Cornwall LTP1 Delivery Report - July 2006

Achievement of BV Performance Indicator.

With a  funding allocation specifically for principal road maintenance at the outset of the LTP1, and a recognised survey type for the national BVPI 96, the early phase of the strategy set out to seek improvement of the condition of the network as measured from deflectograph surveys.  Following two further years of demonstrable improvement in BVPI 96, and with the increasing need to focus resources towards improvement in the condition of non-principal roads, the strategy for principal roads shifted towards improvement of the skidding resistance, as measured from SCRIM surveys (local indicator improved from 21.8% in 2000 to 18.8% in 2004/05).

The SCANNER derived BVPI 223 figure reported in 2005/06 is considered to be very low, and hopefully demonstrates the value in delivering a strategy during the LTP1 that balanced treatment of structural and surface condition defects in an optimum manner.  With the introduction of the red/amber/green categories for the condition of principal roads and with a low 'red' value, our strategy will now focus towards management of the 'amber' category to prevent an unacceptable increase in the BVPI 223 value.  Until the national comparison can be drawn for this new indicator, we are unable to set an appropriate condition level.

The divergence associated with ongoing measurement of the condition of principal roads by deflectograph surveys in 2004/05 and 2005/06 is related to a change in survey regime in accordance with County Surveyors' Society guidance. This guidance encouraged more focused survey regimes towards sections which were previously recorded with residual life less than 10 years.  Consequently, the indicator value increased slightly as a greater proportion of known lower residual life sites were surveyed.

In order to maximise the benefit of maintenance investment, either by integration of maintenance schemes with other planned improvements or by programming to ensure optimum timing, forward planning is essential.  We have combined several maintenance schemes with planned traffic and safety improvements to deliver a combined solution with reduced impact on traffic disruption.  All schemes have considered the inclusion of other routine maintenance objectives, and where practicable, provided additional facilities for pedestrians, cyclists and equestrians; for example in the form of crossing points and visibility enhancement.  Many schemes have also incorporated new infrastructure for public transport (low floor bus stops). 

We have increased the use of recycled aggregates over the LTP1 to a point whereby the Council has purchased its own mobile mixing plant for foamed bitumen.  This material is now used extensively in binder courses and last year alone avoided the need to source 10,000 tonnes of quarried aggregates for road surfacing.

We were recognised for our management and co-ordination of roadworks through a Beacon Council Award in 2003/04.  The programming of works in accordance with agreed seasonal and commuter embargos ensures minimal adverse impact on the economy.  This is particularly important for the tourist industry, which relies on well maintained transport links for the movement of tourists and goods.  It is also essential for the rural economy to maintain links to the trunk road network for the movement of produce and supplies.

For over 14 years we have  carried out condition surveys  on 130 'random' road sites, in order to gather information which could be used for assessment of carriageway deterioration.  This database is understood to be unique, and will allow us to feed into whole life costing models within the implementation of asset management planning, therefore optimising investment.

In partnership with WDM Ltd, and through discussion with the DfT, an initial calculation of carriageway 'backlog' maintenance was undertaken in 2004.  Based on assumed BVPI steady state levels and construction prices at that time, the backlog was estimated at £60m.  An understanding of the factors and methodology behind 'backlog' assessment has been beneficial in comparing relative road category maintenance needs, and will provide a basis for development with latest asset management guidance and criteria.

Whilst the above demonstrates our use of information to understand aspects of overall road condition, we continue to assess evidence that informs our prioritisation of schemes on a safety basis.  The link between skidding resistance and accident rates has been proven.  We have collected information on skidding resistance and accident data over a number of years in order to study the County's relationship between accident rates and SCRIM deficiency.  Early results show strong correlation in some situations, where a rate of return in accident saving can be assessed against investment.

The assessment of bridges on the PRN was completed by 2001, with the assessment of all bridges complete during 2002/03.  The assessment of retaining walls on the PRN was completed by 2004 with the addition in that year of numerous retaining walls on the de-trunked A39.    In excess of 95% of the total number of retaining walls have now been assessed and the remaining assessments are programmed to be complete by the end of 2006.

The initial targets to assess all County structures on the highway network proved to be inappropriate for the level of funding provided and resources employed.  These targets were split in 2003 to reflect this and the revised targets have either been met or are on track.

We have managed our stock of structures using a risk based approach, which has enabled the PRN to remain unaffected by restrictions (for normal highway traffic).  However, great emphasis has been placed on progressing the strengthening of structures on the PRN to ensure access to the PRN is maintained.  This is particularly critical in Cornwall where appropriate secondary and tertiary routes are limited.  All of the bridges on the PRN were strengthened as planned by 2001 and to date, 75% of retaining walls on the PRN have been strengthened (or are currently on site being strengthened). 

The initial target for strengthening all structures on the PRN by 2004 was not achieved.  Although all bridges were strengthened, retaining walls were not because of consultation, procedural  and services difficulties.  The revised target to complete the strengthening of all the structures on the PRN by 2007 is on track to be achieved.

Strengthening of Sub-standard Structures.

