Among the tactics police use to deter and detect sexual offences as part of Project Guardian are "weeks of action", which involve large numbers of additional police officers, both high-visibility and in plain clothes, patrolling the transport network in order to raise awareness, gather intelligence, and detect offences.[9] One of the first, in August 2013, involved 185 police officers and resulted in nine arrests.[7] In a week of action in September 2013, police used Twitter to raise awareness of the initiative, and the crackdown resulted in 15 people being arrested.[3] Another, held in March 2014, resulted in 16 arrests.[10]