TRANSPORT NOTES ROADS AND RURAL TRANSPORT THEMATIC GROUP THE WORLD BANK, WASHINGTON, DC Transport Note No. TRN-2 November 2004 Economically Justified Levels of Road Works Expenditures on Unpaved Roads Rodrigo Archondo-Callao Unpaved roads require periodic road works to maintain a certain road condition over time, comprising typically of routine maintenance, grading, spot regravelling, and regravelling activities, which require planning and economic justification. A main concern in developing counties is defining a proper level of investments and quality of maintenance on unpaved roads. This technical note, targeted to road sector professionals, presents a methodology for an analytical study done to access economically justified levels of road works expenditures on unpaved roads with different traffic levels. The results presented in this technical note should be considered no more than a first approximation of country specific results. To obtain country specific results, the methodology should be replicated and adapted with refined country data. INTRODUCTION characterized by road roughness or vehicles speeds, at the dry and wet seasons, and (ii) generated An economic evaluation measures the economic worth of traffic as a function of a user-defined price elasticity alternative investment and maintenance choices of demand for transport. (project-alternatives) in order to ensure an optimal allocation of resources. It quantifies the economic This technical note presents the methodology and benefits and costs of each project-alternative compared sample results obtained applying RED version 3.1 for the to a "without project-alternative," which represents a evaluation of roads with traffic between 10 and 100 do-minimum scenario. For each project-alternative, motorized average annual daily traffic (AADT), excluding road agency and road user costs are computed for a motorcycles. The methodology consists of defining road defined analysis period, and the resulting flow of net quality levels, estimating road agency and user costs, benefits, compared to the without project-alternative, is and performing the economic evaluation and sensitivity discounted at a given discount rate. The economic analysis. comparison of project-alternatives is done analyzing their net present value of benefits (NPV). Most ROAD QUALITY LEVELS measured benefits are reduction on vehicle operating, passenger time and road accident costs. A simplified The first step is to define possible road quality levels economic evaluation not normally includes measurement provided by a road, which is characterized by surface of social impacts, such as health benefits of all-year type, road access quality and ride quality. Ride quality is access, or environmental impacts, such as dust emis- measured by road roughness that is the irregularity of sions. These impacts are important; therefore, could be the road surface; it affects the dynamics of moving considered during the final decision making process. vehicles, wear of vehicle parts, and the handling of a vehicle. It is difficult to characterize roughness of An economic evaluation is more relevant for roads that unpaved roads because it is (i) difficult to measure with serve an economic function and have established traffic, equipment; (ii) changes quickly over time, and (iii) rather than for roads that serve a social function (i.e., depends on the path taken. A subjective assessment(4)(5) provide access to rural populations), which are typically is, therefore, needed. The table below presents the road very low volume roads with traffic less than 50 vehicles quality levels for unpaved and paved roads defined for per day, for which a cost effectiveness analysis or multi- this study, which considers the entire range of criteria analysis is recommended.