UC Berkeley Earlier Faculty Research
Title A Comparison of High Occupancy Vehicle, High Occupancy Toll, and Truck-Only Lanes in the Sacramento Region
Permalink https://escholarship.org/uc/item/493389jw
Authors Rodier, Caroline J. Johnston, Robert A.
Publication Date 1999-03-01
eScholarship.org Powered by the California Digital Library University of California A Comparisonof High Occupancy Vehicle, High OccupancyToil, and Truck Only Lanes in the SacramentoRegion
Caroline J Rodler Rob¢rt A Johnston
UCTC No 422
The University of California Transportation Center Umversltyof Cahforma Berkeley, CA94720 The University of California Transportation Center
The Umversity of Cahfomm Center actlvlttes Researchers Transportation Center (UCTC) at other umversmes w~thm the ~s one of ten regional umts regmn also have opportunmes mandated by Congress and to collaborate w~th UCfaculty estabhshed m Fall 1988 to on selected studies support research, educatmn, and training in surface trans- UCTC’seducatmnal and portation The UC Center research programs are focused serves federal Region IX and on strateglc planning for is supported by matching zmprowng metropohtan grants from the U.S Depart- accessibility, with emphasis ment of Transportatmn, the on the specml condmons m Calfforma Department of RegmnIX Particular attentmn Transportation (Caltrans), and ~s d~rectedto strategies for the Umverslty using transportatlon as an instrument of economac Based on the Berkeley development, while also ac- Campus, UCTCdraws upon commodating to the regmn’s exlstmg capabll~tles and persistent expansmn and resources of the inst, tutes of while maintaining and enhanc- Transportation Stud,es at ing the quahty of hfe there Berkeley, Davls, Irvme, and Los Angeles, the Insutute of The Center dastnbutes reports Urban and RegmnaI Develop- on ,ts research an workang ment at Berkeley, and several papers, monographs, and m acadermc departments at the repnnts of pubhshed amcles Berkeley, Davis, Irwne, and It also pubhshes Access, a Los Angeles campuses magazine presenting sum- Faculty and students on other manes of selected studies For Umverslty of Cahforma a hst of pubhcatmns m pnnt, campuses may pammpate m write to the address below
DISCLAI~ER Thecontents of this report reflect the wews of the authors, who are responsablefor the facts and the accmacy of the ~formahon presented Umversatyof California hereto.ThFs document ISdJs~emma~ed~ ~under the spons~rsb, lpof the Transportation Center Departmentof Transportation, Umvers~ty T"ansporz~m~l Cente;s Program, mthe interest of mformat~onexchange TheU S Governmentassumes no 108Naval Arehatecture Building Berkeley, Cahfomm94720 I~ablhtyfor the contents oruse thereof. Tel 510/643-7378 FAX510/643-5456
Thecontents of tlus report reflect the ,newsof the author whoas responsible for the facts and accuracyof the data presentedhereto The contents do not necessarily reflect the officml viewsor pohc~esof the State of Cahfommor the U S Departmentof TransponataonTtas report does not constatute a standard, specaficatxon,or regulatmn A Comparisonof High OccupancyVehicle,
High OccupancyToll, and TruckOnlyLanes in the Sacramento Region
A Report to the Umversltyof Cahfornla Transportation Center
by
Caroline J Rodler and Robert A Johnston
Department of Environmental Sclence and Pohcy Unxverslty of Cahfomla One Shields Avenue Davis, CA 95616
March l9, 1999
Rodier, Carohne. (530) 757 -2791 (phone); (530) 752-3350 (fax); c]rodler@ucdavls edu
Johnston, Robert. (530) 582-0700 (phone); (530) 782-0707 (fax); ra}olmston~ucdavls ABSTRACT
As the evidence mounts that HOVlanes will not produce expected reductions m congestion and emission, alternatives are being sought High occupancytoll (HOT)lanes and truck only lanes are attractive alternatives In this study, a region-widesystem of new HOVlanes, HOTlanes, and truck only lanes m the Sacramentoregion are comparedThe travel effects are stmulated with the Sacramentoregional travel demand model (SACMET96)The economic benefits for both personal travel and commercial vehicle travel are obtained from economicwelfare models developedfor use with the travel model The DTIM2model IS used for the emassIons results The scenarios are evaluated against travel, emissions, total economicbenefit, and equity criteria With respect to travel and emissions, the results did not vary muchamong scenarios but the economicbenefit results did have more significant variation The scenarios that included
HOTlanes producedeconomic benefits that were clearly superior to the other scenarios
As a result, it is concludedthat the economicwelfare modelsapplied m this study can be useful tools m the analysis of transportation policies
2 INTRODUCTION
To date nearly 1,200 miles of high occupancyvehicle (HOV)lanes have been built m the
U S Federal and state policies currently promoteHOV lane projects In air quality non- attainment regions, HOVlanes are virtually the only roadwayprojects approved The rational behind these policies is that HOVlanes foster carpoolmgand transit use and thus will reduce congestlon and emissions However,Increasingly the evidence has suggested that HOVlanes may not produce expected reductions in congestion and emissions
