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2. RoadwaysThischapterpresentsanddiscussestheresultsofthetrafficanalysiscompletedforthehorizonyear
2030.
The
analyses
continue
from
the
previous
work
performed
for
the
Existing
Conditions
Report.
An
analysisofthegrowthofpopulation,employmentandtravelinthestudywasconductedandisdetailed
inthischapter.TheanalysesexaminethebaselineconditionsofimplementingtherecommendedEIS
mitigationstrategies,aswellaspedestrianimprovements,andthenidentifyadditionalmeasuresto
improvetrafficconditions.Aseriesofroadwayimprovementsarerecommendedandprioritizedfor
implementation.Costestimatesforconstructionarealsoestimated.
VHBpreviouslycompletedananalysisofexistingconditionsinthestudyareaandtheresultswere
presentedintheWiehleAvenue/RestonParkwayStationAccessManagementPlans:ProfileofExistingConditions,datedJune22,2007whichcanbefoundathttp://www.fairfaxcounty.gov/fcdot/pdf/wr_
sam/existing_conditions_june22.pdf.ThisExistingConditionsReportalsopresentedinformation
relativetotheroadwayclassificationoftheroadwayswithintheStudyArea.
CurrenttrafficoperationswereanalyzedusingthesimulationtoolSynchro(version6),withinputfiles
obtainedfromtheVirginiaDepartmentofTransportation(VDOT).Theintersectionmeasuresof
effectiveness(MOEs)suchasLevelofService(LOS)anddelayweresummarizedbyproducingreportsin
theHighwayCapacityManual(HCM)formatthatwereprovidedintheExistingConditionsReport.The
analysishadshownthatmostintersectionsperformataLOSofCorbetterduringtheAMandPM
peakhours.ThereareonlyahandfuloftheintersectionsthatwereexaminedthatperformedatanLOS
ofDorworse.
TheseresultsraisedseveralissueswithrespecttotheapplicationoftheHCMmethodologytoquantify
intersectionMOEs.
This
methodology
examines
each
intersection
in
isolation;
it
does
not
account
for
meteringfromupstreamintersections,nordoesitaccountforintersectionspillbackfromdownstream
intersections.Forexample,theLOSoftheintersectionofRestonParkwayandSunsetHillswas
computedasLOSEintheAMpeakhour;however,theintersectionofRestonPkwyandthewestbound
DIAAHrampsoperateatLOSF,andoftenspillsbackintothisintersection,preventingvehiclesfrom
leavingtheintersectionofRestonPkwy/SunsetHills.Theactualperformanceofthisintersectionis
thereforeworsethanpredictedbytheHCMmethodology,whichdoesnotaccountforqueuespillback.
ThesecondissuethatwasidentifiedintheanalysiswasthatthecountsthatVDOTprovidedwithintheir
Synchrofilesdonotreflectfulldemand.ThecountersthatfedinformationintotheSynchrofilesonly
reflectintersectionthroughput,ratherthandemand,astheintersectioncannotprocesseveryonedue
to
capacity
constraints
or
downstream
intersection
congestion.
Thus,
when
counts
from
oversaturated
conditionsareused,intersectionMOEsreportedbytheHCMmethodologytendtounderstate
congestionlevelsandshowbetteroperatingconditionsthanactualnetworkperformance.
Forthereasonsdescribedabove,thestudyteamappliedamuchmoresophisticatedtrafficoperations
analysissoftwareprogramforfutureconditions:VISSIM.Thisprogramaccountsforqueuespillback
effectsandproducesmoreaccuratemeasuresofsystemoperationalperformance.
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Thissectionsummarizesprojectedlanduseandtraveldemandfor2030.AsshowninFigure12,the
boundariesofthestudyareaincludetheFairfaxCountyParkwaytothewest,HunterMillRoadtothe
east,FoxMillRoadandLawyersRoadtothesouth,andWiehleAvenuetothenorth.Inaddition,a
stationinfluenceareathatreferstotheareaimmediatelysurroundingthetwoproposedstationswas
identifiedas
away
to
focus
on
the
stations
in
the
station
access
management
plans.
a.
TheMetropolitanWashingtonCouncilofGovernments(MWCOG)Round7.0cooperativelanduse
forecastswereusedtocalculatefuture2030traveldemand.Figure21showsthe2030projected
populationaroundtheRestonarea.Everyzonewithinthestudyareawillhavesomelevelofresidential
populationin2030.Figure21showspercentpopulationchangefrom2005to2030inthisarea.The
totalprojectedpopulationinthestudyareain2030isapproximately82,000,whichincreases
approximately28%fromthe2005totalpopulation.Comparedto2005,theareasthatareexpectedto
increasethemostinpopulationby2030includethestationinfluenceareadirectlyadjacenttothe
stationsaswellastheresidentialareasalongRoute28,withmorethan200%growth.
Figure21:2030StudyAreaPopulation
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Figure23:2030StudyAreaEmploymentProjection
Figure23shows2030projectedemploymentaroundtheRestonarea.Althoughemploymentwillbe
clustered,allzonesinthestudyareawillhavesomelevelofemployment.Figure24showsthepercent
employmentchangefrom2005to2030.Thetotalemploymentinthestudyareain2030is
approximately80,000,anincreaseofapproximately27%overthetotalemploymentin2005.Thetotal
employmentinthestationareain2030isapproximately62,000,alsoanincreaseofapproximately27%
comparedto2005totalemployment.Unlikethepopulationgrowthpattern,thestationarea
experiencesonlymoderateemploymentgrowth,between25%and50%.
Figure22:2005to2030StudyAreaPercentPopulationChange
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Figure24:2005to2030StudyAreaPercentEmploymentChange
Futuretraveldemand,includingautomobile,busandpedestrianmodes,wasforecastusingtwoprimary
sources:1)theFairfaxCountyregionaltraveldemandmodeland2)outputsoftheNorthernVirginia
MajorInvestmentStudyModel(NVMISM)thatwasusedfortheDullesCorridorRapidTransitEIS.The
FairfaxCountymodelwasusedtoforecastvehiculardemand,notincludingbuses;whileNVMISMmodel
outputswereusedtoforecastbuspassengerandpedestriandemandforaccesstothenewMetrorail
stations.AutomobiledemandfortheplannedparkandridestructureattheWiehleStationwas
forecastindependently
of
the
two
models
based
on
the
assumption
that
this
structure
would
be
operatingatcapacityby2030.
TheFairfaxCountymodelisamodifiedversionoftheMWCOGregionaltraveldemandmodel,witha
moredetailedzonesystemwithinFairfaxCounty.TwosetsofrefinedmodelswereprovidedtoVHBfor
thisstudy:1)year2000wasusedasabaseyearand2)year2030ConstrainedLongRangePlan(CLRP)
networkmodelwasusedasthefuturescenario.ThemodelingperiodsincludedtheAMpeakperiod
from6AMto9AMandthePMpeakperiodfrom4PMto7PM.
Asubareamodelingtechniquewasemployedforboththestudyareaandstationinfluenceareain
ordertofocusonthetripsintheareaofinterest,asopposedtothewholeregion.Thetravelforecasting
resultsfordifferentscenarioswereevaluatedbasedonthefollowingthreetriptypes:
InternaltoInternal(II):IItripsarethosetripswhichstartandendinsidethestudyarea.
ExternaltoInternal(XI)orInternaltoExternal(IX):XItripsarethosetripsthatstartoutside
thestudyareaandendinsidethestudyarea.IXtripsarethosetripsthatstartinsidethestudy
areaandendoutsidethestudyarea.
ExternaltoExternal(XX):XXtripsarethosetripsthatstartandendoutsidethestudyarea.
Theyarealsocalledthroughtrips.
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Figure25showsacomparisonoftotalstudyareatripsbetween2000and2030fortheAMpeakperiod.
Overall,thesplitofthethreetriptypesin2030remainsalmostthesameasthebaseyearsplit.Total
tripsin2030areprojectedtobe128,867,whichis34%greaterthanthe95,848totaltripsin2000.II
tripsincreasethemostofthethreetypeswith55%growth.
Figure26showsacomparisonoftotaltripsinthestudyareabetween2000and2030forthePMpeak
period.
Overall,total
trips
in
the
PM
peak
period
are
approximately
55%
greater
than
AM
peak
period
tripsinboth2000and2030.Thesplitofthreetriptypesin2030changesslightlyfromthebaseyear
split.WhiletheXIorIXtripsplitremainsalmostunchanged,23%oftripswouldbeshiftedfromXX
tripstoIItripsin2030.Thereare199,415totaltripsin2030,whichis33%greaterthanthe149,470
totaltripsin2000.IItripsincreasethemostwithgrowthof55%overthe30yearperiod,asintheAM
peakperiod.
0
50,000
100,000
150,000
200,000
250,000
2000 2030
II XIorIX XX
43%
12%
46%
42%
11%
46%
Figure25:ComparisonofStudyAreaAMPeakPeriodTotalTrips
Year 2000 Year 2030 %Growth
I-I 10,129 15,651 55%
I-X or X-I 44,170 59,633 35%
X-X 41,549 53,583 29%
Total 95,848 128,867 34%
IIareinternaltointernaltrips IXareinternaltoexternaltrips
XIareexternaltointernaltrips XXareexternaltoexternalorthroughtrips
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Figure27showsacomparisonoftotaltripsinthestationinfluenceareain2000and2030fortheAM
peakperiod.Incontrasttotravelpatternsinthestudyarea,thesplitofthethreetriptypesin2030
changesfromthebaseyearsplit.34%oftripswouldbeshiftedfromXXtripstoIItripsin2030.There
are87,379totaltripsin2030,whichis32%greaterthanthe66,039totaltripsin2000.IItripsincrease
themostwith227%growth.