The original target of strengthening 125 sub-standard structures by 2006 was met, and the target was revised in 2003 to 210 (including 79 completed prior to the LTP1).  This was particularly challenging in respect of the increased number of retaining walls failing assessment and the anticipated extension to the programme.  Longer term planning was required to allow for negotiations for access and land purchase. A total of 128 structures were strengthened over the six years (2001-2006), bringing the total number of structures strengthened to 207 (excluding permanent weight restrictions). This does not include a total of seven additional structures strengthened during 2005/06 on the de-trunked A39, which were identified and designed in the period covered by the LTP1.

The prioritisation for strengthening of all structures failing assessment was established in  the LTP1 and continuity of this and its application to retaining walls has been important in prioritising expenditure.  The increased costs in strengthening smaller structures (typical of rural routes in Cornwall) to 40T, has been outweighed by the efficiency savings in the use of standard bridge deck and culvert designs. Larger structures on the highway network including retaining walls have been strengthened to 40T as have those required to maintain the Heavy Load Route Network established during this LTP period. Delivery has been consistent and targeted over the period with on average 21 structures strengthened each year.

Delivery was on target despite some delays caused by land negotiations predominantly affecting the implementation of retaining wall strengthening projects.

In order to ensure the safety of the public, we have continued with the adoption of Highways Agency national guidance in the form of BA79 for the management of sub-standard structures. We have also contributed to the consultation on the development of BD79. There are currently 470 sub-standard structures being monitored to BA79.

Hele bridge on the A39 was identified as suffering from the effects of alkali silica reaction and prioritised for strengthening.  Works to replace the structure started in 2005.

All but one of the A39 retaining walls identified during the period have been assessed and (where appropriate) strengthened, and the remaining structure is programmed to be strengthened in the winter of 2006/07. 

The PRN strengthening included  the seven retaining walls strengthened to date and carried out in addition to the core programme to strengthen 128 structures. The additional funding awarded for 2006/07 will enable the remaining walls on the PRN to be strengthened during the LTP2 period.

Strategy – Strengthening Programme - To maintain at least one access route suitable for all vehicles to all communities.

After prioritising the completion of works on the PRN to maintain the availability of the PRN, efforts have focused on maintaining structures on County routes and maintaining suitable routes into communities to ensure inclusion and access to transport services. Reviews of specific areas, for example on Bodmin Moor, have been undertaken to develop medium term strategies for access to maintain existing businesses and enable appropriate development.

The appropriate steady state condition for the structure  stock is currently being defined as part of the development of Asset Management.  The structure stock must be maintained in good condition, at a sustainable level appropriate to maintain the integrity of the Network and have a prioritised maintenance programme.

Work has started to develop route approvals for heavy load routing on county roads and we are actively contributing to the Electronic Service Delivery for Abnormal Loads (ESDAL) project.

Consultation and implementation.

The consultation on the strengthening of highway structures which commenced before 2001 has continued throughout the period of LTP1.   The key stakeholders, including Districts and Parishes, Hauliers and the National Farmers Union, have contributed to the prioritisation and approach to implementing projects.  Local consultation has, where appropriate, also been carried out with local businesses and residents.  Local consultation is developed specifically for each scheme to minimise the impact of disruption. Typically, this has resulted in works being undertaken in appropriate seasons to meet the needs of farming and other local businesses and ensuring that appropriate warnings are given of works taking place.  

Appropriate alternative arrangements for public transport, including school buses, have been planned and delivered for specific schemes.

Environmental and Heritage.

The recommendations and requirements of consultants and statutory bodies have been included in the planning of work programmes to ensure compliance with legislation to protect species and habitats.

Structures recognised by their listed status and those of local distinctiveness and historical interest have received additional resources appropriate to their heritage value.

An appropriate ecological assessment was carried out for each major project undertaken.  Specific issues relating to the protection of species, retention of habitats, risks to the environment including pollution control and risk minimisation are developed from the outset in conjunction with safety risk evaluation and recorded through the life of the project.

Many of the private structures in Cornwall failing assessment belong to Rail Companies and are not on principal routes. It has therefore been possible in most cases to restrict the Highway passing over them.  We have worked closely with Network Rail (NR) in particular to address those structures which are identified as critical to Rail Safety even with restrictions in place.  This is particularly true of cast iron  structures and there are four such structures in Cornwall, three of which are of importance to the highway network.  We have worked with NR and agreed an appropriate level of funding and programme to enable them to strengthen these structures with the highest joint priorities.  These works are currently in design and programmed for implementation in 2006/07.

A total of five privately owned bridges (including the above) have been restricted in the period of the LTP.

There are currently only four bridges without a provisional capacity on the County network.  One is a newly identified structure owned by CCC and the remainder are owned by NR, and British Rail Board (Residuary).  These remaining structures are programmed to be assessed by September 2006. 

The target to assess all Private Structures by 2004 was established in 2003.  Resources required to meet this target were redirected to address issues at Boscastle in 2004/05 and to continue to focus on delivering structural strengthening schemes. To maintain progress, we reallocated  an element of the outstanding assessment work to the  Strategic Partner Consultant.

It was recognised in 2002/03 that continued delivery of the LTP1 programme using only in-house resources would be difficult.  In 2003, we appointed a strategic partner to ensure continued consistent delivery through the LTP1 and into the LTP2.  This has improved our ability to deliver varying amounts of work.