(Dalgren, 1996, Johnston and Ceerla, 1996, Rodler and Johnston, 1997) As a result, alternat~.ves to HOVlanes are being considered
High occupancytoll (HOT)lanes are one attractive alternative HOTlanes have been implementedon State Route 91 in Orange County, CA, I-15 in San Diego, CA, and
1-10 (Katy) m Houston, TX Manyother regions are actively considering HOTfacilities
Truck Only lanes are another alternative to HOVlanes m corridors with high volumesof truck travel Truck freight travel is expected to growrapidly within the next decadewith the potential to increase congestion and emissions and heighten public concern over truck accidents that are dlspropomonatelyfatal The Congestion
ManagementSystems mayfavor the approval of proJects that include Track Only lanes
(Martin and Coogan, 1995)
The Transportation EqmtyAct for the 21~t Century (1998) or TEA-21recogmzes the importance of efficient movementof both people and goods" and reqmres that transportation projects and plans be evaluated for econormcefficiency However,to date, there xs a discrepancy between these requirements and the planning methodsused by metropohtan transportatlon organizations (MPOs)Coogan (1996) describes ad
performancemeasures currently used by MPOsto evaluate freight planning, which are
not measures of economicefficiency and do not meet TEA-2l’s requirements
Efficiency measures based on the correct application of economictheory should be
adopted by all MPOsto meet TEA-21’srequirement and to facilitate a rational
comparisonand integration of reformation about freight and personal mobdltyacross
states and the U S
In this study, a region-wide system of new HOVlanes m the Sacramentoregion is
comparedto a system of HOVlanes and Truck O~ylanes for the year 2015 The travel
effects are s~mulated with the Sacramentoregional travel model (SACMET96)This modelcan be classified as representative of the state-of-the-practlce travel demand model Modelsto obtain the economicbenefits for both personal travel and commercial vehicle travel are developed by us for use with the SACMET96model The DTIM2 modelis used for the emissions results The scenarios are evaluated against travel,
emissions, total economicbenefit, and equity criteria
BACKGROUND
Recent evidence has challenged the rationale behind the adoption of HOVlane projects, namelythat HOVlanes foster carpoohngand transit use and thus will reduce congestion
and emissions Rodier and Johnston (1997) simulate an extensive system of HOVlanes m the Sacramentoregion for the year 2015 They find, comparedto a no-build scenario,
only a modest reduction m congestion, an increase in emissions, and a loss m economic benefits whenthe unobservedprivate cost of additional auto travel is considered Johnston and Ceerla (1996) also fred that new HOVlanes mayincrease vehicle miles
traveled (VMT)and thus emissions comparedto a no-braid scenario Joy Dalgren (1996)
develops a model to estimate person-delay and emissions for a numberof HOVand general purpose lane alternatives She finds that HOVlanes will only be moreeffective m reducing congestion and emissions than general purpose lanes whenthere is a high level of congestion and a high proportion ofHOVsm the general purpose lanes Alan
Plsarski (1996) finds that nationwide carpoohngto workhas declined by 19%during the
1980s and that average vehicle occupancyhas dechned from I 17 m 1970 to 1 09 m
1990, despite the increase in HOVlanes
As the evidence mounts that HOVlanes may not dehver expected reductions in congestion and emissions, HOTlanes are increasingly becomingan attractwe alternative
HOTlanes allow non-ca-pools and somecarpools to use HOVlanes by paying a toll
HOTlanes have been implementedon State Route 91 in Orange County, CA, I-15 In San
]Diego, CA, and 1-10 (Katy) in Houston, TXSince the State Route 91 Express Lanes opened in December1995, there has been a reduction in peak period congestion on adjacent non-toll lanes (ARDFA,1997) However,this reduction in congestion was due to the combinationof the openingof the express lanes as well as the openingof
Metrohnkrail hnes which serves the same corridors These two improvements essentially doubled the person-carrying capacity of the comdorIn San Diego, the HOT lanes on 1-15 have been open since December1996 There has been considerable demandfor use of these HOTlanes (ITE Task Force, 1998) as well as an 11%increase carpoohng (Hamberg, 1998) An express bus service m the corridor has been launched with the HOTrevenues (Hamberg, 1998) The 1-10 HOTlanes m Houston have only recently been opened, but demandis expected to be significant (ITE Task Force, 1998)
Areas throughout the U S are considering HOTlanes including Dallas, TX, Sonoma
County, CA, Contra Costa County, CA, AlamedaCounty, CA, Maryland, Milwaukee,
WI, Portland, OR, Phoemx, AR, Denver, CO, HamptonRoads, VA, Los Angeles, CA, and Mmneapohs, MN