(1) An economic roughness values. The roughness values to be evaluation of project-alternatives can be done using a associated with each road quality level varies by country road investment model such as: due to different road surface materials, climate and maintenance practices; therefore, they should be The Highway Development and Management Model adapted to the characteristics of a particular country. (HDM-4),(2) which estimates over time the annual deterioration of paved and unpaved roads and the Unpaved Unreliable Access represents roads that do not resulting road agency and road user costs, or provide all-year access due to periods when motorized The Roads Economic Decision Model (RED),(3) which traffic is interrupted. The other road quality levels does not estimate over time the annual provide all-year access. Note that although the deterioration of paved or unpaved roads, but is roughness of some unpaved and paved quality levels is customized for the economic evaluation of unpaved similar, the roughness similarity should not undermine roads by estimating: (i) road user costs, other differences between paved and unpaved surfaces, such as dust and other environmental impacts. Page 2 Transport Note No. TRN-2 November 2004 Table 1. Analytical Road Quality Levels for Unpaved and Paved Roads Road Access Quality Ride Quality Dry Season Wet Season Roughness 4 Wheel- 2 Wheel 4 Wheel 2 Wheel Dry Wet Road Quality Level Drive Drive Drive Drive Season Season Unpaved Unreliable Access Unreliable Unreliable Unreliable Unreliable NA NA Unpaved Very Poor Normal Difficult Difficult Difficult 22.0 25.0 Unpaved Poor Normal Normal Difficult Difficult 17.0 25.0 Unpaved Fair Normal Normal Normal Difficult 13.0 22.0 Unpaved Good Normal Normal Normal Normal 10.0 10.0 Unpaved Very Good Normal Normal Normal Normal 7.0 7.0 Paved Very Poor Normal Normal Normal Normal 12.0 12.0 Paved Poor Normal Normal Normal Normal 8.0 8.0 Paved Fair Normal Normal Normal Normal 4.0 4.0 Paved Good Normal Normal Normal Normal 3.0 3.0 Paved Very Good Normal Normal Normal Normal 2.0 2.0 NA = Not Applicable ROAD USERS AND ROAD AGENCY COSTS which were computed for this study, with the HDM-4 VOC module of RED version 3.1, based on medium The second step is to compute unit road user cost and values of data collected worldwide on vehicle unit costs. road agency costs. The table below presents the car The fleet costs are based on a typical vehicle fleet speeds and vehicle fleet vehicle operating costs (VOC), composition comprising 40 percent cars and pickups, 20 value of time costs (VOT), and road user costs (RUC), percent buses, and 40 percent trucks. Table 2: Car Speeds and Unit Road User Costs per Season Dry season Wet Season Car Fleet Fleet Fleet Car Fleet Fleet Fleet Speed VOC VOT RUC Speed VOC VOT RUC Road Quality Level (km/hr) ($/v-km) ($/v-km) ($/v-km) (km/hr) ($/v-km) ($/v-km) ($/v-km) Unpaved Very Poor 28 0.515 0.109 0.624 25 0.560 0.124 0.684 Unpaved Poor 37 0.439 0.085 0.523 25 0.560 0.124 0.684 Unpaved Fair 48 0.375 0.065 0.441 28 0.515 0.109 0.624 Unpaved Good 61 0.330 0.051 0.381 61 0.330 0.051 0.381 Unpaved Very Good 78 0.288 0.040 0.328 78 0.288 0.040 0.328 Paved Very Poor 52 0.360 0.060 0.420 52 0.360 0.060 0.420 Paved Poor 72 0.301 0.043 0.345 72 0.301 0.043 0.345 Paved Fair 84 0.247 0.037 0.284 