In December of 2017, California Senator Dianne Feinstein renewed her longstanding call for a second bridge connecting San Francisco to Oakland with a letter to the Bay Area Metropolitan Transportation Commission.

Now it seems the old idea of a “second crossing” is getting new juice, as San Francisco engineer and Structure magazine contributor Roumen Mladjov spoke up Friday, in the form of a San Francisco Chronicle op-ed, arguing that a second bridge is an inevitable necessity.

First, Mladjov points to the Bay Area’s ever-growing population, which he says is up 27.5 percent since 1990 and projected to grow another 21.3 percent by 2040.

In fact, Mladjov is understating the problem in regards to the East Bay locales most likely to access the bridge: Alameda County specifically is up 28 percent since 1990, from some 1.2 million to more than 1.6 million, and Contra Costa County is up a shocking 41 percent plus, from less than 804,000 in 1990 to more than 1.13 million in 2016.

A bridge designed to serve San Francisco and Oakland in the 1930s, back when the city’s combined populations were a mere 918,000 and change, isn’t going to keep accommodating that kind of growth forever.

Mladjov also argues that as far as major cities and large-scale regional economies go, the Bay Area is severely under-bridged:

If we compare the number of bridges at other developed centers, such as New York City, London, Paris and Sydney, with San Francisco, there are 700,000 people per bridge in Bay Area versus 171,000 for New York City, and around 250,000 to 290,000 for London, Paris, or Sydney! [...] Are we still surprised that our traffic conditions are so terrible?

Again, Mladjov might actually be low-balling the problem here. In 2016, all nine Bay Area counties had an estimated combined population of over 7.65 million and just eight bridges, making for a ratio of one span per nearly 967,000 residents.

Finally, Mladjov argues that city governments would be unable to make up for the capacity of a second Bay Bridge by expanding BART or any other transit service, because commuters prefer cars.

“An additional bay bridge can be built in four to five years, including concept, design and construction [...and] the cost should be comparable to the efficient bridge structures of this magnitude—around $3 billion,” he writes in conclusion.

Plans for a second Bay Bridge are almost as old as the existing span itself. In fact, in 1947 the U.S. Army and Navy—at the time the biggest stakeholders when it came to bay traffic—jointly approved one. The city even considered a (gorgeous) design by Frank Lloyd Wright shortly after the Bay Bridge went up in 1933.

But for decades thereafter, nobody could reach a consensus on precisely where and how to build it, leaving the second crossing a perpetually cross topic.