The most important bus lines have frequencies of between 3 and 15 minutes during the day and between 10 and 40 minutes at night; some lines have service throughout the night. The bright yellow buses are known simply as 'guaguas'.. A 10-ride ticket is available at official shops in the city. The Tarjeta Insular (Island Card) which offered a 20% discount on both municipal buses and Global buses was discontinued on 1 January 2011.