84 0.247 0.037 0.284 Paved Good 85 0.234 0.037 0.271 85 0.234 0.037 0.271 Paved Very Good 85 0.230 0.037 0.267 85 0.230 0.037 0.267 Considering ninety days as the extent of the wet season, annual road roughness and Figure 2 the vehicle fleet the Figure 1 presents the corresponding average unit road user costs, in $ per vehicle-km. Figure 1. Average Annual Roughness (IRI) Figure 2. Average Annual Vehicle Fleet Road User Costs Paved Very Good 2.0 Paved Very Good 0.267 Paved Good 3.0 Paved Good 0.271 Paved Fair 4.0 Paved Fair 0.284 Paved Poor 8.0 Paved Poor 0.345 Paved Very Poor 12.0 Paved Very Poor 0.420 Unpaved Very Good 7.0 Unpaved Very Good 0.328 Unpaved Good 10.0 Unpaved Good 0.381 Unpaved Fair 15.2 Unpaved Fair 0.486 Unpaved Poor 19.0 Unpaved Poor 0.563 Unpaved Very Poor 22.7 Unpaved Very Poor 0.639 0.0 5.0 10.0 15.0 20.0 25.0 0.000 0.100 0.200 0.300 0.400 0.500 0.600 0.700 Roughness (IRI) Road User Costs ($/vehicle-km) Page 3 Transport Note No. TRN-2 November 2004 Figure 3. Annualized Road Maintenance Costs country specific data. Annualized maintenance costs Needed to Maintain a Road Quality Level at the consist of recurrent maintenance activities, such as Same Road Condition ($/km-year) routine maintenance, gradings and spot regravelling, and annualized periodic maintenance activities, such as Paved Very Good 9,000 regravelling or overlays. Figure 3 presents annualized PavedGood 8,000 maintenance costs needed to maintain a road quality level of low volume roads, which were estimated based Paved Fair 6,500 on typical road works unit costs(6). For example, to keep Paved Poor 4,000 an unpaved road in good condition, one needs $3,000 PavedVery Poor 2,500 per km per year, which is comprised of $700 for routine Unpaved Very Good 4,000 maintenance and spot regravelling, $300 for gradings, UnpavedGood 3,000 and $2,000 for annualized regravelling ($8,000 Unpaved Fair 1,500 regravelling cost divided by four years time interval). A Unpaved Poor 1,000 more comprehensive study would estimate different annualized maintenance needs per traffic level. UnpavedVery Poor 500 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 Investment costs needed to improve the road condition Annualized Maintenance Costs ($/km-yr) from a road quality level to a better road quality level are estimated based on country specific data. Table 3 Annualized maintenance costs needed to maintain a presents investments estimated for this study, based on road quality level over the years are estimated based on typical worldwide road works costs.(4) Table 3. Investment Costs Needed to Improve a Road Quality Level (000$/km) To Road Quality Level From Road Quality Unpaved Unpaved Unpaved Unpaved Paved Paved Level Poor Fair Good Very Good Fair Good Unpaved Very Poor 5 10 30 95 155 255 Unpaved Poor 5 25 90 150 220 Unpaved Fair 20 85 145 215 Unpaved Good 65 125 195 Unpaved Very Good 60 130 Paved Fair 70 ECONOMIC EVALUATION with reliable access. For roads with higher traffic, a higher road quality level could be considered to A key element for a proper economic evaluation is the represent the do-minimum scenario. definition of without-project alternative, which repre- The first evaluation considers a road in very poor. Four sents a pragmatic do-minimum scenario and is a project-alternatives are evaluated ranging from improve function of the traffic and importance of the road. On the road marginally to poor condition to improve the this study, considering the relatively low traffic ranging road substantially to very good condition. No paving from 10 to 