0
50,000
100,000
150,000
200,000
250,000
2000 2030
II XIorIX XX
41%
14%
48%
38%
12%
47%
Year 2000 Year 2030 %Growth
I-I 17,708 27,417 55%
I-X or X-I 70,457 95,591 36%
X-X 61,305 76,407 25%
Total 149,470 199,415 33%
Figure26:ComparisonofStudyAreaPMPeakPeriodTotalTrips
IIareinternaltointernaltrips IXareinternaltoexternaltrips
XIareexternaltointernaltrips XXareexternaltoexternalorthroughtrips
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Figure28showsacomparisonoftotaltripsinthestationinfluenceareabetween2000and2030forthe
PMpeakperiod.Overall,totaltripsinthePMpeakperiodareapproximately45%greaterthanAMpeak
periodtripsinboth2000and2030.Thesplitofthethreetriptypesin2030allchangefromthebase
yearsplit.BoththeXIorIXtripsplitandIItripsplitwouldincreaseby3%whiletheXXtripsplit
woulddropby6%in2030.Thereare125,888totaltripsin2030,whichis31%greaterthanthe96,064
totaltrips
in
2000.
IItrips
increase
the
most
with
211%
growth.
Theimpactoftheproposedstationsismoreprominentinthestationinfluencearea.Moretripswould
begeneratedwithoriginsand/ordestinationsthatareinsidetheinfluencearea.
Year 2000 Year 2030 %Growth
I-I 948 3,100 227%
I-X or X-I 17,008 23,929 41%
X-X 48,083 60,350 26%
Total 66,039 87,379 32%
0
50,000
100,000
150,000
200,000
250,000
2000 2030
II XIorIX XX
73%
4%
27%
69%
1%
26%
Figure27:ComparisonofStationInfluenceAreaAMPeakPeriodTotalTrips
IIareinternaltointernaltrips IXareinternaltoexternaltrips
XIareexternaltointernaltrips XXareexternaltoexternalorthroughtrips
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TheDIAAHhasalargenumberoftripsthatpassthroughtheRestonareawithoutleavingthefacility.
Table21showsDIAAHthroughtripsforthestudyareaandstationinfluenceareain2000and2030.
ThevolumeoftripsduringtheAMpeakperiodin2030isprojectedtobe26%33%greaterthanthe
volumeoftripsin2000,whilethecorrespondinggrowthisprojectedtobe4%9%forthePMpeak
period.OneinterestingfindingisthattherearefewerfutureyearAMpeakperiodtripsthanPMpeak
periodtripsinthebaseyear.Thisindicatesthatdemandiscurrentlyapproachingorexceedingroadway
capacityontheDIAAHduringthePMpeakperiod,butnotduringtheAMpeakperiod.
Table21:DIAAHThroughTrips
Year2000 Year2030 %Growth
StudyArea AMPeakPeriod 15,085 19,055 26%
PMPeakPeriod 21,716 22,481 4%
Station
InfluenceArea
AMPeakperiod 15,865 21,054 33%
PMPeakPeriod 23,295 25,492 9%
Year 2000 Year 2030 %Growth
I-I 1,898 5,902 211%
I-X or X-I 25,801 37,925 47%
X-X 68,365 82,061 20%
Total 96,064 125,888 31%
0
20,000
40,000
60,000
80,000
100,000
120,000
140,000
2000 2030
II XIorIX XX
71%
5%
30%
65%
2%
27%
Figure28:ComparisonofStationInfluenceAreaPMPeakPeriodTotalTrips
IIareinternaltointernaltrips IXareinternaltoexternaltrips
XIareexternaltointernaltrips XXareexternaltoexternalorthroughtrips
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ExcludingtheseDIAAHthroughtrips,studyareaandstationinfluenceareatripsforbothAMandPM
peakperiodswerecomparedbetween2000and2030(seeTable22andTable23).SincetheDIAAH
tripswerecountedasXXtrips,thetripsfortheothertwotriptypesremainunchanged.Figure29and
Figure210showthetriptypeproportionsexcludingDIAAHthroughtripsforthestudyareaand
stationinfluencearea,respectively.TheextractionofDIAAHtripsresultsinanincreaseinthe
proportionofIItripsandtheproportionofXIorIXtrips,andareductionintheproportionofXXtrips
whencomparedtotheproportionswhenDIAAHthroughtripsareincluded.Inthestudyarea,the
proportionofII,XIandIXtripswilldropby2%from2000to2030fortheAMpeakperiodwhilethe
proportionwilldecreaseby1%forthePMpeakperiod.Inthestationinfluencearea,theproportionof
II,XIandIXtripswilldropby3%from2000to2030fortheAMpeakperiod,whiletheproportionwill
alsodecreaseby3%forPMpeakperiod.Thisrepresentsareductioninstudyandinfluencearea
throughtripsassociatedwithregionalroadwaysinthefuture,whichindicatesthatthegrowthinlocally
orientedtripsisdisplacingregionalthroughtripdemand.
Table22:ComparisonofStudyAreaTripsExcludingDIAAHThroughTrips
Year2000 Year2030 %Growth
AM
Peak
Period
II 10,129 15,651 55%
I
X
or
X
I
44,170 59,633 35%XX 26,464 34,528 30%
Total 80,763 109,812 36%
PMPeak
Period
II 17,708 27,417 55%
IXorXI 70,457 95,591 36%
XX 39,589 53,926 36%
Total 127,754 176,934 38%
Table23:ComparisonofStationInfluenceAreaTripsExcludingDIAAHThroughTrips
Year2000 Year2030 %Growth
AMPeak
Period
II 948 3,100 227%
I
X
or
X
I
17,008 23,929 41%XX 32,218 39,296 22%
Total 50,174 66,325 32%
PMPeak
Period
II 1,898 5,902 211%
IXorXI 25,801 37,925 47%
XX 45,070 56,569 26%
Total 72,769 100,396 38%
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Figure29:StudyAreaTripPurposeSplitExcludingDIAAHThroughTrips
12%14% 14% 15%
55%55% 54%
54%
33%31% 32% 31%
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
2000AMPeakPeriod 2000PMPeakPeriod 2030AMPeakPeriod 2030PMPeakPeriod
II XIorIX XX
Figure210:StationInfluenceAreaTripPurposeSplitExcludingDIAAHThroughTrips
2% 3%5% 6%
34%35%
36%38%
64%62%
59%56%
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
2000AMPeakPeriod 2000PMPeakPeriod 2030AMPeakPeriod 2030PMPeakPeriod
II XIorIX XX
IIareinternaltointernaltrips IXareinternaltoexternaltrips
XIareexternaltointernaltrips XXareexternaltoexternalorthroughtrips
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Future2030trafficprojectionsweredevelopedfortheAMandPMpeakperiods,asopposedtoonlythe
AMandPMpeakhours.Thisisduetothefactthatsincethepeakhoursareprojectedtobeheavily
congested,whichwillforcethepeakdemandtospreadoutsideofthepeakhours.Whenthisoccurs,
theevaluationofpotentialroadwayimprovementsshouldfocusonmeasuresthataddressdemandover
peakperiods.
The
VISSIM
simulation
model
allowed
for
this
type
of
extended
period
analysis.
Itisalsoimportanttonotethatthe2030trafficprojectionsusedforthisstudymaintainedconsistency
with2030trafficprojectionsdevelopedinapreviousstudyoftheareaaroundtheWiehleStation3.
Figure211andFigure212presenttheAMPeakPeriodandthePMPeakPeriodvolumes,respectively,
thatwereusedfortheanalyses.
Figure211:AM3hourPeakPeriodRoadwayLinkVolumeswithintheStationInfluenceArea(2030)
3DullesCorridorMetrorailProject,TrafficOperationalAnalysisPhase2,CambridgeSystematics,Inc.,March12,2007.
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Figure212:PM3hourPeakPeriodRoadwayLinkVolumeswithintheStationInfluenceArea(2030)
Forthe2030analysis,asetofroadwaycapacityadditions(roadwayactions)wereincludedwiththe
baselineassumptions,andthenadditionalimprovementswereincludedunderamorerobustsystem.
ThebaselineroadwaycapacityadditionsaretheactionsthatwereidentifiedintheDullesRailFEISas
appropriatemitigationmeasures.
Thereisaneedtobalancetheroadwayimprovementswithimprovementsforothermodes,toreflect
thefactthataccesstothestationswillneedtofocusontransitandpedestrianmodes,aswellas
vehicularmodes.Infact,theRestonMetrorailAccessGroup(RMAG)thathelpedguidethisstudy
identifiedpedestrian,bicycleandtransitaccessasprioritiesoverautomobileaccess.Forexample,
wideningaroadwayfrom4to6laneswillimproveroadcapacityandtheabilitytoprocessmore
vehicles;however,thistypeofimprovementcouldpotentiallyhinderpedestrianmovements,especially
atlargerintersections,asitincreasesthecrossingdistanceforpedestrians.
Therearethreegroupingsofroadwayactionsthatwereanalyzedfor2030conditions:1)thoseactions
forroadwaysthatprovideimmediateMetroaccess,2)generalroadwayactionsand3)robustactions
thatwould
be
intended
to
mitigate
congestion
on
along
term
scale,
including
proposed
connectors
over
theDIAAH.
Theactionsdiscussedinthissectionwillprovideincreasedcapacityintheimmediatevicinityofthe
Metrorailstationsonroadwaysthatprovidedirectaccessintothestations.Theseactionsinclude:
1. NewsignalandturnlanesonSunsetHillsRoadforaccessintotheproposedRestonParkway
Metrorailstation.
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2. NewleftturnlaneforwestboundleftturningmovementattheintersectionofSunsetHills
Road/IsaacNewtonSquareW,whichwouldreplacethesharedleftthroughlanebyprovidinga
dedicatedturnlane.
3. Additional(second)leftturnlanefornorthboundtrafficattheintersectionofWiehleAvenue
andthestationentrance(betweenSunsetHillsRoadandtheDIAAH)andprovideasecond
inboundlane.
