1998_structure of the new highway development and management tools (hdm-4)

8/3/2019 1998_structure of the New Highway Development and Management Tools (Hdm-4)

1/13

STRUCTURE OF THE NEW HIGHWAY DEVELOPMENT ANDMANAGEMENT TOOLS (HDM-4)

H.R. Kerali, J.B. Odoki, D.C. Wightman and E.E. Stannard

School of Civil Engineering, The University of Birmingham, Edgbaston, Birmingham UK

Abstract

The paper describes the new Highway Development and Management tools (HDM-4)which has been developed to supersede the World Banks Highway Design andMaintenance Standards Model (HDM-III). The new HDM-4 has a broader scopeincorporating a wider range of technical relationships with three dedicated applicationstools for project level analysis, road work programming under constrained budgets, andfor strategic planning of long term network performance and expenditure needs. Inaddition to updating the HDM-III technical relationships for vehicle operating costs, and

pavement deterioration for flexible and unsealed pavements, new technical relationshipshave been introduced to model rigid concrete pavement deterioration, accident costs,traffic congestion, energy consumption and environmental effects.

1. INTRODUCTION

The Highway Design and Maintenance Standards Model (HDM-III), developed by theWorld Bank (Harral et al, 1979; Watanatada et al, 1987), has been used for over twodecades to combine technical and economic appraisals of road investment projects, andto analyse strategies and standards for road network improvements. The HDM-III model

has been instrumental in justifying increased road maintenance and rehabilitationbudgets in many countries. However, a fundamental redevelopment was required tomeet current needs. In particular new relationships for vehicle operating costs (VOC)were necessary to reflect the significant improvements in vehicle technology over thepast 20 years which have resulted in considerably lower operating costs than thosepredicted by HDM-III (Cox, 1994). In addition, whilst most applications of HDM-III havebeen in developing countries, in recent years many industrialised countries have begunto apply the model. This has resulted in a need for additional capabilities to be included,such as models for traffic congestion, a wider range of pavement types including rigidconcrete pavements and the introduction of environmental effects models. There wasalso a need to apply modern computer technology to meet current user expectations.

In order to address the above issues, the Highway Development and ManagementTools (ISOHDM) was set up in August 1993 to extend the scope of the HDM-III modeland to provide a harmonised systems approach to road management, through a set ofadaptable and user-friendly software tools (Kerali et al, 1996). Emphasis in the HDMstudy was placed on collating and applying existing knowledge, rather than undertakingmajor new empirical studies, and only limited field data collection was undertaken. Inaddition, new applications tools were developed to cater for the management needs ofroad agencies in different countries. The enhancements made to the technicalrelationships are described relative to those in HDM-III.

4th International Conference on Managing Pavements (1998)

TRB Committee AFD10 on Pavement Management Systems is providing the information contained herein for use by individual practitionersin state and local transportation agencies, researchers in academic institutions, and other members of the transportation researchcommunity. The information in this paper was taken directly from the submission of the author(s).


2/13

2. IMPROVEMENTS TO TECHNICAL RELATIONSHIPS

2.1 VOC Relationships and Vehicle Speeds

The HDM-III VOC relationships for a total of 10 representative vehicles were derivedfrom research conducted in Brazil (GEIPOT, 1982), India (CRRI, 1982), Kenya (Hide et

al, 1975) and the Caribbean (Morosiuk and Abaynayaka, 1982). In the new HDM-4,relationships for a total of 16 representative vehicles have been incorporated based onthe original HDM-III relationships updated using results from recent research conductedin New Zealand, South Africa and Australia. The vehicle speed models in the new HDM-4 are calculated separately under free-flow and congested traffic flow conditions.Revised free speed models have been developed based on the constrained speedmodel used in HDM-III. For congested traffic conditions, the three zone model proposedby Hoban (1987) have been extended to incorporate vehicle acceleration noise(Bennett, 1996) and the effects of non-motorised transport (PADECO, 1996; Yuli, 1996).Table 1 gives a list of the changes to the VOC technical relationships in HDM-4 for therepresentative vehicles summarised in Table 2 (NDLI, 1995a; Bennett, 1995).

