Most Drive-In Movie Theaters consist of a large outdoor screen (either a wall painted-white, or a complex steel-truss structure with a complex finish), a projection booth, a concession stand and a large parking area for automobiles. Within this enclosed area, customers can view movies from the privacy and comfort of their cars.

The original Patent Drawings.
The idea originated in the early 1930's in Camden, NJ. and was Patented by Richard M. Hollingshead. His idea began as an experiment in his driveway with a Kodak Projector, mounted on the hood of his car, aimed at a screen that was attached to some trees. He tried different techniques and finally worked-out the parking-arrangement and spacing to allow everyone that attended, an unobstructed view of the screen. Once he had this idea in-place, he was granted a Patent in 1933 and He opened his first Drive-In Theater soon thereafter. This facility only lasted a few years, but the idea caught-on elsewhere to become part of the American Pop-Culture and Landscape to-this-day.

Typical-style of Drive-In Theater Speakers with the Volume Knob.
Sound was originally produced from Speakers in the main screen tower, but the quality wasn't that good and many attempts were made to improve it. In 1941, the RCA corporation found a solution and along-came the in-car speakers with built-in volume controls that most drive-in patrons would come to know. These were better than the original Sound, but still had a very "tinny" sound to them. Later-on, as the technology improved, this system was replaced with Radio Broadcast equipment to allow the sound to be transmitted directly to the vehicles. This was an improved process for sound and also kept damage to the wired Speakers and/or patrons cars that would happen when folks would leave, after a good show of their favorite film, and some people would "forget to remove the speaker" and damage both the speaker and/or their cars in the process (i.e. Windows, or scratches/dents, etc.).
The popularity of the Drive-In's soared after World War II and peaked in the 1950's and 1960's. The theaters would provide cheap, family entertainment including many having a Playground (or other things) for their youngest patrons. For colder-weather, in-car heaters were also offered at many Theaters, much like the Speakers had been.

An "intermission cartoon" to entice patrons to the Concession Stand.
The Concession Stand (or Snack Bar) would have food that could be served very quickly. Hot Dogs, Pizza, Cheeseburgers, Popcorn, Soft Drinks, and a host of other "food" could be found there to enjoy along with the show. This is usually where the Theater makes most of it's profits and much of the promotions are geared towards that area. This was vital to the success of drive-ins, as food revenue increased steadily during the late 1940s and 50s. While some operators experimented with talk-back speakers to take orders and deliver food to the car, others had mobile carts patrolling the lots selling snacks. Over time, owners discovered that concessions could be sold at a high mark-up and that revenues did not have to be shared with film distributors. To this day, food revenue remains extremely important to exhibitors, especially with film rental rates going as high as 80% on opening weekends for some features. In order to promote the concessions, most locations used the now-famous drive-in intermission films, popularized by the Filmack Company, featuring dancing hot dogs and countdown clocks that were supposed to mesmerize the audience members, wet their pallets and open their wallets.

Another Intermission Ad
Many Theaters even had "car-hops" like their Drive-In Restaurant counterparts to make the experience even more appealing for their patrons.

A car-hop, taking an order (California)
The Drive-In owners would later allow other-uses for their large amounts of space which could only be used for the Theater after-sunset. This would usually generate more income for the theaters and some of these uses included Flea Markets, Swap Meets, and even Outdoor Church Services.

A typical Flea Market at the Mission Drive-In, San Antonio, Texas, 1984
Over time, with the advent of other sources of entertainment, as well as the rising cost of Real Estate and other economic factors, Cinematic Landmarks such as these have been slowly disappearing over the years, leaving less than 500 across the United States currently. Many of those which were closed were later demolished and the real-estate used for other things such as Office or Retail Space, with some being replaced on the exact same land with Mutli-Plex indoor Movie Theaters. Some properties have just been left vacant with nothing remaining there but an empty field. However, a very-select few that were closed have even re- opened to be given a new-life with new patrons looking for a very unique movie-going experience.
Many folks feel that these Gems of Americana are very much an endangered part of the landscape. Most, if not all of them, have very fond memories of their time spent there and would love to be able to revisit their favorite Drive-In Theater once again.
The Windsor Drive-In Theatre
Open: 1950's | Closed: 1980's | Vehicle Capacity: 100-200

'Drive in' by Erik Ratcliffe from flickr (Creative Commons)
The Windsor Drive-In opened in the 1950's and had a vehicle capacity of 100-200 vehicles. The Windsor was one of three Drive-Ins in the Windsor area, the other two were the Skyway on County Road 42 and another one in St. Clair Beach.
All three of the Drive-Ins were owned by a family named Dydzak, and they definitely enjoyed their time as owners and made it a "family affair" to be sure.

The Dydzak Family, 1950
The snackbar featured Peerless Ice Cream (a local ice-cream parlor chain) treats and was a huge favorite of many of the theatre-goers. Many folks remember the ice cream drumsticks for just 10¢.
The Windsor Drive In started out as a single-screen Theatre, and that is how it remained during its entire existence here. After it closed in the mid-1980's, the property was sold-off and repurposed into some other things. Much of what made this a Drive In Movie theatre is long-gone...except for the ridges in the ground that made up the ramps for the cars and trucks to park on. Those are quickly being smoothed-out here as the property is being changed.
Up until recently you may have even seen a speaker post sticking up as though they were looking for a long lost friend.
At one time there were 4000 drive-ins across Canada. By 2005, there were only 44 left. Most drive-ins closed in the mid-1980s; the introduction of VCRs meant more people were either staying home to watch movies or going to indoor movie theatres which were getting bigger screens and Dolby sound.

Aerial View (2010)
So, after little more than half a century, an era ended. Most people that visited Drive In's consider themselves lucky. Most don’t remember what movies they saw but many of them do remember how exciting it was to be outside late at night, loading up at the snack bar and then then trying not to fall asleep while watching the flickering movie screen from the comfy backseat of the car.
One theater goer summed up her feelings. "You just worry sometimes that it will be all gone. We felt so sorry to see those others all go. We really enjoyed this place."
Many folks feel that the Drive-in Theater is a part of an Endangered Americana that is missed by all who treasured the times that they had there.
Please BE AWARE OF YOUR SURROUNDINGS and as always, Enjoy the Hunt!