Prepared by

George Lu, Shankar Natarajan

2017 VASITE Annual Meeting, June 29, 2017

Multi-Resolution Traffic Modeling for

Transform 66 Inside the Beltway Projects

Outline

Transform I-66 Inside the Beltway (ITB) projects

Challenges

Modeling methodology framework

Micro-simulation analysis

Mesoscopic analysis

Summary and lessons learned

2

Project Background

3

Outside the Beltway (OTB)

Concurrent HOV and SOV operations

Limited parallel facilities

Available right-of-way

Fixed travel choices

Inside the Beltway (ITB)

HOV-2 only in the peak direction

during peak hours

Four major parallel routes

Limited widening capacity

Various bike and transit options

10 miles25 miles

Inside the Beltway

4

Typical Weekday - 7:00 PM

Roadway congestion (peak and non-peak directions)

Capacity issues at arterial interchanges

Non-HOV users during HOV operation

Metrorail congestion

Adverse impact of roadway congestion on bus

service

Challenges to intermodal transfers

Limitations/gaps in bicycle and pedestrian

accessibility and connectivity

Transform 66 ITB Projects

EB Widening

(DTR – Fairfax Dr)

2020

WB Widening

(Sycamore St – Washington Blvd)

Before 2040

N

Fairfax Dr

I-66 Spot Improvements

Spot 3 - 2020

ITB Tolling

(I-495 – Route 29 in Rosslyn)

2017

5

Modeling Need

Traffic operational analysis to support EA/IJR

Mainly focus on the impacts to freeway operations

Single peak hour only

Static demand inputs and Ods

Freeway corridor network

Regional traffic diversions and dynamic analysis

To assess the impacts of tolling on traffic demand and diversion

A dynamic multi-hour, multi-route analysis

A larger sub-area network

6

Core Study Area

N

Fairfax Dr

7

Project Influence Area

N

Fairfax Dr

8

N

Fairfax Dr

A Hybrid Multi-Resolution

Modeling Approach

Legend

Microscopic simulation

Mesoscopic simulation

9

Traditional Approach –

Macro to Micro

Regional Focus

Macroscopic Modeling

Corridor Focus

Microscopic Modeling

10

A Hybrid Modeling Approach –

Multi-Resolution Components

Regional Focus

Macroscopic Modeling

Subarea Focus - DTA

Mesoscopic Modeling

Corridor Focus

Microscopic Modeling

New Tools Available

Hyb

rid

Ap

pro

ach

11

VISSIM Microsimulation

Network

Microsimulation Analysis

Results

7:30 AM 5

7:35 AM

7:40 AM 15

7:45 AM

7:50 AM 25

7:55 AM

8:00 AM 35

8:05 AM

8:10 AM 45

8:15 AM

8:20 AM 55

8:25 AM

7:30 AM 5

7:35 AM

7:40 AM 15

7:45 AM

7:50 AM 25

7:55 AM

8:00 AM 35

8:05 AM

8:10 AM 45

8:15 AM

8:20 AM 55

8:25 AM

Ex

isti

ng

Mo

de

lIN

RIX

Sp

eed

Co

lor

Scale

(m

ph

)S

peed

Co

lor

Scale

(m

ph

)

I-66 Eastbound AM Peak Hour Speed Comparison

Direction of Travel

EXIT

64

EXIT

66

EXIT

68

EXIT

71

EXIT

69

EXIT

72

EXIT

73

EX

IT75

120

N Washington Lee Highway Lee HighwayLee Highway

7:30 AM 5

7:35 AM

7:40 AM 15

7:45 AM

7:50 AM 25

7:55 AM

8:00 AM 35

8:05 AM

8:10 AM 45

8:15 AM

8:20 AM 55

8:25 AM

7:30 AM 5

7:35 AM

7:40 AM 15

7:45 AM

7:50 AM 25

7:55 AM

8:00 AM 35

8:05 AM

8:10 AM 45

8:15 AM

8:20 AM 55

8:25 AM

Ex

isti

ng

Mo

de

l

Sp

eed

Co

lor

Scale

(m

ph

)

INR

IX

Sp

eed

Co

lor

Scale

(m

ph

)

I-66 Westbound AM Peak Hour Speed Comparison

Direction of Travel

EXIT

64

EXIT

66

EXIT

67

EXIT

71

EXIT

69

EXIT

73

120

N Washington Lee Highway Lee Highway

• Speed Congestion Diagram

13

Mesoscopic Modeling

Sub-Area Network

14

Open Street Map (OSM)

Link Refinement

Node Refinement

Regional TDM

Merged Network Model

15

Trip Table Processing

1. From the sub-area regional

model, aggregate trip tables to

HOV and non-HOV (HOT and

non-HOT for Build scenarios)

2. Expand trip table from peak

period demand to 5 hour

demand using expansion

factors

3. Develop trip tables for every 30

minutes

16

HOT

Non-HOT

Build VISUM Models

HOV (HOV2, HOV3+)

Non-HOV

Existing VISUM Model

SOV-Free

SOV-Toll

HOV2-Free

HOV2-Toll

HOV3-Free

HOV3-Toll

Trucks-Free

Trucks-Toll

Commercial-Free

Commercial-Toll

Airport-Free

Airport-Toll

Regional Model Trip Tables

Mesoscopic Modeling

Methods

17

VISUM Dynamic Traffic Assignment

• Deterministic, pre-determined link capacities and speeds

• With the capability of addressing queue spillover

• Dynamic User Equilibrium Assignment

• Captures time dependent changes to demand and network

VISUM Simulation Based Assignment

• Stochastic analysis based on simplified car following theory

• More realistic in representing congestion effects and queues, but takes more computing and processing time

VISSIM Meso Module

• Stochastic analysis based on simplified car following theory

• Micro and meso hybrid

• Microsimulation ready

Sample MOEs

Demand vs Throughput

18

0

5,000

10,000

15,000

20,000

5:00 5:30 6:00 6:30 7:00 7:30 8:00 8:30 9:00 9:30

Vo

lum

es

(ve

h/h

r)

Time Interval

Total Demand vs. Throughput at All Screenlines: Eastbound Direction

Demand Throughput

19

Sample MOEs

Intersection Operations

Sample MOEs

Average Speeds

20

Summary and

Lessons Learned

Static microscopic simulation

Highest level of details

Static demand and assignment

based on travel demand

forecast

Effort involved in volume

processing, balancing and OD

development

Not able to capture dynamic

variations within peak period

Pre-determined diversions to/from

arterial system

Robust and matured modeling

package

Hybrid mesoscopic DTA

Multi-level analysis resolutions

Multi-hour and dynamic traffic

assignment with time-

dependent demand and OD

data

Micro-regional impacts and

diversion analysis on key

parallel arterials

Expandable for future detailed

targeted analysis

Significant data requirements

Modeling package still under

development

21

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