100 AADT, the without-project alternative alternatives are considered due to low traffic. The table consists of keeping the road in very poor condition, but below presents the project-alternatives being evaluated. Table 4 Project Alternatives Investment Maintenance Average Project Alternative Cost Cost Roughness Alternative Description (000$/km) ($/km-yr) (IRI) Without Project-Alternative Keep Unpaved Very Poor 0 500 22.7 Project-Alternative 1 Improve to Unpaved Poor 5 1,000 19.0 Project-Alternative 2 Improve to Unpaved Fair 10 1,500 15.2 Project-Alternative 3 Improve to Unpaved Good 30 3,000 10.0 Project-Alternative 4 Improve to Unpaved Very Good 95 4,000 7.0 The main economic evaluation assumptions are the Annual traffic growth rate is 3 percent, and the following: generated traffic elasticity of demand is 1.0 for all vehicles. Evaluation period is 15 years and discount rate is 12 percent; The table below presents the resulting NPV and present Traffic composition of cars is 40 percent for traffic value of agency costs for traffic varying from 10 to 100 less than 50 AADT, and 50 percent for traffic motorized AADT. between 50 and 100 AADT, and Page 4 Transport Note No. TRN-2 November 2004 Table 5. Economic Comparison of Project-Alternatives PV Agency Net Present Value (000$/km) Road Quality Level Costs Average Daily Traffic (AADT) (000$/km) 10 20 30 40 50 60 70 80 90 100 Unpaved Very Poor 3.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Unpaved Poor 11.6 -4.5 -2.0 0.6 3.1 5.7 6.9 9.2 11.6 13.9 16.2 Unpaved Fair 19.9 -8.9 -3.8 1.4 6.6 11.8 14.3 19.1 23.8 28.5 33.3 Unpaved Good 49.9 -30.5 -21.3 -12.2 -3.0 6.1 10.5 18.8 27.2 35.5 43.9 Unpaved Very Good 121.5 -89.2 -78.0 -66.7 -55.4 -44.2 -38.8 -28.5 -18.2 -8.0 2.3 The following graphs present the comparison of the project-alternatives in terms of NPV. Figure 4. Net Present Value of Alternative Levels of Service (10 to 50 AADT) 100.0 )mk/$ 50.0 000( 0.0 eulaVt 0.0 20.0 40.0 60.0 80.0 100.0 120.0 enserPteN -50.0 -100.0 Very Poor Poor Fair Good Very Good (23 IRI) (19 IRI) (15IRI) (10 IRI) (7 IRI) -150.0 PV of Investment and Maintenance Cost (000$/km) 10 AADT 20 AADT 30 AADT 40 AADT 50 AADT Figure 5. Net Present Value of Alternative Levels of Service (60 to 100 AADT) 100.0 )mk/$ 50.0 000( 0.0 eulaVtneserPteN 0.0 20.0 40.0 60.0 80.0 100.0 120.0 -50.0 -100.0 Very Poor Poor Fair Good Very Good (23 IRI) (19IRI) (15IRI) (10 IRI) (7 IRI) -150.0 PV of Investment and Maintenance Cost (000$/km) 60 AADT 70 AADT 80 AADT 90 AADT 100 AADT Page 5 Transport Note No. TRN-2 November 2004 The evaluation determines for a given traffic level: (i) which is the one with highest NPV, and (iii) highest lowest economically justified road quality level, which is economically justified road quality level, which is the one the one with lower agency costs yielding a positive NPV; with highest agency costs yielding a positive NPV. The (ii) optimal economically justified road quality level, table below presents the economic evaluation results. Table 6. Economic Evaluation Results: Road in Very Poor Condition Daily Investment Annualized Average Traffic Cost Maintenance Roughness (AADT) Road Quality Level (000$/km) ($/km-yr) (IRI) Lowest Economically Justified Road Quality Level 10 Unpaved Very Poor 0 500 22.7 20 Unpaved Very Poor 0 500 22.7 30 Unpaved Poor 5 1,000 19.0 40 Unpaved Poor 5 1,000 19.0 50 Unpaved Poor 5 1,000 19.0 60 Unpaved Poor 5 1,000 19.0 70 Unpaved Poor 5 1,000 19.0 80 Unpaved Poor 5 1,000 19.0 90 Unpaved Poor 5 1,000 19.0 100 Unpaved Poor 5 1,000 19.0 Optimal Economically