Table 1: Comparison of VOC models in HDM-III and HDM-4

Models HDM-III HDM-4

Free Speed Model based on the 5 limitingvelocities (VDESIR, VBRAKE,VCURVE, VDRIVE andVROUGH)

Same as in HDM-III except for:

VDESIR incorporates XNMT, XFRI

VDRIVE incorporates rollingresistance

VCURVE equation form changed

VBRAKE incorporates critical

gradient length conceptCongestedSpeeds

Not modelled in HDM-III,(included in HDM95)

Model based on the 3-zone speed-flowrelationship

FuelConsumption

Uses the Brazil study fuelconsumption model

New model based on the ARFCOMmechanistic fuel model

TyreConsumption

The Brazil study tyreconsumption model: differentforms of equations for lightvehicles and for heavy vehicles

Based on the HDM-III model for heavyvehicles with;

Changed model coefficients

Congestion effects incorporated

Oil and LubricantConsumption

Predicted as a function ofroughness

Predicted as a function of fuelconsumption, engine oil capacity, and

distance between oil changes.VehicleUtilisation

Three methods are used:

Constant annual km

Constant annual hours

Adjusted utilisation method

Uses the constant annual working hoursmethod only

Vehicle ServiceLife

Two methods are used:

Constant vehicle life method

de Weilles varying life

Two methods are used:

Constant vehicle life method

Optimal vehicle life method

PartsConsumption

Two different forms of equationsare used depending on thetransitional roughness value for

each vehicle type.

One general form of equation is used.

The HDM-III exponential equationform has been dropped.

Congestion effects incorporatedLabour Hours Modelled as a function of parts

consumption and roughness.Modelled as a function of partsconsumption only.




3/13

Table 2: HDM-4 Default Representative Vehicle Classes and Basic Characteristics

Number Vehicle Type Description FuelType

Numberof Axles

Number

ofWheels

Tare

Weight(t)

Operating

Weight(t)

1 Motorcycle Motorcycle or scooter P 2 2 0.1 0.2

2 Small Car Small passenger cars P 2 4 0.8 1.0

3 Medium Car Medium passenger cars P 2 4 1.0 1.2

4 Large Car Large passenger cars P 2 4 1.2 1.45 Light Delivery Vehicle Panel van, utility or pickup truck P 2 4 1.3 1.5

6 Light Goods Vehicle Very light truck for carrying goods (4 tyres) P 2 4 0.9 1.5

7 Four Wheel Drive Land Rover/Jeep type vehicle P 2 4 1.5 1.8

8 Light Truck Small two-axle rigid truck (approx. < 3.5 t) D 2 4 1.8 2.0

9 Medium Truck Medium two-axle rigid truck (> 3.5 t) D 2 6 4.5 7.5

10 Heavy Truck Multi-axle rigid truck D 3 10 9.0 13.0

11 Articulated Truck Articulated truck or truck with draw bar trailer D 5 18 11.0 28.0

12 Mini-bus Small bus based on panel van chassis P 2 4 1.1 1.5

13 Light Bus Light bus (approx. < 3.5 t) D 2 4 1.75 2.5

14 Medium Bus Medium bus (3.5 - 8.0 t) D 2 6 4.5 6.0

15 Heavy Bus Multi-axle or large two-axle bus D 3 10 8.0 10.0

16 Coach Large bus designed for long distance travel D 3 10 10.0 15.0

Note: Fuel Type: P = Petrol, D = Diesel

Source: (NDLI, 1995a)




4/13

Table 3: HDM-4 Pavement Classification System

Surface Category PAVED UNPAVED

Surface Class Bituminous Concrete Block Unsealed

Pavement Type AMGB AMAB AMAP AMSB AMCP STGB STAB STAP STSB STCP JPCP JRCP CRCP RCCP CBSG CBLC GRUP SSUP EAUP SAUP

Surface Type AM ST JP JR CR RC CB BR GR SS EA SA

AC SST

Surface Material HRA DBST

DBM PM

etc. etc.

