ContentslistsavailableatjournalhomepagewwwelseviercomlocateecotraEconomicsofTransportation 22120122seefrontmatter2013ElsevierLtdAllrightsreservedhttpdxdoiorg101016jecotra2013120 ID: 290413
Download Pdf The PPT/PDF document "Implementingtechnologytoimprovepublichig..." is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Implementingtechnologytoimprovepublichighwayperformance:AleapfrogtechnologyfromtheprivatesectorisgoingtobenecessaryCliffordWinston,FredManneringBrookingsInstitution,USAPurdueUniversity,USAarticleinfoKeywords:HighwaysOptimalpricingandinvestmentTechnologyDriverlesscarsPolicymakerscouldimplementavailable,well-testedtechnologiestoimprovetheefciencyofhighwaypricing,investment,andoperations,whichwouldimprovetravelspeeds,reliability,andsafetyandreducehighwayexpenditures.Unfortunately,politicalandbureaucraticimpedimentstoimplementsuch Contentslistsavailableatjournalhomepage:www.elsevier.com/locate/ecotraEconomicsofTransportation 2212-0122/$-seefrontmatter2013ElsevierLtd.Allrightsreserved.http://dx.doi.org/10.1016/j.ecotra.2013.12.004 MohringandHarwitz(1962)developedamodelofefcientlong-runpricingandinvestmentrulesforhighwaysthatprovidedthefoundationforresearchinthisarea.Recentmodelsofhighwaypricingandinvestmenthaveaccountedfordemanduncertainty,lumpyinvestment,heterogeneoususers,andsoon(Lindsey,2012 Pleasecitethisarticleas:Winston,C.,Mannering,F.,Implementingtechnologytoimprovepublichighwayperformance:Aleapfrogtechnologyfromtheprivatesectorisgoingtobe....EconomicsofTransportation(2014),http://dx.doi.org/10.1016/j.ecotra.2013.12.004 EconomicsofTransportation thatincreaseefciencyhavetakenonrenewedimportanceintodayslow-growtheconomy.Unfortunately,theaforementionedpoliticalandinstitutionalimpedimentsalsoapplytoimplementingnewtechnologyonpublichighwaysandtheyareunlikelytobeovercomeinthenearfuture.However,theprivatesectorisdevelopingnewtechnologi-calinnovations,especiallythedriverlesscar,whichwilleventuallyleapfrogthetechnologythatthepublichighwayauthoritiescouldandshouldimplementtoday,thusprovidingroaduserswithmostofthepotentialbenetsfromtechnologicaladvancesinhighwaytravel.2.HighwaycharacteristicsandtechnologiesthatcouldimproveperformanceHighwaysprovidecapacitytoallowaowofdifferenttypesofvehicles,includingpassengercars,buses,andheavytrucks,totravelsimultaneouslyandtheyaredesignedtoprovideaspeciedlevelofdurabilitytobeartheweightofdifferentvehicles,particularlyheavytrucks,andtoresistsurfacewearandstructuraldamagetopavementsandbridges.Technologiesthathelpexpandcapacityandincreasedurabilitycanincreasetheowoftrafcandtheeffectivelifetimeofahighway(beforeresurfacingorreconstructionisneeded).Capacityisafunctionofspeedlimits,thenumberandwidthoflanesandshoulders,andotherfactors;itisreachedwellaftertheroadhasbecomecongested.Economistscharacterizecongestionasoccurringwhenvehiclespeedsdeclinefromfree-owspeed,whichistheobservedspeedwhentrafowislight.TheTransportationResearchBoard(2010)hasdeterminedthatfree-wayshaveacapacityof2400passenger-cars/hr/lanewithafree-owspeedof70mi/hrwhilefreewayshaveacapacityof2250passenger-cars/hr/lanewithalowerfree-owspeedof55mi/hr.Asgreatertrafcvolumecausestheroadscapacitytoeventuallybereached,speedsonthosefreewaysfallto53.3miles/hrand50miles/hr,respectively.Additionaltrafcthencausestheden-sityofvehiclestoexceedfreewaycapacitycreatinganunstableow,whichischaracterizedbystopandgotrafc.Trafengineersdenethisoutcomeashyper-congestedconditions,whichtravelspeedscandeclinerapidly.Forfreeways,theprecedingtravelconditionsaresummarizedFig.1intermsoftherelationshipbetweenspeedandtraf(inpassenger-cars/hr/lane).Thespeed-owrelationshiphasbeenshownempiricallytobeparabolic;thus,twospeedsaregenerallypossibleforeverygivenow:oneinuncongestedorcongestedconditions(trafcdensitieslessthanorequalto45passenger-cars/mile/lane);theotherinhyper-congestedconditions(trafdensitiesgreaterthan45passenger-cars/mile/lane).Forthesameleveloftrafow,theportionofthecurveinhyper-congestedconditionsresultsinamuchslowertrafcspeedthandoestheportionofthespeed-owcurveinuncongestedorcongestedconditions.Transportationofcialsinmanymetropolitanareasattempttopreventmotoristsfromexperiencinghyper-congestedconditionsonfreewaysby,forexample,puttingstopandgosignalsonon-rampstoslowtheowofadditionaltrafDurabilitydependsonpavementthickness,materialcomposi-tion,andotherfactorssuchasdrainageandclimate,aswellasonthebridgedesign.Pavementsbecomewornasthecumulativenumberofvehiclespassingoverthemrises,andtheyeventuallyrequireresurfacingorreconstruction.Damagecausedbyavehicletothepavementdependsonitsweightperaxle,ratherthanonitstotalvehicleweight.Thedamagecausedbyanaxleisdenedintermsofthenumberofequivalentsingle-axleloads(ESALs)causingthesamedamage;thestandardisasingleaxleof18,000pounds.SmallandWinston(1988)foundthatthedamagecausedbyaheavily-loadedvehicleriseswiththethirdpowerwithitsload.Almostallpavementdamagetendstobecausedbytrucksandbusesbecause,forexample,therearaxleofatypical13-tontrailercausesover1000timesasmuchpavementdamageasthatofacar.Bridgesbecomestressedasthecumulativenumberofheavyvehiclespassingoverthemincreasesandtheyneedtoberehabi-litatedbeforetheyexperiencecatastrophicfailure,asintheMinneapolisincidentin2007thatresultedfromadditionalvehicleweightonabridgethatexacerbatedadesignaw.Thebridgewearthatiscausedbyatruckdependsonitstotalvehicleweight,roughlyinproportiontoitsthirdpower(Mosesetal.,1987Privateandpublicenterprisesenhancetheirefciencybyimplementingtechnologiesthataretheproductsoftheirresearchandthathavebeendevelopedbyotherentities.TheFederalHighwayAdministration(FHWA)appearstohaveforeclosedtherstoptionbecauseitsbudgetdevotesonlyasmallamountoffundsforresearchanddevelopment.Specically,$400millionofitsroughly$40billionscalyear2013budgetisallocatedunderresearchprograms,butonlyhalfofthatamountactuallyfundspromisingresearchanddevelopment.Incontrast