Justified Road Quality Level 10 Unpaved Very Poor 0 500 22.7 20 Unpaved Very Poor 0 500 22.7 30 Unpaved Fair 10 1,500 15.2 40 Unpaved Fair 10 1,500 15.2 50 Unpaved Fair 10 1,500 15.2 60 Unpaved Fair 10 1,500 15.2 70 Unpaved Fair 10 1,500 15.2 80 Unpaved Good 30 3,000 10.0 90 Unpaved Good 30 3,000 10.0 100 Unpaved Good 30 3,000 10.0 Highest Economically Justified Road Quality Level 10 Unpaved Very Poor 0 500 22.7 20 Unpaved Very Poor 0 500 22.7 30 Unpaved Fair 10 1,500 15.2 40 Unpaved Fair 10 1,500 15.2 50 Unpaved Good 30 3,000 10.0 60 Unpaved Good 30 3,000 10.0 70 Unpaved Good 30 3,000 10.0 80 Unpaved Good 30 3,000 10.0 90 Unpaved Good 30 3,000 10.0 100 Unpaved Very Good 95 4,000 7.0 The graph below presents the lowest, optimal and highest economically justified annualized maintenance costs. Figure 6. Annualized Maintenance Expenditures per Traffic Level p p 4 ,50 0 4 ,00 0 es urti 3 ,50 0 ndepxEe 3 ,00 0 nc )ry 2 ,50 0 nae m-k/ ntaiM ($2 ,00 0 edzil 1 ,50 0 ua 1 ,00 0 nnA 50 0 0 0 1 0 2 0 30 4 0 50 60 7 0 8 0 90 10 0 Averag e D a ily Traff ic (A AD T) Optim um H igh est Low e st Page 6 Transport Note No. TRN-2 November 2004 The second evaluation considers a road that is in fair alternatives considered, which includes lowering the condition. The table below summarizes the project- road quality level to very poor or poor condition. Table 7. Project-Alternatives Investment Maintenance Average Project Alternative Cost Cost Roughness Alternative Description (000$/km) ($/km-yr) (IRI) Without-Project Alternative Lower Standard to Very Poor 0 500 22.7 Project-Alternative 1 Lower Standard to Unpaved Poor 0 1,000 19.0 Project-Alternative 2 Keep Unpaved Fair 0 1,500 15.2 Project-Alternative 3 Improve to Unpaved Good 20 3,000 10.0 Project-Alternative 4 Improve to Unpaved Very Good 85 4,000 7.0 The table below presents the economic evaluation results. Table 8. Economic Evaluation Results: Road in Fair Condition Daily Investment Annualized Average Traffic Cost Maintenance Roughness (AADT) Road Quality Level (000$/km) ($/km-yr) (IRI) Lowest Economically Justified Road Quality Level 10 Unpaved Very Poor 0 500 22.7 20 Unpaved Poor 0 1,000 19.0 30 Unpaved Poor 0 1,000 19.0 40 Unpaved Poor 0 1,000 19.0 50 Unpaved Poor 0 1,000 19.0 60 Unpaved Poor 0 1,000 19.0 70 Unpaved Poor 0 1,000 19.0 80 Unpaved Poor 0 1,000 19.0 90 Unpaved Poor 0 1,000 19.0 100 Unpaved Poor 0 1,000 19.0 Optimal Economically Justified Road Quality Level 10 Unpaved Very Poor 0 500 22.7 20 Unpaved Fair 0 1,500 15.2 30 Unpaved Fair 0 1,500 15.2 40 Unpaved Fair 0 1,500 15.2 50 Unpaved Fair 0 1,500 15.2 60 Unpaved Fair 0 1,500 15.2 70 Unpaved Fair 0 1,500 15.2 80 Unpaved Good 20 3,000 10.0 90 Unpaved Good 20 3,000 10.0 100 Unpaved Good 20 3,000 10.0 Highest Economically Justified Road Quality Level 10 Unpaved Very Poor 0 500 22.7 20 Unpaved Very Poor 0 500 22.7 30 Unpaved Fair 0 1,500 15.2 40 Unpaved Fair 0 1,500 15.2 50 Unpaved Good 20 3,000 10.0 60 Unpaved Good 20 3,000 10.0 70 Unpaved Good 20 3,000 10.0 80 Unpaved Good 20 3,000 10.0 90 Unpaved Very Good 85 4,000 7.0 100 Unpaved Very Good 85 4,000 7.0 The levels of service found for the road in fair condition needs per traffic level for the lowest, optimal and are essentially the same as for the road in very poor highest economically justified road quality level. condition, thus, confirming the annualized maintenance Page 7 Transport Note No. TRN-2 November 2004 SENSITIVITY ANALYSIS annual growth rate from 0 to 6 percent and the For the road that is in very poor condition, the following generated traffic