear face coverings on May 20, 2020, and installed mask dispensers in all of its buses and light rail cars.
<a href="//commons.wikimedia.org/wiki/User:Steve_Morgan" title="User:Steve Morgan">Steve Morgan</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>