,FHWAsadmin-istrativeexpensesexceed$450million.Newgeneralpurposecommunicationtechnologies(andTrajtenberg,1995)aswellasspecichighwayandvehicletechnologiesgivehighwayauthoritiestheopportunitytomakemoreefcientuseofthecurrentvehicle-carryingcapacityanddurabilityofpublichighwaysbysettingaccuratemarginalcostpricesforroadusersandbyadjustinginvestmentsandoperationstorespondtoreal-timevariationsinhighwaytraveldemand.Generalpurposetechnologiesincludeglobalpositioningsystem(GPS)satellitenavigationservicesthat,amongotherthings,collectinformationaboutmotorists,suchastheirlocationandspeed,andthatcansuggestalternativeroutingsfortheirjourneys;Bluetoothsignalsthatcanbedetectedtomonitorthespeedofcarsandtrucksthroughouttheroadsysteminrealtimeinordertoassistdriversroutechoicedecisionsandtoadjusttrafcsignaltiming;andmobilesoftwareapplications(apps)andwebsitesthatprovidemotoristswithreal-timeinformationaboutdrivingconditionsthroughoutahighwaynetworkandaboutavailableparkingspaces.MotoristsarebecomingincreasinglyawareofthebeneofGPSsystemsthatprovidereal-timetrafcinformation;accord-ingly,theshareofcarsontheroadthatareequippedwiththose Speed (miles/hour) Free-flowspeed 0 Roadway conditions Uncongested conditions(Speed = Free-Flow Speed) Density = 45 passenger-cars/mile/lane Congested conditions(Speed ) Fig.1.Illustrationoftheparabolicspeed-owrelationshipforfreeways. Atcapacity,densityforfreewaysis45passenger-cars/mile/laneregardlessofowspeed(ManneringandWashburn,2013;TransportationResearchBoard,2010 guresarefromhttp://www.fhwa.dot.gov/map21/ha.cfmC.Winston,F.Mannering/EconomicsofTransportation Pleasecitethisarticleas:Winston,C.,Mannering,F.,Implementingtechnologytoimprovepublichighwayperformance:Aleapfrogtechnologyfromtheprivatesectorisgoingtobe....EconomicsofTransportation(2014),http://dx.doi.org/10.1016/j.ecotra.2013.12.004 servicesisexpectedtoclimbfrom10percentasof2013to50percentby2015.chighwayandvehicletechnologiesincludeweigh-in-motioncapabilities,whichprovidereal-timeinformationtohighwaycialsabouttruckweightsandaxlecongurationsthattheycanusetosetefcientpavement-wearchargesandtoenforcesafetystandardsciently;adjustablelanetechnologies,whichallowvariationsinthenumberandwidthoflanesinresponsetoreal-timetrafows;newvehicleattributes,suchasautomaticvehiclebrakingthatcoulddecreasevehicleheadwaysandthusincreaseroadwaycapacities;improvedconstructionanddesigntechnologiestoincreasepavementlifeandtostrengthenroadsandbridges;andphoto-enforcementtechnologiesthatmonitorvehiclesspeedsandmakemoreefuseofroadcapacitybyimprovingtrafowsandsafety.3.TechnologiestoimprovepricingandtoreformtrucksizeandweightlimitsGasolinetaxes,whicharecurrentlyusedtochargemotoristsandtruckersforhighwaytravel,donotvaryappropriatelywiththeirvehiclescontributionstocongestionorwithtruckaxle-weightsthatcontributetopavementwear.Thusthehighwayauthorityshouldsetcongestiontollsandchargesforpavementandbridgeweartoclosethegapbetweenthesocialandprivatecostsofhighwaytravelandtomakemoreefcientuseofavailablehighwaycapacityanddurability.Untilrecently,however,highwayauthoritieshavenothadsatisfactorytechnologytodetermineandefcientlycollectaccu-ratechargesformotoristsandtruckersroaduse.Vickrey(1963)initiallyproposedtoimplementcongestionpricingbyequippingallcarswithanelectronicidentierthatwouldbescannedbyroadsideequipment.Butthetechnologyhadquestionableaccu-racyatthetimeandinvolvedsubstantialtransactionscostsofcreatingrecordsthatwouldbeassembledintobillsthatwouldbemailedtomotoristsforpayment.Today,technologyisavailableforhighwayauthoritiestoeliminatethetransactionscostsassociatedwithhumantollcollectorswhoarestillusedonsomeroadsandtocollectaccuratecongestion,pavement,andbridgewearchargeselectronicallyatlowcosttothemandroadusers.3.1.CongestionpricingBecausefederalpolicymakershavebeenunwillingtoseriouslyconsiderraisingfueltaxes,theyhavebeendesperatelytryingtoadditionalsourcesofhighwayfundingtonanceconstructionofnewroadsandadditionallanes.ButasweknowfromDowns(1962)peak-hourcongestionrisestomeetmaximumcapacitybecauseoflatentdemandthatis,travelerswhousedlesspreferredroutes,modes,andtimesofdayshifttothenewlyconstructedthorough-fares.DownsLawwouldnotapply,however,ifpolicymakerssettollsthatadjustedinreal-timetotrafowsandcongestionbecausesomemotoristswhopreviouslyavoidedhighlycongestedhighwaysandlocalstreetswouldbediscouragedfromusingthosethorough-faresbytheirinitialtolls,whileotherswouldbediscouragedbyhighertollsiftrafcbecamemorecongested.Theinformationalrequirementstosetanoptimalcongestion(onhighwaylinkinaroadnetworkconsistingoflinks)canbegleanedfromitsmathematicalexpression.Foragivenvolumeoftrafperunitoftime,thetollthatahighwayauthorityshouldsetisexpressedas(Lindsey,2012 istheusercostfunction,whichincludestheprivatecostsofatrip,suchasfuelconsumptionandothervehicleoperatingcostslikedepreciation,aswellastraveltimecosts,andisthesvehicle-carryingcapacityperunitoftime.ThehighwayauthoritycandeterminethetrafcvolumeonacstretchofroadduringagiventimeintervalbyusingGPSnavigationservicesandthendrawonplausiblecostestimatesthatareavailableintheempiricalliterature(e.g.,SmallandVerhoef,2007)tosetthespeciccharge,whichitcancommunicatetomotoristsontheirappsbeforetheyreachthetollingareasotheycandecidewhethertotakethetolledroutebasedontheirpreferredcombinationofout-of-pocketcostsandtraveltime.Thosemotoristswhodosowouldhavetheirhighwayaccountreducedbytheamountofthechargeelectronicallyviatheirvehicletransponders,withouttheirjourneysbeingdisruptedortheirprivacyinvaded.Insum,byimplementingavailabletech-nologies,ahighwayauthoritywouldhavethenecessarytrafinformationtosetefcienttollsthroughoutthedayandmotoristswouldbeabletoobtainthepricingandroutinginformationthattheywouldneedtooptimizetheirjourneys.LangerandWinston(2008)estimatedthatbysubstantiallyreducingbutnoteliminatingdelaysandbyreducingresidentialsprawl(becausetheout-of-pocketcostsofcommutingwouldnolongerbeunderpriced),congestionpricinginmajormetropolitanareascouldgenerateannualgainsof$40billion,accountingforthetraveltimesavingsforcommuters,savingsfortaxpayersfromlowercostsofpublicservicesfromgreaterresidentialdensity,andgreaterrevenuestothegovernment.Byalsoimprovingtravel-timereliability,whichSmalletal.