If you build it, they will come

A lot of people (who I assume to be well-intentioned) wonder why we don’t improve traffic flow first, before we allow any new development in Rosemead.

There are two reasons why the "infrastructure, first" strategy won’t work. First, most of the traffic on Rosemead’s roads is coming from and/or going to out of town locations. Second, the flow of traffic is like water–it seeks the path of least resistence.

The first reason is why traffic on our streets keeps getting worse, even though we have added very little new entertainment, dining, or shopping alternatives in our city during the past twenty-five years. Most of the big traffic generators are replacements for other traffic generators we lost: K-Mart was replaced by Builder’s Square, which was replaced by the Ranch 99 market; Montgomery Wards was replaced by Target, etc..

Now, about the "water wants to flow downhill" analogy: If water flowing down a hill hits an obstruction, it will temporarily back up. But, eventually, it’ll find another way down.

The people who model traffic flows (and people walking) have discovered that the movement of people and cars is very similar to the flow of water. If they hit an obstruction (traffic) along one path, it’ll try another way.

So, for example, I live north of Valley, midway between San Gabriel Blvd and Walnut Grove Ave. But I almost never exit the San Bernardino Freeway at Walnut Grove. That’s because I know that, whether I’m coming from the east or the west, it may take me several minutes to even get completely off the ramp and on to Walnut Grove. By contrast, San Gabriel has traffic, but it’s flow is more predictable.

Suppose they were to fix the off ramps at Walnut Grove. Initially, that would open up the flow of Walnut Grove and I could get home quicker by existing there. But, within a year or so, everyone else in the area would figure that out, too. A lot of the traffic that current exits at San Gabriel or at Rosemead will start getting off at Walnut Grove. The result would be that the increased capacity at Walnut Grove will be soon be overwhelmed, again.

Or, suppose we were to add a travel lane on Rosemead Blvd. Initially, the traffic flow on Rosemead Blvd would improve. But, again, within a year or two, word will slowly spread. People who currently use San Gabriel or Walnut Grove or Temple City or Baldwin or even the 605 freeway to head north from the San Bernardino Freeway will decide that Rosemead Blvd is quicker. Unfortunately, that means more traffic on Rosemead. Before long, Rosemead will reach a new equilibrium, with traffic slowing down to the point where it no longer provides an advantage over alternative routes.

That’s why we can’t just try to build our way out of congestion, "first." "If you build it, they will come," and clog your roads up, just like before. Spending money to improve the flow of Rosemead’s streets will just make it easier for our neighbors to get to their destinations on the other side of our town, UNLESS we also give them a reason to stop in our town and spend their money here.

Cool Explanation

Also, I think the anti-condo thing is a tempest in a teapot.

If they don't want the development up on Valley, how about moving it down to San Gabriel, and spreading it kind of low? Then, walking down San Gabriel wouldn't be so boring. Right now, it's all auto stuff and tax accountants.