Feeder Road Prioritization Engineering Issues G2a Cost Estimation Survey G2b Road Condition Survey John Hine / Simon Don

1. Feeder Road PrioritizationEngineering IssuesG2a Cost Estimation SurveyG2b Road Condition SurveyJohn Hine / Simon Done November 2000

2. G2a G2bCost Estimation Survey Road Condition Survey Access Roughness Access Category A Traffickability Access Category B Passability Access Category C Roughness Key Spot Improvements Traffickability Key Full Rehabilitation Passability Key Problems with Spot Imp’ments Effects of imp’ments Cost Est. Survey vs. MPBS Survey Procedure Survey Procedure Consistency is required Typical Results Accessibility Strip Map Calculation of catchment areas

3. Cost Estimation Survey Access The priority is on arriving at the destination rather than doing so quickly or smoothly. Access permits maximum benefit at minimum cost. Access should be reliable if farmers are to plant surplus crops and traders are to buy and operate vehicles. Access is more appropriate for short roads (20 km?) than for long roads (100 km?), and for low traffic than high traffic. Access should be provided for all vehicle types that may use the road. Access should be year round (rather than seasonal), except perhaps for closures of up to a day or two. The biggest threat to access is rainfall and runoff.

4. Cost Estimation Survey Access Category A Sites where, for local vehicle types: Year round access is impossible even if in an emergency Road users are in danger of injury The road is under water for time periods of more than two consecutive days Improvement of Category A sites will provide emergency access in the short term

5. Cost Estimation Survey Access Category B Sites where, for local vehicle types: Year round access is possible, but unreliable Access is likely to be lost in the near future Road condition is likely to deteriorate as each vehicle passes Road condition is likely to deteriorate as each rainstorm passes The road is badly eroded Motor vehicle speed is reduced to below normal walking speed Cyclists are forced to dismount Vehicles are liable to damage as they pass Improvement of Category A & B sites, with maintenance, will provide reliable year round access in the long term. This level of improvement may be termed spot improvements.

6. Cost Estimation Survey Access Category C Sites where, for local vehicle types: Year round access is possible, and reliable Road condition is stable Deterioration is unlikely in the near future under existing conditions Surface roughness is not enough to slow motor vehicles to below walking speed Improvement of Category A, B & C sites will maintain access and permit smooth, comfortable travel. This level of improvement may be termed full rehabilitation

7. Cost Estimation Survey Spot (Accessibility) improvements This refers to the improvement of localised sites where access is: lost, unreliable, at risk in the near future, or dangerous, but leaving those lengths of road where vehicles can pass safely and reliably all year round. The appearance of the road may be variable, but the quality of work carried out is high, and the work should be robust. Spot improvements may be appropriate for the involvement of local communities.

8. Cost Estimation Survey Full rehabilitation This refers to the improvement of the entire road such that access is safe and reliable all year round, and also that a smooth, often gravelled, surface permits comfortable travel along the whole length

9. Cost Estimation Survey Problems with Spot improvements Can be unacceptable to: Politicians Road Authorities Travelling public Tax paying electorate Road contractors But: A cost effective way of providing access to many people at minimum cost.

10. Cost Estimation Survey Cost Estimation Survey MPBS One-off improvement cost Repeated maintenance cost Makes a road maintainable Keeps a road maintainable Fast and approximate Detailed and accurate Used for Prioritization Used for letting contracts Estimates required activities Schedules actual activities Condition allocated to sections Condition allocated to road All possible improvement works Only periodic and routine m’t Groups activities together Keeps activities separate Simplifies to 17 activities Requires 34 separate activities Unit costs are approximate Unit costs are exact Spot imp. & rehabilitation costs Rehabilitation cost only Limited decision flexibility Great decision flexibility

11. Cost Estimation Survey Survey Procedure Survey during the rains if possible Divide the entire road into sections Identify the problem type for each section Identify the vehicle types likely to use the road Record the Access Category of each section Estimate required quantities to treat the problem Transfer the unit cost for each treatment Calculate the total cost for each Access Category Calculate the costs of emergency access, spot improvements and full rehabilitation Incorporate costs into the Prioritization procedure

