Helping Vietnam to Achieve Success as a Middle-Income Country 98272 Improving Vietnam’s Sustainability Key priorities for 2014 and beyond Rural Road Pavement and Surfacing Design Options Key Messages 1. Rural roads that are designed to be compatible with their task and their local environment are more effective in terms of whole life costs than those that are not. 2. Poorly or inappropriately maintained rural roads are very likely to fall short of design life performance targets. 3. Current Vietnam rural road design and construction procedures are, in many instances, out of step with current National and Regional research and International practice. Key Actions 1. Final assessments of the conditions of the trial pavement, particularly with respect to climate impacts. 2. Upgrade of Vietnamese rural road standards, specifications and design guidelines to take into account recent research and potential climate threats. 3. Increased focus on meeting the challenge of funding effective rural road maintenance. Strengthening Competitiveness, Improving Sustainability, Increasing Opportunity Helping Vietnam to Achieve Success as a Middle-Income Country Research Background the Ministry of Transport Rural Road Surfacing Recent research in S E Asia and Vietnam in Research (RRSR) committee. Outcomes were particular, funded by the World Bank and DfID since enhanced by information from complimentary 2003, has focused on improving rural community projects within Lao PDR and Cambodia. access through more sustainable low volume rural road design. More appropriate design ensures that roads built are cost effective in terms of whole life It is increasingly appreciated for Low Volume Rural Roads (LVRRs) that a range of factors, collectively performance. known as the “Road Environment”, needs to be taken into consideration when selecting and Because of increasing recognition that gravel designing rural road pavements. The road surfacing was not always the best solution for rural environment was, therefore, a basic consideration roads in Vietnam, the initial research focused on the in designing, initiating and analysing the RRSR performance of existing unsealed roads and the programmes. The key factors in the road identification of sustainable alternatives. environment are as follows. Subsequent research has focused on the relative performance of the alternative option trials and • Construction Materials. their role in providing a more climate resilient rural • Climate. infrastructure. In general, this work has • Surface and sub-surface hydrology. concentrated on a range of pavements to establish • Terrain. the best performance within a range of physical and • Sub-Grade. socio-economic environments. • Traffic. • Construction regime. This note highlights the findings of the Rural Road • Maintenance. Gravel Assessment Programme (RRGAP) and the • The “Green” Environment. Rural Road Surfacing Trials (RRST phases I, II and III) undertaken within Vietnam under the umbrella of . The Rural Road Surfacing Research Programme strength and laboratory test data from 766 spot The Rural Road Gravel Assessment Programme locations. (RRGAP)1 comprised the evaluation of a representative selection of 269 WB-funded road links from 16 provinces. The road lengths covered a Analysis concentrated on the amounts and range of physical and climatic environments (flat variability of apparent gravel losses in relation to deltas, coastal hills, moderate hills, high plains and the impacting road environment factors. mountainous terrain) by recovering visual, in situ Between 2003 and 2012 three phases of trial road 1 selection, design and construction were undertaken Cook J R Petts R C, 2005. SEACAP 4 The RRGAP Final Report. under the RRST programme. The objective was to Strengthening Competitiveness, Improving Sustainability, Increasing Opportunity Helping Vietnam to Achieve Success as a Middle-Income Country compare new pavement options in terms of RRST Phase I comprised of a number of short construction and in-service performance against a sections (100m to 200m) of different trial options number of standard Vietnamese “control” sections, constructed on single roads. In the second and third Table 1. phases two or three options of longer length (0.5- 2km) were constructed on each road.2 An almost Table 1. RRST Pavement and Surfacing Layers complete coverage of road environments within SURFACING OPTIONS Vietnam has now been achieved3. Bituminous Seals Double emulsion chip seal RRST Phase I construction was completed in 2005; Double hot bitumen chip seal Emulsion sand seal & single chip seal Phase II in 2006; and Phase III in 2012. Monitoring Single emulsion sand seal of the trial sections commenced as soon as Double emulsion sand seal Unsealed granular surfaces construction was completed. A total of 156 km of Gravel Wearing Course (GWC) trial roads have been constructed within a range of Water-Bound Macadam (WBM) Block Surfacing road environments in 16 provinces, from which a Stone Setts representative 123 sections of between 80m to Cobble Stone Fired Clay Brick 200m in length have been selected for ongoing Concrete Brick performance monitoring. The last round of Concrete Surfaces Steel Reinforced monitoring was undertaken in 2012. Bamboo Reinforced Non-Reinforced The monitoring of the completed trial pavements BASE & SUB-BASE LAYERS Water-Bound Macadam (WBM) involved the systematic collection of the following Dry-Bound Macadam (DBM) data: Emulsion Stabilised Sand Cement Stabilised Sand Lime Stabilised Clay  Visual condition: using numeric coded sheets. Armoured Gravel  Roughness: using low cost simple apparatus Graded Crushed Stone Natural Sand (MERLIN). Natural Gravel  Strength: using Structural Number correlations derived from simple in situ tests (DCP). The selection of trial options was based on the  Gravel loss (where appropriate): cross- following guiding principles: sectional leveling.  