Car doors, for many, seem like a standard feature on a car, especially the familiar hinged doors commonly used in everyday passenger vehicles. We open and close them multiple times a day—how could we not be familiar?

But in the history of automotive development, car doors weren't always a given. From the birth of the automobile in 1886, it took decades for doors to become a standard feature.

There are many designs of non-traditional doors, including gull-wing doors, scissor doors, butterfly doors, sliding doors, and swan doors. Let's discuss each:

1. Gull-wing Doors

The earliest gull-wing door design appeared in 1952, pioneered by Mercedes on the W194 300 SL racing car. It was later mass-produced in 1954 on the W198 300 SL street car. Gull-wing doors have hinges positioned on the roof, so when opened, the weight of the entire door is supported by the roof structure. If the door is lightweight, it's manageable, but heavier doors require high demands on the vehicle's structure and frame.

2. Scissor Doors

In 1968, Marcello Gandini designed the Scissor Doors for the Alfa Romeo Carabo concept car (based on the Alfa Romeo Tipo 33 Stradale). The Scissor Door's principle is simple—it has a single hinge that rotates upwards, connecting the frame to the door.

A hydraulic strut provides a second stable point and assists in opening and closing the door. However, Scissor Doors also pose a safety issue; if a vehicle overturns, exiting the car becomes challenging, often requiring breaking the glass. This is a rare scenario given the ground clearance of cars like the Countach and its successors.

3. Butterfly Doors

The first Butterfly Doors were seen on the 1967 Alfa Romeo Tipo 33 Stradale, designed by Franco Scaglione. For a long time, these doors were mainly found on racing cars, especially prototypes for Group C.

They later made their way onto street cars, starting with the Toyota Sera. Inspired by his own Sera, Gordon Murray, the designer of the McLaren F1, incorporated this design into the supercar. Subsequently, McLaren collaborated with Mercedes to produce the SLR McLaren, also featuring Butterfly Doors.

4. Sliding Doors

Many people immediately associate Sliding Doors with minivans, commonly used for their middle doors. However, aside from commercial vans or passenger vehicles derived from them, Sliding Doors also appear on regular passenger cars.

Examples include the Peugeot 1007's sliding doors and the rear sliding doors found on many Kei-cars or small-sized cars in Japan. In addition to horizontal sliding, some doors slide downward, like those seen on the Lincoln Mark VIII and the production version of the BMW Z1.

5. Swan Doors

Swan Doors are similar to conventional hinged doors, but when opened, they slightly angle upward. This design benefits low-ground clearance sports cars, preventing the doors from hitting the ground when opened. The name "Swan Doors" comes from the resemblance to a swan's wing motion.

The first car to use this design was by British car designer Ian Callum. Early in his career, he worked on the Ford RS200 mid-engine sports car. Later, as Design Director at TWR, he designed iconic models like the Aston Martin DB7 and the Nissan R390. During his tenure at Jaguar, he introduced the Swan Doors design with the DB9, a design that Aston Martin has continued to use consistently.

In conclusion, the evolution of car doors has been a fascinating journey, from basic hinged doors to innovative designs that add flair and functionality to different types of vehicles.