An alternative to the conversion of HOVlanes to HOTlanes may be Truck Only lanes, with or without tolls in corridors with a high volumeof truck travel Truck Only lanes for truck freight could potentially provide large benefits to the freight industry
(even with tolls) becauseof the high value this industry places on fast and reliable arrival times (due m part to the trend toward just-m-time delivery) Truck Only lanes mayalso benefit the general pubhc through reduced congestion and emissions and increased safety Moreover, the Congestion ManagementSystem calls for consideration of freight movementm proposed regional tughwayprojects and could favor projects w~th excius~ve truck lanes (Martin and Coogan, 1995) Truck Only lanes are being examinedin the Los
Angeles, CAregion
Nationwide,a very large volumeof freight is transported across the country and truck transport of freight dominatesthe market In 1991, 6 5 bflhon tons of freight traveled about 3 bflhon ton-miles and created freight revenues on the order of 350 billion dollars Trucks transported 41%of the freight tons, traveled 25%of the ton miles, and received 79%of freight revenues (Martin and Coogan, 1995) Freight trucking contributes slgmficantly to the U S economyIn the 1991 trucking industry freight revenues accounted for 5%of the Gross DomestlcProduct (GDP), while all transportation services revenues accounted for 6 4%of the GDP(Martin and Coogan,
1995)
In the U S and the world, growth in freight transport is expected to mcrease
rapidly in the future Someestimate that a doubling of freight transport is possible within
the next 10 years because of increased economicactivity, morespeclahzation and
centrahzatlon, just-m-time dehvery, development &Eastern European and Third World
counmes,and rising global populations (Clarke, 1993) In recent years, France has
experiencedgrowth in freight traffic doublethat of car traffic (Blossevllle, 1996)
Within the next ten years, the U S truclong industry is expected to lose someof
its share of domesticfreight tonnage(by 0 05%)to air freight and mtermodalraft freight
(Martin and Coogan, 1995) However, the hmlted capacity of radroad mamhnesand
terminals sharply restrict the shift of freight fromtruck to rad within metropolitanareas
(Martin and Coogan, 1995)
Meetingfuture increases In freight transport w~thcurrent trucking technologies
could have several negative consequencesfor metropohtanareas, including increased
congemon,heightened pubhc concern over truck accidents (which are dlsproport~onately fatal), and worsemnga~r quahty (Clarke, 1993, Vandersteel et al 1997) National quahty standards and the lack of funding for highwayexpansion point to the need for pohcyalternatives for truck freight travel
Paul Roberts states that "any expansion m hlghwaycapacity wall ~mmedmtelybe filled wlth more single-occupancyvehicles and increases mvehicle-miles traveled are typically assocmtedwith further degradation of mr quality unless a substantial pore.on of the added capacity can be preserved for freight movements,the efficlency of the freight delivery system will not be improved" (TR News, Jan-Feb, 1996) (Dr Roberts
directed the freight programsat Harvard and MITmthe 1960s and 70s and is now
President of TransmodeConsultants )
In recent years, the increase in truck traffic on U S highwayshas raised concerns
about the numberof truck-involved fatal accidents and the significant congestion and
delay resulting from major truck accidents In Vlrglma, Vmdunasand Hoel (1997) report that, partly in response to these concerns, motorists and truckers have been receptweto the idea of excluswe truck faclht~es on the Washingtonbeltway They conducted a benefit-cost analys~s and found that exclusive truck faclhtles wouldbe economically
beneficial due to travel time saving, vehicle operating cost savings, and inJury and
property damagesavings
METHODS
Travel DemandModeling
This study uses the SACMET96travel demand model (DKS & Associates, 1994) The model was developed with a 1991 travel behavior survey conducted m the Sacramento
eglon This modelis an exampleof a state-of-the-practice regional travel demand model Some&the key features of this model include (1) model feedback of assigned travel impedancesto the trip distribution step, (2) auto ownershipand trip generation steps with accesslbihty variables, (3) a joint destination and modechoice modelfor work trips, (4) a modechoice model with separate walk and bike modes,walk and drive access modes,arid two carpool modes(two and three or more occupants), (5) land use, travel time and monetarycosts, and householdattribute variables included in the modechoice
8 models, (6) all modechoice equations in logit form, and (7) a trip assignmentstep that
assigns separate A M, P M, and off-peak periods
Economic Welfare Models
Kenneth Small and Harvey Rosen (1981) show how a consumer welfare measure known as compensatingvariation (CV) can be obtained from d:screte choice models
(1)