Traffic: 12 hour traffic counts (3 or 6 day).  Designs should be appropriate to the road  Photographic records. environments.  Local construction materials should be used The condition monitoring of the Vietnamese trials where possible. has resulted in the assembly of a significant  Maintenance requirements must be closely amounts of data on the performance of a wide matched to local community arrangements and variety of pavement and surfacing types. The RRSR resources. database was developed as a means of managing  Construction techniques should be suitable for and analysing this wide range of data on rural road small contractors and encourage local employment. 2 Mot-DfID, 2006. SEACAP 1: Final Report – 3 Volumes 3 J R Cook 2013. Technical Report to WB Hanoi. Strengthening Competitiveness, Improving Sustainability, Increasing Opportunity Helping Vietnam to Achieve Success as a Middle-Income Country surfaces and pavements in Vietnam. The database  Change of condition with time. includes information on:  Traffic.  Trial pavement designs.  Physical and climatic environments.  Construction costs.  Historic climate  As built condition. Research Outcomes Sustainability of Gravel Wearing Course experience gained with the RRST programme, Surfacing Figure 2. The RRGAP studies that showed unsealed Gravel Figure 2 An Approach to Pavement Selection and Wearing Course (GWC) is not a sustainable option in Design many of Vietnam’s road environments. More than List of available Road 60% of the analysed road sections indicated gravel Road Task Definition LVRR Options Environment Data loss of greater than the 20mm/yr taken as the limit Road Environment of loss sustainability, Figure 1. Losses greater than Assessment 20mm/yr imply a need to re-gravel at 4 years or less Socio-economic Issues for a normal 15-20cm design thickness. In some • Whole -life-Cost model • Local Employment particularly vulnerable environments, for example PHASE I • Gender Issues • Local economy high rainfall and /or steep hill terrain, all analysed road sections could be defined as unsustainable. Is unsealed gravel an identified option? Figure 1 Overall Gravel Loss for 740 road sections Yes No Gravel Loss - (95% Level) Unsealed Alternative Sustainable Gravel Fail Pavement/Surfacing 100.0 Assessment Options 90.0 Survey Sites: Cumulative % 80.0 Short list of sustainable 70.0 Success options 60.0 50.0 Engineering 40.0 Specific Assessment of Sub-Grade Traffic Data Short-listed Options Strength and 30.0 Condition Phase II 20.0 10.0 Final Pavement 0.0 Design(s) 1.0 10.0 100.0 1000.0 Gravel Loss -mm/yr Phase I comprises the identification of appropriate pavement types compatible with the road Pavement and Surfacing Selection and Design environment and may be considered as a A two-phase pavement selection and design progressive screening operation aimed at approach has been developed, based on the identifying one or more options that are compatible Strengthening Competitiveness, Improving Sustainability, Increasing Opportunity Helping Vietnam to Achieve Success as a Middle-Income Country with the road task and its environment. The second Figure 4 Comparative Performance of Different phase is the detailed design of the selected Options on One Trial Road: Roughness pavement option compatible with engineering requirements; primarily traffic, axle load and sub- grade strength. The identification of suitable pavement options can be considered as a filtering process whereby unsuitable or unsustainable options are removed from consideration. Apart from road environment factors, other issues such as involvement of local groups in construction, local employment, development of local resources Environmentally Optimised Design and social safeguard considerations can also be addressed. This process should highlight those The research has supported the concept of options that are most suitable to take forward to Environmentally Optimised Design (EOD) as an final design. over-arching principle applied to pavement selection and design. Its application requires that Phase II of the selection and design process involves the selection and design of pavements must take the detailed design of the general options identified into account the full range of road environment under Phase I. factors that impact upon pavement performance The Comparison of Engineering Performance along the road corridor. The rural road performance database allows The logical extension of this principle allows for the comparative analysis to be made of different adoption of variable surfacing options along the pavement and surfacing options. For example, length of rural road links, including using gravel or Figures 3 and 4 compare options performance on a leaving “as-is” (optimising the use of