TheseroadwayactionswouldimprovedirectvehicularaccessintothetwoproposedMetrorailstations
byprovidingincreasedturningcapacity.Thiscouldreducethepotentialfortrafficvolumesthatexceed
theturnbaycapacityandblockthethroughlanesduringperiodsofhighdemand.
InadditiontotheactionsfordirectaccesstotheMetrorailstations,otherroadwayactionswould
increaseintersectioncapacity,therebyimprovingoperationalperformanceandreducingdelay.These
actionscanrangefromsimplyaddingaturnbayatanintersectiontowideningaroadwaytoprovide
extrathroughlanes.Theactionsanalyzedinthiscategoryinclude:
4. AddanadditionalleftturnlaneontheeastboundDIAAHofframpatWiehleAvenue.
5. Improvethe
right
turn
lane
for
the
eastbound
Sunset
Hills
Road
at
Wiehle
Avenue.
6. ImprovetherightturnlaneforthewestboundSunriseValleyDriveatWiehleAvenue.
7. AddanorthboundthroughlaneonRestonParkwayatSunriseValleyDrive,continuingthislane
totherampforeastboundonramptotheDIAAH.
8. ImprovetherightturnlaneforsouthboundRestonParkwayatSunriseValleyDrive.
TheseactionsarepartoftheEISmitigationprojectslistedintheamendedrecordofdecision.Some
additionalroadwayactionshavebeenidentifiedbeyondtheEISrecommendationsthatareidentifiedin
thefollowingsection.
Thebaseline
traffic
analysis
identified
the
need
for
additional
roadway
capacity
along
Wiehle
Avenue,
as
wellasadditionalconnectionsbetweenSunsetHillsRoadandSunriseValleyDrive.Additionalprojects
weredevelopedthatwouldhelpalleviatetheseissues.Theseimprovements,consideredforthe
robustanalysis,include:
9. AddasecondrightturnlaneonthenorthboundWiehleAvenueapproachatSunsetHillsRoad.
10. AddasecondrightturnlaneonthesouthboundWiehleAvenueapproachatSunriseValley
Drive.
11. AddanadditionalleftturnlaneontheeastboundSunriseValleyDriveapproachatWiehle
Avenue.
12. ProvidetwonewconnectionsovertheDIAAHtoprovidenewlinkstoconnectSunsetHillsRoad
andSunriseValleyDrive:
i. Connectionbetween
Town
Center
Parkway
and
Edmund
Halley
Drive.
ii. ConnectionbetweenSoapstoneDriveandIsaacNewtonSquareW.
Thetrafficsoftwareusedforthe2030analysiswasVISSIM,amicrosimulationprogram.Theadvantage
ofusingsuchaprogramisthatitpermitsanalysisofroadwaynetworksthatareoversaturated(i.e.,
congested)andaccountsforqueuespillbacksaffectingupstreamintersectionsandreductionof
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throughput.TheVISSIMsoftware,bymicrosimulatingthenetwork,isabletodeterminethe
intersectionthroughputonalocationbylocationbasisincongestedconditions.Macroscopicprograms
suchastheHighwayCapacityManualSoftware(HCS)andSynchrocanonlyanalyzeintersectionsinan
isolatedfashion;theydonotaccountforqueuespillbackfromdownstreamintersections.
Theanalysisbeganbyexaminingbaselineconditions,whichincludetheEISimprovements,andincluded
pedestrianimprovements.Basedontheanalysisofthebaselineconditions,additionalroadwayactions
weredevelopedtoimprovevehicularflow.
TheBaselineAlternativeincludedtheroadwayimprovementsindentifiedaboveandshowninFigure
213.(Thenumbersinthefigurecorrespondtothenumberedprojectslistedonpages1920.)In
additiontothoseroadwayactions,pedestrianimprovementsidentifiedbythePedestrianBikeTeam
(anddetailedinChapter3)werealsoincorporated.Theseactionsimprovethecrossingconditionsat
manyintersectionsforpedestriansbyaddingpedestriancrosswalks,pedestriansignalsand/or
pedestrianrefugeislandsthatshortenthecrossingdistance.Bicyclelanes(whilerecommendedin
Chapter5forsomelocations)werenotincludedfortheroadwayanalysis,theprimarypurposeofwhich
wasto
evaluate
intersection
roadway
actions,
including
the
effects
due
to
pedestrians.
Inordertoassesstheabilityoftheroadwaysystemtohandletheforecasteddemand,aVolumeto
Capacity(V/C)calculationwascompletedforthecordonpointstotheStationInfluenceArea(shownin
Figure214).Thisprocesscomparedthedemandforthelinkversustheroadwaycapacityofthatlink.
TheV/CcalculationswereperformedonapeakhourandpeakperiodbasisforboththeAMandPM
peaksandarepresentedinTable24.Theassumedroadwaycapacitiesatthecordonpointsweretaken
fromtheFairfaxCountytraveldemandmodelandthevolumesarethoseusedintheVISSIMmodel.
Fi ure 213: Locations of Roadwa Actions for Baseline Conditions
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Table2
4:2030VolumetoCapacityRatioatCordonPointsforthe
DetailedStudyAreaforAM
andPM
Pea
ksBaselineAlternative
CordonPoint
Location
Direction
Volume
Capa
city
V/C
Volume
Capacity
V/C
Volume
Capacity
V/C
Volume
Capacity
V/C
In
2,6
60
2,8
00
0.9
5
6,6
50
8,4
00
0
.79
1,8
02
2,8
00
0.6
4
4,87
0
8,4
00
0.5
8
Out
1,2
15
2,3
00
0.5
3
3,0
38
6,9
00
0
.44
2,4
80
2,3
00
1.0
8
6,70
3
6,9
00
0.9
7
In
760
1,1
50
0.6
6
1,9
00
3,4
50
0
.55
930
1,1
50
0.8
1
2,51
4
3,4
50
0.7
3
Out
1,2
60
2,8
00
0.4
5
3,1
50
8,4
00
0
.38
821
2,8
00
0.2
9
2,21
9
8,4
00
0.2
6
In
2,4
74
3,8
25
0.6
5
6,1
85
11,4
75
0
.54
2,1
64
3,8
25
0.5
7
5,84
9
11,4
75
0.5
1
Out
2,0
28
4,8
00
0.4
2
5,0
70
14,4
00
0
.35
3,2
99
4,8
00
0.6
9
8,91
6
14,4
00
0.6
2
In
625
850
0.7
4
1,5
63
2,5
50
0
.61
619
850
0.7
3
1,67
3
2,5
50
0.6
6
Out
617
850
0.7
3
1,5
43
2,5
50
0
.60
681
850
0.8
0
1,84
1
2,5
50
0.7
2
In
132
7,0
00
0.0
2
330
21,0
00
0
.02
431
7,0
00
0.0
6
1,16
5
21,0
00
0.0
6
Out
407
7,0
00
0.0
6
1,0
18
21,0
00
0
.05
127
7,0
00
0.0
2
343
21,0
00
0.0
2
In
2,7
15
3,1
50
0.8
6
6,7
88
9,4
50
0
.72
2,4
34
3,1
50
0.7
7
6,57
8
9,4
50
0.7
0
Out
2,0
01
3,7
00
0.5
4
5,0
03
11,1
00
0
.45
2,3
24
3,7
00
0.6
3
6,28
1
11,1
00
0.5
7
In
641
2,4
00
0.2
7
1,6
03
7,2
00
0
.22
1,3
80
2,4
00
0.5
8
3,73
0
7,2
00
0.5
2
Out
2,2
16
2,4
00
0.9
2
5,5
40
7,2
00
0
.77
819
2,4
00
0.3
4
2,21
4
7,2
00
0.3
1
In
2,1
79
1,5
50
1.4
1
5,4
48
4,6
50
1
.17
1,6
33
1,5
50
1.0
5
4,41
4
4,6
50
0.9
5
Out
2,0
83
3,2
00
0.6
5
5,2
08
9,6
00
0
.54
1,6
03
3,2
00
0.5
0
4,33
2
9,6
00
0.4
5
In
952
1,1
50
0.8
3
2,3
80
3,4
50
0
.69
1,3
55
1,1
50
1.1
8
3,66
2
3,4
50
1.0
6
Out
191
3,1
00
0.0
6
478
9,3
00
0
.05
1,0
92
3,1
00
0.3
5
2,95
1
9,3
00
0.3
2
In
890
1,7
00
0.5
2
2,2
25
5,1
00
0
.44
461
1,7
00
0.2
7
1,24
6
5,1
00
0.2
4
Out
271
1,7
00
0.1
6
678
5,1
00
0
.13
883
1,7
00
0.5
2
2,38
6
5,1
00
0.4
7
In
1,2
14
1,7
00
0.7
1
3,0
35
5,1
00
0
.60
841
1,7
00
0.4
9
2,27
3
5,1
00
0.4
5
Out
628
2,8
00
0.2
2
1,5
70
8,4
00
0
.19
1,4
47
2,8
00
0.5
2
3,91
1
8,4
00
0.4
7
In
2,5
12
3,1
50
0.8
0
6,2
80
9,4
50
0
.66
1,9
39
3,1
50
0.6
2
5,24
1
9,4
50
0.5
5
Out
1,2
24
3,1
50
0.3
9
3,0
60
9,4
50
0
.32
3,3
72
3,1
50
1.0
7
9,11
4
9,4
50
0.9
6
In
413
850
0.4
9
1,0
33
2,5
50
0
.40
1,1
94
850
1.4
0
3,22
7
2,5
50
1.2
7
Out
870
850
1.0
2
2,1
75
2,5
50
0
.85
521
850
0.6
1
1,40
8
2,5
50
0.5
5
In
920
1,7
00
0.5
4
2,3
00
5,1
00
0
.45
1,3
43
1,7
00
0.7
9
3,63
0
5,1
00
0.7
1
Out
2,1
50
2,8
00
0.7
7
5,3
75
8,4
00
0
.64
630
2,8
00
0.2
3
1,70
3
8,4
00
0.2
0
AMPeakHour
AMPeakPeriod
PMPeakHour
P
MPeakPeriod
1
SunsetHillsRdw
estofTown
CenterPkwy
2
TownCenter
Pkwy
northofSunset
HillsRd
3
RestonPkwy
northofSunset
HillsRd
4
OldRestonAve
northofSunset
HillsRd
5
SalliemaeDr
northofSunset
HillsRd
6
WiehleAve
northofSunset
HillsRd
7
SunsetHillsRdea
stofMichael
FarradayDr
8
SunriseValley
Drive
eastofWiehle
Ave
9
SoapstoneDr
so
uthofSunrise
ValleyDr
10
ColtsNeckRd
so
uthofSunrise
ValleyDr
11
SouthLakesDr
eastofReston
Pkwy
14
SunriseValley
Drive
w
estofReston
Pkwy
12
RestonPkwy
southofSouth
LakesDr
13
SouthLakesDr
w
estofReston
Pkwy
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BasedontheV/Ccalculations,thedemandvolumesformostofthecordonpointsdonotexceedthe
capacityoftheroadwaylinks.Afewpointsdoexceedcapacity,butmarginally.V/Ccalculationswere
performedonboththepeakhourandthepeakperiodbecausethevolume(orthedemand)isnot
constantacrosseachofthethreehoursinthepeakperiod;ratherthepeakhourvolumeishigherthan
eitheroftheshoulderhours.Inseveralcases,thevolumeexceedsthecapacityduringthepeakhour,
butnotduringthepeakperiod.Thus,itcanbeexpectedthathighercongestionlevelswilloccurduring
thepeakhourwithlowerlevelsofcongestioninthehoursbeforeandafterthepeakhour.This
illustrates
the
fact
that
the
cordon
points
themselves
are
not
the
constraining
factor
of
the
system.
