I confess to NOT trusting the vehicle traffic projections that have been supplied by the consultant who is currently helping Menlo Park on its El Camino Real Corridor Study. Even he admitted some of the projections are counter-intuitive. For example, by adding a third lane in each direction north of Ravenswood the consultant projects that the 50% increase in lane capacity would simply induce 50% more vehicle trips on an average day. So there would be no benefit, traffic congestion on El Camino Real would remain.
While I do not doubt the idea of induced demand I do not find assumption. The total number of existing average daily trips on the north end of El Camino Real is about 36000. So a 50% increase would equal 18000 more vehicle trips on El Camino Real. (Note: traffic in both directions is included.) That is, an additional northbound and southbound lane would “induce” 9000 more trips in each direction.
It is NOT clear where these additional vehicles are either originating or going; they simply appear out of thin air. If existing drivers are changing their routes which ones now have less traffic? Is this a good trade-off? Also, it is impossible to evaluate the consultant projections without understanding risk. I believe the consultant’s traffic projections are ONLY the “expected values” of a range of possible outcomes. What is his confidence level, i.e., the actual range of likely outcomes? Standard deviation?
So what should Menlo Park do? The best way to find out what would happen if El Camino Real had three lanes in both directions its entire length is to run a well-designed experiment. I recommend that Menlo Park do so in 2015 and carefully monitor the impact on El Camino Real and other street that might be impacted. Then we could make well-founded decisions.