A 3-D VR MODEL FOR OPTIMALALIGNMENT SEARCH SYSTEM OFHIGHWAY DESIGN (OHPASS) USINGASTER GDEM
Motoya YAMASAKITokyo University ofAgriculture
Sept １０, 2014

Motoya YAMASAKI
Masaharu INOUE
Takayuki FUKASE
Ichizuru ISHIMOTO
Ippei IWAMOTO
Shunta SHIMIZU

Contents
Introduction
Alignment modelAdoption of Genetic Algorithms
Sample study
Results
Conclusion and future work

Introduction
 How can we design good highway alignments?
 Reduce construction cost for earthwork, bridges, tunnels etc.
 Abide by legal standards and constraints
 Optimize driving safety by minimizing short curves with small radii

 In Japan:
 Most highways go through mountainous areas A great amount of earthwork, long bridges and tunnels are necessary
 Road designers have created alignments using CAD software suchas AutoCAD which includes real terrain data

Designers require automatic optimization or support systems
for designing highway alignments.

Objectives
 Automatic search for optimal 3-D alignments(horizontal and vertical performed simultaneously) Realistic alignment results(including clothoid curves)

 Abides by constraints(Japanese highway design standards)

 Considers realistic earthwork costs (with digital terrain model) andrealistic construction costs for bridges and tunnels
 Avoids inaccessible zones
 Efficient solution algorithm finds global optimum(by reducing parameters and using Genetic Algorithms)

Horizontal and Vertical Alignment
 Horizontal alignments between two passing points areclassified into three types to maximize the radius ofcurvature A curve is replaced with clothoid + circular arc + clothoid tokeep with highway design standards
 Vertical alignments are also determined and classified intothree types*For more details, please refer to the proceedings or ask me later.

Evaluation Functions (1)Construction cost
Earthwork cost
Amount of cut and fill is calculated from detailed
digital terrain data (2m x 2m mesh)
Earthwork balance is also consideredBridges and tunnels
Bridge cost is determined by length and heightTunnel cost depends on its length
Unit cost is derived from actual Japanese highway
examplesEvaluation Functions (2) Constraints and preferable conditions
 Defined by laws and design standards

 Control points (inaccessible zones)
 Horizontal zones (should be avoided, e.g. school or factory)
 Vertical zones (should have a lower elevation than the alignment,e.g. river or road) Penalties are determined

Genetic Algorithm (GA) Optimization
 Each Individual is a real number array representation ofpassing points
 A Population usually includes hundreds individuals
 Evaluation scores are calculated and include earthwork
cost, construction cost for structures, penalties foralignment constraints, preferable conditions, andinaccessible areas

Genetic Operations
 One-point crossover:
Parent individuals are divided
into two parts at the same
cutting point, and childindividuals are created.

 Mutation:
Changes in 1 or 2 parametersof randomly selected passingpoints

Conclusion
 Achievement
 Search for optimal highway 3-D alignments by GeneticAlgorithms
 Realistic alignments, constraints, and cost functions
 Development of the `OHPASS' system and evaluation with a real
highway example
 Significant improvement when compared to past designs

 Future work
 Evaluate system with various other highways
 Increase speed in PC cluster or improve algorithm
 Consider other evaluation functions (e.g.. right-of-way cost or
environmental cost)Digital TeRRAIN DATA IN OHPASS（ASTER GDEM）
Data that covers all the topographic data in the world.

Data Exchange with VR
Data links with the plug-in by UC-win/Road for Civil 3D[OHPASS][UC-win/Road]COM API[OHPASS] data exchange by COM API

Data Exchange with VR Data exchange procedure
STEP 1: Selection of the target road
*Target road list
-Road list in OHPASS-Road list in UC-win/Road*Share transferred road data

Data Exchange with VR
STEP 2: Cross section setup (OHPASSUC-win/Road)*Selection of sub-assembly and editing-Road surface type setup-Texture setup*Setup of slope / step inclines-Angle-Texture setup

Thank you

Please contact us with questions
Motoya YAMASAKI, Tokyo University of Agriculture ： m3yamasa@nodai.ac.jp