TRAFFIC MICROSIMULATION & 3-D VISUALIZATION

Presenters: Fadi Emil Nassar, P.E.Veronica A. Boza, E.I.

FDOT – MAY 4, 2007

MACRO / MICRO TRAFFIC MODELS

MACRO MODEL: TRAFFIC FORECASTMICRO MODEL: OPERATIONAL ANALYSIS NO LONGER SEPARATE FILEDS:

– DISTRIBUTION IMPACTED BY OPERATIONS– CAPACITY CONSTRAINT AT INTERSECTIONS– TRANSIT/MODAL SPLIT IMPACTED BY CONGESTION

GAP CLOSING BTW MACRO & MICRO ANALYSESCONVERGENCE OF SOFTWARE INTEGRATED MODELS:

– CUBE / DYNAMISM– VISUM / VISSIM

TRAFFIC MICROSIMULATION MODELS

ANALYZE THE PERFORMANCE OF TRANSPORTATION SYSTEMS BY SIMULATING THE MOVEMENTS OF INDIVIDUAL VEHICLES ON A SPLIT-SECOND BASIS

ACCOUNT FOR ROADWAY, DRIVER AND VEHICLE CHARACTERISTICS

OPERATIONAL RESULTS (SPEED, QUEUES, DELAYS, ETC) ARE BASED ON TRAFFIC INTERACTION INSTEAD OF EQUATIONS

3D-VISUALIZATION

COMPLEX ROADWAY SYSTEMSBRIDGESOVERPASSES INTERCHANGESAIRPORT TERMINAL RAMPSVIEW FROM CAR

SR 112 - MIAMI

WHEN TO USE MICROSIMULATION

LIMITATION OF HCM / HCSSYSTEM ANALYSIS (COORDINATION)CONGESTION / SPILLBACK / BOTTLENECKQUEUING / STORAGECLOSELY SPACED RAMPSBUS / MULTIMODAL / ITS / RAMP METERINGSIGNAL PRE-EMPTIONCOMPLEX OR UNIQUE GEOMETRY

SIMULATION PROCESS

STUDY OBJECTIVESMODEL SELECTIONDATA COLLECTIONBASE MODEL DEVELOPMENT CALIBRATION / VALIDATIONALTERNATIVE ANALYSISMOE SUMMARY / PREFERRED ALTERNATIVEPRESENTATION OF RESULTS

STUDY OBJECTIVES

GOALS OF MODELING PROCESSESTABLISH NEED FOR MICROSIMULATIONPROJECT SCOPING

– LIMITS OF ANALYSIS / INFLUENCE AREA– BOUNDARY CONDITIONS – TIME PERIOD– PEAK HOUR FACTOR

LEVEL OF DETAIL / EFFORT / BUDGETUNDERSTAND MODEL STRUCTURE

– DELAY, QUEUE, DRIVER BEHAVIOR

MOE DIFFERENT FROM HCM EQUATIONS

MODEL SELECTION

BASIC MODELSCORSIMSYNCHRO/SIMTRAFFIC

ADVANCED MODELSVISSIM / AISUM / CUBE DYNAMISMPARAMICS & OTHERSCOMBINATION OF MODELS

CORSIM

LINK-NODE NETWORK (DEVELOPED BY FHWA)ADVANTAGES:

– WIDELY USED & ACCEPTED– EXTENSIVE VALIDATION IN USA– FREEWAY/RAMP OPERATION– BUS ROUTES – ITS ANALYSIS – RAMP METERING– TIME PERIOD ANALYSIS– LINK AGGREGATION– SHORT/LONG INCIDENT SIMULATION– HEADWAY DISTRIBUTION TYPES

CORSIM (CONTINUE)

DISADVANTAGES:– 2-D ONLY (NO ELEVATIONS)– SIMPLIFIED SIGNAL OPERATION– PROBLEMS WITH SHORT LINKS– RESULTS GROUPED PER LINKS– NO SIGNAL OPTIMIZATION– NO INTERSECTION LOS– IMPROVED BUT LIMITED GRAPHICAL INTERFACE

CORSIM-CYPRESS

Alternative 1

Alternative 2

Partial Cloverleaf Interchange:

•Limited Spacing of Interchange

•Stacks queue in one or more quadrants

•Requires Extensive ROW

•Complex Design

Diamond Interchange•Sufficient Spacing•Simple Design•Narrow ROW•Stopped Condition

CORSIM – INTERCHANGE ALTERNATIVES

SYNCHRO/SIMTRAFFIC

LINK-NODE NETWORK (TRAFFICWARE)ADVANTAGES:

– WIDELY USED– EASY DATA ENTRY / BEST GRAPHIC INTERFACE – EXPORT TO CORSIM / T7F / HCS / VISSIM – DATABASE INTERFACE (VOLUME/SIGNAL/LAYOUT)– INTEGRATED SIGNAL OPTIMIZATION– ROUNDABOUT MODELING (NOT YET VALIDATED)– INTERSECTION LOS (HCM / ICU)– DIAMOND INTERCHANGE / RING & BARRIER– QUEUE LENGTH (PERCENTILE)– EASY TO CREATE SUB NETWORKS

SYNCHRO/SIMTRAFFIC (CONTINUE)

DISADVANTAGES:– NO TRANSIT MODELING– LIMITED FREEWAY CAPABILITY– SIMTRAFFIC RESULTS DIFFER FROM SYNCHRO & NOT

WIDELY ACCEPTED – LINK-BASED MOEs– LIMITED FLEXIBILITY OUTSIDE BASIC INTERSECTIONS

(TOLL PLAZA, AIRPORT, SIGNAL PREEMPTION, ITS, ETC)

SYNCHRO - UNIVERSITY OF MIAMI

SAMPLE SYNCHRO/SIMTRAFFIC NETWORK

Becker Road

I-95

CORSIM Network

PORT ST. LUCIE

ADVANCED - VISSIMLINK-CONNECTORDEVELOPED BY PTV IN GERMANYADVANTAGES:

– INCREASING ACCEPTABILITY IN US– EXTENSIVE TRANSIT MODELING CAPABILITY

• LIGHT RAIL• BUS TRANSIT WITH BUS STATIONS• ROUTE ASSIGNMENT BASED ON SCHEDULE

– EXPLICIT PEDESTRIAN & CYCLIST MODELING– 3D GRAPHIC OUTPUT / IMPACT OF GRADES– ADVANCED SIGNAL CONTROL LOGIC

• IMPORTANT FOR DEMAND RESPONSIVE OPERATION• IMPORTANT FOR SIGNAL PREEMPTION

VISSIM (CONTINUE)

ADVANTAGES:– ADVANCED ORIGIN-DESTINATION– ROUTING FOR ALL VEHICLE TYPES– DYNAMIC ASSIGNMENT (VISUM)– ROUNDABOUT SIMULATION– UNLIMITED VEHICLE TYPE

• IMPORTANT FOR TOLL PLAZA• AIRPORT CURB SIDE OPERATION

– FLEXIBLE DATA COLLECTION– INTERFACE WITH 3-D MODELER– DYNAMIC VISUALIZATION OF RESULTS

VISSIM (CONTINUE)

DISADVANTAGES:– NOT AS WIDELY USED IN FLORIDA– EXPENSIVE (WITH TRANSIT OPTION)– CODING OF DESIRED OUTPUT PARAMETERS– FLEXIBILITY REQUIRES GREATER KNOWLEDGE AND

CODING EFFORTS – NO STANDARD SUMMARIES WHICH COMPLICATE

REVIEW PROCESS– NO SIGNAL OPTIMIZATION (INTERFACES WITH

SYNCHRO)

MIAMI - PROPOSED ROUNDABOUT

DATA COLLECTION

GEOMETRY & LAYOUTTRAFFIC CONTROL: SIGNAL & SIGNVOLUMES (RECONCILE COUNTS)DATA FOR CALIBRATION

– TRAVEL TIME– AVG & FREEFLOW SPEED– QUEUE LENGTH– OBSERVATIONS / WARNING SIGNS

BASE MODEL DEVELOPMENT

DEVELOP LINK-NODE DIAGRAMNODE NUMBERING / PROPER CODINGBASE MAPPINGDATA COLLECTION / FIELD REVIEWCHECK INPUT DATABALANCE VOLUMESDEVELOP O-D MATRIX (RAMPS)SIGNAL TIMINGQA/QC – CHECK SIMULATION RUNSVERIFIABLE / REPRODUCIBLE / ACCURATE

VOLUME CALIBRATIONCONGESTED CONDITIONS

(EX: SR112)

DATA COLLECTION INITIAL CALIBRATION RESULTSADDITIONAL INVESTIGATIONDEMAND PEAK HOUR VOLUMESTRAVEL TIMES

DATA COLLECTION

Legend:Signalized IntersectionUnsignalized IntersectionRoadway Split AreasTurn Lane Storage Length

Posted Speed Limit

1

100'

Ockeechobee Rd/N. River Drive

From SR 112Ramp

1?

130'

110'110'

ToFlyover

250'

Flyover

75'

325'

ToAirport

FlyoverFrom NB

Le Jeune Road

23

4

5

7

EBL used to re-direct traff ic to NBLe Jeune fromOckeechobee &Le Jeune Int.

