A traffic calamity of epic proportions is brewing in what was once a relatively innocuous intersection in San Mateo. And it’s aiming to come to dire fruition in the guise of what is called “transit-oriented development,” or TOD.

It appears that, inexorably, the immediate vicinity of Concar Drive and South Delaware Street is headed for extensive construction, more than 1,600 living units and several hundred thousand square feet of office/retail space. The bulldozers are hard at work. More are coming. The wheels are in motion.

In separate projects, several square blocks of land are targeted for multiple units of apartments, condos, retail businesses and offices. Some of that work is nearly finished. A large portion remains to be approved by city officials.

The area is adjacent to Highway 92 and one long block from Highway 101. That freeway junction is already one of the worst rush hour traffic bottlenecks in Silicon Valley. It seems to get worse with each passing week. Heavily used El Camino Real isn’t far away as well.

A key amenity in the neighborhood is the Hayward Park commuter rail depot. That Caltrain stop is one of the most important excuses for permitting such significant development there — if finished as proposed, it would end up being a small city within a city.

The optimistic planning mantra, a familiar refrain stimulated, in part, by mandates promoted by the state of California, goes like this: The Peninsula, with its booming economy (the word “unemployment” is almost an anachronism here these heady days) and huge surge in office construction, needs more housing for workers; such dwelling units need to be close to public transportation so that people won’t need their cars. It’s going to be a bright, new day.

Really? If that actually is the case, why bother with building garages or parking spaces at all? Very few will need their despised cars, runs the argument. The logic continues to be flawed. What’s occurring in that pocket of San Mateo will likely end up being a classic case of unintended consequences. Anyone with even a middling grasp of suburban reality can see what’s coming down the pike.

Traffic in that neck of the woods, already daunting, will become not just rush hour gridlock; it will be the traffic jam from hell, making conditions on the Highway 92/101 interchange complex, not to mention the local surface streets, much worse than it is now. The word “unbearable” comes to mind.

It boggles the reasonable mind to watch all of this unfolding as the experts blandly tell us that everything will be just peachy and, besides, we need to adjust to the necessary, brave, new world around us.

Lots of luck.

John Horgan’s column appears weekly in the Mercury News. You can contact him by email at johnhorganmedia@gmail.com or by regular mail at P.O. Box 117083, Burlingame, CA 94011.