Thus,virtuallyallofthedemandcanenterandexittheStationInfluenceAreas;however,congestionat
thekeyintersectionswithintheStationInfluenceAreawillactasaconstrainttotrafficmobility.
Figure215andFigure216presentthedistributionofvehicletripstoandfromtheWiehleAvenue
StationintheAMPeakPeriod(3hours)andfromtheWiehleAvenueStationinthePMPeakPeriod(3
hours).Approximately50percentoftripsareto/fromthenorthoftheDIAAH,35percentareto/from
thesouthoftheDIAAHand15percentofthetripsareto/fromtheDIAAH.
Figure214:DetailedStudyAreaCordonPoints
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Source:VHB(2007)
Source:VHB(2007)
TheanalysiswasconductedusingtheVISSIMmodelforthepeakperiods,atotalofthreehours,to
examinehowtheroadwaynetworkoperatesintheshoulderhoursbeforeandafterthepeakhour.The
keymeasureofeffectivenessthatwasusedwasvehicularthroughputatsevenkeyintersections.This
givesameasureofhowwellthedemandisbeingservedbythebaselineroadwaynetwork.Table25
andTable26presentAMandPMpeakperiodthroughputsummariesatsevenkeylocationswithinthe
stationinfluencearea.
WiehleAvenue
MetrorailStation
ToSoutheast:10%ToSouthwest:24%
ToNorthwest:29%ToNortheast:22%
ToEastonDulles
TollRoad:6%
ToWestonDulles
TollRoad:9%
WiehleAvenue
MetrorailStation
FromSoutheast:
10%
From
Southwest:
24%
FromNorthwest:30%FromNortheast:20%
FromEastonDulles
TollRoad:6%
FromWestonDulles
TollRoad:10%
Figure215:DistributionofIngressTripstotheWiehleAvenueMetrorailStation
Figure216:DistributionofEgressTripsfromtheWiehleAvenueMetrorailStation
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Table25:AMPeakPeriodThroughputSummaryatKeyIntersectionsBaselineAlternative(2030)
Intersection EBTotal WBTotal NBTotal SBTotal
Intersection
Total
Approach
TownCenterPkwy/SunsetHillsRd
AMPkPdThroughput 4,868 1,776 1,873 8,517
AMPk
Pd
Demand
6,650
2,940
1,900
11,490
AMPkPdThroughput% 73.2% 60.4% 98.6% 74.1%
RestonPkwy/SunsetHillsRd
AMPkPdThroughput 3,907 1,226 3,916 1,770 10,819
AMPkPdDemand 4,925 3,175 8,710 6,190 23,000
AMPkPdThroughput% 79.3% 38.6% 45.0% 28.6% 47.0%
IsaacNewtonSquare/SunsetHillsRd
AMPkPdThroughput 3,892 3,801 770 549 9,012
AMPkPdDemand 4,030 5,810 755 555 11,150
AMPkPdThroughput% 96.6% 65.4% 102.0% 98.9% 80.8%
WiehleAve/SunsetHillsRd
AMPkPdThroughput 3,016 2,077 5,998 4,475 15,566
AMPkPdDemand 3,065 2,025 11,060 6,790 22,940
AMPk
Pd
Throughput
%
98.4%
102.6%
54.2%
65.9%
67.9%
WiehleAve/SunriseValleyDr
AMPkPdThroughput 3,073 3,302 3,153 9,528
AMPkPdDemand 6,645 5,475 5,085 17,205
AMPkPdThroughput% 46.2% 60.3% 62.0% 55.4%
SoapstoneDr/SunriseValleyDr
AMPkPdThroughput 2,141 1,604 1,788 140 5,673
AMPkPdDemand 4,555 3,875 2,370 150 10,950
AMPkPdThroughput% 47.0% 41.4% 75.4% 93.3% 51.8%
RestonPkwy/SunriseValleyDr
AMPkPdThroughput 742 1,584 5,171 3,433 10,930
AMPkPdDemand 2,300 3,400 6,880 8,138 20,718
AMPkPdThroughput% 32.3% 46.6% 75.2% 42.2% 52.8%
OverallThroughput 70,045
OverallDemand 117,453
AMPeakPdThroughputas%ofDemand 59.6%
Note: PeakperiodtrafficdemandprojectionswerebasedonMWCOGCooperativeForecastsofJobsandHousingand
developedusingtheFairfaxCountyTravelDemandModel.Peakperiodthroughputestimatesweredevelopedusing
theVISSIMtrafficsimulationmodel.
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Table26:PMPeakPeriodThroughputSummaryatKeyIntersectionsBaselineAlternative(2030)
Intersection EBTotal WBTotal NBTotal SBTotal
Intersection
Total
Approach
TownCenterPkwy/SunsetHillsRd
AMPkPdThroughput 1,369 1,716 816 3,901
AMPk
Pd
Demand
4,870
5,715
2,515
13,100
AMPkPdThroughput% 28.1% 30.0% 32.4% 29.8%
RestonPkwy/SunsetHillsRd
AMPkPdThroughput 809 2,492 2,343 2,467 8,111
AMPkPdDemand 4,945 8,680 8,690 5,850 28,165
AMPkPdThroughput% 16.4% 28.7% 27.0% 42.2% 28.8%
IsaacNewtonSquare/SunsetHillsRd
AMPkPdThroughput 635 904 624 1,081 3,244
AMPkPdDemand 5,235 3,725 2,305 1,440 12,705
AMPkPdThroughput% 12.1% 24.3% 27.1% 75.1% 25.5%
WiehleAve/SunsetHillsRd
AMPkPdThroughput 779 1,019 2,297 1,292 5,387
AMPkPdDemand 6,240 4,600 6,465 6,580 23,885
AMPk
Pd
Throughput
%
12.5%
22.2%
35.5%
19.6%
22.6%
WiehleAve/SunriseValleyDr
AMPkPdThroughput 1,568 1,894 1,383 4,845
AMPkPdDemand 3,700 4,410 7,245 15,355
AMPkPdThroughput% 42.4% 42.9% 19.1% 31.6%
SoapstoneDr/SunriseValleyDr
AMPkPdThroughput 1,386 1,332 754 529 4,001
AMPkPdDemand 3,105 5,885 850 985 10,825
AMPkPdThroughput% 44.6% 22.6% 88.7% 53.7% 37.0%
RestonPkwy/SunriseValleyDr
AMPkPdThroughput 1,039 1,287 3,600 3,192 9,118
AMPkPdDemand 3,630 4,055 5,230 9,291 22,206
AMPkPdThroughput% 28.6% 31.7% 68.8% 34.4% 41.1%
OverallThroughput 38,607
OverallDemand 126,241
PMPeakPdThroughputas%ofDemand 30.6%
Note: PeakperiodtrafficdemandprojectionswerebasedonMWCOGCooperativeForecastsofJobsandHousingand
developedusingtheFairfaxCountyTravelDemandModel.Peakperiodthroughputestimatesweredevelopedusing
theVISSIMtrafficsimulationmodel.
Forbothpeakperiods,theinternalroadwaynetworkiscongested.Anumberofintersectionscannot
processthedemand,whichcausesqueuespillbacktoadjacentupstreamintersections.FortheAMpeak
period,60%ofthedemandwouldbeservedmeaningthatofallthevehiclesthatwouldliketodrive
throughthekeyintersectionsduringtheAMpeakperiod,only60%ofthosewillbeableto.Congestion
ofthistypewillleadtochangesintravelbehavior;atleastfourresponsesarelikely:
Changetimeoftravel,inwhichthepeakperiodwillextendbeyondthetraditional3hours.
Changepathoftravel,throughtripswillfindotherroutestoavoidthearea.
Changemodeoftravel,sometravelerswillchoosetousetransitorwalk/bike.
Notmakethetripatall.
ForthePMpeakperiod,43%ofthedemandisserved.Thiswouldcauseanevenlongerlengtheningof
thepeakperiodcomparedtothedemandoftheAMpeakperiod.
