TODAY, the BGC-Ortigas Bridge will be inaugurated, linking two major central business districts (CBDs) in Metro Manila - Ortigas Center and Bonifacio Global City (BGC). Department of Public Works and Highways (DPWH) Secretary Mark Villar has promised reduced travel time - 12 minutes to get from one CBD to the other. Well, it depends.

Whether the bridge becomes mired in bumper-to-bumper traffic or provides a free-flowing corridor even during rush hour will depend on how the bridge is used.

The new bridge was designed as most of our bridges were over the past five decades - as infrastructure mainly for private motor vehicles. What if the new bridge enabled pedestrians, cyclists and convenient public transport to have more efficient travel between BGC and Ortigas Center? I argue in this column that it would deliver the best outcome for everyone, even for those with cars.

When the new bridge was first conceived, its purpose was to shift vehicle traffic away from EDSA - if some of the vehicles going in and out of BGC use the new bridge (instead of passing the Guadalupe Bridge), the traffic on EDSA would be lighter. Accordingly, the new bridge was designed to serve motor vehicles - with two car lanes each way and hardly a sidewalk. No bicycle lanes.

What we have learned from experience is that reducing road congestion by adding more roads or bridges has only a temporary or palliative effect. Because of the phenomenon of "induced demand," lighter vehicle traffic ends up attracting more car users and, before long, congestion is back to where it was earlier or worse.

We need to accept the reality that traffic has steadily deteriorated, despite decades of expanding road space for cars. As they say, fixing traffic by adding more roads is like curing obesity with wider pants.

Private motor vehicles occupy most of the road space in our cities; they give the impression that the needs of motor vehicle owners should be the top priority. Not true. In Greater Manila, only 12 percent of households own a private car; 88 percent of households, the vast majority, depend on public transport, walking or cycling to move around the metropolis.

Building more roads and bridges for cars favors the more affluent minority and contributes to the inequality in our society. The challenge for transportation agencies like DPWH and Department of Transportation is to manage transport infrastructure and services so that the mobility needs of the majority are addressed. If most roads are already choked with cars, why not create car-free corridors where those without cars can move more efficiently?

We should remind ourselves that both BGC and Ortigas Center are already severely congested. It does not make sense to channel more vehicles into these CBDs. To relieve congestion within these business centers, people should be able to get in and out of these districts using sustainable transport modes - public transport, walking and cycling - instead of private motor vehicles.

The completion of the BGC-Ortigas Bridge presents a huge opportunity to alleviate congestion while enhancing the utility and functionality of the bridge. If kept car-free (limited to public transport, pedestrians and bicycles), the new bridge could be a potent weapon against traffic, air pollution and climate change - and move many more people in a highly efficient manner.

Imagine if the new bridge was able to connect the extensive bike lanes found in both BGC and Pasig City, creating a larger bike lane network. It would encourage many more people, including car owners, to switch to bike-commuting. On a bicycle, Ortigas to BGC in 12 minutes would be a real possibility!

If the new bridge could be pedestrian-friendly as well, it would attract thousands to walk between Ortigas Center and BGC. It is about three kilometers between Shaw Boulevard and Uptown BGC - walkable in less than 40 minutes. If the sidewalks along the way could have shade trees, walking between BGC and Ortigas Center would be the healthiest and least-cost option.

The most popular travel option would likely be a high frequency bus service between BGC and Ortigas Center, crossing the bridge, say, every 5 to 10 minutes. Commuters from EDSA, Shaw Boulevard and Ortigas Avenue could catch the bus to get to BGC - and vice-versa. Car users who want to avoid the high cost and shortage of parking in BGC would be potential customers.

As more people choose walking, cycling or public transport instead of a private motor vehicle, even car users would benefit from the reduction in traffic. This "modal shift" would ultimately lead to fewer motor vehicles having to use EDSA and the Guadalupe Bridge, achieving DPWH's purpose on a more durable basis.

How do we achieve these desirable outcomes? One option is to declare the BGC-Ortigas Bridge as "car-free" and restrict it only to public transport, pedestrians and cyclists. A "car-lite" alternative involves keeping one lane for cars and operating the other as a "shared lane" for bicycles and public transport. We could try one of these options for a few months, observe the results, and then make a final choice.

Experience tells us that offering the BGC-Ortigas Bridge to private motor vehicles will eventually create more traffic and pollution within our CBDs and exclude from its use the majority of Filipinos without cars. Let's try something that takes us all to a better normal. When more people decide to shift to sustainable transport modes (walking, cycling and public transport), we know we are moving in the right direction.

Robert Y. Siy is a development economist, city and regional planner, and public transport advocate. He can be reached at [email protected] or followed on Twitter @RobertRsiy