whereL is the individual’s marginalutility of income,Vm IS the lndw:dual’s redirect utdlty of all mchmces, p0 indicates the lnmal point (1 e, before the policy change), and pf indicates the final point (1 e, aRer the policy change) The change mredirect utlhty convertedto dollars by the factor, 1/)~, or the reverse of the individual’s marginalutdlty of income Small and Rosen show how marginal utility of income can be obtained from the coefficient of the cost variable in discrete choxcemodels
The compensatingvariation formula (1) from above was adapted to smt the spec:ficatlons &the SACMET96mode chmce models In the home-based work, shop, and other modechoice models, households are segmentedinto income/workercategories, and person raps are generated for those categories To obtain compensatingvariation for each income/workercategory h, the following formula was apphed for all modesm and for all raps Q betweenall origins : and all destinatlons j (2)
where)~ is provxdedby the coefficient of the cost variable m the modechoice equations
Total compensating variation was obtained by summingthe compensatingvariation obtained from each income/worker group Compensatingvariation was also obtained from the non-home-basedmode choice models, however, these models are not stratified by household/incomeclasses Basedon a review of the literature (e g, Small, 1996), it assumedthat total operating costs are $0 40 per mile Capital and operation and maintenance (O&M)costs of the new facdmes were estimated based on cost figures provided m the Sacramentoregion’s 1996 metropolitan transportation plan (SACOG,
1996) Changem revenues for gas taxes and transit fares are also included m the analysis It is assumedthat tolls from the HOTlane scenarios are used to offset the capital and O&Mcosts of the scenarios (1 e, not only the HOTlanes but also costs of the base case scenario)
Economicbenefits to commercialvehicle travel resulting from transportation policies were obtained from the trip dlstnbutlon modef m SACMET96,which dlsmbutes commercialvehMe raps as a function of zone-to-zone travel times The following formula was applied
Commerclal Vehicle Benefits = ~ ~,, - ~-,~ ~,~ (3) tE I
10 whereB is equal to the net benefits to commercialvehicle travel These include travel
time costs, O&Mcosts, and revenue benefits Travel ttme is obtained from the model
and converted to dollars with the average wagerate of truck drivers in the region ($12 per
hour) VMTfor commercialvehicles is also obtained from the model for each scenario
Total O&M(excluding wages) costs and revenue benefits for the scenarios are obtained
by multiplying the average per mile costs for the region ($0 90 for O&Mand $0 95 for
revenues) by VMTTruck wages, O&Mcosts, and revenues were developed based on
national data and m consultation with the California Trucking Association Very little
local data was available Values used correspondto low estimates for the state of
Cahforma, which are reasonable for the Sacramentoregion While the modeling of truck
travel m SACMET96is not sophisticated, like most MPOmodels, the method used m
this study can be apphedto more sophisticated freight modelsas they are developed
Emission Modeling
The Cahfornia Department of Transportation’s Direct Travel Impact Model2 (DTIM2)
,and the California Air Resources Board’s EMFAC7Fmodel were used m the emissions
~malysls The outputs from the travel demandmodel used in the emissions analysis
included the results of asslgnmentfor each trtp purpose by each t~meperiod (A Mpeak,
P M peak, and off-peak) The Sacramento Area Council of Governments (SACOG)
providedregional coldstart and hotstart coefficients for each hour in a twenty-four hour
summerperiod
11 LIMITATIONS TO THE METHODSOF ANALYSIS
SACMET96cannot capture the effect of changes in the transportation system (1 e, travel
time and cost) on the location of activities Such effects wouldlikely be significant for
large regional transportation projects or pohcychanges, like the ones examinedm ttus
study As a result, SACMET96would tend to underestimate raps, VMT,emissions, and
economicbenefits for the alternative pohcyscenarios examinedm this study
System equihbrmmIs assumedm model operation with full feedback from tnp
assignmentto earlier steps until convergenceusing the methodof successive averages
This implies an elasticity of demandwith respect to capacity of about 1 0 If the actual transportation system does not attain complete equilibrium (as someresearch suggests),
SACMET96would tend to exaggerate the trip length in the new roadwaycapacity
scenarios and overestimate VMT
The inclusion of time and cost varlables (compositeImpedance) IS advised throughout the hierarchy of travel demandmodels m order to strengthen its theoretical basis and to increase ItS policy sensmvity In SACMET96,the auto ownership step indirectly includes travel time variables throughthe retail employmentand transit accesslb~htyvariables In the trip d~smbutlonstep, worktrips are sensitive to travel ttme and cost variables and non-worktraps are sensitive to travel time In the modechotce model, time and cost varmbles are represented for all trip purposes Time-of-dayfactors are applied after modechoice and, as a result, only the worktrip purposesuse peak or congested travel times during the trip distribution and modechoice steps Tnp assignment is only sensltwe to travel times on roadwaysAs a result, the model’s sensitivity to the HOTscenarios is somewhatlimited Becausethe trip assignment step is