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ThefindingsofbothmodelsarethatprojectedtrafficdemandfortheWiehleAvenuecorridoristhe
causeofmuchoftheforecastcongestionanddelayinthestationinfluencearea.Thereareseveral
componentsofprojectedtrafficalongWiehleAvenue:externaltrips,externalinternaltripsandinternal
trips.CriticalsectionsofWiehleAvenueinclude:
1. SouthboundsegmentofWiehlebetweenSunsetHillsRoadandtheDIAAH.
2. IntersectionofWiehleatSunriseValleyDrive
3. IntersectionofWiehleatSunsetHillsRoad
Thefirstbottleneckwillcausecongestionspillovertoadjacentintersectionswithinthestationinfluence
area,includingextendingthequeuesovertoRestonParkway,whichaffectsnorthsouthtravelonthat
arterial.Thelattertwolocationsarelikelytohaveheavycongestion,dueinparttotheproblemscaused
bytheformer.CongestionalongRestonParkwayisprojectedtobeatalowerlevelthanWiehle
Avenue.
TheheavytrafficcomingoutoftheWiehlemetrostationduringthePMpeakperiodwillcauseweaving
conditionsbetweenalltravellanesonthesouthboundsegmentofWiehleAvenuebetweenSunsetHills
RoadandtheDIAAH,astheycomeoutofthemetrostation.Mostvehiclesarenotdestinedtothewest,
sothey
must
weave
over
at
least
one
lane.
If
avehicle
is
destined
to
the
eastbound
DIAAH
ramp,
they
mustweaveacross4lanestoenterintotheturnbays.Itisonly320feetfromtheWiehlemetrostation
accesstotheintersectionwiththewestboundramps,andafurther500feettotheintersectionforthe
eastboundramps.Thisweavingcausesturbidityasvehiclesforcetheirwayoverbetweenthetravel
lanestoreachthelanetheydesiretoreachtheirdestination.Mostvehiclesthatturnrightwhenthey
exittheWiehleAvenuemetrostationentrancewilllikelybedestinedtoSunriseValleyDriveandpoints
southandthuswouldhavetoweaveacrossatleastonelane.Figure217illustratesthisweaving
phenomenon.
Conflictpoint
Note:hollowarrowsillustratethelanesthatarepartoftheturnbayatthenextsignalbeyondthisintersection
Theother
bottlenecks
along
Wiehle
Avenue
are
at
the
intersections
with
Sunset
Hills
Road
and
Sunrise
ValleyDrive.Thelackofturnlanesforthesignificantmovementsaddstothedelaysatthese
intersections.
ThecurrentroadwaynetworkprovidesfortwocrossingsoftheDIAAH;traffictravelingwithinthearea,
toandfromtherailstations;andenteringandleavingtheDIAAHallwillcompeteforthesameroad
spaceonWiehleAvenueandRestonParkway.Providingalternativeroutingpaths,suchasnew
Figure217:IllustrationofWeavingonWiehleAvenuewithMetroEgress
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connectorsovertheDIAAH,wouldpermitinternaltripsandsometraffictoandfromtherailstationsto
avoidbothRestonParkwayandWiehleAvenue.
A
series
of
roadway
actions,
beyond
those
recommended
in
the
EIS
and
assumed
for
the
future
baseline
analysis,weredevelopedtoaddressthebottlenecksalongWiehleAvenue.Theseimprovementswould
increaseintersectioncapacityandprovidealternateroutingchoicesforvehicles.Connectorsacrossthe
DIAAHwouldprovidenorthsouthalternativestothecongestedRestonParkwayandWiehleAvenue.
Intersectionmodifications,suchasaddingturnlanescanalsoreducetrafficdelayatintersections.The
roadwayactionsthatcouldbeconsideredtoreduceforecastdelayatbottlenecksonWiehleAvenueand
RestonParkwayareillustratedinFigure218andinclude:
9. AddasecondrightturnlaneforthenorthboundWiehleAvenueapproachatSunsetHillsRoad.
10. AddasecondrightturnlaneforthesouthboundWiehleAvenueapproachatSunriseValley
Drive.
11. AddanadditionalleftturnlanefortheeastboundSunriseValleyDriveapproachatWiehle
Avenue.
12. Providingtwo
new
connections
over
the
DIAAH
to
provide
new
links
to
connect
the
major
east
westroadways:SunsetHillsRoadandSunriseValleyDrive:
i. ConnectionbetweenTownCenterParkwayandEdmundHalleyDrive
ii. ConnectionbetweenSoapstoneDriveandIsaacNewtonSquare
Theproposedconnectorswoulddivertvehiclesfromthemajornorthsouthroadwayswithinthestation
influencearea.TheseconnectorswouldbegradeseparatedfacilitiesfromtheDIAAHandwouldnot
includerampsto/fromtheDIAAHasexemplifiedbytheMonroeStreetconnectortothewest,which
passesovertheDIAAHwithoutarampconnection.Forexample,atripfromSoapstoneDrivetothe
WiehleMetrorailStationcoulduseoneoftheseconnectorsandavoidthetrafficonSunriseValleyDrive
andWiehleAvenue,byaccessingtheStationdirectly.ThepotentialfortripsdivertingfromReston
Parkwayand
Wiehle
Avenue
were
estimated
manually
and
assigned
on
the
new
routes.
Figure
219
presentstheestimatednumberoftripsexpectedtomakethisdiversionduringtheAMandPMpeak
periods.ItshouldbenotedthattheFairfaxCountyParkwayliesoutsidethestationinfluencearea,so
therecouldbepotentialfortripdiversionfromthatfacilitytotheTownCenterParkwayandEdmund
HalleyDriveconnector.
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Figure218:LocationsofRoadwayActionsassumedfortheRobustAlternative
Figure219:EstimatedTripDiversionduetoProposedConnectors(2030)
Note:AM(PM)volumespresentedherearepeakperiod(3hour)volume)
TheactionsincorporatedintherobustconceptwereaddedtothebaselineroadwaynetworkinVISSIM,
andthetripswerereassigned.TheactionsareprojectedtohaveagreatereffectinthePMpeakperiod,
asthecombinedthroughputatthesevenkeyintersectionsisprojectedtoincreasebyapproximately
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36%comparedtothebaseline.Theincreasewouldbealmost10%intheAMpeakperiod.Table27
andTable28presentAMandPMPeakperiodthroughputsummariesforthesevenkeyintersections.
Table27:AMPeakPeriodThroughputSummaryatKeyIntersectionsRobustAlternative(2030)
Intersection
EBTotal
WB
Total
NB
Total
SB
Total
Intersection
Total
Approach
TownCenterPkwy/SunsetHillsRd
AMPkPdThroughput 5,677 2,029 163 1,814 9,683
AMPkPdDemand 6,650 2,890 150 1,905 11,595
AMPkPdThroughput% 85.4% 70.2% 108.7% 95.2% 83.5%
RestonPkwy/SunsetHillsRd
AMPkPdThroughput 4,256 1,432 3,931 5,494 15,113
AMPkPdDemand 4,690 3,175 8,565 6,190 22,620
AMPkPdThroughput% 90.7% 45.1% 45.9% 88.8% 66.8%
IsaacNewtonSquare/SunsetHillsRd
AMPkPdThroughput 4,018 3,243 622 520 8,403
AMPkPdDemand 4,015 4,875 1,680 555 11,125
AMPkPdThroughput% 100.1% 66.5% 37.0% 93.7% 75.5%
WiehleAve/SunsetHillsRd
AMPkPdThroughput 2,567 1,847 6,359 3,428 14,201
AMPkPdDemand 2,870 2,025 10,130 6,790 21,815
AMPkPdThroughput% 89.4% 91.2% 62.8% 50.5% 65.1%
WiehleAve/SunriseValleyDr
AMPkPdThroughput 3,893 2,800 2,862 9,555
AMPkPdDemand 5,390 5,480 4,790 15,660
AMPkPdThroughput% 72.2% 51.1% 59.7% 61.0%
SoapstoneDr
/Sunrise
Valley
Dr
AMPkPdThroughput 4,177 1,337 2,033 426 7,973
AMPkPdDemand 4,555 3,595 2,365 430 10,945
AMPkPdThroughput% 91.7% 37.2% 86.0% 99.1% 72.8%
RestonPkwy/SunriseValleyDr
AMPkPdThroughput 1,486 1,341 3,937 5,063 11,827
AMPkPdDemand 2,150 3,400 6,875 7,801 20,226
AMPkPdThroughput% 69.1% 39.4% 57.3% 64.9% 58.5%
OverallThroughput 76,755
OverallDemand 113,986
AMPeakPdThroughputas%ofDemand 67.3%
Note: PeakperiodtrafficdemandprojectionswerebasedonMWCOGCooperativeForecastsofJobsandHousingand
developedusingtheFairfaxCountyTravelDemandModel.Peakperiodthroughputestimatesweredevelopedusing
theVISSIMtrafficsimulationmodel.
