An old saying (in the pre-mobile devices age) is that to locate a good restaurant in a town, just check the parking lots. A crowded parking lot means that there’s good food inside the establishment.
 
It’s not known when the saying began. “The family style platter has attracted the traveling public and attesting to this fact is the ever-crowded parking lot in front of the establishment” was cited in 1960. “My ex-wife used to tell me a crowded parking lot usually indicates good food” was cited in a 2001 book.
 
   
Old Fulton NY Post Cards
8 July 1960, Homer (NY) Independent, “Dining Is Unique at O’Briens,” pg. 6, cols. 5-6:
The family style platter has attracted the traveling public and attesting to this fact is the ever-crowded parking lot in front of the establishment.
   
Chicago (IL) Tribune
Clearing Not Fancy But Stable
In A Holding Pattern South Of Midway Airport
February 05, 1986|By Nadine Epstein.
(...)
Only two years ago, Jim Magafas chose 63d Street as a site for his family-style Dallas Restaurant, 7050 W. 63d St.
 
“I have no regrets,” said Magafas, whose crowded parking lot testifies to his restaurant`s success.
   
The Artful Diner
Tiger’s Tale Bar & Grill
1290 Route 206 South
Rocky Hill, Mercer County, New Jersey
(609) 924-0262
By The Artful Diner
Special to New Jersey Online
8/23/99
The Tiger’s Tale (as in Princeton Tiger) has enjoyed a long, full life: fourteen years under its current eponym and, in previous incarnations, as Black Bart’s and The Foolish Fox. And one glance at the crowded parking lot should be enough to convince you that this popular happy-tappy is still going strong.
 
28 July 2000, Aberdeen (SD) American News, “Selecting good restaurant takes detective work” by Susan Ager, pg. 6A, col. 2:
You can’t rely anymore on the old clue: a crowded parking lot. Now it only suggests that the food inside is middle-of-the-road, which means fatty, salty and sweet and served in huge portions.
     
Google Books
A Place in the Mountains
By Brett Taylor
Victoria, BC: Trafford Publishing
2001
Pg. 94:
There were no open parking spaces in front, or on either side of the restaurant. Apparently, the place did a good business. My ex-wife used to tell me a crowded parking lot usually indicates good food.
 
Google News Archive
8 February 2007, Pittsburgh (PA) Post-Gazette, “Munch goes to The Hop House,” pg. W-26, col. 2:
Don Quixote of La Munch-a, the ravenous knight-errant, and Sancho Panza of Munch (SPAM), set out for The Hop House and noticed two things: one, a crowded parking lot, which is a good sign for a new restaurant.
 
Google Books
Crooked Path
By Henry Hall
Lulu.com
2012
Pg. 225:
“Hidmore, I have always heard that you should look for a crowded parking lot to find a place that serves good food.”
   
Jax Food Critic (Jacksonville, FL)
February 11, 2012
Cinotti’s Bakery Restaurant Review Jacksonville Beach
(...)
They have been in this location for 26yrs and the locals will make sure you see it due to the crowded parking lot. And we all know a crowded parking lot is a sign of good food!
 
World Less Traveled
Picking a Restaurant in a New Town
DATE April 29, 2015
POSTED BY admin
You’re in an unknown town and you’re hungry…your kids are whining for dinner.  You don’t want fast food. You don’t want pizza. How do you find the best place for your family? Try this method. It always works! Look for the restaurant with the most crowded parking lot. Restaurants with poor service and bad food get a poor reputation and that reputation gets around. But word gets around about a good restaurant too! More often than not a crowded parking lot means good food, good service and a place that locals love!
 
tripadvisor
“Crowded parking lot”
4 of 5 stars
Kathleen Rene, Indianapolis
Reviewed June 4, 2015
When there’s ALWAYS a crowded parking lot, you know there’s good food inside!
     
Mommy’s Minivan Monologues
June 21, 2015
Father’s Day 2015: 7 Reasons to Take a Road Trip with My Dad
(...)
A crowded parking lot means good food: Daddy was the original foodie when it came having the most accurate radar to spot the best Dives, Diners and Drive-ins.  It seems he always knew how to pinpoint lip-smacking local fare, especially when it came to finding authentic Soul Food and Southern down home cooking on the road – even in Utah!
 
To him, a crowded parking lot meant happy customers. That’s reason enough to bring the car to a screeching halt.
   
Twitter
Jim Byers
‏@JimByersTravel
An age-old saying, but follow the cars. A crowded parking lot = good food! #RoadTripUSA #TravelSkills A2
11:15 AM - 2 Jul 2015