San Diego — 'Hi gang! Having a wonderful time in Tijuana. Wish you were here. Write back soon." I address the postcard, a view of the Jai Alai Fronton Palace on Revolución to myself in San Diego. I take it up the steps of Tijuana's main post office, on 11th and Negrete. It has a similar feel to San Diego's downtown post office. If anything, it's larger, airier, with shorter lines, a more relaxed feeling.

The teller charges me 4 pesos and 20 centavos for the stamp, around 45 cents. The distance the card has to travel is 20 miles. The card arrives in my mailbox in San Diego...ten days later. Two thousand years ago Julius Caesar was able to get a letter from Paris to Rome (around 1000 miles) in a week. On Roman roads, on horseback. Average speed, six miles per hour. I figure that my post card averaged two miles per day. Average speed, a quarter of a mile per hour.

On the brink of the Third Millennium Mexican mail is 24 times slower than pre-Christian Roman mail. Not to jump to conclusions, I try it the other way around. Last July 26 I mailed a card in the other direction, from San Diego to Héctor, a friend in Tijuana. Ten days later (on the 5th) Héctor tells me nothing has arrived yet. What's going on here?

Personal correspondence makes up 4 percent of today's mail, so it's not just birthday cards to friends and family that are affected. It's trans-city invoices, direct-mail advertising, offers of credit cards.

"Part of the lengthy time it takes is due to us," admits Mike Cannone, communications manager for the post office's San Diego postal district, "because mail addressed to San Diego from Tijuana doesn't come directly to San Diego. A little over a year ago, the postal service was instructed to reroute all incoming Tijuana mail up to Los Angeles first, where U.S. Customs could review it. I guess they have sniffing dogs or something. Only then does it come back down here for delivery. There is an issue about drugs in the mail and contraband and so much of it getting across the border."

Nobody seems quite sure why Customs can't come to San Diego to do their inspection work. Cannone says the other problem is the difference in automation and operating budgets between the USPS and its Mexican counterpart, SEPOMEX (Servicio Postal Mexicano). "In Mexico, by and large, there's a big difference in the way they process, distribute, and deliver their mail. The carriers use bicycles. They don't have a lot of mechanization. The sorting is by hand.

"To give you an idea, there are still postal zones in Tijuana, like back in the '40s, when you had 'New York 17, New York.' They only have zones in their largest metropolitan areas, and that's as fine as you can break down the destination of mail: to a postal zone in Tijuana, for instance. And a zone could be as big as Pacific Beach.

"In the United States, we can break down a delivery location as fine as part of a block. When we're sorting the mail here at our processing center, we can group mail to even one address and sort it to the carrier, and the carrier gets the mail in delivery sequence. Their route is a set pattern, every day, because it is the most efficient line of travel. When they get the mail in the morning from our processing center, almost 90 percent of it is already sorted in delivery sequence. So they don't have to stand there at their case and sort it up as they used to.

"All of our mail-sorting is automated. Electronic optical character readers. In Mexico, they get all that mail, and very little of it has been sorted by machines. So they're virtually hand-sorting almost everything. And it takes many, many different sortations to finally get it down to the zone in Tijuana. So it's a different concept.

"Our letter carriers deliver their mail in compressed natural gas vehicles, state-of-the-art stuff. Tijuana carriers use bicycles for their routes, or they use public transportation, or their own cars. Or they walk."

Enrique López (not his real name), who works within Tijuana's Mexican postal service and asks to remain anonymous, says Cannone's analysis is substantially correct, but that U.S. post office officials are also to blame for mail delays.

