HERTFORDSHIRE COUNTY COUNCIL
REPORT ON THE DEVELOPMENT OF A COUNTY WIDE
FOOTWAY STRATEGY
Report to the Highways and Transport Panel
22 September 2005
Author: Chris Allen-Smith
1.
Agenda Item
No.
6
Tel: 01707 356573
Purpose of report



To inform Panel Members of progress to date on preparing a
countywide footway strategy.
To examine whole life costs for various footway surface types, taking
into account the ongoing maintenance and insurance claim costs.
To propose a policy to replace most costly surface types and so reduce
whole-life costs.
2.
Background
2.1
The Footway Network
2.1.1 The countywide network consists of 5134km of footways. Each section
of footway is placed in a hierarchical system prioritised from 1 to 5. These are
listed below with their percentage of the whole network:
1.
2.
High Traffic (4%)
Medium Traffic
(10%)
3.
Low Traffic (High
Risk) (2%)
4.
Low Traffic (Urban)
(79%)
Low Traffic (Rural)
(5%)
5.
Mainly town centres
Busy urban footways leading from housing estates
to town and city centres, transport interchanges,
frequently used public amenities. Main streets in
villages.
Housing estates with high incidence of defects
due to age of footway, extensive utility trenches or
vandalism. Lengths where there is significant high
numbers of vulnerable users, e.g. outside old
peoples homes
Housing estates and other urban footways
Little used rural footways.
2.2 Footway Surface Types
2.2.1 The main surface types and their percentage of the whole network are
listed below.
1




Bituminous (78%) [Bitmac/tarmac and other ‘black’ surfaces]
Concrete flag (16%) [Standard paving slabs and newer, smaller types]
Block Paving (3%) [Brick sized concrete blocks, often coloured]
Other (3%) [Includes special or enhanced surfaces ]
2.2.2 Some of the main causes for the deterioration of the existing footway
network can be attributed to utility openings, vehicle overrun, tree roots,
weathering and fair wear and tear. The effects of these can vary depending
upon the surface type. For example, bituminous surfaces become brittle and
break down over a period of time due to the effects of weathering, more so
than would a concrete flagged footway. Conversely, a concrete flagged
footway is more likely to result in trip hazards due to the effects of vehicle
overrun or tree roots, and is more difficult to reinstate properly following utility
works.
3. Analysis of Lifecycle costs, ongoing maintenance and insurance
claim costs
3.1
Different Types of Costs Incurred
3.1.1 Whole life costs for a particular surface type comprise of several
elements. There will be the initial construction costs which could be followed
by regular planned maintenance to prolong the serviceable life. For example,
this could include slurry sealing a bituminous surface to extend the life and
restore the surface. At the end of its serviceable life the cycle begins again
with the renewal/replacement of the footway. During the lifecycle there are
also regular ongoing costs required to maintain the footway in a safe and
serviceable condition. These costs will include reactive maintenance, such as
fixing trips as they occur, and insurance claim costs and will tend to increase
as a footway approaches the end of its life.
3.2
Construction and Planned Maintenance Costs
3.2.1 Lifecycle costs for various surface types and maintenance scenarios
are shown in Appendix 1. This shows that the cheapest is a bituminous
surface treated with a slurry seal or similar on a regular basis costing an
average of £1.13 per m2 per year. A concrete flagged footway is the most
expensive - nearly twice as much at £2.23 per m2 per year.
3.2.2 Each lifecycle includes a construction/reconstruction cost since
footways will periodically need full or partial rebuilding to restore them to
optimum condition although the frequency of such reconstructions can be
significantly reduced with a well-planned maintenance regime.
3.2.3 The diagram below illustrates the concept of the lifecycle of a footway
and demonstrates how, in some circumstances, a series of inexpensive
surface treatments, applied at the correct time, can be used to maintain the
condition and prolong the life of a footway cheaply and effectively.
