Here’s something I miss more each summer: the drive-in movie theater.

It’s a uniquely American creation, after all.

According to Kerry Segrave, author of “Drive-in Theaters: A History from Their Inception in 1933,” only two other countries, Canada and Australia, were able to come close to America’s “intense love affair with drive-ins.”

In order for drive-ins to spring up over America during the post-World War II boom, a unique blend of conditions had to exist.

First, there had to be an abundance of relatively inexpensive land, as drive-ins take up a lot of real estate —- and America had lots of affordable farmland near our newly formed suburbs.

Second, there had to be wealth. Families needed to not only be able to afford comfortable automobiles but to also “enjoy an emotional relationship” with them.

“A country whose inhabitants regarded automobiles as simply a mode of convenience to get from A to B would never develop a drive-in industry of any extent,” writes Segal.

The next ingredient necessary to the success of the drive-in theater was large baby boom families.

Whereas taking the kids to an indoor theater in the city was a costly hassle, the drive-in was convenient and affordable. Parents could load all of the kids into the car, enjoy their family theater event, then return home with minimal hassle.

At a time when mom and dad wore formal wear to the office every day, the last thing they wanted to do on the weekends was dress up —- and the younger kids could be dressed in pajamas, allowing mom and dad to put them directly to bed as soon as they returned home.

The first large-scale drive-in movie theater was built in Camden, N.J. in 1933, the brainchild of a young entrepreneur, Richard Hollingshead.

His idea wouldn’t catch on in big numbers until after World War II —- in part because of Hollywood moguls who only screened their A features in the movie theaters they owned. Drive-in theaters were limited to B features until 1949 when the courts broke up Hollywood’s monopoly system.

Another change happened in 1949. Hollingshead lost his patent on the drive-in movie concept and outdoor theaters began popping up everywhere. The ‘50s and ‘60s became the golden era of the drive-in theater with nearly 5,000 in operation across America.

Some argue that federal laws mandating an extended Daylight Saving Time in the early ‘70s —- which made the shows start an hour later —- is what began to kill the drive-in phenomenon. But there are lots of other reasons for its decline.

As the suburbs continued expanding, real estate costs soared. Increasing lawsuits eliminated the drive-in playground and insurance costs soared. The family unit began to change in the late ‘70s into the ‘80s —- families had fewer children and lots more divorce. Increasing fuel costs caused cars to get smaller —- making them less suitable to a comfortable drive-in experience.

One of my last great drive-in memories dates to 1969, when my parents took my five sisters and I to see “Herbie the Love Bug.” My father tested several parking spots before finding a speaker that worked.

Soon, the blue sky fell dark and the film projector began rattling behind the concession stand. Black and white numbers —- “5, 4, 3, 2, 1…” —- flashed onto the screen. Yellowed 1950’s footage advertised hot dogs, popcorn and other concession items. And then the feature film would begin and our eventful family outing kicked into high gear.

So I am nostalgic for the golden era of the American drive-in, a historic slice of Americana that I long for this time every year.

Tom Purcell, author of “Misadventures of a 1970’s Childhood” and “Wicked Is the Whiskey,” a Sean McClanahan mystery novel, both available at Amazon.com, is a Pittsburgh Tribune-Review humor columnist.