"A lot of people, even within the U.S. Postal Service, don't realize there is a direct-mail service between San Diego and Tijuana," says López. "Our van and a San Diego postal truck meet every morning at around 8:00 at the border at Otay Mesa. They exchange mail. Direct. Daily! People [in Tijuana] should receive letters within two or three days. But many people -- officials themselves in post offices like, say, Escondido or El Centro -- don't know this. So they fill up their sack with mail for Mexico. They tag it, and they ship it via San Francisco or Dallas and overland to Mexico City. They don't realize they could come straight through the border here. Of course, by air, everything goes through Mexico City. If you're in [San Diego or] Oklahoma and you're sending an [airmail] letter to me in Tijuana, Oklahoma will send it direct to a central point, El Paso or Dallas, then they fly it to Mexico City airport, Benito Juárez. There, everything has to go through customs, before your letter comes back up to me in Tijuana."

The result of all this is predictable: direct post-office-delivered mail between the four million-plus people of San Diego/Tijuana is down to a relative trickle. "I imagine that we deliver probably 30 trays of letter mail a day to Tijuana that we exchange over the border," says Mike Cannone. "One 30-foot truck does it. It's not a whole lot of mail. We get more mail to San Diego's smallest community, say, Paradise Hills, each day than we send to Mexico through Tijuana each day." "Our van brings maybe three, five sacks to the border each day," says López. Both men acknowledge it's not a lot. So what happens when Tijuana, a burgeoning city of 1.5 million and growing, receives less mail from San Diego than does Coronado, a city of 20,000?

"Ant contraband!" say López. "That's what we call it. 'Contrabando hormiga.' They do it themselves. Lines and lines of people, each carrying his piece of mail back or forth [across the border.]" He's talking about San Ysidro's unbelievable mailbox phenomenon. "You have one government postal service," he says. But do you know how many [private] mailboxes are available in San Ysidro? There's one on every corner!"

Gladys Anderson, the manager of the San Ysidro post office, knows all about it. "I have never seen so many private-mailbox centers in my life. And I've been in San Diego for over 35 years in different offices. This is unique. Our post office here at San Ysidro has 6000 mailboxes alone. Plus we have around 40 commercial mail-receiving agents like Postal Annex, Mail Boxes Etc., in San Ysidro. That's around 25,000 additional boxes we service. There are [even] some commercial mailbox companies that pick up mail from here and take it across the border [to deliver to] customers at their 'Postal Annex'-type shops over there."

Which makes great business for the mailbox companies and the U.S. post office. But isn't the Mexican post office losing a lot of money?

"Of course," says López, who himself confesses to owning his own mailbox north of the border. And it's not just San Ysidro. NAFTA has brought a raft of companies to Otay Mesa wanting to take advantage of Mexico's labor but not its postal service, says Mike Cannone. One of the biggest at Otay is North American Communications (NAC), which prints bulk mailings such as insurance and credit card solicitations in Tijuana, only to truck it back up to San Diego for actual mailing. But Gary Fallowes, vice president of NAC's West Coast operation, says his company is not stiffing the Mexican post office.

"We can't mail from Tijuana. It's United States Postal Service mail. If we mailed from Tijuana it would become international. We create anywhere from 8 to 12 million pieces [of mail] a week. We pass 8, 9, 10, 12 trucks every day [across the border]. But we also do some mailing from Tijuana [to Baja California addresses]. The Mexican postal service is excellent. Getting better and better every year."

López concedes Tijuana could speed things up with some optical-sorting machines and delivery vans for each letter carrier. For those who do want to communicate by mail to families and businesses sometimes only 50 yards across the line, the problem of "snail" mail remains.

"It's definitely a cross-border phenomenon in terms of communication," says associate director Kevin Cottrell of UCSD's San Diego Dialogue. "But there's been no initiative [to streamline the cross-border mail service] that I'm aware of. And it's nothing that we have looked at. We always use courier or fax or e-mail." How closely do San Diego and Tijuana post office officials work together? A request for names of San Diego postal execs' contacts across the border elicits an illuminating answer. "Unfortunately no one can find the name or telephone number of [our] contact at the Mexican post office in Tijuana." Héctor calls. He finally got my postcard -- 11 days after I mailed it.