In peaceful circumstances, they are usually installed by the police or road transport authorities; they are also commonly employed during wars and are usually staffed by heavily armed soldiers in that case. During protests and riots, both police and demonstrators sometimes use roadblocks.
- Who Approves of Those Who Block Roads to Protest in the Americas? http://www.vanderbilt.edu/lapop/insights/IO921en.pdf
- Clearing the Path for Land Rights, One Road Block at a Time: How Peru’s Indigenous Population can Assert Their Land Rights Against Peru’s Government, 1 Global Bus. L. Rev. 229 (2010-2011)