2
Condition of Footway
Good
Minimum
acceptable
condition
Failed
Time
Initial deterioration curve of footway
Deterioration curve showing multiple, early interventions
Deterioration curve showing a single, late intervention
3.3
Ongoing Reactive Maintenance Costs
3.3.1 The regular ongoing costs of maintaining a footway can be divided into
three groups:



CAT 1 – Category 1 costs (works of a reactive nature required to put
right an unsafe condition, for example, filling potholes or replacing
broken/rocking slabs).
CAT 2 – Category 2 costs (minor maintenance works, for example,
relaying a section of uneven paving slabs, or resurfacing a small area
of bituminous footway)
Insurance Claims – Costs associated with compensation payments for
personal injury and damage to property.
3.3.2 In the period from 06/01/03 to 25/05/05 a total of £3.7million was spent
on CAT 1 repairs across all footway surface types. This equates to an
average annual cost of £0.15/m2 /year.
3.3.3 In the period from 27/03/04 to 19/05/05 a total of £1.1million was spent
on CAT 2 repairs across all footways. This equates to an average annual cost
of £0.11/ m2/year.
3.3.4 In the period 01/10/02 to 31/05/05 a total of £1.4million was spent/set
aside for settling compensation claims relating to defects on the footways.
This equates to an average annual cost of £0.05/m2/year.
3
3.3.5 The overall ongoing costs per square metre per year for each surface
type are shown in Figure 1. Bituminous footways which make up the majority
of the network cost £0.26/m2 per year compared with £0.59/m2 per year for a
concrete flagged footway. A breakdown of the costs across each hierarchy
can be seen in Appendix 2.
Average Cost per m2/year by surface type
£0.700
£0.592
Cost per m2/year (£)
£0.600
£0.500
£0.454
£0.400
£0.300
£0.256
£0.196
£0.200
£0.100
£0.000
Bitmac
Concrete Flagged
Blocks
Other
Surface Type
Ongoing Maintenance - Average cost per m2/year
3.4
Overall Lifecycle costs
3.4.1 Overall lifecycle figures are obtained by combining all the costs
together for a particular surface type. This shows that a bituminous footway on
average will cost £1.39/ m2 per year to compared £2.82/ m2 per year for a
concrete flagged footway.
4.
Comparison of Options for Footway Surfaces
4.1
This analysis concentrates on the two most common types of footway
surface – concrete slabs and bitmac – as these comprise the vast majority of
the network and are consequently where the greatest impact can be made.
4.2
A comparison of the lifecycle costs presented in Section 3 shows that
bituminous footways are less expensive to build and maintain than a concrete
flagged footway, generally have a longer service life between major repairs,
attract fewer ‘Category 1’ defects and fewer insurance claims.
4.3
From the analysis presented in the various Appendices, it will be seen
that the cost of converting a paving slab footway to a bituminous footway is
slightly higher than the cost of lifting and relaying the slabs to renew the
footway surface. However, this does depend on how many of the slabs are
4
broken and need to be replaced – in some cases relaying in bitmac will be
cheaper than relaying the slabs. However, this higher initial cost is more than
offset over time by the longer life and lower ongoing maintenance costs. In the
past the higher initial cost might have made this option less attractive
however, when considering the options as part of a life-cycle cost (a key
element of the Asset Management approach to highway maintenance
championed by Hertfordshire) we can see the whole-life benefits.
4.4
Analysis of the figures suggests that if concrete flagged footways were
replaced with bituminous material then a cost saving could be achieved within
5 years. Refer to Appendix 3 for details.
4.5
Bitmac and other bituminous footways also offer a number of other
advantages over paving slabs besides the lower whole-life costs:
4.5.1 Health & Safety: New guidance on manual handling means that the
large, heavy concrete slabs now pose an identified health & safety risk to
workers moving and laying them. Under the Construction (Design &
Management) Regulations HCC, as the client for the works, has a duty to
consider the safety and well-being of workers not just during construction but
during subsequent maintenance operations. For this reason, identified risks
should be eliminated where practical.