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Table28:PMPeakPeriodThroughputSummaryatKeyIntersectionsRobustAlternative(2030)
Intersection EBTotal WBTotal NBTotal SBTotal
Intersection
Total
Approach
TownCenterPkwy/SunsetHillsRd
AMPkPdThroughput 1,250 2,314 146 827 4,537
AMPk
Pd
Demand
4,865
5,700
365
2,515
13,445
AMPkPdThroughput% 25.7% 40.6% 40.0% 32.9% 33.7%
RestonPkwy/SunsetHillsRd
AMPkPdThroughput 813 3,619 2,549 2,433 9,414
AMPkPdDemand 5,095 8,673 8,320 5,850 27,938
AMPkPdThroughput% 16.0% 41.7% 30.6% 41.6% 33.7%
IsaacNewtonSquare/SunsetHillsRd
AMPkPdThroughput 786 1,326 1,162 1,381 4,655
AMPkPdDemand 5,245 3,325 2,595 1,445 12,610
AMPkPdThroughput% 15.0% 39.9% 44.8% 95.6% 36.9%
WiehleAve/SunsetHillsRd
AMPkPdThroughput 1,174 1,362 4,167 2,251 8,954
AMPkPdDemand 5,265 4,595 6,040 6,580 22,480
AMPk
Pd
Throughput
%
22.3%
29.6%
69.0%
34.2%
39.8%
WiehleAve/SunriseValleyDr
AMPkPdThroughput 2,640 3,387 2,241 8,268
AMPkPdDemand 3,175 4,415 5,730 13,320
AMPkPdThroughput% 83.1% 76.7% 39.1% 62.1%
SoapstoneDr/SunriseValleyDr
AMPkPdThroughput 2,706 1,934 867 1,819 7,326
AMPkPdDemand 3,090 4,365 850 2,430 10,735
AMPkPdThroughput% 87.6% 44.3% 102.0% 74.9% 68.2%
RestonPkwy/SunriseValleyDr
AMPkPdThroughput 1,130 1,500 3,232 3,317 9,179
AMPkPdDemand 3270 4055 5230 9080 21635
AM
Pk
Pd
Throughput
%
34.6%
37.0%
61.8%
36.5%
42.4%
OverallThroughput 52,333
OverallDemand 122,163
PMPeakPdThroughputas%ofDemand 42.8%
Note: PeakperiodtrafficdemandprojectionswerebasedonMWCOGCooperativeForecastsofJobsandHousingand
developedusingtheFairfaxCountyTravelDemandModel.Peakperiodthroughputestimatesweredevelopedusing
theVISSIMtrafficsimulationmodel.
TheactionthatwouldhavethegreatesteffectintheincreaseofthroughputfortheAMpeakperiodis
thenewSoapstoneDrivetoIsaacNewtonSquareWconnector.Thisconnectorwoulddiverttripsaway
fromWiehleAvenue,includingthosevehiclesthatwouldotherwiseresultinheavyvolumesofleft
turningvehiclesintotheMetroStationaccesspoints.Thisconnectoralsoreducestheamountoftraffic
exitingfrom
the
proposed
Wiehle
Avenue
Metrorail
Station
onto
Wiehle
Avenue,
thereby
reducing
the
demandaswellasreducingthevolumeoftrafficthatisweavingfromtheMetroaccessandtheDIAAH
ramps.Thisconnectorwouldproviderelieftothecongestionthatwouldotherwiselikelybefoundon
WiehleAvenue.
TheproposedSoapstoneConnectoralsoplaysakeyroleasanadditiontothebusnetworkinRestonby
providingdirectaccessacrosstheDIAAHandtothestationwithoutrequiringtravelonWiehleAvenue.
Inordertoensurethatthisdirectaccessisavailabletotransitvehicles,dedicatedbuslanesshouldbe
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includedaspartofthisfacility.Asproposed,thefacilitywouldincludepedestrianfacilitiesandtwo
travellanesineachdirection:oneforgeneraltrafficandonededicatedlaneforusebybicyclistsand
buses.ThisconnectioncouldsignificantlyspeedbusoperationsintoandaroundtheWiehleAvenue
stationandshouldbeconsideredindetailasredevelopmentaroundtheWiehleAvenuestationoccurs.
EvenwiththeSoapstoneConnectorinplace,theforecastssuggestthatheavycongestionalongWiehle
Avenuewillcontinuetoexist.Toreducethiscongestionandresultingdelay,itwouldbenecessaryto
furtherwidenroadways,ortoencouragealargershifttononautomobilemodes.Anaggressive
programofTravelDemandManagement(TDM)willhelptoencouragethemodalshiftthatwillbe
necessarytoreducetrafficcongestioninthestationareas.
Theotheractionslistedabovedoimproveoperationsofthekeyintersections,thoughtheseactions
wouldprovideonlymarginalbenefit.Additionaltestingwascompletedtoseeifanyofthespecific
actionswerenotrequired.Forexample,additionaltestingshowedthataddingasecondsouthbound
rightturnlanefromWiehleAvenuetowestboundSunriseValleyDriveactionwouldnotresultina
significantbenefittotrafficoperations,butwouldmakepedestriantravelmoredifficultatthis
intersection.
Theanalysishasillustratedthattrafficspeedsintheareawillbesignificantlyslowerinthefutureas
trafficgrowthcontinuesinthearea.Carsandbusesbothwillhavetotravelinthesametraffic,andbus
speedsareexpectedtobesignificantlyslowerin2030thantheyarein2007.Withoutdedicatedlanes,
bustraveltimewillbenobetterthanSOVandtherewillbealowerprobabilityofpromotingthedesired
shiftfromSOVintobuses.Thishastheeffectofrequiringmorevehiclesandmoredriverstooperatea
recommendedlevelofservice,increasingthecostofthesystem.Onealternativethatcouldrelieve
someoftheincreaseinoperatingcosts,driverstaffandfleetrequirementswouldbetoimplementbus
onlylanesthatallowforfreeflowtrafficconditionsfortransitvehicles.Theselanescouldbeusedonly
duringpeak
hours
and
would
function
as
traditional
travel
lanes
during
the
off
peak
periods.
These
laneswouldhavethedualbenefitsofincreasingbusspeeds(andinturnsignificantlydecreasingthe
operationalcostsandthenumberofnewvehiclesrequired)whilesimultaneouslyattractingmore
passengerstothetransitsystemandawayfromtheircars,thusalleviatingtrafficcongestion.
Theroadsexpectedtohavetheworstcongestionproblemsin2030areWiehleAvenueandReston
Parkway.Buslanesontheseroads,andpotentiallyatmajorintersectionswiththeseroads(likeSunset
HillsandWiehleAve)wouldprobablyhavethemostbeneficialeffectsfortransitriders.Acarefulstudy
oftheimplicationsofbuslanesontheseroadsshouldbeundertakentodetermineifthissolutionwould
benefittheresidentsofReston.Implementationofbuslanesintheimmediatevicinityofeitherofthe
stationsalongtheseroadwayswouldpresentmanychallengesinrightofwayacquisition,operations
andenforcementandwouldrequirethereconstructionandexpansionofthebridgesacrosstheDIAAH.
However,therearelocationsinRestonwherebuslanesmightbebothpossibleandbeneficial.Sunset
HillsRdisincludedasasixlanefacilityintheFairfaxCountyTransportationPlan,andthisexpansionis
includedintheFairfaxCountyComprehensiveLongRangePlan(CLRP).Theroadwayexpansioncouldbe
completedbyconstructingtheadditionallanesaspeakhourdedicatedbusfacilitiesbetween(atleast)
OldRestonAvenueandWiehleAvenue.Thesefacilitieswouldprovideacongestionfreeeastwest
routeintheheartofRestonfortransitvehicles.Significantrightofwayacquisitionandconstruction
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costswouldbeassociatedwiththisproject,howeveradetailedstudywouldbenecessaryinorderto
determinetheexactquantitativebenefitsofthebuslanes.
The
transportation
network
around
the
Wiehle
Avenue
station
is
comprised
primarily
of
major
thoroughfares(i.e.WiehleAvenue,SunsetHillsRoadandSunriseValleyDrive)andmuchsmallerstreets
anddrivewaysthatprovideaccesstoindividualbuildingsanddevelopments.Becauseofthis,most
vehiclestravelingintheareamustuseoneofthemajorcongestedroutesorintersections.The
potentialexiststodevelopadditionalroadwayconnectionsasawayforlocaltraveltoavoidthemore
congestedmajorroadways.
Muchoftheinfrastructurethatwouldbenecessarytodevelopthisinternalgridofstreetsalreadyexists
intheformofsmallaccessroadanddriveways.Someoftheseexistingfacilitiescouldbeexpanded
alongwithintersectionimprovementsattheaccesspointstoeasetrafficcongestionandvehicledelays.
Theseconnectorstreetswouldhavetheaddedbenefitofprovidingmoredirectconnectionto
pedestriansandbicyclists,asubjectthatwillbediscussedfurtherinChapter4.
ThepreviouslydiscussedSoapstoneConnectorwouldprovideadditionalconnectionsthroughtheback
doortotheWiehleAvenuestation.ExtendingthisroadwayacrossSunsetHillsRoadontoIsaacNewton
SquareWprovidesfurtherconnections.Likewise,IsaacNewtonSquareS/RogerBaconDrcanprovide
aneastwestconnectionnorthofSunsetHillsRd.Otherprivatedrivewaysinthestationareacouldalso
beupgradedtocarrylocalthroughtraffic.
TheanalysesoftheBaselineandRobustAlternativesprovidedinsightintotheroadwayactions
neededtohandletheprojecteddemand.TheactionsidentifiedfortheBaselineroadwayshouldallbe
implemented,andaselectfewfromtheRobustAlternativeshouldalsobeincluded.Thelistingof
recommendedprojects,
illustrated
on
Figure
220,
is
as
follows:
A. NewsignalandturnlanesonSunsetHillsRoadforaccessintotheproposedRestonParkway
Metrorailstation
B. NewleftturnlaneforwestboundleftturningmovementattheintersectionofSunsetHills
Road/IsaacNewtonSquareW,thiswouldreplacethesharedleftthroughlanebyprovidinga
dedicatedturnlane.
C. AddasecondleftturnlanefornorthboundtrafficattheintersectionofWiehleAvenueand
MetroAccess(betweenSunsetHillsRoadandtheDIAAH)andprovideasecondinboundlane
D. AddanadditionalleftturnlaneontheeastboundDIAAHofframpatWiehleAvenue
E. ImprovetheexistingrightturnlanefortheeastboundSunsetHillRoadlegatWiehleAvenue
F. Improvethe
existing
right
turn
lane
for
the
westbound
Sunrise
Valley
Drive
approach
at
Wiehle
Avenueleg
G. AddnorthboundthroughlanefortheRestonParkwayatSunriseValleyDrive,continuingthe
lanetotherampforeastboundDIAAH
H. ImprovetherightturnlaneforthesouthboundRestonParkwaylegatSunriseValleyDrive
I. ProvideanewconnectionovertheDIAAHtoconnectthemajoreastwestroadways:Sunset
HillsRoadandSunriseValleyDrive.TheconnectionwouldbebetweenSoapstoneDriveand
IsaacNewtonSquareWandwouldincludeonesharedbus/bikelaneineachdirection.