in-situ or single road in a high rainfall environment existing materials) and focusing on critical areas Figure 3 Performance of Different Options on a (SPOT improvements). EOD includes consideration Single Trial Road: Visual Assessment. of appropriate drainage structures at watercourse crossings. The adoption of this strategy allows a more focussed use of limited construction resources where budgets are severely constrained. Spot Improvements can be prioritised according to defined criteria, such as gradient, flood-prone areas or a dust-free road through a village4. A section of unformed road that provides access and is not dangerous may be left, while other sites are 4 S Done, J Cook. 2009. Low volume rural road environmentally optimised design manual. For DfID and MPWT Lao PDR Strengthening Competitiveness, Improving Sustainability, Increasing Opportunity Helping Vietnam to Achieve Success as a Middle-Income Country improved. It is perfectly feasible, therefore, to • Missing or ineffective drainage could be balance low-cost surfacing solutions such as gravel directly linked to poorly performing or failing or even engineered natural surfaces for low-risk pavements. areas with higher-cost solutions for the most-at-risk areas. Construction Costs Specifications and Quality Control There was considerable regional provincial variability in constructions cost of the trialled The RRSR programme has prepared a library of option. Table 2 summarises some typical costs relevant rural road pavement specifications in relative to specification-compliant unsealed GWC English and Vietnamese. These have been modified based on experience gained during RRST Table 2 Typical Relative Construction Costs construction and monitoring phases. In addition, Vietnam Region some further specifications have been developed Pavement options Coastal Northen Centre Mountain Highland from research in Lao and Cambodia. GWC (20cm) 1 1 1 One of the outcomes from the RRST work is the recognition that the standard of contractor DBST/GCS Base-sub- 3 to 4 2.5 - 3 4.5-5 base compliance with specifications is variable and that DBST/lime or cement poor quality control can be directly related to poor stabilised base- sub- 3 6 n/a base in-life service performance, and increased the vulnerability to climate impact. Existing supervision NRC/sub-base 5 4 7 arrangements in the rural road sector do not appear to be sufficiently effective. Areas of particular Stone block/Sub- base 5 n/a n/a concern are:  Inadequate testing of materials prior to One significant problem was noted as being the construction. tendency for contractors cost and to then use cheap  Inadequate testing of as-delivered materials. non-compliant GWC material.  Lack of required in situ testing. Whole Life Costs  Poor control on cross sectional shape.  Poor maintenance of site records. The significant difference in the initial construction  Use of inappropriate construction equipment costs per kilometre between unsealed and sealed, block paved or concrete roads is a major issue in the Pavement Drainage budget-constrained rural infrastructure sector. This is commonly exacerbated by the unrealistically low Although drainage was not a direct component of pricing of surfacing gravels based on the use of the pavement trials its impact on the performance cheaper sub-standard, non-compliant materials. of the pavements was assessed and the following These prices make the gravel option seem falsely general conclusions arrived at: more attractive in terms of initial cost, when in fact • Side drainage was often poorly constructed the use of sub-standard materials will have and frequently omitted altogether. significant negative impacts on pavement Strengthening Competitiveness, Improving Sustainability, Increasing Opportunity Helping Vietnam to Achieve Success as a Middle-Income Country performance, with consequent social and local construction costs over road design life period, has economic impacts. been developed for use in the RRSR programme and is included in the final RRST reporting. A simplified Whole Life Asset Cost (WLAC) approach, assessing both maintenance and .. Maintenance The lack of routine or periodic maintenance Concrete pavements: This is a low-maintenance undertaken on the RRST roads since 2005 reflects option, not a “no-maintenance” option. the general position in the rural road sector as a Maintenance of joint seals is a major requirement whole in Vietnam. However, by analysing the and this will be greater in the case of pavements deterioration patterns of the trial options over 6-7 with a central joint. Cracked slabs are expensive to years it has been possible to assess the relative repair. maintenance costs and to arrive at some overall conclusions regarding rural road maintenance in Sealed Flexible Pavements: If well-constructed this can give generally a “window” of 3-5 years before Vietnam. significant maintenance other than routine edge Table 2 indicates general relative maintenance cost and occasional pothole repairs and minor sealing is levels of pavements including both routine and required. Unless a system maintenance regime is periodic maintenance and surfacing averaged out then functioning, high rehabilitation costs over a 12-year design life. These costs will vary associated with the repair of failed road sections depending on