"Chasing Cars" is the second single from Snow Patrol's fourth album, Eyes Open. It was recorded in 2005 and released on June 6, 2006 in the US and July 24, 2006 in the UK as the album's second single. "Chasing Cars" gained significant popularity in the United States after being featured on the popular medical drama Grey's Anatomy. It became notable as one of the songs that revealed the impact of legal downloads on single sales in the UK. The song is Snow Patrol's biggest-selling single to date, ending 2006 as the UK's fourteenth best-selling single of the year and 2007, on the strength of downloads, as the UK's thirty-fourth best-selling single of 2007.
As of March 2009 the single has spent 130 weeks in the UK Singles Chart Top 100 and has sold 505,000 copies in the UK, despite missing the Top 5.
Gary Lightbody, frontman of Snow Patrol, stated it is the "most pure and open love song ever written." The phrase "Chasing Cars" came from Lightbody's father, in reference to a girl Lightbody was infatuated with, "You're like a dog chasing a car. You'll never catch it and you just wouldn't know what to do with it if you did."
The song was first heard on the band's 2005 Final Straw Tour, when they began playing it, along with two other newly written songs ("Your Halo" and "It's Beginning to Get to Me") they had intended to release on their upcoming album. Since then, the composition of the song was changed slightly, and most of the lyrics were rewritten.
Snow Patrol played "Chasing Cars" on an appearance on Late Night with Conan O'Brien. The song was also performed as the last live performance on long-running British music programme Top of the Pops. The band also performed the song when they were the musical guest on the March 17, 2007 episode of Saturday Night Live, hosted by Julia Louis-Dreyfus. Additionally, the band played the song live in their appearance at Live Earth. On July 7, 2007, this song was performed during the London leg of the Live Earth concert at Wembley Stadium and at Oxegen later on that night in Ireland.
"Chasing Cars" was heard on the TV show One Tree Hill episode "The Show Must Go On", which aired in the US on May 3, 2006. The show is popular amongst the teenage crowd, and the episode gained around 3.06 million viewers. It was not until several weeks later when the song appeared on the second season finale of Grey's Anatomy on May 15, 2006 that the song found a larger listening audience and pushed its way onto the download and pop charts in the United States. The song was made into a music video for the show, serving as a promotion for its third season. The music video shows scenes from the first and second seasons as well as previously unseen scenes from the third season, with clips in-between from the UK music video of the song.