Base Type GB AB AP SB CP GB AB AP SB CP GB SB EB AB SG LCWBM AC CS JPCP WBM AC CS JPCP

Base Material WM HRA LS JRCP WM HRA LS JRCP

etc. DBM etc. CRCP etc. DBM etc. CRCP

etc. etc. etc. etc.

Subgrades GN

FN

Source: (NDLI, 1995b)

Notes: Surface Types Base Types MaterialsAM Asphalt Mix GB Granular Base AC Asphalt ConcreteST Surface Treatment AB Asphalt Base HRA Hot Rolled AsphaltJP Jointed Plain AP Asphalt Pavement DBM Dense Bitumen MacadamJR Jointed Reinforced SB Stabilised Base SST Single Surface TreatmentCR Continuous Reinforced CP Concrete Pavement DBST Double Surface Treatment

RC Roller Compacted EB Emulsified Base PM Penetration MacadamCB Concrete Block SG Sand/Gravel WBM Water Bound MacadamBR Brick LC Lean ConcreteGR GravelSS Set Stone SubgradesEA Earth GN GranularSA Sand FN Fine




5/13

2.2 Road Deterioration and Maintenance

A comprehensive framework for road deterioration relationships has been designed forHDM-4. A set of generic models, based on those used in HDM-III (Paterson, 1987), has

been specified with different parameter values to cater for a wide range of pavementtypes. The pavement classification system used in HDM-4 depends on the surface typeand base type, as given in Table 3 (NDLI, 1995b). Separate relationships are providedfor the pavement defects summarised in Table 4.

Table 4: Pavement defects modelled in HDM-4

Bituminous Concrete Block*

Unsealed

Cracking Cracking Rutting Gravel lossRutting Joint spalling Surface texture Roughness

Ravelling Faulting RoughnessPot-holing FailuresEdge break Serviceability ratingSurface texture RoughnessSkid resistanceRoughness

* - Not yet implemented in HDM-4Source: (Paterson, 1987; Riley and Bennett, 1996; LAST, 1995).

2.3 Road works

Road works in HDM-4 have been categorised as follows (Odoki, 1995):

(i) Routine maintenance: Works that should be undertaken each year, normallywithin the recurrent budget. These include cyclic and reactive maintenanceactivities.

(ii) Periodic maintenance: Works planned to be undertaken at intervals of severalyears and are typically funded within recurrent or capital budgets. These include;preventive maintenance, resurfacing, overlays and pavement reconstruction.

(iii) Special works: The frequency for these cannot be estimated with certainty.These are typically funded from special or contingency budgets, but sometimesfrom recurrent budget. This category includes emergency and wintermaintenance.

(iv) Development: Road network improvements planned at discrete points in timeand normally funded from the capital budget. These include widening,realignment and construction of new road sections.

The effect of road works on pavement performance depends on the characteristics ofthe individual works activity and the frequency of application.

2.3.1 Effect of road works

The impact of road works is normally felt in terms of vehicle speed changes and




6/13

stop/start conditions. This results in additional travel time and vehicle resourceconsumption. A stand-alone road works effects module has been designed for HDM-4 toestimate the additional travel time and VOC resource consumption (Greenwood, 1996).The results from this can be included within the HDM-4 economic analysis framework.Table 5 gives a summary of changes to the road deterioration and maintenance effectsrelationships in HDM-4.

