Looking into Detection, Model Results and Message Quality

Looking into detection, modelresults and message qualityTomas Epp, PTV Austria GmbHAndreas Schmid, PTV AG

Forecast in a service meansTake into accountthe situation whichwill be presentonce you will getto a place.This is different fromthe current situation!Mid Term orDay forecastShort TermforecastCurrentsituation10/22/2010 3

Forecast in a service requires fusionASDA/FOTO currentsituationof various informationover time and space(there is rarely one goodsource for all).Redundant informationcan cover leaks.Quality assuranceon the final resultnot reasonableShort Term forecastsMedium Term forecastsLong Term forecastDigital map10/22/2010 4

Insight - current traffic stateby ASDA/FOTOSpatial interpolation:simple, but wrongbetter: model basedDetect dangerous jam endseven where no detector is!timeASDA = Automatische StaudynamikanalyseFOTO = Forecasting of Traffic ObjectsBoris S. Kerner, 2004. The Physics of Traffic5

ANS – ASDA/FOTO Native SciagramTime‐spacex‐rayimageRoad driving directionMQ, Det133,135MQ, Det123,456VLINKVLINKVLINKVLINKVLINKVLINK00:00 00:00 h12:00 12:00 h24:00 24:00 hVLINKtime6

ANS – ASDA/FOTO Native SciagramDetector measurementsconverted to coloursRoad driving directionMQ, Det133,135MQ, Det123,456VLINKVLINKVLINKVLINKVLINKVLINK24:00 24:00 hVLINKZeit7

ANS – ASDA/FOTO Native SciagramRoad in driving directionDetektor1,2,3Detektor4,5,6measurement locationDetektor7,8,9Detektor10,11,12Detektor13,1412 13 14 15 16 17 18 19MinuteintervalsKeyFaulty measurementsLOS freeLOS denseLOS JAMNo dataTime (minutes of the day)10/22/2010 8

ANS – ASDA/FOTO Native SciagramASDA/FOTO Objects: : JAM or SYNC flowRoad driving directionMQ, Det133,135MQ, Det123,456SYNCJAMVLINKVLINKVLINKVLINKVLINKVLINK00:00 00:00 h12:00 12:00 h24:00 24:00 hVLINKtime9

ANS – ASDA/FOTO Native SciagramLevel of Service (LOS) on a link>= 1 jamObjekt?>=1 Sync-Objekt?Road driving directionMQ, Det133,135MQ, Det123,456SYNCJAMVLINKVLINKVLINKVLINKVLINKVLINK00:00 00:00 h12:00 12:00 h24:00 24:00 hVLINKtime10

ANS – ASDA/FOTO Native SciagramMessagesSource 1Source 2Source 3Source 4Road driving directionMQ, Det133,135MQ, Det123,456Deviation in time and spaceVLINKVLINKVLINKVLINKVLINKVLINK00:00 00:00 h12:00 12:00 h24:00 24:00 hVLINKZeit11

ANS – ASDA/FOTO Native Sciagram„Real world“ example (www.bayerninfo.de(system)12

Insight: Prognosis diagrams10/22/2010 13

Insight: travel time• How does it work• Examples of Vienna10/22/2010 14

How does it work• Using FCD information• About 3000 Taxis (Vienna)• Velocity is sent every 15 minutes10/22/2010 15

How does it work• Given on each link• Filtering ofExclusive Lanesfor Taxi Cabs andBuses• Coverage ca. 85%10/22/2010 16

How does it work• Comparison of travel times– Setting the test track– Calculate travel time based on forecast results– Calculate travel time based on Taxi Cabs information• Calculate the deviation–difference = 1 −forecastTaxi10/22/2010 17

Examples of Vienna• 11x2 main routesthrough Vienna• Calcuated every 15minutes10/22/2010 18

Examples of Vienna• Example: week 20 (May 2010)10/22/2010 19

Examples of Vienna• Example: 20 May 201010/22/2010 20

Examples of Vienna• Example: three forecast steps10/22/2010 21

Metrics – automatic control• Images good for– Human interpretation(always richer than machines!)– Limited, dedicated (test) locations• Statistic figures needed– For large scale evaluations10/22/2010 22

Metrics – what figure to use?• Looking at Volumesexpected measured missed5000 veh/h 4800 veh/h ‐4% 200 veh100 veh/h 96 veh/h ‐4% 4 veh500 veh/h 300 veh/h ‐67% 200 veh10/22/2010 23

Metrics – a figure and its parameterLooking for a perceived quality index parameter nlist of values perceived as "same quality"count Model n Quality metrics:computedvalue−"truth"10 20 0,67 Q = ∆/T n QualityIndex =20 36 0,67 ∆ = |model result - count result|("truth") n50 85 0,63 T = "Truth", e.g. count result or 0.7*count + 0.3*model100 160 0,61 n: parameter (to be determined)200 300 0,59500 700 0,54 Result: Median: Average1000 1300 0,52 n = 0,61 0,612000 2400 0,575000 5700 0,51 Values should be on a line (same "qualty parameter")10000 11000 reference20000 21600 0,68 Values outside [0,1] not logical50000 53000 0,6810/22/2010 24

Metrics – ExampleValue (e.g. flow)7.0006.0005.0004.0003.0002.0001.00010987654321Quality index"truth"comparison basecomputedvaluesQuality =difference/ truth00 4 8 12 16 20 24time [h]010/22/2010 25

Metrics – Alternative• Geoffrey E. Havers1970’se.g. adopted in UK Highways Agency'sDesign Manual for Roads and Bridges(DMRB)M = Model ValueC = Count Value10/22/2010 26

Thank youfor your attention!Thomas.Epp@ptvaustria.atAndreas.Schmid@ptv.de