Sulky

A sulky is a lightweight cart having two wheels and a seat for the driver only but usually without a body, generally pulled by horses or dogs, and is used for harness races. The term is also used for a light stroller, an arch mounted on wheels or crawler tracks and used in logging, or other types of vehicle having wheels and usually a seat for the driver, such as a plough, lister or cultivator.

A sulky for horses is a lightweight two-wheeled, single-seat cart that is used as a form of rural transport in many parts of the world. A special development of this is now used in most forms of harness racing in Argentina, Australia, Canada, the United States and New Zealand, including both trotting and pacing races. They are called "sulkies" because the driver must prefer to be alone

Race sulkies come in two categories,

An "improved sulky" with pneumatic tires and adjustable height was patented at the United States Patent Office by W.J. Hamill on the 15th of August 1893. (see Google patents) The asymmetric sulky was patented in Australia in the 1980s and came to prominence in 1987 when a two-year-old gelding named Rowleyalla used one to break the then world record for his category, at 3.4 seconds under the existing mark.

In 1990 the asymmetric sulky was introduced into North America, winning seven of its first nine starts at Freehold, NJ. Today the great majority of sulky manufacturers in North America are producing asymmetric sulkies.

An additional sulky type is the "team-to-pole" or "pairs" sulky, a lightweight single seat sulky designed for draft by two horses abreast.

...
Wikipedia