Posts Tagged 'Pravin Varaiya'

Berkeley Professor says HOT lanes will lose money and infuriate drivers, but he overlooks his own findings

Pravin VariyaPravin Varaiya of UC Berkeley’s electrical engineering and computer sciences department claims that HOT lanes will loose money and infuriate drivers by making traffic worse. This is a blow to the San Francisco Bay Area MTC and this website which has vehemently supported the HOT lane proposal.

Yet, Varaiya’s assessment of HOT lanes is flawed. The East Bay Express says that,

He concludes that the new toll lanes will lose money for two main reasons. In less-congested areas, not enough people will use them. And on the Bay Area’s more-congested freeways, heavy demand from carpoolers won’t leave enough room for those single-occupancy vehicles that would pay the new toll.

The first flaw with this argument is that in less congested areas he is using current data, not future growth trends. Furthermore he completely neglects that these same areas generally do not have carpool lanes already in place. As such, they are part of the second phase of the HOT lane proposal that will build new lanes, but not for about a decade. The levels of congestion will almost certainly change by then.

The second flaw in Varaiya’s critique of HOT lanes is that he neglects to take into account that adjustments can be made. He says that in the areas were congestion is a problem carpool lanes require just two people in a car to use a carpool lane which makes them just about as congested as any other lane. He then points out that because of this there is limited space for toll paying single occupancy vehicles without causing congestion in the HOT lanes themselves. He neglects to mention that in this scenario the MTC will almost certainly change the requirement to three people per car to qualify as a carpool. This would reduce congestion in the HOT lane and simultaneously increase congestion on the other lanes, thus making the HOT lanes appealing to toll paying passengers.

It should be noted that Varaiya is basing his assessment of HOT lanes from previous studies that show carpool lanes are ineffective in reducing traffic and encouraging people to carpool. From these studies he also found that there is unused roadway capacity in many carpool lanes that could be used to reduce congestion on some freeways if these lanes were converted to ordinary freeway lanes (mixed flow lanes). In all probability Varaiya is right on this issue. Yet, this only supports the case for HOT lanes. Rather than simply granting the extra capacity over to all freeway users, why not sell it? This achieves a better result than simply turning the lane over to mixed flow use because when needed a HOT lane raises the toll to discourage drivers from using the HOT lane. Thus, a HOT lane is impervious to congestion. Because a lane that is full, but not congested, moves far more people then a congested roadway this means that since people using the HOT lane are taken from the mixed flow lanes, more people are taken out of the mixed flow lanes if a HOT lane is used than if that lane is simply converted over to a mixed flow lane.

So what alternative does Varaiya propose to ease congestion? He proposes signaling, specifically like that used on the Bay Bridge. However, the Bay Bridge signaling works because it can signal all drivers across the entire freeway, but this is not possible on most freeways. For a similar plan to be effective throughout the Bay Area every freeway would need signals on each freeway entrance and everywhere a freeway merges with another freeway. However, if signals where installed wherever freeways merge, this would create a backup on the freeway people are merging from – such a signaling system would not work. Yet, without this type of signaling system it is impossible to control the traffic flow on an interconnected freeway network. That is why signaling used only at on ramps does not eliminate freeway congestion, despite its’ extensive use in places such as LA.

Given the facts that Varaiya lays out, his assessment of the HOT lane proposal may be correct. However, he does not address the the fact that things can change. This makes his assessment of the HOT Lane proposal wrong. Furthermore, he completely neglects to mention how freeway lanes that do not become congested, such as HOT lanes, benefit transit and encourage people to switch modes.

Advertisements


© Brian A. Tyler and SwitchingModes.com, 2009.
Unauthorized use and/or duplication of this material and/or concepts without express and written permission from this websites’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Brian Tyler and SwitchingModes.com with appropriate and specific direction to the original content.

Page copy protected against web site content infringement by Copyscape
October 2017
M T W T F S S
« Sep    
 1
2345678
9101112131415
16171819202122
23242526272829
3031  

Calandar