TAMPA — Just how big is the opening of the area's first Trader Joe's on Friday?

The city of Tampa has deemed it a matter of public safety and will deploy a half a dozen police officers to direct traffic and patrol the neighborhood.

On top of that, Trader Joe's has hired three off-duty officers to keep the calm Friday, Saturday and Sunday.

History says it should. Trader Joe's openings attract huge crowds hungry for Genova Pesto, Cowboy Caviar Salsa and other specialty foods you can't get anywhere else.

At the most recent opening of a Trader Joe's in Florida — in Pinecrest outside Miami in October — adjacent property owners had 55 cars towed because they were taking all the parking for their businesses. Exasperated police said they knew the store was going to attract crowds but had no idea to what extent.

Blame it on a disconnect between the size of a Trader Joe's — about the square footage of a Walgreens — and the traffic it will attract. City parking requirements don't account for the grocer's cult-like popularity.

So Tampa police and neighbors are bracing for gridlock.

• • •

Locals cheered when Trader Joe's announced last year it was opening stores in Tampa and St. Petersburg. After years of watching the region get passed over for other locations in Florida, it was a sign the area had finally arrived.

But with the anticipation came a big asterisk for the Tampa location, at 3808 W Swann Ave. just west of Dale Mabry Highway. While the site is centrally located, residents moaned that the area is already congested and difficult to access.

"I was happy when I heard Trader Joe's was going to come to Tampa, but I was really disappointed that it had to be in that spot,'' said Theresa Zacek, who lives nearby in South Tampa. "I don't like that corner now.''

A member of the Shapes fitness center that was demolished to make way for Trader Joe's, Zacek said the parking lot used to be just big enough for the most popular gym classes. Add the Trader Joe's traffic, and she expects it will be a mess.

The store has 70 parking spaces, which meets the city of Tampa's rules based on the building's square footage of 12,300. It needed no zoning change or special approval to build on the site, except for a variance for a large exterior sign. About two dozen of the spaces are for compact cars, a challenge for the soccer moms in minivans and SUVs expected to invade the place.

By comparison, the St. Petersburg store opening later this year along Fourth Street N between 27th and 28 avenues will have 89 spaces — significantly more than the 53 required by the city. The 12,765-square-foot Trader Joe's will share the site with a vitamin shop in a small, separate building.

Trader Joe's didn't have to make any improvements to Dale Mabry or Swann, but city of Tampa transportation officials will monitor the intersection closely to determine if any changes are needed, said Transportation Manager Jean Duncan.

Nothing will happen quickly. Because Dale Mabry is a state road, any changes would require approval from the Florida Department of Transportation. It also takes money, which the city would have to budget.

The intersection has a traffic light with left turn lanes but no turn signals. If warranted, the city could lengthen the green light cycle on Dale Mabry and/or Swann but adding turn arrows would be more complicated, Duncan said. The city would need to do a study, which the state would have to approve. Then funding would have to be secured. It's also possible that adding turn signals would create too much weight on the signal lines, which would require the city to redo the intersection supports.

"We just have to see what happens there and try to minimize the frustration of people who live around there or want to go there,'' she said.

The intersection, while already annoying to some locals, isn't high on the list of problem intersections in Tampa and wasn't up for improvement before Trader Joe's announced its plans, Duncan said. She's hopeful that once the initial excitement of Trader Joe's dies down, the intersection will return to normal or close to it.

"We know at first it's going to be popular and there will be more traffic on Swann and back ups on Dale Mabry, but we'll keep an eye on it,'' she said.

Those congestion concerns, combined with the limited parking, create a "public safety issue'' warranting extra police patrol, said spokeswoman Janelle McGregor. Complicating matters is the Tampa Bay AirFest 2014 happening this weekend at MacDill Air Force Base, drawing heavy traffic to Dale Mabry.

• • •

Tampa's Trader Joe's will be the sixth in Florida. In addition to the St. Petersburg store, others are planned for Boca Raton, Wellington, Orlando, Delray Beach, Palm Beach Gardens and Winter Park as part of a major Florida expansion for the California-based retailer.

Trader Joe's was founded in 1958 by Joe Coulombe and later acquired by a family trust set up by one of the two brothers behind the German discount supermarket chain Aldi. Privately held, it does more than $8 billion a year in sales.

The chain, which competes against Whole Foods and Fresh Market as well as more traditional grocers, had been scouting the Tampa Bay area for years before deciding on the sites. The nearest store in Sarasota opened in September 2012.

Susan Thurston can be reached at sthurston@tampabay.com or (813) 225-3110.