8 th Road Pavements Forum 17 Nov 2004 SABITA PROJECT: Warrants for upgrading SuperSurf J Lea and P Paige-Green

BACKGROUND T ransportek 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? 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? Not a forecasting tool Does not identify options Is not a substitute for HDM4 or CB Roads

STRUCTURE 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

PROCESS l Determine financial and economic costs of base case – maintenance, rehabilitation, VOC, accident, social and environmental l Can make use of shadow costs for maintenance and rehabilitation inputs l Add options – same inputs –Defaults built in – better to use actual

INNOVATIONS l Vehicle operating costs – DBSA models and average inflation rate l Shadow cost facility for construction, maintenance and rehabilitation l Environmental costs l Social benefits l Paved road performance

SHADOW COSTS l Default in road user costs l Optional in construction, maintenance & rehab costs

SHADOW COSTS

ENVIRONMENTAL COSTS l Can “estimate” costs for different options related to various operations/activities

SOCIAL BENEFITS l Similar to environmental costs

PAVED ROAD STRATEGIES l Simple exponential deterioration model l Similar to those in most PMS’s, but based entirely on roughness

OUTPUT l Pseudo agency and economic costs l Internal Rate of Return of various options compared with base (existing) case