12 not directly sensitive to travel cost and only the home-basedwork trips use congested times, toll modeswere included only in the home-basedwork modechoice model as a separate modeIn ad&tion, the home-based work modechoice model only uses three uacomegroups, whmhrestricts the sensitivity of the simulation wlthln incomegroups
Thus, this simulation wouldtend to generally underestimatevehicle hours of delay,
VMT,and economicbenefits that mayresult from this scenario
A model’s sopbamcatlonin modelmgtravel ttme and congestion play an important role m the accuracy of the estimated travel, emissions, and economicbenefits
Savings m travel time comprise a large pomonof consumerbenefits created by new transportation pohcies and projects SACMET96uses the user-equihbrmmtraffic assignment method(capacity restrained) and models separate peak (1 hour and 3 hours) and off-peak periods SACMET96does not include a time-of-day choice model and cannot simulate the phenomenonknown as peak spreading Thus, the volume of travel during peak hours maybe overestimated m very congested scenarios because the propensity of travelers to moveoffthe peak Is not represented
The assumption of constant VMTper vehicle per year mayresult m an overestimationof private costs for policy scenarios that increase VMT(e g, scenarios that Include expanded roadway capacity) However,travel reductmns may be underestimated for the HOTscenarios because the auto ownership step is not sensmveto travel costs
The propensity for auto drivers to switch to HOVlanes m the presence of higher auto travel time and cost is likely underestimated in the SACMET96model This is an artifact of the cross-sect~onal data used to estimate the modelSacramento currently has
13 one relatively short HOVfacihty and thus cross-sectional data on travel behavior collected m this area would contain httle variation in HOVmode choice
SACMETalso assumes that a fixed percentage of shared ride vehicles will use an
HOVlane if they are on that facility It does not include an HOVlane use model for the entire network(although one is avadable for one corridor) that esnmates the number shared ride vehicles that will use the HOVlanes based on vanables such as ttme savings and difficulty of changing lanes As a result, HOVlane usage maybe underestimated m the model
In the simulation of the HOTand Truck Only scenario, the analys~s maybe htmted because of the model’sinability to capture the potennal aversion of auto users to sharing HOTlanes wlth trucks As a result, we mayhave overesnmatedthe use of the
HOTlane by autos
Commercialvehicle trips are represented as a single purpose (and not by weight class) in SACMET96At the time the model was developed, no local data was available to estimate commercLalvehicle submodelsand thus data from relatwely current regional surveys of commercial vehicle travel m Phoemxand Chicago were used Local surveys have nowbeen conducted but a new truck model has not yet been developed for
SACMET96A ~etter commerclal vehicle model would be dlsaggregated by vehicle type and use local data A better economicanalysis would also use local cost and revenue data dlsaggregated by vehicle type as well as inJury and property damagesavings from scenarios Wefound such data to be largely unavailable
14 2015 SCENARIOS IN THE SACRAMENTOREGION
Base Case The base case scenario represents a financially conservatlve
expansionof the Sacramentoregion’s transportation system and serves as a point of
comparisonfor the other scenarios examinedm this study This scenario includes a relatwely modest numberof road-widening projects, new major roads, one freeway HOV lane segment,and a ltmlted extension of light ratl (east to MatherField Road)
High OccupancyVehtcle (7-10Vs) Lanes. The HOVlane scenario represents an extensive expansion of the Sacramentoregion’s HOVlane system to encourage the use of carpoo|s and reduce traffic congestion and emissions The HOVlane system xs expandedeast on SR-50past Folsomnear the El DoradoCounty hne, northeast on 1-80 to
Douglasin Rosevllle, northwest on I-5 to the SacramentoInternational Airport, and west on 1-80 to Davis See Figure 1 In this scenario, HOVlanes are increased from 26 lane miles m the base case scenario to 179 lane males Mixed-flowfreeway lanes are increased by 6%over the base case scenarios Express bus servtce that takes advantage of the HOVlanes is also added to the transit network HOVlanes are separately coded m the highway network used in SACMET96
High OccupancyTolled (HOT)Lanes. In this scenario, the HOVlanes m the
