Re: [TMIP] PCEs for medium-duty and heavy-duty truck static assignment

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hudifebys
Re: [TMIP] PCEs for medium-duty and heavy-duty truck static assignment

In our regional model for the Greater Toronto megaregion and the Province-wide model for Ontario, we use 1.75 and 2.5 as the PCE factors in the multiclass static user equilibrium assignment.

The question I have for MPO modellers is how you treat generalised cost of toll road usage for different user classes, namely autos vs medium and heavy trucks. The other question is if you use parameters that are calibrated for current conditions, do you vary them for future horizon years?

Thanks
Sundar

Good Day!

________________________________
From: grousseau=atlantaregional.org@mg.tmip.org <grousseau=atlantaregional.org@mg.tmip.org> on behalf of Guy Rousseau <grousseau@atlantaregional.org> Sent: Friday, November 15, 2019 4:41:47 PM
To: TMIP <tmip@mg.tmip.org> Subject: Re: [TMIP] PCEs for medium-duty and heavy-duty truck static assignment

Hi Scott, great question. Our definition of trucks is the same as yours, thus based upon, and consistent with, FHWA's 13-bin vehicle classification https://www.fhwa.dot.gov/policyinformation/tmguide/tmg_2013/vehicle-type.... So currently at ARC with the Atlanta regional travel demand model, as a result of assigning separate truck trip tables, we use PCEs in the volume/capacity calculation to reflect the greater influence of trucks on V/C. A PCE value of 1.5 is used for Medium-duty Trucks and 2.0 for Heavy-duty Trucks. Incorporating passenger-car equivalents (PCEs) allows to adjust the volume/capacity calculation so as to represent the true impact of trucks on capacity. According to the HCM Highway Capacity Manual, large trucks use up more roadway capacity than other vehicles, due to their large size and slow acceleration. As such, the relative accuracy of ARC's capacity-restrained assignment is improved, as truck volumes are factored upwards to represent their disproportionate impact on the V/C calculation. In general, PCE for heavy trucks appears to be in the range of 2.0 to 4.0. Medium trucks perform a bit more like passenger-cars and should feature a smaller PCE. This gets even more interesting for performance measurement and traffic congestion analysis when one tries to assign vehicles into separate user classes for II, EI/IE, and EE. At a minimum, one can leverage model trip tables and distance/time matrices to compute VMT, by simply multiplying trip tables by distance skims to compute VMT, then use congested travel times / free-flow travel times in the same manner to show congested VHT and free-flow VHT.

Guy Rousseau
Atlanta Regional Commission

From: sramming=drcog.org@mg.tmip.org<mailto:drcog.org@mg.tmip.org> On Behalf Of sramming_drcog
Sent: Monday, November 4, 2019 2:44 PM
To: TMIP
Subject: [TMIP] PCEs for medium-duty and heavy-duty truck static assignment

Greetings,

My agency is interested in exploring assignment of medium-duty trucks (FHWA classes 5 through 7) and heavy-duty trucks (FHWA classes 8 through 13) as separate classes within the static traffic assignment component of our current regional travel demand model. We currently use a PCE of 3.0 for the combined class.

For our peer agencies with similar model systems and separate truck classes, what PCE values do you use for the medium-duty and heavy-duty truck classes? Thank you!

Scott Ramming, PhD PE | Senior Travel Modeler | Transportation Planning & Operations
Direct: 303-480-6711 | Fax: 303-480-6790 | Email: sramming@drcog.org<mailto:sramming@drcog.org>

[2016DRCOG-Logo-Side-PMS.png] 1001 17th St. * Suite 700 * Denver, CO 80202
main: 303-455-1000 * email: drcog@drcog.org<mailto:drcog@drcog.org> * web: drcog.org

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