When I was growing up, it was, oddly enough, the junior high parking lot. It was kinda mix between people getting it on and a party spot for drinking. I didn’t go there myself, but I’d hear the stories later on.
In Mexico, where I lived in my late 20s (late 1990s), this need is served by pay-by-the-hour “hot pillow joint” motels at the edge of town, where you drive in and someone closes a big curtain behind your car. You access the bedroom right from your car, and no one ever sees anything else (and no passerby will see your car).
Or so I’m told. 
When I was 20 or so, I went by train to London for an interview. The interview was in the morning and I arrived mid-afternoon, the previous day.
I went in search of somewhere cheap for the night and settled on a rather nondescript hotel in a back street behind the station. There was a desk and a bell in the front hall and a woman appeared when I rang. Yes there was a room available and she quoted a very low price.
“For the night,” I asked, surprised,
“No luv, for an hour,” she replied.
I was sure that I’d read of a disc jockey in New York who used to broadcast “submarine races” on the radio in the 1950’s : “Today folks, it’s the Skipjack versus the Nautilus…”. The author gave it as an example of how certain “events” didn’t even have to be real in order to draw a crowd. But now I can’t find that cite.
Anyway, I’ve read of the term Lovers’ Lane used for roads that were made especially pretty, lined with dogwoods & flowers for the “young folks to go a-courtin on a buggy ride”.
I live near a road called “Lover’s Lane”, it’s a pretty road through woods and hills and fields but I’ve never seen anywhere you could park and make out. It’s all private property from what I can tell.
That would be Murray the K.
another joke - cop sees boy in front seat , girl in back seat. He asks the boy how old is she? He looks at his watch and says in 10 minutes she will be 18. 
Haven’t read the thread yet, but in my high school years '64-68 the Drive-In theaters served the purpose for all levels of teenage sex. They were called “Passion Pits” for a reason. Several fond memories.
I’m 72. I grew up in the Chicago area (south suburbs) and yes there were “Lover’s Lanes” all over the place. Everybody in the local area knew where they were. I think it’s fair to say it gave everybody a chance to explore their sexuality. Besides fucking, you could practice eating pussy and sucking dick. Yes, there were still dark alleys and deserted roads you could find in a hurry. But if you pulled into a “Lover’s Lane” on a hot Friday night it would be packed. You could tell who was engaged in some hot sex because their windows were all steamed up, which increased your own anticipation and arousal. The police, in the main didn’t really bother you too much, unless you were in a town that was in the midst of a moral crackdown.
And yes, outdoor drive-in theaters was a hot bed of making out and steamy sexual activity – especially if this was the only opportunity you had to get your sexual interest in a person in an intimate setting for 2-3 hours ( they showed two movies back then). You both had an opportunity to take your time, kiss, get hot and sweaty and do what they call “edging” now. And then you could do it again, and again before the double feature was over… Ahh it was nice. Don’t ask me about movies I saw. lol
Growing up in Lorain, Ohio it was well known that couples would park at Lakeview Park overlooking Lake Erie. The local euphemism was “watching submarine races”.
Going home from some event that I attended with my parents on the LSU campus in Baton Rouge one evening, I noticed several cars with people in them parked around the big lake in the middle of the campus. I was probably 9 or 10 at the time. Upon asking my parents what those people were doing I was told they were watching the submarine races. For several years afterwards, whenever I passed through the LSU campus after dark I always looked for periscopes, wakes, or some other sign of the racing submarines but never saw any. Yet there were always cars there anyway. Go figure!
Nothing local about that euphemism. The “submarines” are not in your local lake; they’re sperm in your local woman. Or better yet in your even more local condom, but sometimes that part gets skipped in the heat of battle.
Murray the K issued a pre-Beatles record called Gassers for Watching Submarine Races. I’ll bet the euphemism started shortly after WWII made submarines a headline word.
Despite @LSLGuy’s raunchy explanation, it’s more likely that it started as a joke about lover’s lanes overlooking bodies of water, which were common everywhere. “What were you doing there?” “Watching submarine races.” Ha, ha.
Or the submarine-esque appendages from which (something something).
Or, as documented in the opening of Night Of The Creeps, the axe-wielding escapee from the local asylum.
In the immortal words of Spinal Tap, “I want to sink her with my pink torpedo.”
Lover’s Lane predators have probably always been a thing, but gained notoriety with Caryl Chessman. . Along with the above mentioned, it was showcased at least once on Alfred Hitchcock Presents .
Rape had long been a capital offense, used inordinately against Blacks and minorities. The Scotsborough Boys began the shift away from that, and Chessman, safety white, made for a good test case to clear it off the statutes once and for all. (The case somehow also contributed to Pat Brown’s replacement by Ronald Reagan).
A 1970s liberal-minded TV movie was made about Chessman, with Alan Alda. One 1970s conceit was one of the victims brought into court on a stretcher, raving mad from having been forced to perform oral sex (the implication being “oh come off it 1940s people, why so uptight?”).
ETA a story I watched a few days ago on Forensic Files: Gerald Mason, a lover’s lane rapist who then killed two El Segundo policemen in 1957, and was captured in 2003
Like a lot of people, I’ve been interrupted at a lover’s lane by the police. I now don’t begrudge them doing it.
A soon as I saw the OP’s question, I started thinking, “Why bother? You really need bench seats for a good Lovers’ Lane session.” I guess there are enough vans and SUVs around, but we always wanted to be in the front seat if someone (cops or property owners) showed up. Much less awkward to explain, even if you were dshabille.
Bless those old Plymouth Furys…