Gridlock (Doctor Who)

Gridlock is the third episode of the third series of the British science fiction television programme Doctor Who, first broadcast on BBC One on 14 April 2007. It is written by Russell T Davies and directed by Euros Lyn.

The episode is set in New New York, a futuristic city located on the planet New Earth, 30 years after the events of the episode "New Earth". The Tenth Doctor (David Tennant) and Martha Jones (Freema Agyeman) arrive in the city hoping for a pleasant visit, but quickly discover that the entire population, estimated to be billions, is trapped in a gigantic motorway system. Known as the Motorway, the cars are locked in perpetual gridlock due to chronic overpopulation and airborne diseases.

The reason for the gridlock is that the surface of New New York is too toxic to inhabit. The privileged live above in cleaner levels, but the less fortunate are forced to exist within their cars, with generations having lived and died within the confines of the Motorway. They pass the time by chanting hymns and taking mood-altering drugs.

The Doctor and Martha investigate the mysteries of the Motorway, discovering the sinister Macra, crab-like creatures, have resurfaced and are preying on the stranded motorists. The Macra were believed to have been eradicated.

The plot revolves around the search for a missing wife and the Doctor and Martha's attempts to find her, while also uncovering the underlying cause of the gridlock and the threat posed by the Macra. Ultimately, the Doctor uses his sonic screwdriver and knowledge to develop a solution to clear the Motorway, allowing the citizens to escape and repopulate the upper levels of the city. The episode addresses themes of overpopulation, social stratification, and the reliance on technology and medication for escapism.