Table 5. Comparison of Road Deterioration Models in HDM-III and HDM-4

RDMIE Models HDM-III HDM-4

Road Surface Classes BituminousUnsealed

BituminousUnsealedConcreteBlocks (proposed)

Pavement StrengthMeasures

Structural NumberBenkleman Beam deflection

Structural NumberBenkleman Beam deflectionFWD (proposed)

Construction Quality A single indicator (CQ), with adiscrete value of 0 or 1

Two indicators CDB and CDR,continuous variables rangingbetween 0 and 1.5

Cracking Comprises:All cracking, Wide cracking,Indexed cracking

Comprises:Structural cracking (All, Wide,Indexed), Reflection cracking

Ravelling As in HDM-III, but changes inmodel coefficients

Potholing Predicted as percentage area ofthe carriageway

Predicted as number of potholesper km

Edge Break Not modelled Included

Rutting Initial densificationStructural deterioration

Initial densificationStructural deteriorationPlastic deformationWear by studded tyres

Roughness (IRI) Comprising:Structural deterioration, CrackingRutting, Potholing, Environment

Comprising:Structural deterioration, CrackingRutting, Potholing, Environment,Patching

Texture Depth (TD) Not modelled IncludedSkid Resistance Not modelled Included

Road Maintenance Additional works types:Mill and replace, Inlay, Edgerepair, Crack sealing

Road Improvements (i.e.,Capacity improvement)

Not modelled Additional types:Widening, Realignment

New Construction withDiverted Traffic

Diverted traffic not considered Diverted traffic included




7/13

2.4 Road Accidents, Energy Consumption and Environmental effects

The new HDM-4 incorporates accident costs within the economic analysis framework.The estimation process applies user specified accident rates and monetary values for

different accident severity according to road stereotypes (Kerali et al, 1996).

Energy consumption models have been incorporated for estimating the total life cycleenergy consumption due to road works, vehicle operation and vehicle production. Theseare calculated in terms of both national and global energy consumption totals (ETSU,1996).

Vehicle emission relationships have been developed for estimating volumes of thefollowing; hydrocarbons, carbon monoxide, nitrogen oxides, carbon dioxide, sulphurdioxide, lead and particulates. The relationships are based on a number of parametersincluding pavement condition, road alignment, speed limit, and road cross-section(Hammerstrom, 1995).

Table 6. Additional Models included in HDM-4

Components HDM-III HDM-4

Road Safety Not modelled Includes road accidents on sectionsand at nodes

Vehicle Emissions Not modelled Different types of emissions arepredicted as a function of fuelconsumption, vehicle speed and

average vehicle lifeEnergy Balance Not modelled Models global and national life-cycle

energy use as a function of fuel, oil,tyre and parts consumption.Includes energy used in vehicleproduction and fuel production.

3. DATA REQUIREMENTS

3.1 Road Network Definition

The road network representation in the new HDM-4 views a road network as anintegrated set of sections and nodes (Kerali et al, 1996). Each section is analysedseparately as a homogeneous unit.

Within a road network, nodes mark points at which traffic characteristics or road featureschange significantly. Although the specification of nodes in HDM-4 is optional, thefacility is provided for future extensions and for compatibility with pavementmanagement systems (PMS) and geographic information systems (GIS). The types ofnodes catered for in HDM-4 are;




8/13

(i) intersections or junctions,(ii) intermediate nodes (e.g. start or end of dual carriageways, administrative

boundaries, etc.), or(iii) dead-ends (i.e. start or end of a road).

In future extensions to HDM-4, nodes may be included in the analyses of accidents atintersections, or in transportation models of traffic movements.

A section is a segment of road which is homogeneous in terms of its physicalcharacteristics. The homogeneous section is the default entity for all calculations ofpavement deterioration, construction and maintenance costs, and road user effects. Thedata required to define sections in HDM-4 include the physical characteristics,pavement condition, average daily traffic, and a number of calibration parameters.

3.2 Data Structure

The new HDM-4 requires a wider range of data input, when compared to HDM-III.Consequently, a tiered data structure has been designed. The first tier comprisesmandatory data which define the characteristics of the road network (e.g., length, width,pavement type, terrain, climate, etc.), and the representative vehicle characteristics(e.g., fuel type, weights, etc.). Some of this data could be specified in aggregate terms,for example, the terrain could be specified as either flat, rolling, hilly or mountainous.User defined default attributes are then assigned to the variables required in the HDM-4models based on the aggregate data. The second tier comprises detailed data requiredto define precisely the parameters in the HDM-4 models. These include details of the

pavement structure, material characteristics, geometric characteristics, etc.

