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101 Partial Cloverleaf conversion causes death + injury shortly after opening

From: domainremoved <Gary>
Date: Tue, 31 Jan 2017 11:09:21 -0800

In my memo to you all 11 Months ago (February 23, 2016), which is on the MP web site at:
http://ccin2.menlopark.org/att-12874/Memo_to_MP_City_Council_re-Willow-101_Interchange.pdf <http://ccin2.menlopark.org/att-12874/Memo_to_MP_City_Council_re-Willow-101_Interchange.pdf>
and an updated version is at: http://bit.ly/bad2worse <http://bit.ly/bad2worse>
I cited a number of problems with partial cloverleaf (parclo) interchanges and cited my sources. I was trying to keep the memo short to maximize the P(being read), so I cited the CalTrans safety stats and omitted one of the intrinsic defects of partial cloverleafs that contribute to reduced safety: a much higher propensity for drivers to enter the wrong way (which leads to higher injury and fatality rates). 23 months ago on 2/19/15, I wrote to CalTrans’s project manager for the Willow/101 project:
> This will probably make that intersection's congestion even worse than it already is as it has done at the Marsh Rd. exit. I am baffled by CalTrans's policy to replace cloverleaf intersections with parclo's. I understand the concern about weaving, but parclo's have their safety issues as well. Signalized intersections have severe accidents, and From p. 25 of this:
> http://d2dtl5nnlpfr0r.cloudfront.net/tti.tamu.edu/documents/4128-1.pdf <http://d2dtl5nnlpfr0r.cloudfront.net/tti.tamu.edu/documents/4128-1.pdf>
> "full cloverleaf interchanges had the lowest wrong-way entry rate, with 2 incidents per 100 ramp-years." "Parsonson and Marks (1979) also determined that the half-diamond (3.9 per month), partial cloverleaf (“parclo”) loop ramp (11.0 per month), and parclo AB loop ramp (6.7 per month) had the highest wrong-way entry rates."
> Is there a policy paper that explains the rationale for replacing cloverleaf with parclo's?

The above source’s title is “Countermeasures for Wrong-Way Movement on Freeways.”
Many of my questions got responses (although rarely true answers), and this one was totally ignored (as have all of my safety questions).

Nine months after I asked that question, this scenario played out on a parclo that had been recently converted from a cloverleaf in San Jose, as reported here:
San Jose: One killed, one hurt in wrong-way driver crash on Highway 101 – The Mercury News
> http://www.mercurynews.com/2015/12/04/san-jose-one-killed-one-hurt-in-wrong-way-driver-crash-on-highway-101/ <http://www.mercurynews.com/2015/12/04/san-jose-one-killed-one-hurt-in-wrong-way-driver-crash-on-highway-101/>

> As you can see from this, that project was justified in much the same way as the Willow/101 project:
http://www.vta.org/projects-and-programs/highway/interchange-projects <http://www.vta.org/projects-and-programs/highway/interchange-projects>
A picture of that parclo from Google Maps is appended below.

Despite the many defects of of this design, CalTrans does not have any studies to prove or disprove their safety claims. They do however have the DATA that can be rapidly analyzed to assess this. The analysis that I gave you this week was done in one evening, and it should not take much more data to evaluate the safety questions. I filed a CPRA with CalTrans to provide that data in September, and they have yet to provide data that is any more usable than what was in the TOAR, which is what I gave you last week.
Again, my recommendation is that the MPCC defer the project (not cancel it) until the important questions get answered. Also, I think the most fruitful way of getting to the truth on this would be for some kind of direct engagement between me and whomever is advocating for this since there have been many non-responsive answers repeated by them (and by MP). This could be in public or private (preferable).

Continuing forward on this project without the safety questions being answered convincingly (i.e. with data, not a verbal assurances), is IMHO irresponsible since MP is the project sponsor.


-Gary Lauder

PS: Tunneling, which was brought up at the last meeting, is actually a good idea, and Elon Musk’s having brought it up last week will cause it to be more seriously considered. Last week I met the US representative of a company that finances, builds and operates toll roads via public-private partnerships. This could be a great solution for Menlo Park traffic in a way that is self-funding. Were this project to be pursued, it’s not clear how compatible a reconfigured Willow interchange would be to the subsequent tunnel…yet another reason to postpone in order to study & plan. Another tunnel-related thought for you: the probable route under El Camino Real would need to have 4 entry and exit ramps on ECR. This would have implications for development just north of the Stanford Park Hotel.

Google Maps image of the SJ partial cloverleaf that was converted from a cloverleaf in 2014, resulting in the above-mentioned fatal accident:
Received on Tue Jan 31 2017 - 11:12:45 PST

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