Police have warned drivers about leaving their keys in the ignition after 10 vehicles were stolen in separate incidents over three weeks.
Thieves have taken vehicles from Aspley, Bestwood, Bilborough, Hempshill Vale, Wollaton and Mapperly Park - all in Nottinghamshire.
One of the thefts was from a driving instructor who left the keys in the car while picking up a student.
Insp Steve Payne said thieves were on the lookout for "lapses of judgement".
"People think that they are only going to be away from their vehicles for a few minutes so nothing will happen. Thieves then take advantage of this," he said.