(2005)havefoundtobevaluedbymotoristsasmuchastheyvaluereductionsinaveragetraveltime,thebenetsfromcongestionpricingwouldbeevengreater.Informationtechnologycouldalsofacilitateefcientpricingofhighwayshouldersandcurbparking.Becauseautomakershavecontinuedtoimprovevehiclereliabilityinrecentyears,break-downsrarelyoccurtodayandthebenetstomotoristsfromopeningashouldertoincreasehighwaycapacityandreducecongestionarelikelytoexceedthecostoflimitingspaceforvehicleincidents.Togetafeelforthepotentialbenets,weusetheBureauofPublicRoads(BPR)formula,whichdeterminestraveltimeonaroadaccountingfordelaysduetocongestion.TheBPRformulashowsthatopeningashouldertotrafc(inthepeaktraveldirection)onafour-lanefreewaythatnormallyoperateswithatrafowof90%ofhighwaycapacitywouldreducemotoriststraveltimebyroughlyone-third(ManneringandWashburn,2013Pricingtheshoulderefcientlywouldproduceadditionaltraveltimesavings.Asnoted,motoristscoulduseanapptohaveknowledgeinadvanceofwhethertheshoulderwasopentotrafcandthepricetodriveonit. ThisforecastisfromJimBakofInrix,aprovideroftrafcsoftwareanddata,asreportedinSteveHargreaves,YoureGettingStuckinTrafcLess,CNNMoneyFebruary5,2013.Fleming(2012)arguesthatthecollectioncostsofelectronictollingarequitelow,inthevicinityof5%oftherevenuecollectedusingprovenmethodsandtechnology. Tomaintainprivacy,thehighwayauthoritycouldsendmotoristsamonthlysummaryofthedeductionsfromtheiraccountwithoutanyinformationindicatingthetimeandthepartofthehighwaytheyused.Small,Winston,andYanfoundthatthevaluethatmotoristsplaceonthestandarddeviationoftraveltime(orthedifferencebetweentwofractilesofthedistributionoftraveltime)wassimilartothevaluetheyplaceonaveragetraveltime.TheBPRformulafortraveltimeonahighwaylinkisgivenbybyþ(vl/Kl)],whereisthetraveltimeonhighwaylinkinminutes;isthefree-owtraveltimeonthislinkinminutes;isthetrafcvolumeonthelinkinminutes;isthecapacityofthelinkinvehiclesperhour;andandareparametersthatrespectivelytakethevaluesof1.1491and6.8677forfreeways.MinneapolishasbeguntoexplorethispolicybyintroducingdynamicpricedshoulderlanesonInterstate35.C.Winston,F.Mannering/EconomicsofTransportation Pleasecitethisarticleas:Winston,C.,Mannering,F.,Implementingtechnologytoimprovepublichighwayperformance:Aleapfrogtechnologyfromtheprivatesectorisgoingtobe....EconomicsofTransportation(2014),http://dx.doi.org/10.1016/j.ecotra.2013.12.004 Forthemajorityoftheirtrips,includingworktrips,motoristsfacesub-marketpricesforon-streetparking;thus,theyincursearchcoststhemselveswhenlookingforparkingspaceswhilealsoimposingcantcostsonotherdriversbyaddingtocongestiononsurroundinglocalstreets(Shoup,2005).Fieldstudiessuggestthatasmuchasone-thirdoftrafcinsomepartsofNewYorkCityandLosAngelesisattributabletodriverscirclingastheyhuntforvacantparkingspacesandextrapolationsfromthosestudiessuggestthatnationwidecostsareinthebillionsofdollars.cientpricingforparkingspacesreducescongestiononlocalstreetsbyreducingmotoristsincentivetosearchforscarceon-streetspaces(whichisspurredbythepricedifferencebetweenunder-pricedon-streetandcostlyoff-streetparking),andbyincreasingtheturnoverofstreetspaces,whichreducesthesearchtimerequiredtondavacantspace.Asbefore,GPSnavigationservicescoulddeterminetrafclevelsonlocalstreets;basedonthattrafc,realtimepricescouldbesetatparkingmeters;andmotoristscoulduseappstodeterminetheavailabilityofparkingspacesandtheirprices.SanFrancisco,Chicago,andLosAngelesarecurrentlyconductingexperimentsthatsetpricesforon-streetparkingthatvarybylocationandtimeofday,whilealsomakinginformationonmeterratesandvacantspacesavailableinrealtime.PierceandShoup(2013)provideevidencethatSanFranciscospilotpricingprogramisallocatingparkingspotsmoreefcientlybynarrowingthevariationinon-streetparkingoccupancyratesacrossthecity.3.2.PavementandbridgewearpricingBecausepavementdamageisrelatedtoatrucksweightperaxleandbridgestressisrelatedtoatruckstotalweight,efhighwaypricesfortrucksshouldencouragetruckerstoreducethoseweightswheneverpossible.Anefcientshort-runmarginalcostpavement-wearcharge,,encouragestruckerstoreducetheirESALs.Theinformationalrequirementstosetthischargecanbegleanedfromitsmathematicalexpression,whichisgivenperESALmileas(SmallandWinston,1988 isaparameter,)isthecostofresurfacingahighwayofwidth,asmeasuredbythenumberoflanes,and)isthelifetimeofaroadofdurability,asdeterminedbythenumberofESALsthatcanpassoveritbeforeitmustberesurfaced.AhighwayauthoritycanestimateatrucksESALmilesbyusinghigh-speedweigh-in-motion(WIM)technologies.WIMusessen-sorsthatareinstalledinoneormoretrafclanestoidentifyavehicleandrecorditsnumberofaxles,vehicleload,andjourneywhileitcontinuestotravelinthetrafcstream(Jacob,2010).ThetotalchargewouldthenbesenttothetrucksownerastheproductofthetrucksESALmilesandaplausibleestimateoftheresurfacingcostsperESALmile.Smalletal.