Transcript Interfacing NGSIM Lane Selection Algorithm with TSIS/CORSIM Li Zhang, Ph.D., P.E. Guanghua Zhang, JiZhan Gou Fatemeh Sayyady, Di Wu & Fan Ye January 20, 2007

Interfacing NGSIM Lane Selection
Algorithm with TSIS/CORSIM
Li Zhang, Ph.D., P.E.
Guanghua Zhang, JiZhan Gou
Fatemeh Sayyady, Di Wu & Fan Ye
January 20, 2007
Introduction
 TSIS/CORSIM is one of the best popular
traffic simulation software package in use
by many traffic engineers.
 NGSIM now has the Lane Selection Model
(LSM) available which describes the
freeway lane changing behavior
 Interfacing NGSIM Lane Selection
Algorithm with TSIS/CORSIM
Outline
 Introduction
 System Architecture
 Theoretic Issues
 Algorithms: Comparison
 Randomness
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Examples on Lane Change
Interface Verification
Project Progress
Summary
System Architecture
Call RTE Functions
Exported CORSIM
TShell
(TSIS)
CORSIM
Driver
Component
CORSIM
Server
Functions
RTE
Exported
Memory
Read
Write
NGSIM
Interface Options
RTE
Road Properties
Vehicle Properties
Driver Properties
Translator
NGSIM
Lane Information
RTE
CORSIM Shared Memory
LSA
Road Properties
Vehicle Properties
Driver Properties
NGSIM
CORSIM Language
Recommended Interface
Driver
Control/Detector
CORSIM
Component
Service
Component
Properties
Vehicle->
UpdateLaneInf
NGSIM
Vehicle
Translator
Road
CORSIM Lane Change Model
Subtle
Technical
Influences
(If/Then)
Simple Principles
& Rules (If/Then)
Kinematics
Model
Rule
Exceptions
(If/Then)
Complex
Modeling
CORSIM Discretional Lane Change
 Supply
 Motivation/Intolerable Speed: desire to
perform lane change>a random number
 Advantage: gaining in making lane change
loss in remaining in current lane
 Urgency: Urgency and Impatient Factor
 Demand: Acceptable Deceleration
CORSIM Implementation
 Mandatory Lane Change
 Motivation and Advantage are obvious
 Acceptable Deceleration calculation is the function
of different reasons (lane drop/exit)
 Anticipatory Lane Change
 Motivation is obvious
 Advantage is the function of volume
 Hiatus Period: unsafe/overlap tolerance
 Shadow vehicles: an extra vehicle on
candidate lane during Hiatus Period
NGSIM
 Demand
 Logit choice/Utility function model
 Weighted factors: distance, space, density, path
plan (exit), driver aggressiveness
 Implementation
 Explicit lane choice: relative utilities of current,
all left side lanes, and all right side lanes
 Highest lane as target lane
 Critical Gap vs. available gap
 Driver aggressiveness
 Speed difference
 Random disturbance
Comparison (1)
 Kinematics (+ If/then) vs human
driving model (utility choice)
 CORSIM
 Shadow vehicle + hiatus period
 Hard coded many parameters
 Explicit Lane changes
mandatory/discretional/Anticipatory
 Microscopic comparison with vehicle
trajectory data in BW PKW video
Comparison (2)
 NGSIM
 Considers utilities across all lanes
 Integrated mandatory/discretionary
lane changes
 Code to implement highest lane as
target lane is not found to support
the claim
 Weights may need to be calibrated
from vehicle trajectory data, how?
 Time to perform lane change is not
found in the model.
Randomness
 CORSIM
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Driver type
Motivation
Seed? Not good enough
Random number generator, good
 NGSIM
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Driver aggressiveness
Random disturbance in utility function
Seed: Computer Internal Clock Time
Random number generator: no documentation
NGSIM/LSA Using CORSIM Data
 CORSIM Provide Enough Data?
 Observe Lane Change in TRAFVU
 3 Discretional+3 Mandatory
 A Utility Program is developed to
capture data for Lane Change
 Manually Calculate the Lane Changes
 In CORSIM/NGSIM
 NGSIM Makes Mandatory Changes as
Well!
Interface Design Verification
Progress
 NGSIM LSM and FRESIM lane
changing algorithm comparison
 Manually calculate 3 cases in each
algorithm.
 Interface RTE program to change the
VLANE value (show video/TRAFVU)
 Pseudo-code of the NGSIM algorithm
 Understand the theory
Progress
 System Architecture about Interface
 Research on Both Algorithms
 Theoretic Issues
 Algorithms/Randomness
 Manually Calculation of 6 NGSIM
Examples using CORSIM Data
 Verified Interface
 Pseudo-code of the NGSIM algorithm
 Understand the theory
Future Work
 Finish Coding
Recommendation for NGSIM
Project
 An collection of source code (compliable),
consistent documentation and instructions
 An executable file and data set, output
vehicle trajectory data, intermediate utility
function data, gap data etc.
 Examples and Excel Calculations
 Improved documentations
 Data dictionary and programmers guide
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Variables
Constant
Functions
Class
Comments
Contact
Li Zhang, Ph.D., P.E.
Assistant Professor
Mississippi Transportation Research Center
Department of Civil Engineering
Mississippi State University
[email protected]
(662)3259838
http://mtrc.msstate.edu