HOVlane scenarios are converted to HOTlanes HOTtrips are assigned to the separately coded HOTlanes A $0 05 per mile toll Is charged for using the HOTlanes Tolls are charged to single occupant vehicles (SOVs)and two occupant vehicles but no tolls are charged to vehicles with three or more people Wherecongestion Is not ehmmatedon the
HOTlanes with the $0 05 toll, a $0 50 per male toll Is imposedm order to achieve non- congested con&tlonson those roadwaysegments This toll level was selected after
15 !i /,
0 numerousother tolls were tried to obtain the lowest toll level that wouldehmanate congestion on the HOTfinks To s~mulate the use of HOTlanes m SACMET96,the modechoice model for the home-basedwork trip purpose was expanded to include the
HOTmode (using variable coefficients specific to the drive alone mode)and shared-ride two occupancytoll mode(using variable coefficients specific to the shared-ride mode)
Truck Only Lanes In this scenario, the HOVlanes m the HOVlane scenarios are converted to Truck Only lanes This Truck Only network was selected based on poor level of service ratings on parallel freeway faclht~es and m consultat:on w~th SACOG officials In the assignment step, only commercialveh:cles are allowed on the Truck
Only lanes
HOT~Truck(HOTT) Lanes The HOTlanes m the HOTlane scenario allow commercialvehlcle travel m this scenar:o and commerclaIvehicles that use these lanes do not pay a toll
RESULTS
Travel
The results of the travel modelslmulatlons of the alternatwe scenarios for vehicle raps,
VMT,and vehtcle hours of delay (VI-ID), whichas a measureof congestion, are presented aa Table 1 All the alternative scenarios increase VMTand decrease VII comparedto l~.he base case scenario The HOTscenario provides the greatest increase m VMT comparedto the base case scenario (w:th a 2 2 percentage change), followed by the HOV and HOTTscenario (both with a 1 9 percentage change), and then the Truck Only
,~cenario (1 5 percentage change) The HOTTscenario provides the greatest reduction
17 VHDcompared to the base case (14 7 percentage change), followed by the HOTlane scenario (7 7 percentage change), and then the HOVand the Truck Only scenario (5 and 5 17 percentage change, respectively) Amongthe scenarios there is little variation m the numberof vehicle trips made, however,all the alternatwe scenarios increase vehicle trips somewhat
Table 1. Daily Vehicle Travel Projections 2015 Policy Scenarios for the Sacramento Region
VehicleMiles Hoursof Travel Trips (md[ions)Traveled (millions) Delay~ (thousands) BaseCase 6.8 62.2 243.3
HOV 6.8 63.3 230.7 (0.2%) (1.9%) (-5.20%) HOT 6.8 63.5 224.5 (0.3%) (2.2%) (-7.7%) TruckOnly 6 8 63.1 2307 (0 1%) (1 5%) (-5 17%) HO’CI" 6.8 63.3 2076 (0 3%) (1 9%) (-14 7%) a Vehtcfehours of delayare vehiclehours traveled under congested speeds minus veNcle hours of travel underfree flow speedson the samefacdlty b Figuresin parenthesesare percentagechange from the basecase scenario
In general, the increased highwaycapacity in the alternatwe scenarios results m an increase m VMTand a decrease m VHDIn the HOVscenario, carpool vehicles are diverted to the HOVlanes to take advantageof faster travel times m those lanes, VHDis reduced mthe adjacent muNpurposelanes or other parallel facdltles, and vehacle trip lengths and VMTare increased
In the HOTscenario, carpools (3+ occupants), tolled carpools (2 occupants), tolled SOVsare allowed to use the HOVlanes Given the congestion levels on the
18 parallel facdmes, manydrwers are wllhng to pay the toll to use this faclhty As a result,
HOTlanes attract more vehicles than the HOVlanes and VHDis reduced and VMTis increased comparedto the HOVlane scenario
In the Track Only scenario, only commercialvehicles are allowed to use the new highway lanes This scenarxo performed almost as well as the HOVscenmo with respect to reduction of VHDbut not as well as the HOTscenario Th:s Is most likely because the heaviest volumeof truck travel occurs dunngthe off-peak period whenthere is not a lot of congesnonm the region
In the HOTTscenario, HOTlanes are opened up to commercial vehMesThis scenario produces the greatest reductlon m VHDcompared to all the other scenarios As noted previously, this result maybe overesnmatedsomewhat because the model was not able to represent potential aversions that somedrivers mayhave to sharing lanes with commercialvehicles The higher levels of congestion reduction in this scenario suggest that the new lanes are underutlhzed m the other scenarios In the base case scenario congesnonxs present on almost all the facflmes wherethe new lanes are added It appears that the level of congesnonis not high enoughto encourage morecarpoohng or to entice moreSOVs to pay a toll to use a faster facility However,as mennoned previously, it is also possible that use of the HOTlanes by tolled SOVsis underestimated m this study because only home-basedwork trips are charged a toll and only three
Incomegroups are represented in the modechoice model
Emissions
All of the alternatxve scenarios increase em:sslons over the base case alternatwe The
HOVlane scenario prowdedthe lowest overall increase, followed by the HOTlane