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J. ExpandSunsetHillsRoadbetweenWiehleAvenueandOldRestonAvenuetosixlanes.
Additionallaneswillbeoperatedasdedicatedbuslanesinpeakperiods.
Figure220:LocationsofRecommendedRoadwayActions
Actions9,10,11and12(i),previouslyidentifiedfortheRobustAlternative,arenotrecommended.
Theseprojectswereasfollows:
9. AddingasecondrightturnlaneforthenorthboundWiehleAvenueatSunsetHillsRoad.
10. AddingasecondrightturnlaneforthesouthboundWiehleAvenuelegatSunriseValleyDrive.
11. Addan
additional
left
turn
lane
for
the
eastbound
Sunrise
Valley
Drive
leg
at
Wiehle
Avenue.
12. (i)ProvidingaconnectionbetweenSunsetHillsRoadandSunriseValleyDriveviaTownCenter
ParkwayandEdmundHalleyDrive.
Itshouldbenotedthatevenwithimplementationofalltheroadwayactions,thepeakperioddemand
forboththeAMandPMperiodscannotbeservedwithinthethreehourpeakperiod.Lengtheningof
thepeakperiodshouldbeexpected.
Thenorthsouththoroughfaresareheavilytravelled,buttheeastwestroutesareasimportantto
overallmobilityinthearea.Currently,bothSunriseValleyDriveandSunsetHillsRoadareconsidered
minorarterialsaccordingtotheFairfaxCountyComprehensiveTransportationPlan.Thenumbersof
laneson
both
facilities
vary
depending
on
location.
For
the
most
part,
Sunrise
Valley
Drive
is
a4lane
facility,exceptnearHunterMillRoad,whereitisa2laneroadway.SunsetHillsRoadvariesbetween2
to6lanesdependingonthesection.Themajorfactorofimpedancetoeastwestmobilityistheconflict
forgreentimewithnorthsoutharterialslikeFairfaxCountyParkway,RestonParkwayandWiehle
Avenue.Thesenorthsoutharterialscarrymoretrafficthantheformer.Ifgreentimewereincreased
fortheeastwestarterialswheretheycrossthemajornorthsoutharterials,thenitwouldcomeatthe
expenseofnorthsouthmobility.
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Theothermeanstoimproveeastwestmobilityinthisareaistoprovidemoretravellaneseastwest.
However,thereislimitedpotentialtoimplementthisoptionduetotherightofwayconstraintsthat
existatsomesegmentsalongtheroadway.TheCountysComprehensiveTransportationPlanshows
SunsetHillsRoadasacomplete6lanefacilityfromFairfaxCountyParkwaytoWiehleAvenue,anda4
lanefacilitytoHunterMillRoad.ThelatterwouldlikelyrequireimprovementstoHunterMillRoadat
theDIAAHinterchange.Thiswouldimprovetrafficoperations,butwouldnotbeabletosatisfythe
demandforthisfacility.TherearenotcurrentlyanyplanstowidenSunriseValleyDrive,howeverthe
additionofpeakperioddedicatedbuslanesisrecommendedasalongtermsolutiontocongestion.
IntersectionimprovementsalongthisSunriseValleyDrive,suchasaddingorlengtheningturnbays,
wouldprovidemorestoragetoaccommodateturningtrafficthatwouldnotblockthethroughlanes.
AnotherprojectthatcouldoccurontheedgeoftheStudyAreaisatrafficcalmingprojectonHunterMill
Road.TheHunterMillRoadTrafficCalmingStudy,astudyconductedbytheNorthernVirginiaRegional
Commission,offersanumberofinnovativeapproachestoimprovesafetyalongHunterMillRoad,
provideforthehighvolumeoftraffic,allthewhileimprovingthelevelofservice.Thereportoutlines
"contextsensitivesolutions"suchasroundaboutsandsplitterislandsatacostlowerthanorequalto
traditionalexpansionofhighways.
Othermeansofimprovingcirculationwithinthestationinfluenceareawouldbetoimproveprivate
parcelaccess(ingressandegress)drivewaysbycombiningtheseaccesspointsatlocationswith
signalizedintersections.Byprovidingseparateturnlanesfortheleftturnandrightturnmovementon
thesedriveways,ratherthanasinglelane,itwouldreducethenecessarygreentimefortheminorlegs,
whichinturnprovidesformoregreentimeforthemainthoroughfare.Anexamplewouldbethenorth
legofIsaacNewtonSquareWattheintersectionwithSunsetHillsRoad.
Finally,itisrecommendedthatasredevelopmentoccursintheWiehlestationarea,localstreet
connectorsbeprovidedasawayforlocaltraveltoavoidthemorecongestedmajorroadways.Four
connectorsofthistypearerecommendedtohelpcreateaninternalgridofstreetsaroundtheWiehle
Avenue
station
as
illustrated
in
Figure
2
21.
The
four
connectors
include:
K. IsaacNewtonSquareWestfromIsaacNewtonSquareSouthtothestationasanextension
oftheproposedSoapstoneConnector.
L. TheStationEntrance(alreadyplannedforimprovementsaspartofstationconstruction)
shouldbeextendedacrossWiehleAvenuetothePrivateDrivewayasfareastasSamuel
MorseDr.
M. MichaelFaradayCourtextensionfromthenewroadwaydescribedin(L)northtothe
extendedRogerBaconDrdescribedin(N)
N. Extension/improvementstoIsaacNewtonSquareSouthfromIsaacNewtonSquareWestto
WildlifeCenterDrive.
Itmaybepossibletoconstructorexpandseveralofthesenewconnectorsaspartofthedevelopment
processas
the
area
surrounding
the
Wiehle
Avenue
station
redevelops.
Proffers
and
other
development
toolscanbeusedtominimizetheexpensetotheCountyofthesefacilities.Dependingonthescaleand
patternofredevelopmentinthearea,thesectionsofcompletelynewroadwaythatwouldconnectto
WildlifeCenterDrivemaystillrequireasignificantCountyinvestment.
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AstheStudyAreacontinuestogrow,actionstotheroadwaynetworkwillbeneededtohelp
accommodatetheprojectedgrowth.Thefourteen(14)roadwayactionsidentifiedintheprevious
sectionarerecommended,aswellasthepedestrianimprovementsindentifiedinChapterIIIandthebus
serviceenhancementsdescribedinChapterIV.Thefullsetofimprovementswillhelptoimprove
mobilityforalltravelersinthestationareasregardlessoftheirmodeoftravel.Improvementstothe
pedestrian,bicycleandtransitnetworksarenecessarytohelpdiverttripsawayfromSOVstoother
modes.Tosupportthismodechoiceshift,thissectionrecommendssomepoliciesthatshouldbe
encouragedin
the
vicinity,
including
Travel
Demand
Management
and
Intelligent
Transportation
Systems.
By2030,congestionintheRestonareawillbeasignificantproblem.Roadwayexpansionand
improvementprojectswillnotbeabletoprovidethecapacitytoaccommodateallofthevehicle
demandduringthepeakperiods.TravelDemandManagement(TDM)strategiesareprogramsand
Figure221:PotentialLocalConnectors
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policiesestablishedwiththegoalofreducingthenumberofvehicletripsmadeduringthepeakperiods.
TDMstrategieshavebeenimplementedsuccessfullyinareasthroughouttheWashingtonregion,
includingthenewlyrevitalizedurbanareaaroundSilverSpring,MD.SuccessfulTDMactionswill
encouragethetravelertotakeoneormoreofthefollowingactions:
Changetimeoftravel.
Change
path
of
travel,
such
that
trips
not
destined
to
the
area
find
other
routes
and
avoid
the
congestion.
Changemodeoftravel,sometravelerswillchoosetousetransit,sharearideorwalk/bike.
Notmakethetripatall.
TheincreasedcongestionexpectedintheRestonareaby2030willforcemanycommuterstocarefully
considertheirtransportationoptionstofindthebestsolutionforthem.Itisnecessarytoprovideawide
arrayoftransportationoptionssothateachindividualcanfindthesolutionthatworksbestforthem
whilesimultaneouslyreducingthelevelofcongestionexperiencedduringthepeakperiods.Transit,
bicyclingandwalkingmustbemadeviableoptionswhereverpossible,asdetailedinChapters3and4.
TDMpoliciesandprogramssupportedbyFairfaxCountyandlocalinterestsinRestonmayincludeanyof
thefollowing:
Transitfare
subsidies;
Parkingfeesatofficebuildings;
Preferentialparkingforcarpools;
Flexibleworkschedules;
Telecommutingopportunities;
Onsitesalesoftransitfaremedia;
GuaranteedRideHomeprograms;
Ridematchingprograms;
Transitinformationonsite;
OnsiteTDMcoordinator;
Carsharing;
VanpoolSupport;
and
Onsiteshowerfacilitiesforbicyclists.
Whenmarketedandadministeredappropriately,thecombinedeffectsofalloftheseprogramscanhave
asignificantimpactonthenumberofSOVtripsthataremadeduringapeakperiod.Forexample,in
studiesrecentlyconductedfortheTysonsCornerarea4,ithasbeenestimatedthatanaggressiveTDM
programwillbeimportantinachievinganonSOVmodeshareof20%inthearea.
IntelligentTransportationSystems(ITS)usetechnologytoimprovethetravelexperiencebyproviding
additionalinformation,
removing
delays
or
creating
amore
comfortable
environment
for
the
trip.