4.5.2 Improving Access: Quite aside from reducing the risks to workers,
removing paving slab footways helps to reduce the risk to pedestrians,
especially the elderly and wheelchair/pushchair users, who tend to find the
sharp trips that are created when slab footways become uneven especially
difficult to negotiate.
4.5.3 Durability: Although the theoretical life of a concrete slab is almost
unlimited, in the modern environment vehicle over-running, stats trenches and
tree roots are major factors in the deterioration of footways. Bituminous
surfaces tend to be more forgiving in such situations compared with slabs
which are more prone to breaking and presenting trip hazards. This is
reflected in the higher whole-life cost of slabs.
4.5.4 Visual Amenity: The main advantage offered by slabs is that, at least
when in good condition, they are often considered a more attractive surface
than bitmac. This is an important factor in the street scene, especially in towncentre areas, and it is proposed that suitable surfaces should be maintained in
town-centre shopping streets and similar prestige areas.
5.
Proposals
5.1
Given the cost savings that could be achieved and other advantages of
bituminous surfaces, it is proposed to introduce a Policy to the effect that,
when a concrete flagged footway is due to be renewed then it would be with a
bituminous surface. The Policy would also require that any new footways
would be built with bituminous materials. There would be exceptions to this,
5
such as when the location is within a main shopping centre. A proposed
footway Policy wording is shown in Appendix 4.
6.
Issues for the panel to consider
6.1
The Panel is asked to support the introduction of the Footway Policy as
shown in Appendix 4.
7.
Appendices:
Appendix 1:
Lifecycle Costs
Appendix 2:
Costs associated with CAT1/CAT2 repairs and
insurance claim costs
Appendix 3:
Analysis of potential cost savings
Appendix 4:
Proposed Footway Policy
6
Appendix 1:
Lifecycle
costs
Treatment
1
Bitumen
Bitumen +
slurry seal
Bitumen +
microasphalt
Concrete slab
footway
Slab footway
converted to
Bitumen*
2
3
4
5
6
7
8
9
10
11
12
13
Year
14
15
16
17
18
£24.85
19
20
21
22
23
24
25
£24.85
£24.85
£6.00
£6.00
£24.85
£6.00
£12.67
£29.05
£12.67
£29.05
£36.08*
£12.67
£12.67
Treatment
Year
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
Bitumen
£24.85
Bitumen +
slurry seal
£6.00
£6.00
£6.00
Bitumen +
microasphalt
£12.67
£12.67
Concrete slab
footway*
£29.05
£29.05
Slab footway
converted to
Bitumen
£12.67
£12.67
*The cost of relaying a slab footway assumes that a portion of the slabs are suitable for reuse. Where this is not the case, the cost of this option will be higher.
**The cost to convert a slab footway to a bituminous surface includes a significant allowance for reconstructing the foundation layers of the footway. In
practice this is not always necessary and so this cost is a conservative estimate.
7
50
Treatment
Adjustment to 50 yr life
Cost over 50 years
Cost per m2/yr
Bitumen
-£5.52
£49.70
£0.99
Bitumen + slurry seal
-£4.50
£42.85
£0.86
Bitumen + microasphalt
-£10.56
£50.19
£1.00
Concrete slab footway*
-£4.47
£58.10
£1.16
Slab footway converted to
Bitumen
-£10.56
£61.42
£1.23
Notes: The 'Adjustment' is the amount of life remaining at the end of the fifty-year period, this is deducted for the total costs to give the cost of a
fifty-year life-cycle so that all treatments can be compared on a similar basis.
