Stagecoach X5 is an inter-urban bus service linking Oxford and Bedford via Bicester, Buckingham and Milton Keynes The route started in 1992 with an hourly service which was increased to half-hourly in 2005; new vehicles were introduced in 2009 and again in 2015. It operates with a 30-minute frequency for much of the day. Vehicles advertise free WiFi access, air conditioning and leather seats and are wheelchair accessible. The route carried 500,000 users in 2008; passenger numbers have grown by 150% between 2004 and 2009, leading to some problems with overcrowding.