The
fullrangeofapplicationsofITSisstillbeingdevelopedandmaychangesignificantlyby2030.However,
someapplicationsthatwillbeusefulintheRestoncommunitymayincludethefollowing:
Realtimebuslocators;
Realtimebusarrivalinformationfortransitpassengers;
4Fairfax County Comprehensive Plan, 2007 Edition.
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Signalpriorityfortransitvehicles;and
Realtimetrafficinformation.
Anadditionalstudywouldbenecessarytodeterminethebestapplicationsandlocationsfortheseand
otherforthcomingtechnologies.
Thischapterhasdetailedmanyprojectsandpoliciesthatarerecommendedfortheareassurrounding
theWiehleAvenueandRestonParkwayMetrorailstations.Theseactionswillhelpeasetraffic
congestioninthearea,improvecirculationforallmodesoftravelandprovideeasieraccessandegress
tothestationsthemselves.Eachoftheseprojectsmustcompetewitheachotherandwiththeother
improvementsrecommendedinlaterchaptersofthisreportforscarceresources,includingtimeand
funding.Detailedengineeringanalysishasnotbeenperformedonanyoftherecommendedprojects,
howeverplanninglevelcostestimateshavebeendevelopedbasedonsimilarprojectsthathavebeen
completedinthearea.
Timingwillbeakeyissueinimplementationoftheserecommendedactions,asthereisalotofworkto
bedone
in
alimited
timeframe.
Based
on
the
phased
opening
of
the
two
stations
in
this
study,
some
of
theimprovementswillbenecessaryforaccesstotheWiehleAvenuestation(scheduledtoopenfirst)
andotherswillberequiredfortheopeningoftheRestonParkwaystation.Stillotherprojectswillbe
necessaryinthelongruntoeaseexpectedcongestioninthearea.Thesectionsbelowprovidecost
estimatesforeachoftheproposedactionsandalistofprioritiesfortheroadwayprojects.Integrated
prioritiesbetweenallofthedifferentmodescanbefoundinChapter5.
Fourteenroadwayimprovementprojectshavebeenidentifiedinthischapterthatwillimprove
accessibilityaroundtheproposedWiehleAvenueandRestonParkwayMetrorailstations.Costwillplay
animportantroleintheimplementationoftheseprojects,asfundingmustbeassuredbeforeany
designor
construction
can
begin.
Potential
funding
sources
for
projects
recommended
throughout
this
reportcanbefoundinChapter5.Roughcostestimateshavebeendevelopedforeachofthe
recommendedprojectsinthischapter.Theseestimatesarein2007dollarsandpricesareexpectedto
increaseannually.
Table29showstheestimatedcostforeachtypeofroadwayimprovement,thequantityofeach
recommendedinthestudyareaandthetotalestimatedconstructioncost.Thesecostsincludethe
constructioncostsforeachitemandasubstantialcontingencyforrightofwaycosts,engineeringwork
andotherpotentialexpenses,howeveractualcostsmaybemoreorlessdependingonthe
circumstancesencounteredateachlocation.Majorutilityrelocationisnotincluded,asinformationon
existingutilitiesisnotknown.Utilityrelocationcanbeexpensive.Annualcostsformaintenanceand
operationhavenotbeenincludedintheseestimates.
Ifalloftherecommendedprojectswereconstructedin2007,thetotalcostwouldbeapproximately$70
milliondollars.Almosthalfofthattotal(49%)isassociatedwiththevariouscontingenciesandrightof
waycoststhatcannotbeascertainedatthistime.Byfarthemostexpensiveitemintherecommended
roadwayprogramistheconstructionoftheSoapstoneConnectorovertheDIAAH,withatotal
estimatedcostof$32millionforthebridgeitselfandanadditional$10millionforotherroadway
construction,whichismorethanhalfofthetotalprogramcost.Theroadwaywideningassociatedwith
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theinternalstreetgridisestimatedtocostanadditional$11million,whilethebuslanesonSunsetHills
Rdareexpectedtocostapproximately$8.1million.
Table29:EstimatedRoadwayImprovementCosts
RoadActions Units Quantity UnitCostContingency
PerUnit TOTAL
NewSignal
Installation
EA.
4
$319,500
$431,300
$3,003,200
Installnew,orimproveexistingturnbay EA. 8 $213,000 $287,600 $4,004,800
NewtravellaneonRestonParkway mile 0.38 $1,863,800 $2,516,100 $1,659,100
Addinternalroadwaylinks mile 1.28 $3,727,500 $5,032,100 $11,212,300
Improve/Widenroadwayfrom2to4lanes mile 0.66 $8,413,500 $6,478,400 $9,871,500
NewbridgeoverDIAAH sqft 56,000 $320 $250 $31,920,000
BusLanesonSunsetHillsRd mile 1.86 $1,863,800 $2,516,100 $8,146,600
TOTAL $69,817,500
AppendixAincludesthetotalestimatedcostforeachofthefourteenimprovements(AN)
recommendedinthischapter.
Eachoftheroadwayprojectsthatarerecommendedinthischapterisimportantinordertoprovidethe
bestpossibleaccesstotheWiehleAvenueandRestonParkwayMetrorailstations.Someimprovements
provideagreaterincreaseinaccessibilitythanothers,andarethereforeprioritizedmoreheavily.
Additionally,astheraillineisscheduledtobeopenedinRestonintwophases,thefirstprioritymustbe
placedonprovidingaccesstotheWiehleAvenuestation,whichwillbeopeninginthefirstphase.Table
210belowshowsthefourteenrecommendedroadwayprojectsaccordingtothepriorityforproviding
improvedaccessibilityintheimmediatestationvicinities.Thisprioritizationtablerecognizesthat
importancedoesnotalwaysmatchwitheaseofimplementationandthatsomeoftheveryimportant,
highpriorityprojects(suchastheSoapstoneConnector)arelargescaleprojectsthatwilltake
significantlylonger
than
smaller
projects
to
plan,
engineer
and
construct.
Still
others
may
be
lower
prioritysmallprojects,orprojectsthatcanbecompletedinassociationwithredevelopmentprojectsin
thearea.Whenopportunitiesarisetoimplementtheseactionstheyshouldnotbepassedbysimply
becausetheyarelowerontheprioritylisting.
Table210:RoadwayImprovementPriorities
Project Priority
Includedin
RecordOf
Decision Comments
B
Newleftturnlaneforwestboundleftturningmovementat
SunsetHillsRd&IsaacNewtonSq.Thiswouldreplacethe
sharedleftthroughlanebyprovidingadedicatedturnlane.
1st
Priority Yes
C
Addasecond
left
turn
lane
for
northbound
traffic
at
Wiehle
Ave&MetroAccess(betweenSunsetHillsRd&DIAAH)and
provideasecondinboundlane.
1st
Priority Yes
DAddanadditionalleftturnlaneontheeastboundDIAAH
rampatWiehleAve
1st
Priority Yes
EImprovetheexistingrightturnlaneoneastboundSunset
HillsRdatWiehleAve
1st
Priority Yes
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Includedin
RecordOf
Decision Comments
FImprovetheexistingrightturnlaneforwestboundSunrise
ValleyDratWiehleAve
1st
Priority Yes
I
Provideanew
connection
over
the
DIAAH
between
SoapstoneRdandIsaacNewtonSqW,toconnectthe
majoreastwestroadways:SunsetHillsRd&SunriseValley
Dr.
1st
Priority No Longtermimprovement
K
IsaacNewtonSquareWestfromIsaacNewtonSquare
Southtothestationasanextensionoftheproposed
SoapstoneConnector.
1st
Priority No
ANewsignalandturnlanesonSunsetHillsRdforaccessinto
theproposedRestonParkwayMetrorailstation
2nd
Priority Yes
G
AddnorthboundthoughlaneonRestonParkwayatSunrise
ValleyDr,continuingthelanetotherampforeastbound
DIAAH
2nd
Priority Yes
HImprove
the
right
turn
lane
for
southbound
Reston
Parkway
atSunriseValleyDr2
nd
Priority Yes
JProvidebuslanesonSunsetHillsRdfromWiehleAvetoOld
RestonAve
3rd
Priority No Longtermimprovement
L
TheStationEntrance(alreadyplannedforimprovementsas
partofstationconstruction)shouldbeextendedacross
WiehleAvenuetothePrivateDrivewayasfareastas
SamuelMorseDr.
3rd
Priority No
Tobeconstructed(if
possible)inassociation
withredevelopment
M
MichaelFaradayCourtextensionfromthenewroadway
describedin(L)northtotheextendedRogerBaconDr
describedin(N)
3rd
Priority No
Tobeconstructed(if
possible)inassociation
withredevelopment
NExtension/improvements
to
Isaac
Newton
Square
South
fromIsaacNewtonSquareWesttoWildlifeCenterDrive.
3rd
Priority No
Tobeconstructed(if
possible)in
association
withredevelopment
AlloftherecommendedprojectsthatwereincludedintheRecordofDecision(ROD)aremitigation
effortsrequiredaspartoftheconstructionoftherailproject.Theseprojectswillnotbepaidforby
FairfaxCountyandshouldallbeconstructedinconjunctionwithPhaseIoftherailproject.Basedon
thisstudy,thoseRODprojectsthataredirectlyadjacenttotheWiehleAvenuestationaredesignatedas
firstprioritybecausethisstationwillopenfirst.Inaddition,theSoapstoneConnectoranditsextension
acrossSunsetHillsRdtoIsaacNewtonSquarearealsorankedas1stpriorityprojectforthesame
reasons.SecondpriorityprojectsarethosewhichimproveaccessprimarilytotheRestonParkway
station.Thethirdprioritygroupingisreservedforprojectsthatwillhelprelievesomeofthecongestion
thatis
expected
on
along
term
basis
in
the
station
areas.
Amultimodalprioritylistingthatincorporatestheaboveprioritiesandalsoincludesallofthemodes
studiedinthisplanisthemainsubjectofChapter5.