Pavement Management System For A National Highway Network In
India
• It is extremely important to collect all the pavement related
information for their effective management. Major part of the data,
especially on road inventory, road condition, and traffic, etc. have
been collected using manual and automated data acquisition
systems like Fifth Wheel Bump Integrator, Benkelman Beam,
Portable Falling Weight Deflectometer and Portable Skid Resistance
Tester, etc.
• All the collected data has been categorized and stored in ‘National
Highway Network’, ‘National Vehicle Fleet’, and ‘Maintenance Works
Standards’ databases, created in HDM-4.
Pavement Deterioration Models:
the deterioration model is to predict the future condition of a given
pavement section under the combined action of traffic and
environmental factors.
• The pavement deterioration models of HDM-4 incorporate both the
functional as well as structural evaluation of pavements.
• The functional evaluation of pavements is taken care of by the
cracking, ravelling, and potholing models, whereas the roughness
model takes care of both the functional as well as the structural
evaluation of pavements
• Calibration factors for various deterioration models incorporated in
HDM-4, such as cracking, ravelling, potholing and roughness models
have been obtained for Indian conditions (Aggarwal et al, 2003).
These calibration factors have been given in Table 2
• These calibrated pavement deterioration models form the basis of
prediction of future pavement distresses under the combined action
of traffic loading and climatic characteristics.
• The validity of these models has also been checked to test the
efficacy of these models, by comparing the distress predictions
made by the calibrated deterioration models with those actually
observed on the selected pavement sections.
Selection of Alternative M&R Strategies
Base Alternative: comprise of routine pavement maintenance
activities in terms of crack sealing and pothole patching only.
• The maintenance works included in the ‘Base Alternative’
are the same for all pavement sections
M&R Alternative: includes resealing, overlays and reconstruction
work activities.
• the maintenance and rehabilitation works will vary
depending upon the maintenance serviceability level, i.e.,
high, medium or low, as per the current traffic volume level
of the pavement section.
Beuib
Life-Cycle Cost Analysis of Highway Network
Maintenance and rehabilitation costs and road user benefits have
been quantified for every combination of alternative maintenance
strategies.
Costs are then computed over the analysis period and then discounted
to a base year to find the net present worth of the same.
Based ed upon this model, a decision support system has been
developed to prioritize maintenance needs of the various pavement
sections of the highway network in the event of constrained budget
allocations.
• Summary of Life-Cycle Cost Analysis - After selection of the
alternative M&R strategies, the programme analysis application
module of HDM-4 has been used to compare the total life-cycle
costs including the highway agency costs and road user costs,
predicted under the ‘Base Alternative’ of scheduled routine
maintenance against those predicted for the condition responsive
‘M&R Alternative’. The programme analysis application is run, for
doing the life cycle cost analysis of the whole pavement network.
After this analysis, the options with the highest Net Present Value
(NPV) are assigned for each pavement section. A summary of the
life-cycle cost analysis, showing the increase in highway agency
costs, and decrease in road user costs as a result of selecting the
‘M&R Alternative’ in comparison to the ‘Base Alternative’, is given in
Table 4. All these costs have been discounted to the base year 2003,
with a discount rate of 10%. Economic indicators, such as NPV/Cost
ratio and the Internal Rate of Return (IRR) have also been computed
for each pavement section.
•
• Unconstrained Works Programme –
• Year-wise Budget Requirements –
•
•
In the unconstrained works programme, if the budget required for each period is below the available budget, no
further economic analysis is necessary and the unconstrained works programme can be adopted as such.
However, if the budget needs are higher than the available budgets, two options are available: (i) Revise
maintenance standards and run the life-cycle analysis again. This will essentially include lowering the intervention
criteria for each M&R works to be applicable. (ii) Execute budget optimization
The main objective of this analysis is to compare the average condition of the highway network in terms of
pavement roughness under various levels of budget allocations.
Effect of Budget Reduction and Deferred Maintenance on Highway
Network Condition
•
nd the same has been shown in Figure 5. It is quite evident from this figure that the average roughness value of
the highway network will not change much if the maintenance is delayed by one year, but in case the application
of maintenance activities is deferred by two years, the roughness value will rise very sharply to 6 m/km IRI in the
year 2005. A further delay of one year will cause rise in roughness value up to 8 m/km IRI in the year 2006. This
will result in very high vehicle operation cost for the road users. Thus, it may be concluded that deferring the
maintenance activities has a very detrimental impact on the overall condition of the highway network. Therefore,
the M&R activities should not be delayed much from the time they have been activated by the respective
intervention levels.
CONCLUSIONS