19 scenario, then the Truck Only scenario, and finally the HOTTscenario The h~gher emissions for the scenarios with the Truck lanes can be explained by an rncrease m VMT for comrnerclal vehicle travel in those scenarios Commercialvehicles tend to have h~gher emission rates than personal vehicles Generally, however, the results do not vary much across scenarios
Table 2, Daily Emission Projections 2015 Policy Scenarios for the Sacramento Region
TOG(ton) CO(ton) NOx(ton) PM(ton) Base Case 33.10 222.26 78.57 19.13
HOV 33 46 227 25 81 10 19 50 (ta 09%) (2 25%) (3 22%) (1 93%) HOT 33 45 227 43 81 41 19 55 (1 06%) (2 33%) (3 61%) (2 20%) Truck Only 33 44 227 93 81 6 19 44 (1 03%) (2 55%) (3 86%) (1 62%) HO’]-[" 33 39 227 93 82 04 19 53 (0 88%) (2 55%) (4 42%) (2 09%) a Rguresin parenthesesarepercentage change from the base case scenario
Economic Benefits
The change rn total economic benefits from the base case for both personal and commercial vehlcle travel for alternatwe scenarlos is presented m Table 3 With respect to economic benefits, the HOTlane scenarios are clearly superior to the HOVand Truck
Only scenarios For personal travel, the HOVand Truck Only scenario result rn a small total econornlc loss ($0 01 per tnp) when the full, unobserved cost of addmonaltravel included rn the analysis Both scenarios produce slmdar reductions m VDHand increases in VMTFor comrnercml vehicle travel, both scenarios produce a small
20 economicbenefit resulting from cost savings due to avoided delays and increased revenues for more potential travel Commercialvehicle benefits were not muchgreater in the Truck Only scenario than m the HOVlane scenario However, benefits from
Truck Only lanes maybe underestmaatedIn this analysis because avoided costs from inJury and property damageare not included m the analysis
Tablea 3. 1995 Present Value of the Changein EconomicBenefits from the Base Case Scenario 2015 Policy Scenarios for the Sacramento Region
TotalwithoutComrnerclal Total Cornmeroa/Vehicle Total with Commercial VehicleTravel Travel VehicleTravel Total PerTrlp Total PerTrip Total PerTrip HOV -$56,20167 -$0 01 $1,16865 $0 O0 -$55,03302 -$0 01 HOT $281,83245 $0 03 $15,64532 $0 02 $297,47777 $0 03 Truck Only -$64,90234 $001 $1,33979 $0 O0 -$63,56256 -$001 HOTT $494,62784 $0 06 $19,77311 $0 03 $514,40095 $0 06 a Includes CapItal andO&M Costs
As discussed m the previous section, most commerciaIvehicle travel occurs during the off-peak period whenthere Is muchless congestion than during the peak period and the potential benefits to commercialvehicles in this scenario are hmlted As a result, a tolled TruckOnly lane does not appear to be feastble based on this analysis
Tolls would be low and would not be great enough to cover the capital and O&Mcosts of the new Truck Only facihty
The HOTscenario results In an economicbenefit of $0 03 cents per trip for personal travel because of travel time saving to travelers with high values &tame,whlch
21 more than offsets the unobservedcost of additional travel Economicbenefits to commercialvehicles are also sigmficant because of the greater reduction mVHD an this scenario comparedto the HOVand Truck Only scenarios As discussed m the methods section, it is assumedthat revenues fromthe HOTlanes are used to offset the capital and
O&Mcosts of the HOTlanes and the new transportation facilities Included in the base case scenario This approach Is similar to the I-15 HOTlanes in San Diego
The HOTTscenario provides the greatest economicbenefits to both personal and commercialvehicle travel The HOTTscenario results in an economicbenefit of $0 06 cents per trip for personal travel becauseof travel tlme saving to travelers with high values ofttme, which morethan offset the unobservedcost of additional travel In addmon,the increase m VMT(and thus the increase m the unobserved cost of addmonal travel) for this scenario is smaller than the HOTscenarm Economicbenefits to commercialvehicles are larger than those obtained for the HOTscenario, again, because of the greater reduction m VHDin th~s scenario comparedto the HOTscenarm
]Equity
The results of the eqmty analys~s are presented m Table 4 For the HOVand Truck Only scenario, there is no slgmficant difference amongthe benefits and losses for the different incomeclasses on a per trip basis However,the highest incomeclass clearly benefits more from the HOTand the HOTTscenario This is because &the time sawng to travelers with a higher value of time For the HOTand HOTTscenarios, benefits increase w~thlevel of income
22 Tablea 4. 1995 Present Value of the Changein EconomicBenefits from the Base Case by Income Class per Trip 2015 Policy Scenarios for the Sacramento Region
LowIncome MEddleIncome H~ghIncome HOV $o.oo -$o.ol $o.oo HOT $o.oo $o.ol $o.o8 TruckOnly -$o.ol -$o.o~ $o.oo HOTT $o.oo $O,Ol $o.o7 ’~ IncludesCaptta[ andO&M Costs
SUMMARY AND CONCLUSIONS
WLthrespect to congesUonreduction, several findings are suggested mthis study of the
,Sacramentoregion Farst, the travel results mdacatethat the HOTlane scenario maybe