elasticity of demand from 0.5 to 1.5 for table presents a sensitivity analysis varying the traffic all vehicles. Table 9. Traffic Growth Rare and Elasticity of Demand Sensitivity Analysis Optimal Economically Justified Road Quality Level Traffic Growth = 0% Growth = 3% Growth = 6% (AADT) Elasticity = 0.5 Elasticity = 0.5 Elasticity = 0.5 10 Unpaved Very Poor Unpaved Very Poor Unpaved Very Poor 20 Unpaved Very Poor Unpaved Very Poor Unpaved Very Poor 30 Unpaved Very Poor Unpaved Fair Unpaved Fair 40 Unpaved Fair Unpaved Fair Unpaved Fair 50 Unpaved Fair Unpaved Fair Unpaved Fair 60 Unpaved Fair Unpaved Fair Unpaved Fair 70 Unpaved Fair Unpaved Fair Unpaved Good 80 Unpaved Fair Unpaved Good Unpaved Good 90 Unpaved Fair Unpaved Good Unpaved Good 100 Unpaved Good Unpaved Good Unpaved Good Traffic Growth = 0% Growth = 3% Growth = 6% (AADT) Elasticity = 1.0 Elasticity = 1.0 Elasticity = 1.0 10 Unpaved Very Poor Unpaved Very Poor Unpaved Very Poor 20 Unpaved Very Poor Unpaved Very Poor Unpaved Very Poor 30 Unpaved Very Poor Unpaved Fair Unpaved Fair 40 Unpaved Fair Unpaved Fair Unpaved Fair 50 Unpaved Fair Unpaved Fair Unpaved Fair 60 Unpaved Fair Unpaved Fair Unpaved Good 70 Unpaved Fair Unpaved Fair Unpaved Good 80 Unpaved Fair Unpaved Good Unpaved Good 90 Unpaved Good Unpaved Good Unpaved Good 100 Unpaved Good Unpaved Good Unpaved Good Traffic Growth = 0% Growth = 3% Growth = 6% (AADT) Elasticity = 1.5 Elasticity = 1.5 Elasticity = 1.5 10 Unpaved Very Poor Unpaved Very Poor Unpaved Very Poor 20 Unpaved Very Poor Unpaved Very Poor Unpaved Very Poor 30 Unpaved Very Poor Unpaved Fair Unpaved Fair 40 Unpaved Fair Unpaved Fair Unpaved Fair 50 Unpaved Fair Unpaved Fair Unpaved Good 60 Unpaved Fair Unpaved Fair Unpaved Good 70 Unpaved Fair Unpaved Good Unpaved Good 80 Unpaved Good Unpaved Good Unpaved Good 90 Unpaved Good Unpaved Good Unpaved Good 100 Unpaved Good Unpaved Good Unpaved Good The following table presents a sensitivity analysis done and 50 percent for traffic between 50 and 100 AADT to for the same road varying the percent of cars and 20 and 30 percent respectively and 60 percent and 70 pickups from 40 percent for traffic less than 50 AADT percent respectively . Table 10. Cars and Pickups Composition Sensitivity Analysis Optimal Economically Justified Road Quality Level Traffic Cars & Pickups Cars & Pickups Cars & Pickups (AADT) 20% to 30% 40% to 50% 60% to 70% 10 Unpaved Very Poor Unpaved Very Poor Unpaved Very Poor 20 Unpaved Very Poor Unpaved Very Poor Unpaved Very Poor 30 Unpaved Fair Unpaved Fair Unpaved Very Poor 40 Unpaved Fair Unpaved Fair Unpaved Fair 50 Unpaved Fair Unpaved Fair Unpaved Fair 60 Unpaved Fair Unpaved Fair Unpaved Fair 70 Unpaved Good Unpaved Fair Unpaved Fair 80 Unpaved Good Unpaved Good Unpaved Fair 90 Unpaved Good Unpaved Good Unpaved Good 100 Unpaved Good Unpaved Good Unpaved Good Page 8 Transport Note No. TRN-2 November 2004 Traffic projections in terms of annual traffic growth rate, evaluation period. The table below presents the expected generated traffic, and traffic composition sensitivity analysis for an evaluation period of 10, 15 influence the results. Other important factors are road and 20 years. agency and road user costs and the definition of the Table 11. Evaluation Period Sensitivity Analysis Optimal Economically Justified Road Quality Level Traffic (AADT) 10 Years 15 Years 20 Years 10 Unpaved Very Poor Unpaved Very Poor Unpaved Very Poor 20 Unpaved Very Poor Unpaved Very Poor Unpaved Very Poor 30 Unpaved Very Poor Unpaved Fair Unpaved Fair 40 Unpaved Fair Unpaved Fair Unpaved Fair 50 Unpaved Fair Unpaved Fair Unpaved Fair 60 Unpaved Fair Unpaved Fair Unpaved Fair 70 Unpaved Fair Unpaved Fair Unpaved Good 80 Unpaved Fair Unpaved Good Unpaved Good 90 Unpaved Good Unpaved Good Unpaved Good 100 Unpaved Good Unpaved Good Unpaved Good SUMMARY 2. Highway Development and Management Model (HDM- 4) Version 1.3. 