Abstract:
Highway Development and Management Tool (HDM-4) is a powerful system for the analysis of road
management and investment alternatives and it used to prepare road investment programmes and to
analyze road network strategies.
In this study HDM-4 tool is used to find the thresholds based on traffic, subgrade and climate for
upgrading minor roads in Sri Lanka.
Several road sections were defined based on different possible traffic, subgrade and Climatic
conditions for Gravel, Penetration Macadam (PM), Surface Dressed (SD), Portland Cement Concrete
(PCC) and Asphaltic Concrete (AC) pavement types. All together more than 300 sections were modeled
in the HDM-4. Level-1 calibration was done in HDM-4 to harmonize with Sri Lankan condition. Using
HDM-4 strategy analysis different rehabilitation and improvement alternatives were analyzed
maintaining existing pavement as considering base case. Analysis were done for 20 years period and
optimized to get maximum NPV.
The outcomes of the analysis, that is NPV and EIRR were compared in tabular and graphical forms in
order to identify the thresholds of traffic, subgrade and climate for each pavement category for
upgrading the surface type. This saws traffic volume is significantly affected and effect of subgrade
condition and climate is less. It saws upgrading of Gravel road to PM is not feasible unless average daily
traffic is greater than 150 vpd and it is not worthy to upgrade to PCC under considered conditions.
Upgrade of PM road to SD is feasible if traffic is greater than 600 vpd and not worthy to upgrade to AC or
PCC under the considered conditions. Upgrading of SD road to AC or PCC is not feasible under
considered traffic and other conditioned. Furthermore it can conclude minor roads in Sri Lanka can
used Gravel, PM or SD pavement type with proper maintenance under traffic volumes less than 1500
vpd and it is more economical than upgrading to AC or PCC. But AC or PCC roads can last long in good
condition even without any maintenance.
Citation:
Piyasena, Y.P.S.R., & Mampearachchi, W.K. (2011). Finding thresholds based on traffic, sub-grade and climate for upgrading surface type of roads using HDM-4 model [Abstract]. In H.R. Pasindu (Ed.), Proceedings of the Transportation Research Forum 2011 (p. 23). Department of Civil Engineering, University of Moratuwa. https://uom.lk/sites/default/files/civil/files/TRF%202011_0.pdf