:~omewhatbetter at reducing congestaon than the HOVlane scenario However,our samulataonof the scenario mayunderestamate the demandfor th~s facdaty and thus ats efficacy at reducing congestaon Second, the Truck Only lane scenario produces reductaons m congestaon s~mdar to that of the HOVlane scenario Sagmficant congesuon i eductlon does not occur mthis scenario because the heawest volumeof truck travel occurs dunngthe off-peak period whenthere as not a lot of congestion These results suggest that Truck Only lanes maybe more appropriate m regaons that experience congestaon during both the peak and off-peak periods Thard, the HOTTlanes produce a moresagmficant reduction m congestaon than all the other pohcles Th~s result maybe overestimated somewhatbecause the modelwas not able to represent potential aversions that some drwers mayhave to sharing lanes wlth commercmlvehicles However,th~s scenario does makemore apparent that the HOTand Truck Only lanes are not fully
23 utdlzed m the other scenario This region is not severely congested
All of the scenarios Increase vehicle trips, VMT,and emlsslons comparedto the base case scenario There is not a great deal of variation amongthe scenarios with respect to vehicle trips and VMT,however, the emissions resuks showa somewhatmore pronounced&fference and a &fference that &dnot strictly rank wlth the ordering of vehxcle trips and VMTfor the scenarios The HOT,Truck Only, and HOTTscenario all produce higher overall enussions than the HOVlane scenario The HOTTscenario has the htghest overall emissions, followed by the Truck Only scenario, and then followed by the HOTscenario The higher emissions for the scenarios wtth the Truck lanes can be explained by an increase mVMT for commercialvehicle travel in those scenarios
Commercialvehicles tend to have hlgher emission rates than personal vehicles
Wathrespect to economacbenefits for the scenarios, the HOTlane scenarios
(HOTonly and HOTT)are clearly superaor to the HOVand Truck Only scenario The
HOVand Truck Only scenarios each have a small total economacloss for personal travel whenthe full, unobservedcost of ad&taonaltravel Is included mthe analysls Both
:~cenanos produce an economicbenefit for commercialtravel resulting from cost savings due to avoided delays and increase revenues for morepotentaal travel, but benefits are not
]large because congestion reduction is not sagnlficant A tolled Truck Only lane does not appear to be feasible based on this analysis because toll levels and revenues wouldbe l lmtted The HOTscenarao and HOTTscenarao produce comparatwely large economic benefits for personal travel because &travel tame sawngto travelers with high values of lame, which more than offsets the unobservedcost of addlt~onal travel Econormc benefits to commercxalvehicles are also s~gnlficant because of the greater reduction in
24 VHDin this scenario comparedto the HOVand Truck Only scenarios
The eqmtyanalysls indicates that the highest incomeclass clearly benefits more
(on a per trip barns) from the HOTand the HOTand Truck scenarios This is because the ttme saving to travelers with a higher value ofttme However,there IS no slgmficant difference amongthe benefits and losses for the different incomeclasses on a per mp basis for the HOVand Truck Only scenarios
The ranking of the scenarios m this study wlth respect to VHDand economic benefits indicate that the HOTTis best followed by the HOTscenario This is probably because ttus reglon is not severely congested The rankmgsof the scenarlos examinedm this study wall depend on the levels of congestion m a pamcularregion
This study showslittle variation mthe travel and emlssmnsresults across scenarios However,more slgmficant variation was found m the economicbenefit results amongthe scenarios The scenarios that included HOTlanes produced economic benefits that were clearly superior to the other scenarios As a result, It is concludedthat the economicwelfare modelsapplied in this study can be useful tools m the analysis of transportation pohcles
Whilethe results &this study did producesome interesting findings, its conclusions should be interpreted in the context of the described hmlts of the model
These limitations are not only present in the SACMET96model but are present m almost all MPOmodels in the U S Most MPOmodels lack a land use model that is used with a travel model, poorly represent tune and cost variables throughout the of the model system, and lack the local data that are neededto develop commerclalvehicle travel submodels SACMET96is, however, one of the more advanced MPOregional travel
25 demandmodels m the U S As a result, this study underscores someof the difficulties that regional travel demandmodels have in simulating more mnovanvetransportation pohcles
ACKNOWLEDGEMENTS
Wewould like to thank the Umversityof California Transportation Center and the
EnvironmentalProtection Agencyfor funding this research The views expressed and any errors are those of the authors
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