8 th road pavements forum 17 nov 2004 sabita project: warrants for upgrading supersurf j lea and p...
TRANSCRIPT
8th Road Pavements Forum 17 Nov 2004
SABITA PROJECT:
Warrants for upgrading
SuperSurf
J Lea and P Paige-Green
BACKGROUNDBACKGROUND
• Transportek has made use of a simple spreadsheet for assessing the economics of upgrading for some time
• Sabita requested us to improve and formalise it
• To include various other components• Sort of “grandson” of SURF +
WHAT IS SUPERSURF?WHAT IS SUPERSURF?
• Does detailed economic analyses of various strategies for upgrading unsealed roads
• Tool to assist in making decisions regarding upgrading
• Economic justification for these decisions• Formalised structure
WHAT IS SUPERSURF NOT?WHAT IS SUPERSURF NOT?
• Not a forecasting tool• Does not identify options• Is not a substitute for HDM4 or CB Roads
STRUCTURESTRUCTURE
• Setup of standard inputs (discount rate, analysis period, etc)
• Standard base case – existing gravel road• Various options for upgrading
• Stage construction• Dust palliative• Bituminous surfacing
PROCESSPROCESS
Determine financial and economic costs of base case – maintenance, rehabilitation, VOC, accident, social and environmental
Can make use of shadow costs for maintenance and rehabilitation inputs
Add options – same inputs– Defaults built in – better to use actual
INNOVATIONSINNOVATIONS Vehicle operating costs – DBSA models
and average inflation rate Shadow cost facility for construction,
maintenance and rehabilitation Environmental costs Social benefits Paved road performance
SHADOW COSTSSHADOW COSTS
Default in road user costs Optional in construction, maintenance & rehab costs
ENVIRONMENTAL COSTSENVIRONMENTAL COSTS Can “estimate” costs for different options related
to various operations/activities
PAVED ROAD STRATEGIESPAVED ROAD STRATEGIES Simple exponential deterioration model Similar to those in most PMS’s, but
based entirely on roughness
Rou
ghne
ss
Initial
Failure
ESALsDesign Life Overlay Life
Initial Performance
No reseal 1 reseal 2 reseals
Overlay