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It’s all about the Lane Miles

Updated: Sep 14, 2020

I have undertaken a great number of development impact fee studies in the Southern California area and as a result I read a lot of Circulation Master Plans.  One insight I have come across: traffic demands are increasing, everywhere, and they are not ever going to get any better.  Why?  Most cities that we once considered as “mature and developed” have all their major roadway lane miles constructed and have no ability to construct any more major lane miles. The massive land right-of-way acquisition required to do so is simply too high and too drastic to undertake.  Enter residential intensification, be it in the form of multi-level mixed use concept development (every city is experiencing these), or more likely, the many major amendments to the General Plan Land Use Element increasing the residential density.  An additional factor is that many industrial properties are being sold because the land has become more valuable as new residential housing, which is additional housing that the probably more-balanced General Plan had not anticipated so very long ago.  Nobody anticipated continued development of what appeared to be largely developed cities.  EIR’s seem to easily dodge the issue with a few simplistic findings and require maybe a token circulation movement project. But they are incapable of dealing with the growing transit problems.

Lane miles have a finite capacity.  A six lane arterial at a given speed has a limit as to how many vehicles can be moved along that segment from point A to point B.  Exceed that vehicle capacity and the speed limit drops dramatically.   Some of my clients from largely developed-city may experience a 20% or more increase in traffic demand with little, if any ability, to increase lane miles.  And it does cost you in the form of time, and as the old saw says, time is money, especially when that task you sent your employee on now takes two hours instead of one. Simply stated, if your circulation system is at its maximum in terms of lane miles, but all of a sudden you have to absorb a 20% increase in traffic demand, you have a transit problem.

Now for some anecdotal observations:

Two months ago my spouse and I headed up to Ojai for a brief get-way. Our trip involved the I-405 through West L.A. on a Friday so we drove there and back on Monday at the usually safe 11:00 a.m. time slot.  To my surprise, we averaged no more 35-45 MPH along the I-405 through West L.A. and the 101 all the way to Ventura. The $1.1 billion Cahuenga Pass widening was no help and has been widely considered a failure, a finding that is supported by the results of a traffic study by Seattle-based traffic analytics consulting firm Inrix that indicated commute speeds during the evening drive time on the northbound I-405 have not improved or are even slightly slower.  On the way back we stopped just north of the LAX area for a cold frosty beverage and saw a row of maybe six 1960’s-era two story apartment complexes (the old style 24-unit affairs built around a communal kidney-shaped pool, now-fenced or filled in). They were in various stages of being torn down and replaced with four story, higher density apartments or condominiums, at least a doubling over the prior 24 units in the old apartment complex. The already moribund major street that these tenants would be using on a daily basis was incapable of being widened to increase the number of lane miles.

A well-known “built-out” beach city in Orange County had controversially approved an additional 4,500 attached dwelling units along two of the City’s busiest arterial thoroughfares requiring space for an additional 90,000 trip-miles daily. After some of the new residential complexes were built and the existing residents saw the results there was a backlash and the number of approved units was reduced to 2,100 (although I suspect all 4,500 will end up being built).  The streets in front of the 4,500 proposed units are also incapable of being widened; in fact every major street in the City is currently at maximum General Plan width meaning that traffic flow will never be any better than it is today. Their circulation plan improvements are limited to improving traffic signals, an important and noble effort, but again, no more lane miles.  Add all the turn lanes, traffic signals and round-a-bouts you can, but when you add more vehicles to the mix, it’s all about the lane miles.

More recently I needed to attend a public hearing in the Inland Empire and needed to drive from where I live in Orange County (see beach city previously mentioned). The travel time was two hours and thirty minutes or about an hour over what I had estimated.  I almost missed my item (which successfully passed 7-0 by the way), but will now need to add an additional hour for travel time in the future.

Every major roadway and freeway has its day in the sun, that day that it moves the most passengers, goods and services at the optimum or designed maximum speed.  We have to address the fact that those days are well past us, and without creative ideas and swift action it will not get any better, certainly not in terms of lane miles; there simply isn’t room.  We all need to agree that it’s time for a new circulation paradigm, or the old punchline, “Oh, you can’t get there from here” won’t be so funny anymore.

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