the road environment. will start to become significant. Table 2. General Levels of Maintenance Costs Stone Block Pavements: This is a low-maintenance option. Costs for block pavements with joints filled Relative Pavement Pavement with sand/fine chippings are higher than the cost Construction Maintenance Costs Option Costs for block pavements with mortared joints and are almost exclusively associated with replenishing the Very High Unsealed Low fine material, which should be done every 2 years. (US$2-3000/km/yr) granular Brick-Block Pavements: The rehabilitation costs of Moderate-Low mortared joints in block pavements are relatively Sealed Flexible Moderate (USS$ 1500/km/yr) low. Indications are that the sand emulsion seals should be rehabilitated after 2 years of operation. Stone block Low Moderate to Unsealed Granular Pavements (GWC and WBM): and mortared (US$ 500-1000/km/yr) high brick These are high maintenance options. If left unmaintained, the rehabilitation costs in many Non Very Low regions after 24 months of operation are very high Reinforced High (US$200-300/km/yr) Concrete and can be equivalent to 50% of the construction cost. Strengthening Competitiveness, Improving Sustainability, Increasing Opportunity Helping Vietnam to Achieve Success as a Middle-Income Country Pavement and Surfacing Performance Unsealed Granular Pavements regime. The exceptions are where significant problems with the quality of concrete were Analysis of the trial control section data confirmed recorded during construction and the slabs have the conclusions from the separate gravel studies now significantly deteriorated. (RRGAP) that unsealed GWC or water-bound macadam (WBM) surfacings are not sustainable Other important factors include options in areas of flood, high rainfall, or steep  Poor construction and curing procedures and gradient. Monitored trial sections in the lower sub-standard sub-base are factors in the rainfall, flatter, regions in the Vietnam Central premature cracking of the concrete slabs. Plateau in similar traffic environments, have shown  Bamboo reinforcement has been shown to have satisfactory performance when well-constructed no advantage over properly constructed non- with appropriate materials. Important issues reinforced concrete. include:  Poor shoulder maintenance and consequent  The regular maintenance of cross-sectional erosion and under-cutting of concrete slabs give shape is essential. rise to cracking and eventual failure.  Gravel materials must reasonably comply with Sealed Flexible Pavements specified grading and plasticity requirements.  There must be sufficient gravel resources for A major outcome from the RRSR is evidence that maintenance as well as construction. the combination of emulsion double chip seal on  Gravel loss is likely to be excessive where dry-bound macadam base/sub-base is performing annual precipitation is greater than as well or better than the Vietnamese standard 2000mm/yr. option of hot bitumen seal over water-bound  Gravel should not be used on gradients greater macadam base/sub-base. Other key points are: than 6% in medium to high rainfall areas (1500- 2000mm/yr). Gravel erosion may be significant  Penetration macadam trials are amongst the on long gradients of more than 4%. best performing options. However some  Even in simple combinations of some of the evidence from monitored sections indicates it above factors, gravel can be lost from the road is susceptible to shallow potholing or ravelling surface at a rate of more than 30-40mm per deterioration under heavy truck traffic and year, leading to the need to re-gravel at once this occurs the subsequent deterioration frequent intervals. is likely to be rapid.  Penetration macadam consumes a high Concrete Pavements quantity of bitumen per unit area and is not an efficient use of this expensive and high carbon The concrete trial roads are generally performing footprint material. well. Even on the sections exhibiting some cracking,  The single sand emulsion seals are showing the great majority of the pavement slabs are still distinct signs of erosion. However most of performing adequately in a zero-maintenance these seals are now over 5 years old and Strengthening Competitiveness, Improving Sustainability, Increasing Opportunity Helping Vietnam to Achieve Success as a Middle-Income Country current international advice recommends a The pavement is effective in providing a sustainable second layer of sand seal should be laid within surface/road-base in mountainous areas, albeit with six months of construction. high roughness consequences.  The performance of a significant number of the Brick Pavements poorly performing sites is being influenced by underlying structural issues in the road base In general, the performance of fired clay or and/or sub-grade related to axle overloading. concrete block pavements appears to be variable.  