According to Wikipedia:
First car built for general public
According to Wikipedia, the year 1886 is regarded as the birth year of the modern car when German inventor Karl Benz patented his Benz Patent-Motorwagen. Cars became widely available in the early 20th century. One of the first cars that were accessible to the masses was the 1908 Model T, an American car manufactured by the Ford Motor Company.
First car built with automatic transmission
The first automatic transmission using hydraulic fluid may have been developed in 1932 by two Brazilian engineers, José Braz Araripe and Fernando Lehly Lemos; subsequently the prototype and plans were sold to General Motors who introduced it in the 1940 Oldsmobile as the "Hydra-Matic" transmission.
First car with power steering
Chrysler Corporation introduced the first commercially available passenger car with a power steering system on the 1951 Chrysler Imperial under the name "Hydraguide".
Progression of car brakes
In 1901, Wilhelm Maybach designed the first Mercedes with a simple mechanical drum brake, wherein steel cables were wrapped around the drums of the rear wheels and were operated by a hand lever. But it was Louis Renault who was credited with inventing the drum brake that became the standard for cars. Another improvement came about in 1918 when Malcolm Lougheed (later changing his name to Lockheed, of aviation fame) invented a hydraulic braking system.
First car with air conditioning
The 1953 Chrysler Imperial was one of the first production cars in 12 years to offer modern automobile air conditioning as an option, following tentative experiments by Packard in 1940 and Cadillac in 1941.
Inventor of first car heater
In 1893, the first car heater was invented by a female mechanical engineer named Margaret Wilcox and born in Chicago in 1838. The heater was a notorious experimental invention that is considered still to be most valuable.