(1989)estimatethatreplacingthefueltaxwithanaxle-weight(marginalcost)chargewouldencouragetruckerstoshifttovehicleswithmoreaxlesthatdolessdamagetoroadpavements,therebyreducingmaintenanceexpendituresandproducingannualwelfaregainsexceeding$12billion(in2013dollars).WIMcouldalsobeusedtomeasuretheconsiderablestresscausedbytruckscrossingabridge(NationalCooperativeHighwayResearchProgram,2003)andtodetermineefcientbridge-wearchargesasafunctionofvehicleweightandbridge-age;thelatteruenceisimportantbecauseolderbridgesbecomemoresus-ceptibletoheavyloadsasaresultofmetalfatigueandpossibleage-relateddeteriorationofconcretereinforcingbars(BarkerandPuckett,2007).Basedontheirplannedroutings,truckscoulddeterminetheirchargesonlineandreducethembyeitherredu-cingtheirloadsorbytakingalternativeroutingstoavoidhigher-pricedbridgecrossings.Asaresult,bridgeswouldlastlongerandthelikelihoodofunexpectedcatastrophicbridgefailure,expensiverepairs,andthelossoflifewouldbeless.3.3.TrucksizeandweightlimitsTrucksizeandweightlimitshavebeenestablishedtokeeptrucksthatmightcauseexcessivepavement/bridgedamageandjeopardizesafetyoffofcertainroads.Atthesametime,thoselimitsraisethecostsoftruckingoperationsbyrequiringtruckerstodisrupttheirjourneystostopatweighstationsforvehicleinspections,andbyforcingtruckingcompaniestousesmallertruckstomakeadditionaltripstomovethenationsfreight.WIMtechnologieswouldenablehighwayauthoritiestoaccuratelymonitortrucksizesandweights,whichwouldeliminateinspec-tionsatweighstations.Andinformationtechnologythatfacilitatesmoreefcienthighwaypricingcouldspurvehicledesignimprove-ments,suchasstrongerbrakesthatwouldallowtruckingcompa-niestouselargertruckswithmoreaxlestoreduceaverageoperatingcostswithoutcompromisingsafety.McKinnon(2005)providessomeillustrativeevidencefromtheUnitedKingdomthatrelaxingtrucksizeandweightlimitscouldcantlyincreasetruckingproductivityandreducesocialcosts.Heestimatedthatincreasingmaximumtruckweights6700lbs(amodest7.3percentincreaseoverthepreviousweightlimits)resultedintrucking-industryannualoperating-costsavingsofnearly$250million(in2013dollars),andbysignicantlyreducingvehicle-milestraveled,reducedcongestionandgreenhousegasemissions.Similarly,theU.S.surfacefreighttransportationsystemstandstoincreaseitsefciencywithoutnecessarilyincreasingthecostsoftruckingaccidentsbyimplementingtechnologythatpermitsmoreexibleandhighertrucksizeandweightlimits.4.Technologiestoimprovehighwayinvestmentsincapacityanddurabilityrstblush,investmentstoexpandhighwayvehicle-carryingcapacityandtoincreasedurabilityappeartobeveryexpensiveundertakings.Buttechnologycouldbeimplementedtoenablecertaininvestmentstoimprovethosehighwaycharacteristicsatmodestcost.NgandSmall(2012)pointoutthatmosthighwaysinmajormetropolitanareasoperateincongestedconditionsduringmuchoftheday,yethighwaydesignstandardsarebasedonfree-travelspeeds.Highwayauthoritiescouldeffectivelyexpandcapa-cityduringpeaktravelperiodstoreducedelaysbyadjustingthenumberandwidthoflanesonafreewayinresponsetoreal-timetrafcvolumesthataremeasuredbyGPSnavigationservices.Thustoenablevehiclestomovefaster,heavytrafcvolumeswouldcallformorebutnarrowerlanes,whilelightertrafcvolumeswould AsreportedinTheNewScienceofParking,July9,2007,Transporta-tionAlternatives,aNewYorkadvocacygroup,conducteda2006eldstudyof15blocksintheupperwestsideofNewYorkCityandProfessorDonaldShoupofUCLAconductedastudyofWestwoodVillageinLosAngeles.Thestudiesestimatedthatmotoristssearchforon-streetparkingoveraoneyearperiodinthoselocationsrespectivelygenerated366,000and950,000additionalvehiclemilestraveled.GiventhethousandsoflocationsthroughoutU.S.metropolitanareaswheresuchsearchoccursandapplyingSmallandVerhoefs(2007)estimateofthesocialmarginalcostofavehiclemileof$1.08,suggestsanestimateofparking-searchcostsintheUnitedStatesinthebillionsofdollars. Truckershaverespondedtohigheroperatingcostsbyadoptingimprove-mentsinvehicledesign.Forexample,inresponsetohigherfuelprices,sometruckersincreasedtheirvehiclesfueleconomybyusingtheTrailerTail,developedbyATDynamics,toreducetheaerodynamicdraggeneratedattherearofatrailer.C.Winston,F.Mannering/EconomicsofTransportation Pleasecitethisarticleas:Winston,C.,Mannering,F.,Implementingtechnologytoimprovepublichighwayperformance:Aleapfrogtechnologyfromtheprivatesectorisgoingtobe....EconomicsofTransportation(2014),http://dx.doi.org/10.1016/j.ecotra.2013.12.004 callforfewerbutwiderlanes.Technologyexiststoinstalllanedividersthatcanbeilluminatedsothattheyarevisibletomotorists,andthatcanalsobeadjustedinresponsetotrafcvolumestoincreaseordecreasethenumberoflanesthatareavailable.Asnotedinthecaseofopeningahighwayshouldertotrafc,creatinganadditionallaneduringpeaktravelperiodswouldresultinsubstantialtraveltimesavingsformotorists.Andalthoughitwouldbeeasierandlesscostlytoinstallvariablelanewidthsfornewroadsthanforexistingroads,implementingthistechnologywheneverpossiblewouldbelessexpensivethanconstructinganadditionallanethatmeetsstandardwidthrequirements,especiallyforfreewaysindenseurbanareaswherelandisscarceandaddingtoroadcapacityisaveryexpensiveproposition.Therapidevolutionofmaterialscience(includingnanotechnolo-gies)hasproducedadvancesinconstructionmaterials,constructionprocesses,andqualitycontrolthathavesignicantlyimprovedpave-mentdesign,resultingingreaterdurability,longerlifetimes,lowermaintenancecosts,andlessvehicledamagecausedbypotholes.Forexample,Littleetal.(1997)estimatedthattheSUPERPAVEeffortinthelate1980sand1990s(TransportationResearchBoard,2005),whichdevelopednewasphalticbinderspecicationsforrepaving,producedroughly$0.6billion(in2013dollars)insuchbenets.Otherinvest-mentsthatapplyrecentadvancesinmaterial-sciencetechnologiesarealsopossible,buttheyareoftendelayedbecausestateDepartmentsofTransportationtrytominimizetheirexpendituresratherthanthesumofthoseandhighwayuserscostsandbecausetheyawardcontractsonthebasisoftheminimumbid,notonthetechnologicalsophistica-tionofthecontractor(Winston,2010Finally,stateDepartmentsofTransportationhavebeenslowtoimplementadvancesinroadwaystructuralmonitoringtechnolo-giesthatwouldallowthemtomonitorthehealthofbothpavementsandbridgesonacontinuousbasis,providingvaluableinformationforoptimalrepairandrehabilitationstrategiesthatcouldreducethecostofhighwayservices(Lajnefetal.,20115.HighwayoperationsthataffectsafetyThelargebenetsofhighwaytravelhavebeentemperedbytherecurringsocialcostsofvehicleaccidents,whichhavebeenestimatedbyCambridgeSystematics(2011)toberoughly$300billionformajorurbanareasin2009.Bothautomakersandhighwayauthoritieshaveattemptedtoreducethosecosts.Auto-makershavecontinuedtomakeautomobilessafersincetheyintroducedthemtothepublicbyimprovingvehicledesignandstructuralstrengthening,installingseat-belts,anti-lockbrakes,andairbags,andthelike.Recentsafetyinnovationsincludeelectronicstabilitycontrol,warningandemergencybrakingsys-tems,speedalerts,andmirrorswithblindspotwarnings,whichwillalsoincreaseroadcapacitybyenablingvehiclestotravelclosertogetherwithoutcompromisingspeed.Policymakersandhighwayauthoritieshaveattemptedtopromotesafetybysettingspeedlimits,institutingtrafcsignals,enforcingtrafclaws,andrespondingtotrafcincidents.Technologiescouldbeimplemen-tedtoimprovetheeffectivenessofthoseactions.LaveandLave(1999)concludedthatCongressionalactionthatsetanationalmaximumspeedlimitof55miles/hin1974,butsubsequentlyabolisheditin1996andallowedstatestosettheirownmaximumspeedlimits,showedthathigherspeeddoesnotnecessarilykill.Instead,theyconcludedthatitshowedlivescouldbesavedbysettingspeedlimitsthatpeoplewouldobeybecausetheywerealignedwithdrivingconditions.Accordingly,highwayauthoritiescouldimplementtechnologytoimprovesafetyandreducetraveltimesbysettingvariablespeedlimits(VSLs)thatareproperlyalignedwithreal-timetrafowsandotherdrivingconditionssuchasweather.Papageorgiouetal.(2008)foundthatVSLsdisplayedonroadsidevariablemessagesignshaveledtosubstantialimprovementsinsafetyinmanycountries;evidencethattheyimprovehighwaysafetyintheUnitedStatesalsoexistsWashingtonStateDepartmentofTransportation,2007ThetrafccontrolsysteminmostU.S.citieswasdevelopedbyinexperiencedpublicofcialswhentheautomobilewasanewmodeoftransportation.Todd(2004)pointsoutthatinmanydrivingsituations,all-waystopsandroundaboutswouldbemoreeffectivethantrafcsignalsinreducingmotoristandpedestrianfatalities,aswellasinreducingtrafcdelays.Toaddtotheproblem,poorsignaltimingandcoordination,oftencausedbyoutdatedsignalcontroltechnologyorrelianceonobsoletedataonrelativetrafcvolumes(AtkinsonandCastro,2008),contributestosome300millionvehiclehoursofannualdelayonmajorroadwaysNationalTransportationOperationsCoalition,2007).Technologythatenablestrafcsignalstorespondtoreal-timetrafowsbyoptimizingthedurationoftrafcsignalsandtheuseofashing-redsignalsatintersectionswhentheyarelightlyusedandbyprovidingawarningsignaltostoppedmotoristsatintersectionsofanimpendinggreenlighttoreducestart-updelayscouldbemorewidelyappliedtoenhancesafetyandreducetraveltimes.Start-updelaysamounttoabout6percentofthetimethatatrafc-signalisgreenatatypicalintersection.ManneringandWashburn(2013)estimatethatcuttingthosedelaysinhalfcouldreducethedelayscausedbysignalsnearly20percent,withlittleeffectonsafety.Finally,thecostsofenforcingtrafcsafetylaws,whichincludehigh-speedpolicechasesthatoccasionallyresultinfatalaccidents,couldbesubstantiallyreducedbyusingphoto-enforcementtech-nology(roadsidecameras)toidentifyandissuecitationstomotoristswhorunstopsignsortrafcsignals,orwhoexceedthespeedlimitbyapredeterminedamount,suchas15miles/h.Shinetal.(2009)evaluatedanexperimentinArizonaandfoundthatautomatedspeedenforcementononlya6.5milestretchoffreewayinScottsdalereducedenforcementcostsasmuchas$17millionperyear.Vehicleincidents(accidentsanddisablements)accountforalargeshareoftrafccongestionandtheycanbeverycostly.GarrisonandMannering(1990)estimatedthattheaverageper-minutecostintraveltimedelaysofanincidentonSeattlefreewayswas$3500(in2013dollars).Highwayauthoritiescouldmakemuchgreateruseofcommunicationstechnologytoreducethosecostsandhelpaccidentvictimsreceiveassistancemorequicklybydetectingdisruptionsintrafowsandspeedsthatindicateanincidenthasoccurred.Incidentresponseteams,includingtowtruckstoremovethedisabledvehicle(s),couldthenbequicklyalertedanddispatched,whilemotoristsontheroadcouldbeedofdisruptionsandadvisedtoavoidthetroubledareaandtomakewayforresponseteamsthatareaddressingtheproblem.Wilde(2013)estimatedthataone-minuteincreaseinresponsetimecouldincreasethevictim-mortalityrateasmuchas17percent; Currently,highwaydesignstandardsassumethatthecapacityofafreewaywitha70miles/hfree-owspeedis2400passengercarsperhourperlane(withaspeedatcapacityof53.3miles/h),whichisbasedontheobservationthatdriverstypicallyleaveroughly100feetwhenfollowinganothercaratthatspeed.Technologies,suchasthosenotedinthetext,whichcouldhalvethatdistancewouldresultinasubstantialincreaseincapacitytoroughly4300passengercarsperhourperlane(assuminganaveragecarlengthof16.5feet). Photo-enforcementtechnologyhasencounteredlegalchallengesinsomebutnotallstates.TheFederalHighwayAdministrationputstheshareashighas25percent,http://ops.fhwa.dot.gov/program_areas/reduce-non-cong.htm,whiletheTexasTransportationInstitutesUrbanMobilityReportputsthesharecloserto50http://mobility.tamu.eduC.Winston,F.Mannering/EconomicsofTransportation Pleasecitethisarticleas:Winston,C.,Mannering,F.,Implementingtechnologytoimprovepublichighwayperformance:Aleapfrogtechnologyfromtheprivatesectorisgoingtobe....EconomicsofTransportation(2014),http://dx.doi.org/10.1016/j.ecotra.2013.12.004 hence,reducingresponsetimescouldpotentiallysavethelivesofmanymotoristsinvolvedinaccidents.6.ImpedimentstoimplementinghighwaytechnologyTechnologicalinnovationshavelongbeenrecognizedasamajorsourceofeconomicgrowthandimprovedlivingstandards,butanalystshavebeenhard-pressedtoexplainhowtheycanbespurredbypolicymakers.Inthecaseofhighways,however,policymakersareclearlyimpedingtechnologicalchangebyfailingtoimplementrecentinnovationsthatcouldsignicantlyimprovethespeed,reliability,andsafetyofmotoriststrips,whilereducingthecostofhighwayservices.InTable1,wesummarizethepositiveeffectsontravelandhighwayauthoritiesbudgetsthatcouldbeachievedifthosetechnologieswereimplemented.Unfortunately,empiricalestimatesofmanyoftheirbenetsareeithernotavailableorbasedonlyonlimitedexperiments.Asanaïveaccountingexercisebasedontheavailablenationalestimatesthatwereportedpreviouslyandonplausibleextrapolationsoftheestimatesinthecasestudieswenoted,weestimatethattheaggregateannualbenetsamounttoatleast$100billion.WhyhasthepublicsectorfailedtoimplementthosetechnologiesinatimelymannertorealizethelargebeneWinston(2010)arguesthatthefederalgovernmentisbiasedtowardthestatusquoinmanagingandoperatingthenationstransportationsystembecauseofagencylimitations,regulatoryconstraints,andpoliticalforces.InthecaseoftheFederalHighwayAdministration,itmaylacktheexpertisetoensurethattechnologiestoimprovethehighwaysystemareimplementedeffectivelyandefciently.Indeed,wenotedthatFHWAsbudgetdoesnotplaceapriorityondevelopingnewtechnologiestoimprovehighways.Likeotheragencies,FHWAmayalsoberisk-averseandwanttoavoidthemistakesandwell-publicizeddelaysinimplementingnewtechnologythat,forexample,havetarnishedtheFederalAviationAdministrationsreputationtomanageairtrafccontroleffectively.Fromapoliticalperspective,implementingthelatesttechnol-ogymaybehelpfulinovercominghighwayusersoppositiontocertainpoliciessuchascongestionandpavementwearpricing.Untilrecently,thepublicunderstandablyconceivedofroadpricingasrequiringhumantollcollectors,whichforcesmotoriststowastetimeinalineatatollbooth,topayafeethatcouldrealisticallybeinterpretedsimplyasarevenueraisingdevicethatissensitivetothepoliticalelectioncycle(Finkelstein,2009).Motoristshaveindicatedthattheyvaluetheoptiontopayanelectronictolltoexpeditetheirtripsasindicatedbythegrowingadoptioninseveralmetropolitanareasofthecountry,suchasAtlanta,LosAngeles,SaltLakeCity,andWashington,D.C.,ofhigh-occupancy-tolllanes,wheresolomotoristscanpayatolltotravelinaless-congestedcarpoollane.AsmoremotoristsuseGPSservicestoexpandtheirroutechoiceoptions,theymaybecomemoreenthusiasticaboutcomprehensiveroadpricing,especiallyifpricesandtraveltimesvaryondifferentlanestocatertomotoristsheterogeneouspreferencesfortraveltimeandreliability(etal.,2006).Inresponsetopoliticalpressures,policymakerscouldreducechargesonagivenlanetoselectedusers,suchascarpoo-lersandlow-incometravelers,viasmallerdeductionsontheirtransponders.Truckinginterestshavebeenabletodissuadepolicymakersfromsignicantlyreformingtruckchargesdespiterepeatedpro-testsfromrailroadandautomobileintereststhatthefueltaxdoesnotfullychargetrucksfortheirfairshareofhighwaycosts.WIMtechnologieswouldmakethetruckingindustryshighwaycostsmoretransparentandmayeventuallybreakthestalemateamongthemodalinterests,whiletruckersresistancetoreformingtruckchargesmightbelessenediftheyweregivengreaterexibilityintheirchoicesoftrailersizesandloadsthattheycouldcarry.Wespeculatethatalthoughimplementingnewtechnologiescouldhelpaddresspoliticalimpedimentstoefcientpricing,transportationofcialscontinuetomaintainstatusquopoliciesbecausetheyfearcertainusersobjectionstohigherchargesandbecauseFHWAmaynotstandtogainmuchfromtechnologythatreducesthecostofbuildingandmaintaininghighwaysifthosesavingsleadtoreductionsinitsbudget.Accordingly,wemustlooktotheprivatesectortoimplementtechnologythatcouldimprovehighwaytravel.7.LeapfrogtechnologyfromtheprivatesectorIfthepublicsectorisunlikelytomakeasubstantialefforttoimplementnewtechnologytoimprovehighwayperformance,itisusefultoconsidertheprivatesectorspotentialtodoso.Oneofthemajorbenetsofintercitytransportationderegulationwasthatitfreedrailroads,truckingcompanies,andairlinestodevelopandimplementtechnologiesthatthefederalgovernmentseconomicregulationshadthwartedfordecades(Gallamore,1999;MorrisonandWinston,1999).Itisthereforehardlysurprisingthatthe Table1cialactionsthatcouldbefacilitatedbyimplementingtechnology.ActionEffectsontravelandhighwayCongestionpricingonlanesforcarsandtrucksTraveltimesavings,increasedrevenue,reducedsprawlMorereliabletraveltimesCongestionpricingonshouldersforcarsCanreducetraveltimesasmuchasone-thirdIncreaseinrevenuesReal-timepricingandinformationonavailablespacesforon-streetReducesearchcostsandcongestionandincreaserevenuePavement-wearpricingfortrucksReducemaintenanceexpendituresBridge-wearpricingfortrucksReducethelikelihoodofcatastrophicfailure,fatalities,bridgerepairsTrucksizeandweightlimitsMonitortrucksizesandweightswithoutmanualinspectionsandhavemoreexiblesizeandweightlimitsImprovetruckingproductivityInvestmentsAdjustnumberoftrafclanesinresponsetotrafcvolumesCanreducetraveltimesasmuchasone-thirdNewpavementdesignprocedurestoincreasepavementdurabilityExtendpavementlifetimes,reducemaintenancecostsandvehicledamageSafetyoperationsVariablespeedlimitsImprovetrafowsandsafetyRetimeandoptimizetrafcsignalingImprovetrafowsandsafetyIntroducephoto-enforcementtechnologyReducethecostandimprovetheeffectivenessofenforcementExpediteresponsetoincidentsReducedelaysIncreasesafetyC.Winston,F.Mannering/EconomicsofTransportation Pleasecitethisarticleas:Winston,C.,Mannering,F.,Implementingtechnologytoimprovepublichighwayperformance:Aleapfrogtechnologyfromtheprivatesectorisgoingtobe....EconomicsofTransportation(2014),http://dx.doi.org/10.1016/j.ecotra.2013.12.004 governmenthasimpededtechnologicaladvanceinpublichigh-waysandquitepossiblethattheprivatesectorcouldspuranadvanceifgivenanopportunity.Onepossibilitymaybepublic-privatepartnerships(PPPs)involvinghighways,suchastheIndianatollroad,whichhavebeeninitiatedduringthepastfewdecades.Futurepartnershipscouldincludearequirementinthecontractthattheprivateoperatorhastoinstallthelatesttechnology(underpenaltyofane)toimprovepricing,investment,andsafetyoperations.Unfortunately,manyPPPshavebeencompromisedbyawedcontractsthathavebeenpoorlydesignedandhavehadtoberenegotiated(Engeletal.,2011),whileothershavesufferednancialproblemsfromtheGreatRecession.Thus,itappearsunlikelythatPPPswillbeasourceofsignicanttechnologicaladvanceinhighwayservicesatanytimeinthenearfuture.Fortunately,moreencouragingprivate-sectorhighwaytravelinnovationsareunderway.Themostpromisingistherecentrevela-tionofthedriverlesscar,whichdoesahumandriversnormaljobandmuchmore,andhasraisedthepossibilityofanentirelyneweraofhighwaytransportation.Driverlesscarsareoperatedbycomputersthatobtaininformationfromanarrayofsensorsonthesurroundingroadconditions,includingthelocation,speed,andtrajectoriesofothercars.Theon-boardcomputersgatherandprocessinformationmanytimesfasterthanthehumanmindcanprocessit.Bygatheringandreactingimmediatelytoreal-timeinformation,andbyeliminat-ingconcernsaboutriskyhumanbehaviorsuchasdistractedandimpaireddriving,thetechnologyhasthepotentialtopreventcollisionsandgreatlyreducehighwayfatalities,injuries,vehicledamage,andcostlyinsurance.Anditcansignicantlyreducedelaysandimprovetravel-timereliabilitybycreatingasmoothertrafowandbyroutingand,whennecessary,reroutingdriverswhohaveprogrammedtheirdestinations.Driverlesstrucksarealsointhedevelopmentalstage.Forexam-ple,dozensofsuchtrucksarebeingusedtohaulmaterialsataniron-oremineinAustraliaandatotherlocationsawayfrompublicthoroughfares.Inadditiontocontributingtoimprovedtrafandmotoristssafety,driverlesstruckswouldbenetindustrybysubstantiallyreducinglaborcosts,insurance,andoperatingcosts.Thusfar,sevenstatesincludingCalifornia,Florida,andNevadahavelegalizedthetestingofdriverlesscars,andseveralotherstatesareconsideringdoingthesame.Competitionamongautomakersandotherrmstodevelopthebesttechnologyisalreadyunderway.Googlehasloggednearly500,000milestestingitsversionofadriverlesscar;GeneralMotorsisworkingonamodelwithresearchersatCarnegieMellonUniversity;Audi,BMW,Toyota,andVolvohavedemonstratedtheirdriverlessmodels;andNissanhasclaimedthatitwillofferafulllineofdriverlesscarsinthenextdecade.Inshort,some,admittedlyoptimistic,forecastsindicatethatdriverlesscarscouldbeacommonsightonU.S.roadsby2025.EmpiricalestimatesoftheirbenetsaresparsebutonestudyFagnantandKockelman,2013)showsthattheyarehighlydepen-dentonthespeedofadoptionandextentofmarketpenetration.Thoseauthorsaccountforthereductioninfatalitiesandinjuries,lessvehicledamage,andsavingsintraveltime,fuel,andparkingcostsandestimatethatevenamodest10%penetrationofdriverlesscarswouldgenerateannualbenetsof$40billion.Annualbeneamounttoaneye-popping$200billionifmarketpenetrationreaches50%.Theoptimumsocialoutcomewouldcallforacombinationofinvestmentsbythepublicsector,toimprovehighwayinfrastruc-turetechnology,andbytheautomakersandotherprivatesectorrms,toperfectdriverlesscartechnologies.Wehaveargued,however,thatitisunlikelythatthisoutcomewouldbeachievedbecausethepublicsectorwillnotmaketherequiredinvestmentsinthenearfuturetoimprovehighwayinfrastructuretechnology;incontrast,theprivatesectorisclearlydeterminedtoperfectandimplementdriverlesscars.Thusdriverlesscartechnologiesarequitelikelytoeffectivelyleapfrogmostoftheexistingtechnologiesthatthepublicsectorcouldbuthasfailedtoimplementtoimprovehighwaytravel.Driverlessvehicleswouldsigniexpandthecapacityofthehighwaysystemandreducedelaysandcongestionforallaspectsoftravelincludingparking;greatlyreducetheprobabilityofvehicleaccidentsandtheirassociatedcosts;andthedriverlesstechnologiesadoptedbytruckerscouldpotentiallyreducethedamagetopavementsandbridgesbyadjustingroutingsanddeliverytimestoavoidthemostvulnerableinfrastructureandtodecreasecongestionthatstrainsbridges.Driverlessvehiclesareinevitablebutthemajorobstacletomotoristsandrmsfromadoptingthemassoonaspossibleiswhetherthegovernmentwilltakeprudentandexpeditiousapproachestohelpresolveimportantquestionsaboutassigningliabilityintheeventofanaccident,theavailabilityofinsurance,andsafetyregulations.TheNationalHighwayandTrafcSafetyAdministration(NHTSA),whichisresponsibleforregulatingauto-mobilesafety,hasissuedcautiousrecommendationsaboutdriverlesscars.Thatmaybeappropriateatthisstageofthevehiclesdevelop-ment,butNHTSAshouldalsobecautiousaboutsharingFHWAlegacyofnotpromotingtimelyinnovationinhighwaytravel.8.ConclusionKahnemanandKrueger(2006)reportevidencethatoverthecourseofthedayindividualscommutesaretheleadingactivityforwhichtheirdominantemotionisnegative.Motoristswouldprobablyfeelevenworseiftheywereawareoftheevidencesummarizedherethatpolicymakerscouldimplementavailabletechnologyontheroadsystemthatwouldreducemuchofthecongestionanddelaysthatmakeroadtravelsoonerousandwouldalsoimprovesafety.Ourdiscussionofpolicymakersfailuretoimplementthistechnologyhasculminatedintheeternaldebateoverwhetherthepublicortheprivatesectorisbetterabletospurtechnologicalchangethatcontributestogrowth.Inthecaseofhighways,weconcludethatitislikelythattheprivatesectorwilleventuallyimplementdriverlesscartechnologies,andthatthosetechnolo-gieswillbenetmotoristsbyleapfroggingthetechnologicaladvancethatthepublicsectorhasputonhold.Ifthisinnovationisnotimpededbygovernmentregulationsanddoessucceed,socialwelfarecouldpossiblyincreasefurtherbyexploringpriva-tizationoftheroadsystemsothatitcouldoperateatthesameleveloftechnologicalsophisticationasthevehiclesthataredrivenonit.ReferencesAtkinson,RobertD.,Castro,DanielD.,2008.DigitalQualityofLife:UnderstandingthePersonalandSocialBenetsoftheInformationTechnologyRevolution.InformationandTechnologyFoundation,Washington,D.CBarker,Richard,Puckett,Jay,2007.DesignofHighwayBridges:AnLRFDApproach,secondeditionJohnWiley&Sons,NewYork,NYBresnahan,TimothyF.,Trajtenberg,M.,1995.GeneralPurposeTechnologies:EnginesofGrowth?J.Econom.65(1),83108CambridgeSystematics,2011.Crashesvs.Congestion:WhatstheCosttoSociety?,PreparedfortheAmericanAutomobileAssociation,November. Smith(2012)arguesthatdriverlesscarsarelegalintheUnitedStatesanddiscussestheissuesinvolvedindeterminingtheirlegality. WinstonandYan(2011)indicatecompetitiveconditionsunderwhichhighwayprivatizationwouldimprovemotoristswelfare.C.Winston,F.Mannering/EconomicsofTransportation Pleasecitethisarticleas:Winston,C.,Mannering,F.,Implementingtechnologytoimprovepublichighwayperformance:Aleapfrogtechnologyfromtheprivatesectorisgoingtobe....EconomicsofTransportation(2014),http://dx.doi.org/10.1016/j.ecotra.2013.12.004 Downs,Anthony,1962.Thelawofpeak-hourexpresswaycongestion.TrafcQ.16(3),393Engel,Eduardo,Fischer,Ronald,Galetovic,Alexander,2011.InfrastructurePPPs:WhenandHow,DraftBookManuscript,DepartmentofEconomics.YaleUniversity,NewHaven,CTFagnant,DanielJ.,KockelmanKaraM.,2013.PreparingaNationforAutonomousVehiclesEnoCenterforTransportation,Washington,DC.Finkelstein,Amy,2009.E-ZTax:taxsalienceandtaxrates.Q.J.Econ.124(3),1010Fleming,DarylS.,2012.Dispellingthemyths:tollandfueltaxcollectioncostsinthe21stcentury.ReasonFound.PolicyStudy409Gallamore,RobertE.,1999.Regulationandinnovation:lessonsfromtheamericanrailroadindustry.In:Gomez-Ibanez,JoseA.,Tye,WilliamB.,Winston,Clifford(Eds.),EssaysinTransportationEconomicsandPolicy:AHandbookinHonorofJohnR.Meyer.Brookings,Washington,DC.