HOV / HOT 

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What does ARISTOTLE have to do with modern urban transportation planning ?


Essays and Links Many of the following documents are available in either html or pdf format. Better prints of tables and graphs are available in the pdf format. To read and print pdf you will need the Acrobat reader which may be downloaded free from Adobe.

HOV and HOT Lanes

The Five Classical HOV Lane Fallacies pdf


Hundreds of HOV lane effectiveness studies have found them effective.  At least 99% of these, however, are based on just a few classical plausibility "finding" prototypes, which are necessary but not sufficient elements of effectiveness.  The implication that these "findings" prove HOV more effective than general or mixed-flow operation of the lane is a serious logical error. 5/11/03
Frequently Quoted Myths  about HOV Lanes pdf
As H. L. Menken said "For every complex problem there is a simple solution --- and it is usually wrong." 
Exploring some of the many  myths surrounding HOV lanes. 
The Best Evidence on HOV Lane Effectiveness


The best, and arguably only, valid evidence on HOV lane effectiveness is in the results of comprehensive Traffic Planning Models. Ten such studies comparing HOV or HOT lanes to mixed flow are summarized. Unrestricted mixed flow is almost always found more effective in all congestion, air quality and energy consumption measures. 6/28/03
CA. Leg. Analyst's Report on HOV Effectiveness link Link to a report of the California Legislative Analyst office,  "HOV Lanes, Are They Achieving Their Goals".  1/7/00
Critique of CA. Leg.  Analyst's Report on HOV Lanes  pdf
A critique of "HOV Lanes, Are They Achieving Their Goals".  Its overall conclusions are broadly agreeable to all parties.  But in its  reporting of the many selective half-truth mis-implications that form the bulk of HOV lane support literature, it appears to uncritically accept these specious arguments, without analysis of the faults in those arguments, or addressing the much stronger arguments to the contrary.   1/20/00  
  "Competent Engineering Estimates" pdf California VC 21655.5 requires that before any HOV lane may be established, Caltrans must provide a "Competent Engineering Estimate" of its effectiveness. Critical analysis of the 9 such known to Caltrans as of 1998 reveals that every one suffered from one or more critical, and mostly common errors.  In this author's opinion, not one could be called "competent".   7/29/01
HOV Lane Effectiveness pdf
An overall effectiveness analysis for the SR-55 (Costa Mesa) freeway HOV lanes. Traffic distribution and speed are taken from loop count data. Induced "benefit" carpooling is inferred by a discrete choice model method based on the measured HOV lane travel time saving . The effect of HOV operation is a loss of 47% of potential lane capacity to underutilization, and a gain of 7% from benefit carpooling for a net loss of 40% of a lane. For the Los Angeles/Orange County  HOV system, the lost travel time due to this much wasted capacity would be worth $133 million per year.  12/7/99
A Simple Definitive Experiment to Determine HOV Lane Effectiveness pdf HOV lane motivated carpooling is essential, but difficult if not impossible to measure directly for reasons discussed. This paper proposes an experiment, designed around the opening of a new HOV lane, to measure exactly the overall traffic impact neglecting new benefit carpooling formation, and to correct that data for such benefit carpooling estimated on the basis of modal choice modeling based on  known, measured  HOV lane time saving.  
HOV Lanes -Their Time Has Expired


HOV ("Carpool" or "Diamond") lanes are widely adopted as a means of improving congestion and air quality but there has been no proof that they do so. Transportation planners ignore substantial evidence that they are less effective than the unrestricted or Mixed Flow alternative.   12/7/99

HOT Lane Effectiveness on the SR-91


A recent OCTA study, found HOT lanes "feasible", but stopped just short of comparative congestion or air-quality benefits. Using the data and methods of the study, this paper completes the study and finds that compared to the unrestricted mixed-flow alternative, HOT operation would result in 50% more total congestion-time-delay and 24.7% more total CO emissions.  3/9/00

 Efficient Tolls pdf Urban congestion is widely viewed as a "failure of the commons";  occurring  because a  user does not pay the full "external" cost of the congestion his use imposes on other users.  This paper quantifies these considerations and finds  that even for a severely congested area like Los Angeles, the average driver's internal cost is already greater than the external cost imposed by him, so the optimal toll is zero. Implications for congestion pricing.10/1/03
The Fable of the Ajax Mining Company pdf
A modern fable illustrating the fallacy in the main HOV effectiveness "proof", the "More People in the Lane" finding. 1/14/01
Text of SB308
HOV Bill
link Existing legislation requires that "Competent Engineering" estimates of its performance be provided prior to establishing an HOV lane.  This requirement  has been frustrated by considering only part, the more favorable half, of the whole truth  (see "Competent Engineering Estimates").   Senator McClintock's SB308 would establish minimum  required considerations for a "competent? estimate and require certification thereof by the University of California.  
Congestion Pricing link Link to the University of Minnesota Congestion Pricing Homepage. THE center for resources on this matter of growing interest.
The Statistical Distribution of Willingness-To-Pay pdf
Willingness To Pay tolls for time-saving is commonly represented as a simple number, characteristic of a particular instance.  In fact, individual WTP varies over a wide range within any typical traveling population.  Issues such as optimal revenue or congestion pricing tolls require the statistical  distribution function of WTP.  Illustrated by the derivation  from SR-91 ridership data. Fits a log-normal distribution. Surprising implications for maximal return pricing.   1/24/00


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