2000. World Road Association (PIARC), The road quality level of roads is characterized by sur- Paris, France. face type, road access quality and ride quality. The http://hdm4.piarc.org/ benefits of improving or maintaining a road quality level can be measured by a life-cycle economic evaluation in 3. Roads Economic Decision Model (RED) Version 3.0. terms of reduction on road user cost, but the resulting 2003. Sub-Saharan Africa Transport Policy Program economic indicators not often measure social or envi- (SSATP). Model developed by World Bank, Washington, ronmental impacts. Nevertheless, economic evaluation is DC. a good tool to help define proper levels of road quality of http://www.worldbank.org/html/fpd/transport/roads/too roads that carry an established traffic, typically with ls.htm traffic greater than 50 vehicles per day. 4. Typical Unpaved Roads Roughness Predicted By the This note presents a methodology for the evaluation of HDM-III Model. 1999. Rural Transport Technical Note 1. unpaved roads with traffic between 10 and 100 World Bank, Washington, DC. motorized AADT, using the RED model, and the type of http://www.worldbank.org/html/fpd/transport/publicat/t results that are obtained by which a first judgment can dinflst.htm - rural be made to determine a proper level of investments and maintenance on unpaved roads. If this screening test for 5. Unpaved Roads: Roughness Estimation by Subjective a given unpaved road is "positive" then it is necessary to Evaluation. 1999. Rural Transport Technical Note 2. perform a more rigorous project level economic World Bank, Washington, DC. evaluation. http://www.worldbank.org/html/fpd/transport/publicat/t dinflst.htm - rural The key element of an economic evaluation is the definition of the without-project alternative, which 6 Road Costs Knowledge System (ROCKS), Version 2.0. should represent a pragmatic do-minimum scenario and 2002. Transport and Urban Development Department, should be a function of the traffic and importance of the World Bank, Washington, DC. road. The sensitivity analysis shows that the results are http://www.worldbank.org/htm/fpd/transport/roads/rd_t influenced by the traffic projections, road agency and ools/rocks_main.htm road user costs, and the definition of the evaluation period; therefore, the results presented in this note Transport Infrastructure Notes are available on-line should be considered no more than a first approximation at: of country specific results. To obtain country specific http://www.worldbank.org/html/fpd/transport/publicat/p results, the methodology should be replicated and ub_main.htm adapted with refined country data. Transport Notes are available on-line at: TO LEARN MORE http://www.worldbank.org/html/fpd/transport/publicat/p ub_main.htm 1. Lebo, J. and D. Shelling. 2001. Design and Appraisal Urban Infrastructure Notes are available on-line at: of Rural Transport Infrastructure: Ensuring Basic Access http://www.worldbank.org/html/fpd/urban/publicat/pub for Rural Communities. Technical Paper 496. World _note.htm Bank, Washington, DC. http://www.worldbank.org/transport/publicat/twu- Urban Notes are available on-line at: 45.pdf http://www.worldbank.org/urban/upgrading/urban- notes.htm