(pp.493Garrison,D.,Mannering,F.,1990.Assessingthetrafcimpactsoffreewayincidentsanddriverinformation.ITEJ.60(8),19Jacob,Bernard,2010.Weigh-in-MotionforRoadSafety,Enforcement,andInfra-structure.LCPC,Paris,FranceKahneman,Daniel,Krueger,AlanB.,2006.DevelopmentsintheMeasurementofSubjectiveWell-Being.J.Econ.Perspect.20(1),3Lajnef,N.,Rhimi,M.,Chatti,K.,Mhamdi,L.,Faridazar,F.,2011.Towardanintegratedsmartsensingsystemanddatainterpretationtechniquesforpavementfatiguemonitoring.Comput.-AidedCivilInfrastruct.Eng.26(6),513Langer,Ashley,Winston,Clifford,2008.Towardacomprehensiveassessmentofroadpricingaccountingforlanduse.Brook.-Whart.Pap.UrbanAff.,127175Lave,Charles,Lave,Lester,1999.Fueleconomyandautosafetyregulation:isthecureworsethanthedisease.In:Gomez-Ibanez,JoseA.,Tye,WilliamB.,Winston,Clifford(Eds.),EssaysinTransportationEconomicsandPolicy:AHandbookinHonorofJohnR.Meyer.Brookings,Washington,DC.(pp.257Lindsey,Robin,2012.RoadPricingandInvestment.Econ.Transp.1(1),49Little,D.N.,MemmottJ.,McFarlandF.,GoffZ.,SmithR.,WootanC.V.,ZollingerD.,TangT.,EppsJ.,1997.EconomicBenetsofSHRPResearch.TexasTransportationInstitute.AvailableinPDFfromTRISOnlineat:http://trisonline.bts.gov/search.Mannering,FredL.,Washburn,ScottS.,2013.PrinciplesofHighwayEngineeringandTrafcAnalysis,ftheditionJohnWileyandSons,NewJerseyMcKinnon,AlanC.,2005.Theeconomicandenvironmentalbenetsofincreasingmaximumtruckweight:theBritishexperience.Transp.Res.Rec.PartD10(1),Mohring,Herbert,Harwitz,Mitchell,1962.HighwayBenets:AnAnalyticalFrame-work.NorthwesternUniversityPress,Evanston,IllinoisMorrison,Steven,Winston,Clifford,1999.RegulatoryreformofU.S.intercitytransportation.In:Gomez-Ibanez,JoseA.,Tye,WilliamB.,Winston,Clifford(Eds.),EssaysinTransportationEconomicsandPolicy:AHandbookinHonorofJohnR.Meyer.Brookings,Washington,DC.(pp.469492)Moses,Fred,C.Schilling,K.Raju,1987.FatigueEvaluationProceduresforSteelBridges.NationalCooperativeHighwayResearchProgramReport299,Novem-ber,NationalResearchCouncil,Washington,D.C.NationalCooperativeHighwayResearchProgram,2003.EffectofTruckWeightonBridgeNetworkCosts.Report495,TransportationResearchBoard,Washington,D.C.NationalTransportationOperationsCoalition,2007.ExecutiveSummary:2007NationalTrafcSignalReportCard,Washington,D.C.Ng,ChenFeng,Small,KennethA.,2012.Tradeoffsamongfree-owspeed,capacity,cost,andenvironmentalfootprintinhighwaydesign.Transportation39(6),12591280Papageorgiou,M.,E.Kosmatopoulos,I.Papamichail,2008.Effectsofvariablespeedlimitsonmotorwaytrafow,TransportationResearchRecord2047,JournaloftheTransportationResearchBoard,pp.3748.Pierce,Gregory,Shoup,Donald,2013.Gettingthepricesright:anevaluationofpricingparkingbydemandinSanFrancisco.J.Am.Plan.Assoc.79(1),67Shin,K.,Washington,S.,Schalkwyk,Idavan,2009.EvaluationofthecityofScottsdaleloop101photoenforcementdemonstrationprogram.Accid.Anal.Prev.41(3),393Shoup,Donald,2005.TheHighCostofFreeParking.PlannersPress,ChicagoSmall,KennethA.,Verhoef,ErikT.,2007.TheEconomicsofUrbanTransportation.RoutledgePublishers,LondonSmall,KennethA.,Winston,Clifford,1988.Optimalhighwaydurability.Am.Econ.Rev.78(3),560Small,KennethA.,Winston,Clifford,Evans,CarolA.,1989.RoadWork:ANewHighwayPricingandInvestmentPolicy.BrookingsInstitution,Washington,D.CSmall,KennethA.,Winston,Clifford,Yan,Jia,2005.UncoveringtheDistributionofMotoristsPreferencesforTravelTimeandReliability.Econometrica73(4),13671382Small,KennethA.,Winston,Clifford,Yan,Jia,2006.Differentiatedroadpricing,expresslanes,andcarpools:exploitingheterogeneouspreferencesinpolicydesign.Brook.-Whart.Pap.UrbanAff.,53Smith,BryantWalker,2012.AutomatedVehiclesareProbablyLegalintheUnitedStates.TheCenterforInternetandSociety,StanfordUniversity,PaloAlto,CATheRoadInformationProgram,2013.BumpyRoadsAhead:AmericasRoughestRidesandStrategiestoMakeourRoadsSmoother,Washington,D.C.,October.Todd,Kenneth,2004.TrafcControl:AnExerciseinSelf-Defeat.RegulationMagazine27(3),10TransportationResearchBoard,2010.HighwayCapacityManual.NationalResearchCouncil,NationalAcademies,Washington,DCTransportationResearchBoard,2005.SuperiorPerformingAsphaltPavement:SUPERPAVE,PerformancebyDesign,FinalReportoftheTRBSUPERPAVECommittee,NationalAcademies,Washington,DC.Vickrey,WilliamS.,1963.Pricinginurbanandsuburbantransport.Am.Econ.Rev.53(2),452WashingtonStateDepartmentofTransportation,2007.ActiveTrafcManagement(ATM)FeasibilityStudy,Availablefrom:http://psrc.org/assets/524/ATMfeasiblitystudy.pdfWilde,ElizabethTy,2013.DoEmergencymedicalsystemresponsetimesmatterforhealthoutcomes?Forthcom.HealthEcon.,http://dx.doi.org/10.1002/hec.2851Winston,Clifford,2013.OntheperformanceoftheU.S.transportationsystem:cautionahead.J.Econ.Lit.51(3),773Winston,Clifford,2010.LastExit:PrivatizationandDeregulationoftheU.S.TransportationSystem.BrookingsInstitution,Washington,D.CWinston,Clifford,Yan,Jia,2011.CanprivatizationofU.S.Highwaysimprovemotoristswelfare?J.PublicEcon.95(78),9931005 C.Winston,F.Mannering/EconomicsofTransportation Pleasecitethisarticleas:Winston,C.,Mannering,F.,Implementingtechnologytoimprovepublichighwayperformance:Aleapfrogtechnologyfromtheprivatesectorisgoingtobe....EconomicsofTransportation(2014),http://dx.doi.org/10.1016/j.ecotra.2013.12.004