Map of BART and standard gauge rail in the Bay Area, showing proposed second Bay tube, plus the aerial structure and bridge alternative in green. Base map courtesy SPUR.

BART, now over 40, is suffering from old age. It was designed to carry 250,000 persons per day and now transports approximately 400,000 per day on a weekday with recurring delays and stoppages. Current proposals, to improve the capacity constraints and rider effectiveness, call for constructing a second tube that has a price tag of $50 billion. We can make it a Better, Faster and Different (BFD) for under $3 billion.

The four downtown San Francisco stations garner the system’s highest patronage making the Bay Tube the choke point. There have been recent suggestions for a second BART Bay crossing to relieve this congestion. Also, there is a need to provide Bay-crossing redundancy in case of a Bay Tube upset or for maintenance.

Currently BART operates a maximum of 23 trains per hour each way of the existing Bay Tube. This is one train every 2.5 minutes each way. Modern transit systems, like in Paris, operate trains every minute (60 an hour) and this can be reduced to every 40 seconds using modern train control systems. More rapid headways (trains per hour) would not only increase ridership it will reduce the crush in stations.

BART is planning a new train control system that will increase headways to two minutes each way. If implemented, there will still be another 100% ridership capacity if one-minute headways were achieved in the future with a modern train control system.

Making it Better

To address redundancy and operational efficiency, I propose an aerial structure and bridge (AS&B) that connects the Bay Fair Station with the Millbrae BART Station. This route would be 16 miles and take about six minutes at 160 mph, double the current BART speed of 80 mph. This proposed crossing and higher speeds would make the Fremont/Warm Springs and Dublin/Pleasanton stations equidistant from the downtown San Francisco stations, whether you go through the existing tube or the AS&B route. For extensions to Livermore or San Jose, travel time to the downtown San Francisco stations would be shorter using the AS&B. There is sufficient right of way in the public domain to facilitate the above proposal.

Making it Faster

The proposed AS&B thus will shorten many other trip times. Currently, the BART system takes most riders out of direction. For example, many Berkeley and other East Bay riders could access the San Francisco airport or CalTrain on the peninsula with the proposed AS&B route. These trip reductions would relieve the demand on the Bay Tube as well as accommodate new ridership. Moreover, this proposal would balance the system so that trains would be full in both directions.

Making it Different

As we look to the future, the proposed AS&B route can facilitate high-speed rail’s (HSR) connection to the East Bay’s Capital Corridor rail line benefitting Berkeley and other East Bay cities. The bridge could be designed to accommodate HSR more inexpensively than putting it in a tube. HSR operates on a different gauge (track width) than BART so it needs a separate guideway. The current plan, for example, calls for Berkeley riders to access HSR through a long BART ride to San Jose, or a BART ride to the Embarcadero and then a half mile hike to the Transbay Terminal which is unacceptable especially for those carrying luggage.

For an admittedly rough cost comparison, I extrapolated the 5.4-mile Warm Springs BART extension that cost $890 million including one station or $165 million per mile. Using that per-mile cost, my AS&B vision would cost $2.6 billion (note my proposal does not include any additional stations). Some transit advocate groups have proposed a 10-mile second BART tube and subway. The cost of this tube excluding any additional stations would cost $50 billion based on the extrapolation of the cost of the new 2.2-mile Hudson River Tunnel in New York. This tube is estimated to cost $11 billion without any stations or $5 billion per mile or 30 times the cost an aerial bridge. If a separate set of tracks were included to accommodate HSR, the tube would cost even more.

We need affordable improvement to BART that can be implemented with the $3.5 billion already existing in Measure RR. A new tube with additional stations is unnecessary and will take years to fund and build. The proposed bridge would take a tenth or less time to build. We need congestion relief now.

Bryan Grunwald is an architect and planner based in the East Bay
Bryan Grunwald is an architect and planner based in the East Bay