Traffic commanders take command of traffic management arrangements at an incident (such as a motor vehicle collision) and liaise with other response agencies such as the police, and assist in clearing the road and minimising the effects and disruption to traffic. Traffic Emergency Patrols vans patrol major road routes and respond to unplanned incidents with the aim of returning the road to normal operating conditions as soon as possible. Both traffic commanders and TEP units carry a wide array of traffic management devices such as traffic cones, barrier boards and road signage. Both also are permitted to use and display red and blue emergency lighting and are designated as 'emergency vehicles'.