3.3 Calibration and Validation

The new HDM-4 is designed to be used in a wide range of environments. Acomprehensive calibration facility has been developed to facilitate its adaptation indifferent countries. The technical relationships described above incorporate parametersthat can be adjusted to suit the observed performance of roads and vehicles in mostcountries. A number of default calibration data sets will be provided for different regionsto simplify initial use throughout the world. These may be updated in each countrywhere HDM-4 is used to obtain more accurate predictions of pavement and vehicle

performance.

4. APPLICATION MODULES

Separate application modules have been developed for project analysis, workprogramming, and network strategy analysis (Kerali et al, 1995).

4.4 Project Analysis

Project analysis is concerned with the evaluation of one or more road projects or

investment options. Each road section can be assigned user-specified treatments. The




9/13

costs and benefits for these are calculated for each year of the analysis period.Economic indicators are then determined by comparing different investment options.Typical project analyses include the appraisal of maintenance and rehabilitation optionsfor existing roads, widening or geometric improvement schemes, pavement upgrading,new road construction, etc.

4.5 Work Programming

Programme analysis is concerned with the preparation of work programmes in whichcandidate investment options are identified and selected, subject to resourceconstraints. Road networks are analysed section by section and estimates are producedof road works and expenditure requirements for each section over a funding periodwhich is typically less than 5 years. Programme analysis may be used to prepare multi-year rolling work programmes.

4.6 Network Strategy Analysis

Strategic planning is concerned with the analysis of a chosen network as a whole. Atypical application is the preparation of long range planning estimates of expenditureneeds for road network development and maintenance under different budgetscenarios. The road network is characterised by lengths of road in different categoriesdefined by parameters such as road class, surface type, pavement condition or trafficflow. Estimates are produced of expenditure requirements for medium to long termperiods of between 5 to 40 years.

5. SYSTEM STRUCTURE

The overall structure of the new HDM-4 software is illustrated in Figure 1. Separatesoftware modules have been developed using Visual C++ and object-oriented databasetools to operate under Microsoft Windows for each of the applications:

Project analysis Programme analysis Network strategy analysis

The analysis tools operate on data objects defined in the following data managers:

Road network manager; defines characteristics of the road network elements(sections and nodes).

Vehicle fleet manager; defines the characteristics of the representativevehicle fleet.

HDM-4 set-up; defines the default data to be used during the analysis. A setof default data will be provided with the system, but users will have to modifythese to reflect local conditions and circumstances.

HDM-4 file converter; facilitates data exchange with external systems, suchas pavement management systems.




10/13

Figure 1. HDM-4 Software Modules

6. CONCLUSION

The software development phase of the International Study of HDM was followed byextensive software testing and full scale field trials of the completed HDM-4 softwareunder real project conditions. The objective was to validate the technical relationshipsbuilt into the modules and to conduct a comprehensive test of the software.Comparisons were carried out between the results obtained from HDM-4 analysesagainst those produced by HDM-III. The results of the pilot trials will be used to prepare

regional default data sets which will be supplied with the final software package.Regional training centres will be established to disseminate and train a wide cross-section of users. The overall benefit of the new HDM-4 to the international communitywill be the introduction of a standardised set of applications for project analysis, workprogramming and budgeting, and for road network strategy analysis.

ACKNOWLEDGEMENTS

The development of HDM-4 has been sponsored by several agencies, including theWorld Bank, the United Kingdom Department for International Development (DFID), theAsian Development Bank (ADB), the Swedish National Road Administration (SNRA),

the Federation of Intra-American Cement Manufacturers (FICEM), and the Finnish RoadAdministration (FinnRA). Many other organisations and individuals in a number ofcountries have made significant contributions by providing information, or undertakingtechnical review of products. The study has been co-ordinated by the ISOHDMSecretariat based within the Highways Management Research Group (HMRG) withinthe School of Civil Engineering at the University of Birmingham in the United Kingdom.The key organisations involved in the HDM-4 development were:

the HMRG responsible for system design and software development. N D Lea International Limited based at the Road Research Institute in

Malaysia (IKRAM) were responsible for updating the technical relationships

for road user costs and for road deterioration and maintenance effects.




