Car

Cars or automobiles were a very common means of transport for humans on Earth during the 20th and 21st centuries. By 2009, there were 800 million cars, 400 million of which were equipped with ATMOS. (DW: The Sontaran Stratagem)

20th century
In 1926, Agatha Christie's car was abandoned by a lake the night her memory lapsed in the struggle against the Vespiform. (DW: The Unicorn and the Wasp)

During his exile on Earth the Third Doctor drove a yellow roadster called "Bessie" (DW: Doctor Who and the Silurians). The Brigadier procured Bessie as part of an agreement to persuade the Doctor to work with UNIT, after the Doctor had expressed fondness for a similar vehicle which he had "borrowed" shortly after arriving on Earth. (DW: Spearhead from Space) A time eddy snatched the Third Doctor, along with Bessie, out of 20th century Earth into the Death Zone on Gallifrey. (DW: The Five Doctors) Bessie remained (in UNIT's care) on Earth when the Doctor regained his time travel knowledge, and was used by his fourth, seventh and eighth incarnations on subsequent visits to Earth. (DW: Robot, Battlefield, NA: The Dying Days)

While still affiliating with UNIT "post-exile", the Third Doctor also briefly used a different car with a "space-age" look and hovering/flying capabilities. (DW: Invasion of the Dinosaurs, Planet of the Spiders)

Sarah Jane Smith was seen to drive multiple small cars over time, while a companion of the Doctor (DW: Robot, School Reunion) and after. (KAC: A Girl's Best Friend, SJA: Invasion of the Bane)

In 1987, Peter Tyler was killed in a hit and run incident. Rose Tyler saved his life, causing a massive paradox, and the car that had previously killed him to disappear and reappear across the same stretch of road. Returning the timeline to normal, Pete was killed when he ran in front of the looping car. (DW: Father's Day)

21st century
In his eighth incarnation the Doctor used a Volkswagen Beetle, that he could drive into his TARDIS (it resided within its own alcove). The Doctor traded it for information from the Faction Paradox concerning Samantha Jones whilst in San Francisco in 2002. (EDA: Vampire Science, Unnatural History)

Mickey Smith used a car to break into Deffry Vale High School. (DW: School Reunion)

John Ellis used a car to commit suicide by carbon monoxide poisoning. (TW: Out of Time)

Donna Noble had a pivotal moment while driving her car, where turning left brought about her first meeting with the Tenth Doctor. When elements of the Trickster's Brigade caused her to instead turn right, an alternate world was created in which she never met the Doctor, causing his death and dramatic changes to the history of Earth. She was able to time travel and correct the error, once again turning left and restoring events to their original course. (DW: Turn Left)

Luke Rattigan created ATMOS, a device which stopped cars from producing CO2. In actuality, ATMOS would release a gas that would suffocate humans, but allow Sontaran clones to thrive on Earth. ATMOS was also used to exert control over cars, and drown those that opposed Rattigan. The Tenth Doctor narrowly escaped from one of these attempts on his life. (DW: The Sontaran Stratagem/The Poison Sky)

When the population of Earth was warp shunted away by the Automatons, the planet's cars were left in place, rather than being allowed to crash. (SJA: The Empty Planet)

In 2011, Jack Harkness, Gwen Cooper, Esther Drummond and Rex Matheson, who would eventually form a revived Torchwood team, escaped the CIA in Esther's car. (TW: Rendition) Gwen was later forced to kidnap Jack by car to take him to Olivia Colasanto's people. (TW: Immortal Sins)

In 2011, Amy Pond and Rory Williams wrote a message in a field using their car to attract the Eleventh Doctor's attention. (DW: Let's Kill Hitler)

Far future
In the far future cars such as the New Earth Car could hover. (DW: New Earth, Gridlock)

Donna's World
In an alternate timeline caused by the Time Beetle, the poverty of Great Britain following the destruction of London by the starship Titanic meant that the country had far fewer ATMOS installed cars. (DW: Turn Left)