1

Bridge overMiami River From SR 112

Ramp

NW 36 Street

5

WB - NW 36 Street

2

6

3

FromSR 112 500'

4

7

EB -NW 36 Street

To EB SR 112Ramp

ToNW 42 Ave

6

100'

Driveway

65'

WB SR 112 Ramp toOckeechobee Road:

Fourth lane starts west ofNW 32nd Ave and ramp

separat ion starts atNW 35th Ct

30MPH

30MPH

1

11

6

5

4

2

1

9

108

3

Intersection Count Location

Machine Count Location

Ramp Count Location

1

1

5

4

6

9

1

3

7

8

2

7

6

5

4

3

2

1

8

7

12

INITIAL CALIBRATION RESULTS

VISSIM not replicating observed queues with measured volumes:– Traffic backups on ramps and intersections

– Tri-Rail and Freight Train Impact on traffic

Significant difference is travel times

Need for additional investigation

ADDITIONAL INVESTIGATION Intersections Peak Hour Factors (PHF) greater than 0.95

suggests constrained conditions.

Intersection AM Peak Hour PM Peak Hour

Le Jeune Rd/SE 8 St 0.98 0.97

Le Jeune Rd/Okeechobee Rd: 0.98 0.99

Le Jeune Rd/NW 36 St 0.97 1.00

Le Jeune Rd/NW 31 St 0.95 0.95

NW 36 Street/Lee Dr 0.98 0.98

NW 36 St/S. River Dr 0.97 0.95

NW 36 St/N. River Dr 0.97 0.97

ADDITIONAL INVESTIGATION

Location TO/FROMQuality Counts

FDOT Stations

AM PM AM PM

WB SR-112 Off Ramps

To Okeechobee RdTo NW 36 StreetTo AirportTo SB Le Jeune Rd

5.2%8.0%6.7%6.7%

3.5%6.3%7.5%8.9%

4.2%8.7%n/a6.3%

11.1%5.8%n/a7.2%

EB SR-112 On Ramps

From Okeechobee RdFrom NW 36 StreetFrom AirportFrom NB Le Jeune Rd

12.3%9.7%4.2%5.7%

4.7%8.1%9.5%7.6%

10.9%n/an/a4.2%

5.3%n/an/a8.4%

Peak to daily factors (K-factor) less than 8.5% on freeways and 9.0% for arterials suggest constrained conditions.

Ramps:

ADDITIONAL INVESTIGATION

Location AM PM

Le Jeune Rd, South of NE 8 St 5.8% 7.1%

Le Jeune Rd, South of NW 31 St 5.8% 4.4%

N. River Dr, West of Flyover merge

8.6% 6.6%

N. River Dr, North of NW 36 St 6.6% 5.8%

N. River Dr, South of NW 36 St 6.9% 7.5%

S. River Dr, East of Le Jeune Rd 6.5% 6.2%

S. River Dr, West of NW 36 St 6.5% 9.4%

NW 36 St, West of N. River Dr 6.5% 6.4%

NW 36 St, East of N. River Dr 5.1% 6.1%

Arterials

VOLUME ADJUSTMENT

Adjustment to achieve demand volumes based on FDOT Quality/Level of Service Handbook:– Ramps:

•Minimum K100 is 8.5%; and

•Average Peak to daily ratio percent difference is 28% and 26% for the AM and PM Peak Hours respectively.

– Arterial Road:•Minimum K100 is 9.0%; and

•Average Peak to daily ratio percent difference is 27% for both the AM and PM Peak Hours.

VOLUME BALANCING (SEASONAL FACTOR / TRUCKS / ETC)

CALIBRATION / VALIDATIONDRIVER BEHAVIOR

– STARTUP DELAY & REACTION TIME– MINIMUM HEADWAY/GAP ACCEPTANCE– LANE CHANGE PARAMETERS– CAR FOLLOWING SENSITIVITY

VEHICLE CHARACTERISTIC– TRAFFIC COMPOSITION– MAXIMUM ACCELERATION / DECELERATION

ROADWAY CHARACTERISTICS– FREE FLOW SPEED– CHANNELIZATION– PARKING ACTIVITY

TRAVEL TIMES AM Peak Hour

SegmentCollected Travel

Time Range (Sec)

VISSIM Travel Time

(Sec)

SR-112 Off ramp

232 - 291 235

EB NW 36 St 178 - 295 195

WB NW 36 St 273 242 PM Peak Hour

SegmentCollected Travel

Time Range (Sec)

VISSIM Travel Time (Sec)

SR-112 Off ramp

430 - 580 394

EB NW 36 St 180 - 655 204

WB NW 36 St 229 - 380 368

NB Le Jeune Rd

248 - 303 266

SB Le Jeune Rd 281 - 445 285

ALTERNATIVE ANALYSIS / MOE

SIMULATION GREAT FOR ALT ANALYSIS SIMPLIFIED REALITY / LIMITATIONS ESTABLISH MOE & MATRIX EVALUATION

– SPEED– DENSITY– TRAVEL TIME– QUEUE– DELAY

PERFORM MULTIPLE RUNS (SEED #) SENSITIVITY ANALYSIS PRESENTATION OF RESULTS

– GRAPHIC SIMULATION– OPERATIONAL RESULTS