8
Appendix 2: Costs associated with Cat 1/Cat 2 repairs and Insurance Claims
HCC Hierarchy
1
(High)
2
(Medium)
3
(Lo - Hi risk)
4
(Lo - Urban)
5
(Lo - Rural)
Hierarchy and
surface type not
recorded
Totals
Surface Type
Area of
footway
(m2)
CAT 1
Repairs (£)
CAT 1
Repairs
£/m2/year
CAT 2
Repairs (£)
CAT 2
Repairs
£/m2/year
Insurance
Claims
(£)
Insurance
Claims
£/m2/year
Total
£/m2/year
Bitmac
Concrete Slab
Blocks
Other
Bitmac
Concrete Slab
Blocks
Other
Bitmac
Concrete Slab
Blocks
Other
Bitmac
Concrete Slab
Blocks
Other
Bitmac
Concrete Slab
Blocks
Other
367587
131232
63962
21197
843029
148716
24682
10628
191249
19965
3091
2738
6097422
1277610
207471
257104
390601
6632
1454
23768
268924.03
163394.37
50686.81
25605.69
332773.19
65677.51
14529.55
6786.74
84460.31
9970.42
658.7
170.5
1823820.7
507889.91
64302.57
98001.25
55611.19
1365.28
487.56
1133.97
£0.307
£0.523
£0.333
£0.508
£0.166
£0.186
£0.247
£0.268
£0.186
£0.210
£0.090
£0.026
£0.126
£0.167
£0.130
£0.160
£0.060
£0.086
£0.141
£0.020
36845
13761
1849
0
72748
27170
3650
0
11391
4254
572
0
645147
240948
32367
0
19483
7277
977
0
£0.100
£0.105
£0.029
£0.000
£0.086
£0.183
£0.148
£0.000
£0.060
£0.213
£0.185
£0.000
£0.106
£0.189
£0.156
£0.000
£0.050
£1.097
£0.672
£0.000
60246
127188
16274
2478
50194
105967
13559
2064
13479
28456
3641
554
284879
601416
76952
11716
9331
19699
2521
384
£0.061
£0.363
£0.095
£0.044
£0.022
£0.267
£0.206
£0.073
£0.026
£0.534
£0.441
£0.076
£0.017
£0.176
£0.139
£0.017
£0.009
£1.112
£0.649
£0.006
£0.469
£0.991
£0.457
£0.551
£0.274
£0.635
£0.601
£0.341
£0.272
£0.957
£0.716
£0.102
£0.249
£0.532
£0.425
£0.177
£0.119
£2.296
£1.462
£0.026
-
10090138
119295.04
3695545.29
-
1118439
-
1430998
-
-
9
Surface Type
Bitmac
Concrete Flagged
Blocks
Other
Average cost m2/year/across all hierarchies
Insurance
CAT1
CAT 2
claims
Total
£0.137
£0.100
£0.020
£0.256
£0.198
£0.185
£0.209
£0.592
£0.183
£0.131
£0.141
£0.454
£0.175
£0.000
£0.020
£0.196
Notes:
Cat 1 costs based on the period 6/01/03 to 25/05/05 (870 days/2.38 years)
Cat 2 costs based on estimated annual spend by district and distributed across by hierarchy as per the HERMIS data for the period 27/3/04 to
19/5/05.
Insurance claims from the period 1/10/02 to 31/05/05 (973 days/2.67 years) and are based on actual costs plus amounts set aside for claims
not yet settled
10
Appendix 3: Analysis of Potential Cost Savings
Countywide area of concrete flagged footways is 1,584,155m2
The total area of concrete flagged footways in ‘High’ category is 131,232m 2
which equates to approximately 8%.
Assume that concrete flagged footways in ‘High’ category areas will not be
affected by the proposed footway policy to replace them.
Therefore, potentially at least 92% (1,452,923 m 2 ) of concrete flagged
footways could be converted to bitumen.
From the lifecycle costings, the cost to convert to bitumen is £36.08/m 2
The total cost to convert would be £36.08 x 1452923 = £52,421,462.
The ongoing cost savings per year would be the difference in concrete flagged
costs minus bitumen costs, ie £0.592-£0.256 = £0.336/m2 /year. (from table in
Appendix 2).
