Streetscape Workshop: Traffic

One of the obvious issues a lot of people were ignoring was the “diversion” of HWY 101 traffic onto Vulcan. Vulcan is mostly residential, with a school. North Vulcan is at least as dangerous as HWY 101 for bikes. I avoid walking my kids to Little Oaks Park because walking north Vulcan between Hillcrest and the park is sketchy.

At workshop four, Mike Murphy recognized that the 101 wasn’t situated in a vacuum and asked what would be done for “traffic calming” along Vulcan and Hermes. Later the consultants acknowledged that the impacts would have to be mitigated (That sounds like an EIR will be required).

I spent most of my “break-out” time with the traffic engineer (it was pretty lonely over there). The engineer made the point that the diversion traffic shouldn’t be considered a big deal because Vulcan will be far from capacity. His point was that Vulcan can handle a lot more traffic. After questioning him, he said HWY 101 was also far from capacity and we agreed that decisions about HWY 101 weren’t being made based on roadway capacity, but apparently that would be the case for Vulcan. Are we throwing Vulcan under the… traffic?

Under the different alternatives it is going to take longer to drive across Leucadia on the 101. As we know from our experiences with the I5, longer drive times motivate cut through traffic. The objectives of the streetscape are directly related to a reduction in drive time, so nobody should be surprised that we will be inducing cut-around traffic unless all the diverted cars go onto the I5 (BTW: If you’d like to help keep the I5 flowing send me an email. Keeping the I5 flowing is important for Leucadia and too few people pay close attention to what Caltrans and SANDAG are doing).

There are people who will disagree with my point. Mr. Eubank(?) made a statement during the workshop that could be a rallying cry for the mob that is going to chase me down. It was something like, “We can drive out cut-through traffic and send traffic back to I5!”


The engineer’s model projects the following impacts for Alt 4a:

4000 ADTs divert to the I5
2000 ADTs to Vulcan

Under alternative 5:

1000 ADTs divert to I5.
? ADTs to Vulcan

It is totally counter intuitive to me that twice as many drivers will drive the I5 instead of going down Vulcan, which turns into a straight shot down to San Elijo through Cardiff-by-the-Sea.

The engineer made a couple interesting points that should make people chill out before they tie me to a stake. Here are a couple issues:

1) The traffic projections for this model are built off Austin-Foust’s model. A couple years ago I successfully organized a review of Austin-Foust’s work and successfully managed a campaign to keep the work from being approved by the city council (It was clear that the council only ducked the approval because we did the analysis and presented it to the public in a clear and compelling manner).

It seems that we are relying on the Austin-Foust work for the L101 reports.

Funny thing is, I asked the engineer about the quality of the model. He did not say the model needed to be made more specific to fit the project, instead he agreed that the Austin-Foust model was lacking and needed corrections. It was not clear if all the needed corrections were included in the HWY 101 study.

2) The traffic model that produced all the projections was based on optimizing all of the movements through the intersections. Optimizing through flow would likely result in very different numbers, but that becomes an issue of what are the objectives.

3) He was not compelling to me when explaining how the model decides if a driver turns down Vulcan or HWY 101. If its faster to go down Vulcan wouldn't you expect most drivers to eventually decide to make a habit of turning down Vulcan? And, it didn't sound like the model deals with habit and herding behavior.

Then there was a guy name Steven that spoke during the workshop. He said that the models were based (parametrized?) on traffic data collected on Tuesdays through Thursday traffic. He thought that summer weekends are the most impacted. I don’t know, but it seems like there is some seasonality to our traffic. We have seen plenty of times that we can’t count on staff to ensure that data are collected at reasonable times and A LOT of people involved in the streetscape project know it.

People on HWY 101 know what it is like to be ignored. Drive North Vulcan early on a Sunday morning or walk it at 5 in the afternoon. We should be advocating and planning for Vulcan’s future too. Indeed, the city may not have the choice.