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SANDAG Regional Transportation Plan Derailed, What's Next?

I am a transportation planning professional who has worked for the past 15 years to improve the quality of transportation planning in San Diego County. In the process, I have worked extensively with SANDAG and its planning processes, and I believe I can offer some insight into why SANDAG has been unable to produce a viable long-range plan..

The issue has a technical root. Any proposed transportation is *modeled* to ascertain ridership demand, and it is ridership that ultimately determines whether a project is cost-effective. SANDAG is very proud of its Regional Travel Model, a hugely complex network of data tables and equations, and there are many features of this model which are commendable and even state of the art.

But there's an area of the model that isn't helping us: the part that determines how many people will use transit services. The way the model is constructed, it will assign very few riders other than the poorest of the poor to any transit service, no matter how fast and convenient. When I pointed this out to SANDAG in meetings with their modeling staff, I offered as evidence that the model may have correctly projected ridership on the Coaster commuter rail (because of some fudge-factors built in to the model, not because the model's native assumptions would have been correct), but that almost certainly it incorrectly projected the income level of riders. It turns out that this was exactly the case, so SANDAG modelers included another "custom" fudge-factor to manually change the results.

The problem is this: if we were to come up with new transit projects that truly provided fast, frequent, and convenient service that actually, in the real world, would attract appreciable numbers of middle-income riders (an example would be the Commuter Express buses on the I-15 corridor, which attract exactly that market), the model won't show that ridership.

This is the core issue: THE MODEL DOES NOT FAIRLY ACCOUNT FOR WHAT MAY ATTRACT A MIDDLE-INCOME PERSON TO TRANSIT, and therefore, as a result, tells SANDAG planners that only a road-heavy plan can deal with increased transportation demand. The model leaves potentially hundreds of thousands of transit trips on the table (assuming the right transit projects), forcing planners to conclude that there is little transit can do to make a difference.

How do we solve this issue? If SANDAG makes a serious effort to first learn more about what would attract a broader market to transit and then updated its model--and its planning knowledge—it could then devise a transportation plan that achieves our broader goals.

December 6, 2012 at 7:25 p.m. ( | suggest removal )