The lifecycle cost savings per year between concrete flagged and bitumen are
£2.23 -£1.13 = £1.10/m2 /year.
Therefore the total cost savings of bitumen over concrete flagged is £1.10 +
£0.336 = £1.44/m2 /year.
Assuming that all the concrete flagged footways that could be were converted
to bitumen then the cost saving would be £1.44 x 1,452,923 = £2,092,209 per
year.
Assuming an initial cost of £52,421,462 to convert it would take 25 years to
recover these costs. However, assuming that these flagged footways would
otherwise be reinstated with like for like at a cost of £29.05. The additional
cost to convert to bitumen over and above this is £36.08-£29.05 = £7.03/m2
/year.
Therefore the additional costs over what would otherwise be spent are £7.03 x
1,452,923 = £10,214,049. This divided by the cost savings of £2,092,209 per
year gives a figure of just under 5 years in which costs could be recovered.
11
Appendix 4: Proposed Footway Policy
1 The options for the replacement/renewal of various footway surfaces within
specific area types are detailed below:
Type A - Town Centre – Main shopping street
i)
ii)
iii)
If the existing surface is already bituminous then
replacement/renewal shall be with a bituminous material.*
If the existing surface is of pre-cast concrete paving slabs then
replacement/renewal shall remain as slabs or change to another
appropriate form of surface treatment such as modular or block
paving.*
If the existing surface is modular, block or already enhanced
surface then replacement/renewal shall be with a similar standard of
material so far as is practicable, although the precise nature of the
finish may need to be varied.*
* In Type A streets it may be considered appropriate to enhance the
existing surface if a 3rd party is willing to contribute the additional costs
involved. However the choice of material should fit the County
Council’s long term maintenance needs in terms of durability and
sourcing replacement materials.
Type B - Non Town Centre and all other areas including local
shopping precincts, residential, commercial and rural areas.
i)
ii)
If the existing surface is already bituminous then
replacement/renewal shall be with a bituminous material.
If the existing surface is a non-bituminous surface then replacement
shall be with a bituminous material.*
* Exceptionally, at the discretion of the local District Manager a Type B
footway with an existing enhanced surface, such as yorkstone paving
may be maintained to that standard rather than being replaced with a
bituminous material.
Refer to Table 1
2. With the exception of Type A, footways in new developments to be
adopted and maintained at public expense shall be constructed in
bituminous materials. The same standards shall be applied to
improvement or enhancement schemes promoted on the public highway
by HCC or partner organisations.
3. When renewing/replacing all surface types of footways, and where not
already present, consideration shall be given to the provision of dropped
kerbs and tactile paving in line with current guidance where necessary.
12
Footway Surface Type
Type A
(Main shopping
streets of a town
centre)
Existing surface material
Type B
(All others areas not
covered by type A,
including, local shopping
precincts, residential,
commercial and rural
areas)
Bituminous.
Bituminous
Bituminous.*
Precast concrete slabs
A range of options for
finished surface can be
considered including precast concrete slabs, blocks,
bitumen or other
appropriate surface.*
Existing surface can be
maintained at a similar
standard so far as is
practicable although the
precise nature of the finish
may need to be varied.*
Bituminous.
Existing surface can be
maintained at a similar
standard so far as is
practicable although the
precise nature of the finish
may need to be varied.*
At the discretion of the local
District Manager the
existing surface can be
maintained at a similar
standard so far as is
practicable, although the
precise nature of the finish
may need to be varied.
Modular paving/blocks
Enhanced surface (eg
yorkstone paving)
Bituminous.
Table 1 - Acceptable replacement/renewal surface types for footways
based on area type and existing surface material.
* In Type A streets it may be considered appropriate to enhance the existing
surface if a 3rd party is willing to contribute the additional costs involved.
However the choice of material should fit the County Council’s long term
maintenance needs in terms of durability and sourcing replacement materials.
13