Surface reflection cracking associated with lime However, this conclusion should be further or cement stabilised bases is evident in some considered in terms of the scale and types of sections. defects, as follows;  Cement stabilised bases and sub-bases have, however, performed well and analysis of  The single sand seals overlying brick options structural strengths have shown them have performed very poorly. Although despite continuing above the required design strength this the brick pavements themselves have over the monitoring period. continued to perform satisfactorily with little  Analysis of the structural strength of the lime or no maintenance. stabilised base and sub-base trials in the  The use of mortared joints appears to have Mekong Delta, has shown a significant and on- some advantages over sealed sand joints in going deterioration in strength since the initial high erosion environments; however, there surveys. This is considered to be related to could be a disadvantage in the loss of inter- seasonal water level movement within the block flexibility. embankment and pavement immediately  Joint and surface deterioration are the following construction. dominant defects. Significant block damage  The trial flexible sealed options have been was found where compliance with brick shown to be the most vulnerable to traffic and strength specifications was an issue. axle loads over and above the design criteria. Carriageway Shoulders  Mechanical mixing of two granular components (eg clay and gravel or aggregate) Road shoulders were constructed with a variety of was not trialled in Vietnam but is known to be materials in the following general groups: an effective regional option.  Unsealed Water Bound/Dry Bound Macadam. Stone Block Pavements  Sealed Water Bound/Dry Bound Macadam.  Gravel. The performance of the two stone cobble or stone  Quarry run – usually a coarse granular quarry sett trial pavements is good and they have been waste product. shown to be highly resistant to rain-storm and flood erosion. The inherently high roughness of this  Lime or cement stabilised local materials. option has, however, been shown to increase  Local soils. significantly without maintenance, leading to a Based on the visual assessment of the shoulders tendency for two-wheeled traffic to try to use the over the 4-5 year monitoring period the following shoulders. conclusions were reached: Strengthening Competitiveness, Improving Sustainability, Increasing Opportunity Helping Vietnam to Achieve Success as a Middle-Income Country  In general the shoulders were not maintained  There was a significant increase in shoulder and were in a poor condition. deterioration after about 2 years with no  In many cases the erosion of shoulders was overall maintenance. impacting on the performance of otherwise  Full-width construction should be considered sound pavements. where the additional costs are justified.  Coarse quarry-run materials were clearly the best performing shoulder materials with sealed WBM/DBB a second best. Key Recommendations A number of important technical lessons have either been learnt or re-affirmed by the RRSR and Table 3 Pavement Option for Typical Physical related programmes in S E Asia. Environments 1. The design and construction of rural road Typical Road Potentially Suitable Options networks should be founded on a four key environment principles: Flat terrain Sealed armoured gravel (very adequate supplies thin aggregate base layer)  Roads must suit their function. of good quality Sealed gravel base/sub-base  Design must be suitable for the local gravel Sealed cement/lime modified gravel base/sub-base environment Table 3. Unsealed gravel wearing course  Locally available materials should be used Flat deltaic or Non-reinforced concrete on coastal terrain cement stabilised sand sub-base except where neither technically nor subject to potential Mortared concrete or fired clay financially feasible. flooding. No gravel bricks on cement stabilised sand or aggregate sub-base  Roads should be constructed with whole life nearby, some sand Sealed DBM/WBM over cement deposits stabilised sand sub-base costs that will not place excessive burdens Sealed cement stabilised sand on the local management budgets. base-sub-base Rolling terrain to Sealed lime stabilised gravel 2. It is not possible for local authorities, designers hilly terrain with base/sub-base or contractors to accept research-based variable quality hill Sealed WBM or DBM base/sub- gravel base outcomes their adoption by Ministries. This is Sealed WBM or DBM base, an essential pre-requisite for effective take-up gravel sub-base or lime stabilised gravel sub-base. of the RRSR research. Unsealed gravel wearing course 3. An appropriate classification for rural roads is a River valley, Sealed WBM or DBM base/sub- abundant alluvial base necessary step in providing the context and sands, gravel, Non-reinforced concrete on control framework within which local resource- cobble DBM/WBM sub-base Stone sett/cobbles on gravel based pavement options may be assessed and sub-base selected for appropriate use. Mortared concrete or fired clay bricks on DBM/WBM or gravel 4. For rural roads a key initial question should be- sub-base “What roads can I build with the locally available materials?” rather than “Where can I 5. The use of technical standards and find materials to meet general specifications”. specifications that are focussed on up-to-date Strengthening Competitiveness, Improving Sustainability, Increasing Opportunity Helping Vietnam to Achieve Success as a Middle-Income Country regional or national requirements is essential, 9. Effective pavement drainage, cross-pavement such as those developed for the RRST trials drainage and earthwork drainage are essential 6. The RRSR has shown that unsealed GWC roads elements of a sustainable rural road. Apparent are not a sustainable option in many road cost-saving on drainage will inevitably lead to environments in Vietnam. poor performance and higher whole life cycle 7. Composite construction using different costs. pavement designs along a road link can be 10. WLAC assessment of pavement options must be appropriate. part of the overall design approach. 