Chelsea tractor

Etymology
From, a wealthy area of London in which this type of vehicle is popular, and , an ironic allusion to a large, off-road vehicle, as a humorous juxtaposition between the vehicle's size and power and its use on low-speed roads in a city environment. Potentially also an allusion to their reputation for causing unnecessary traffic congestion, due to their unsuitability for small roads, in a similar fashion to tailbacks caused by tractors on rural roads.

Noun

 * 1)  An SUV or 4x4 vehicle which is chiefly driven on urban or suburban roads for light duties, such as taking children to school.