Introduction and Applications

HDM-4 Concept Predicts road network performance as a function of: Traffic volumes and loading Road pavement type and strength Maintenance standards Environment / Climate Quantifies benefits to road users from: Savings in vehicle operating costs (VOC) Reduced road user travel times Decrease in number of accidents Environmental effects The HDM-4 analytical framework is based on the concept of pavement life cycle analysis. This is applied to predict the following over the life cycle of a road pavement, which is typically 15 to 40 years: Road deterioration Road work effects Road user effects Socio - Economic and Environmental effects Once constructed, road pavements deteriorate as a consequence of several factors, most notably: Traffic loading Environmental weathering Effect of inadequate drainage system

Life Cycle Analysis Roughness Time / Traffic Loading Road Agency Cost Rehabilitation Time / Traffic Loading Maintenance Standard Pavement Performance Curve Good Poor Road Agency Cost Rehabilitation Cost Time (years) Cumulative Maintenance The figure illustrates the predicted trend in pavement performance represented by the riding quality that is often measured in terms of the international roughness index (IRI). When a maintenance standard is defined, it imposes a limit to the level of deterioration that a pavement is permitted to attain. Consequently, in addition to the capital costs of road construction, the total costs that are incurred by road agencies will include the periodic maintenance, or rehabilitation works applied during the life of a pavement. These in turn depend on the standards of maintenance and improvement specified by HDM-4 users.

Rutting Rutting (mm) Pavement Age (Years) Weak Pavement Strong Pavement Pavement Age (Years)

How long does it take in Bulgaria? Crack Progression dACA = annual increase in area cracked Kcpa = calibration factor YE4 = traffic loading SNP = pavement strength How long does it take in Bulgaria?

Crack Progression Calibration

Model Calibration

Road User Effects Vehicle operating costs Travel time Road accidents fuel, oil, tyres, parts consumption vehicle utilisation & depreciation Travel time passengers cargo Road accidents Energy consumption Vehicle emissions & noise The impacts of the road condition, as well the road design standards, on road users are measured in terms of road user costs, and other social and environmental effects. Road user costs comprise: Vehicle operation costs (fuel, tyres, oil, spare parts consumption; vehicle depreciation and utilisation, etc.), Costs of travel time - for both passengers and cargo, and Costs to the economy of road accidents (that is, loss of life, injury to road users, damage to vehicles and other roadside objects). The social and environmental effects comprise vehicle emissions, energy consumption, traffic noise and other welfare benefits to the population served by the roads. Although the social and environmental effects of often difficult to quantify in monetary terms, they can be incorporated within the HDM-4 economic analyses if quantified exogenously. Note that in HDM-4, road user effects can be calculated for both motorised transport (motorcycles, cars, buses, trucks, etc.) and non-motorised transport (bicycles, human powered tricycles, animal pulled carts, etc.).

Vehicle Operation Costs Heavy Truck Bus Road User Costs ($/veh-km) Pickup/utility Car The figure illustrates the impact of road condition (represented in terms of the IRI) on the operating costs of different types of vehicles. Road User Costs in HDM-4 are calculated by predicting physical quantities of resource consumption and then multiplying these quantities by the corresponding user specified unit costs. It is necessary to ensure that the vehicle resource quantities predicted are in accordance with the range of values observed in the area of application. Rickshaw Good Road Condition (IRI) Poor

HDM-4 Applications Road sector policy studies Strategic planning of road network development, improvement & maintenance Preparation of multi-year road work programs Economic appraisal of individual road projects Research studies

Strategy Analysis Objectives: The analysis of entire road networks to determine funding needs and/or to predict future performance under budget constraints Objectives: Determine budget allocations for road maintenance and improvement Prepare for work programmes Determine long term network performance Assess impact on road users 2

Network Condition Summary Roughness in 2008 < 3.5 IRI 28% 3.5 < IRI < > 5.0 IRI 5.0 64% 8%

Impact of Budget Levels Class I Roads Annual Budget 6.0 $10m 5.0 $15m Average Roughness (IRI) 4.0 $20m Target = 3.5 IRI 3.0 2.0 2003 2004 2005 2006 2007 2008 2009

Impact of Budget Allocations Class III Roads $30m/yr Class II Roads $35m/yr Class I Roads $20m/yr

Program Analysis Preparation of single or multi-year road work and expenditure programs under specified budget constraints. Objective: prioritise candidate road projects in each year within annual budget constraint Annual budgets obtained from strategic maintenance plan

Work Program Output 2003 2004 2005

Work Program Output (2)

Project Economic Analysis Project types New construction, upgrading Reconstruction, resealing Widening, lane addition Economic indicators Net present value (NPV) Economic rate of return (ERR) Benefit cost ratio (BCR), NPV/C First year rate of return (FYRR)

Road Management Systems Data Collection Decision Support Management Information Database Inventory Condition Structures Traffic Furniture Unit Costs Standards RDBMS (RIMS) Life Cycle Analysis (HDM-4) Standard & Custom Reports

Conclusions – Why HDM-4? Transparency of analysis Economic analysis capable of: Short, medium & long term analyses What-if analysis Internationally accepted analysis framework Availability of technical expertise Local calibration