8. Spot Improvement solutions may be effectively applied in cases where there is insufficient budget to supply a sustainable whole road link solution. Some Practical Outcomes of the RRSR Programme Under SEACAP and subsequently under World Bank the outcomes from the RRSR work have been disseminated through technical papers and workshops. Practical outcomes from the RRSR may be summarised as follows: 1. Strategic change in pavement option selection between RT2 and RT3 in Vietnam; under RT2 the roads were approximately 80% unsealed whilst in RT3 the roads are approximately 85% sealed. 2. ADB have adopted a policy of promoting sealed or non-reinforced concrete pavements (rather than as previously adopting unsealed gravel) for irrigation project roads in their rural road programmes in Vietnam and in Lao 3. Outcomes from the RRSR work were incorporated into aspects of the World Bank funded Ethiopian Low Volume Road Design Manual and are included in the DFID-funded South Sudan Low Volume Road Design Manual. 4. RRSR outcomes formed part of the recommendations on Appropriate Standards and Specifications to the relevant Cambodian and Lao PDR ministries between 2007 and 2009. 5. The RRSR principles with respect to the Road Environment and Low Volume Road design have been included in a current ADB climate resilient infrastructure projects in Bangladesh and Laos. 6. RRSR recommendations on the road environment and pavement design have been included in the current Lao Poverty Reduction Fund programme (PRF-II, funded by World Bank). 7. The incorporation of RRSR content within teaching and research modules at the University of Transport and Communications (Vietnam). Strengthening Competitiveness, Improving Sustainability, Increasing Opportunity Helping Vietnam to Achieve Success as a Middle-Income Country What needs to be done? As as noted previously it is unreasonable to expect There is in addition a need to take on board the executing agencies to accept research-based impacts from increasingly severe climate events and pavement solutions without their adoption by the incorporate these in a much more flexible and regulatory authorities into formal standards and regionally focussed framework of standards and operational manuals. In addition to completing the specifications. monitoring and analytical work on the trial roads in a logical manner, the development of the RRSR At recent World Bank workshops in Vietnam there work should further mainstream the research has been a growing request at provincial level for outcomes and to work closely with the relevant the adoption of more flexible and rural road departments or institutes under the MoT to standards. Much, therefore, remains to be done therefore in terms of championing the updating of produce updated practical rural manuals and Low Volume Road National Standards, guidelines. Specifications and Guideline documents. . Further Discussion Authors (Intech-Associates) and David Salter (ADB, formerly Jasper Cook is a Geotechnical and Road Engineering SEACAP Manager). Short Term Consultant with the World Bank offices in Hanoi, Vietnam and Vientiane, Lao PDR. This note is part of a series of Vietnam Transport Notes to share experience about the transformation Pham Gia Tuan is Vietnam based Road Engineering of the Vietnamese transport sector. It is built on a Short Term Consultant with the World Bank office in combination of the outputs from the DFID funded Hanoi, Vietnam. South East Asia Community Access Programme (SEACAP) and the World Bank Rural Transport 3 Acknowledgements programme with additional support from GFDRR The achievements of the RRSR project are due to the with respect to climate resilient issues. For contributions of a large number of persons over an comments, please contact Tran Thi Minh Phuong extended period of time. Peter O’Neill and Simon (ptran1@worldbank.org), from the Hanoi World Lucas of DFID played key roles in setting up the Bank Office or Fei Deng (fdeng@worldbank.org) project. The support and commitment of the from the Washington, DC World Bank Office. Ministry of Transport and the Steering Committee has been a vital facilitating framework for the Any findings, interpretations, and conclusions research and dissemination work. The continuing expressed herein are those of the authors and do strong support by Tran Thi Minh Phuong, current not necessarily reflect the views of the World Bank. World Bank TTL, has been absolutely vital. The Neither the World Bank nor the authors guarantee efforts of the various project teams from Intech-TRL; the accuracy of any data or other information ITST; TDSI and OTB Engineering have ensured the contained in this document and accept no successful project delivery. In particular the responsibility whatsoever for any consequence of fundamentally important contributions of Rob Petts their use. Strengthening Competitiveness, Improving Sustainability, Increasing Opportunity