12. Cost Estimation Survey Consistency is required during survey Dividing a road into sections Recording the Access Category Recording the Problem Type Estimating required quantities

13. Cost Estimation Survey Typical results - a road of 5.26 km Full rehabilitation (Cat A+B+C) $52,081 100% Spot Improvements (Cat A+B) $15,909 30% Emergency Access (Cat A) $4,067 8%

14. Cost Estimation Survey Accessibility Strip Map Used to record: junctions sites where access is lost sites where access is difficult In order to assess the social impact of: existing road condition expected road condition On the affected population

15. Cost Estimation Survey Calculation of catchment areas Identify all water crossings - GPS, landmarks, etc Locate the crossing on map - 1:50,000 Measure catchment size Use catchment size to estimate cost of structure

16. Road Condition Survey Roughness – Definition This refers to the surface condition of the road. Definitions of four roughness levels are suggested, and it is possible to correlate each level to an IRI value, or the comfortable travel speed of a vehicle, although the latter requires careful calibration. Roughness is recorded by: Direct assessment of IRI Correlation with description - ‘good gravel’, ‘average’, ‘poor’, ‘extremely poor’ Roughness Key - based on correlation with comfortable travel speed

17. Road Condition Survey Traffickability – Definition This refers to factors that significantly reduce traffic volumes (but do not absolutely prevent movement) such as poor road condition in the wet season or, on occasion, extreme roughness. E.g. a road may be said to have traffickability problems if, at some point in the year, the wet season traffic is less than 50% of the dry season traffic. Traffickability is recorded by: Assessment of length and duration of traffickability problems Traffickability Key - based on correlation with the proportion of the road of Category A or B

18. Road Condition Survey Passability – Definition This refers to the inability of vehicles to travel along the road on grounds of poor road condition. A road is said to have passability problems if, for a period of at least two days at some point in the year, a vehicle which would normally use the road is unable to pass. Passability is recorded by: Assessment of duration of passability problems Passability Key - based on correlation with the Cat. A water crossing of greatest cross section (or length of carriageway of Cat. A)

19. Road Condition Survey Roughness Key This refers to the surface condition of the road. Definitions of four roughness levels are suggested, and it is possible to correlate each level to an IRI value, or the comfortable travel speed of a vehicle, although the latter requires careful calibration. Description IRI Speed (kph) G – Good gravel 6 > 60 A – Average 9 40 – 60 P – Poor 12 20 – 40 E – Extremely poor 17 < 20

20. Road Condition Survey Traffickability Key The Traffickability Key is based on the assumption that a single, isolated, difficult site will not in itself cause traffic levels to drop, but that as the total length of road where access is difficult increases, more traffic will be dissuaded from travelling and the duration of problems will extend. Thus the percentage of the road length which is of Category A or B is used to estimate the duration of the problems. L(A+B) / Ltotal (%) Duration of traffickability problems (months) 0 – 10 0 10 – 30 0.25 x Rainy season 30 – 50 0.50 x Rainy season > 50 0.75 x Rainy season

21. Road Condition Survey Passability Key The Passability Key is based on the assumption that closure of a road depends on a single site, rather than an accumulation of sites in the Traffickability Key. Only Category A sites are considered, since the definition of this Category is the loss of access. Sites of Category A Duration of passability Channel XS Area problems (months) 0 – 1 m2 0.25 x Rainy season 1 – 3 0.50 x Rainy 3 – 10 0.75 x Rainy > 10 1.0 x Rainy season Any rain related carriageway problem of Cat. A 0.50 x Rainy season

22. Road Condition Survey Effects of improvements on Road Condition The improvement works have the following effect upon: Improvements are made to sites of Access Category:RoughnessTraffickabilityPassability Category A   Remains rough Problems remain Problems remain Category A & B   (spot improvements)Remains rough, Problems solved Problems solved but may reduce somewhat Category A, B & C    (full rehabilitation)Smooth Problems solved Problems solved

23. Road Condition Survey Survey Procedure Assess existing overall roughness, passability and traffickability of the road - by interview, direct observation, or using ‘Keys’ Assess expected overall roughness, passability and traffickability after the road has been improved to a Spot Improvement or a fully rehabilitated standard. Guidance is provided for this assessment Incorporate existing and expected conditions into the Prioritization Index