11/13


12/13

Research Laboratory.

HIDE, H, (1982). Vehicle operating costs in the Caribbean: results of a survey of

vehicle operators. TRRL Laboratory Report 1031. Crowthorne: Transport and Road

Research Laboratory.

HOBAN, C J, (1987). Evaluating traffic capacity and improvements to geometry.Technical Paper Number 74, The World Bank, Washington DC, USA.

KERALI, H R, R ROBINSON and V MANNISTO, (1995). Strategic and Programme

Analysis Specifications. International Study of Highway Development and

Management Tools, School of Civil Engineering, The University of Birmingham.

KERALI, H R, J B Odoki and D C Wightman (1996). The New HDM-4 Analytical

Framework. Proceedings, Combined 18th ARRB Transport Research Conference andTransit New Zealand Symposium, Christchurch, New Zealand, Part 4 (AssetManagement).

KERALI, H R et al(1996). HDM-4 Inception Workshop, October 1993. Proceedings,Combined 18th ARRB Transport Research Conference and Transit New ZealandSymposium, Christchurch, New Zealand, Part 4 (Asset Management).

LAST (1995). Concrete Pavement Performance Equations. Latin American StudyTeam, International Study of Highway Development and Management Tools, School ofCivil Engineering, The University of Birmingham.

MOROSIUK, G and S W ABAYNAYAKA, (1982). Vehicle operating costs in the

Caribbean: an experimental study of vehicle performance. TRRL Laboratory Report

1056. Crowthorne: Transport and Road Research Laboratory.

NDLI (1995a). Modelling Road User Effects in HDM-4. Final Project Report, AsianDevelopment Bank, RETA 5549, N.D. Lea International Limited, Vancouver, Canada.

NDLI (1995b). Modelling Road Deterioration and Maintenance Effects in

HDM-4. Final Project Report, Asian Development Bank, RETA 5549, N.D. LeaInternational Limited, Vancouver, BC, Canada.

ODOKI, J B and H R KERALI, (1996). Road Maintenance and Improvement Effects

Models. International Study of Highway Development and Management Tools, Schoolof Civil Engineering, The University of Birmingham.

PADECO (1996). HDM-4 Non Motorised Transport Modelling. International Study ofHighway Development and Management Tools, School of Civil Engineering, TheUniversity of Birmingham.

PATERSON, W D O (1987). Road Deterioration and Maintenance Effects: Models

for Planning and Management. The Highway Design and Maintenance Standards




13/13

Series. The World Bank, Johns Hopkins Press, Baltimore, USA.

RILEY, M J and C R BENNETT, (1996). Specifications for HDM-4 Road Deterioration

and Maintenance Effects Models. International Study of Highway Development and

Management Tools, School of Civil Engineering, The University of Birmingham.

YULI, P (1996). Development of Speed and Fuel Consumption Models for Chinese

Vehicles. PhD Thesis, School of Civil Engineering, The University of Birmingham.

WATANATADA, T et al, (1987). The Highway Design And Maintenance Standards

Model Volume 1: Description of the HDM-III Model. The Highway Design andMaintenance Standards Series. The World Bank, Johns Hopkins Press, Baltimore, USA.

KEYWORDS

Project Appraisal, Highway Economics, Vehicle Operating Costs, Energy Consumption,Vehicle Emissions.


TRB Committee AFD10 on Pavement Management Systems is providing the information contained herein for use by individual practitionersin state and local transportation agencies, researchers in academic institutions, and other members of the transportation researchcommunity The information in this paper was taken directly from the submission of the author(s)

1998_structure of the new highway development and management tools (hdm-4)

Documents