South Wales Trunk Road Agent
Other
Disputed
The South Wales Trunk Road Agent responded by detailing the presalting treatment undertaken prior to the collision, including instruction times, spread rates, and confirmation via a Daily Operational Report. They also outlined their route-based forecasting service, implicitly providing evidence that existing procedures were followed and challenging the coroner's concern that the road surface was not treated in accordance with guidance. (AI summary)
View full response
Dear Sir RE: A465 LLANGUA,
1 refer fo your letter dated 13 Febreary 2014 regarding the fatal collision which occurred on the 10 February 2014 near Liangua and in particular the request for delails in relation to wintcr maintenance treatment undertaken prior to the collision.
In response te your request | haye outlined details as follows:
i, Date and times any road surface treatment may have been applied in relation lo the surface conditions prior to the reported collision.
Presaiting was instructed on Sunday 9 February 2014 commencing at L700hts at a spread rate of 20g/sqm. the record of instruction to Parinership Service Providers is attached with route highlighted in yellow.
2. What records are heid fo determinc that these works toak place together with the level of substance applied?
Foliowing the instruction South East Partnership returned a Daily Operational Report on ff February 2014 indicating treatment undertaken (attached with route highlighted in yellow).
wou Cecing 5 Read of Service - kr Wales Trunk Read Agent
F nena. 7 Pennaeth Gwasanaeth - Asiant Ceinftyrdd Be Cyrare $ easter : Unit 12, ttandarey House, The Courtyard. Liendarcy, Neath SATO bF} %, ooo taal a E-mail: enquizics@saunthwales-tra.govuk Fesscssarneo? Tel: 01792 325960, Eax: Of792 325902
wrew suunthwates-lra.govak Ps 3 ieg
What carriageway surface temperaiure equipment is availabic to you near this collision site, and what records of temperature were given during the night prior to this collision?
SWTRA obtain a route based forecasting service provided by the Welsh Government’s specialist ‘all Wales’ forecast provider, MeteoGroup, who consider a number of factors and use various sources of data to produce their weather forecast models.
This will include data from roadside weather sensors which record information such as read surface temperature and air temperature. One of these sensors is located on the A465 at Liangua.
A text based forecast for the 24 hours ahead is provided by 1300hrs each day and includes a cofour coded graphical representation of the predicted road surface temperatures across the network, a tabulated route schedule that indicates those routes likely to require treatment including minimum road surface temperatives and worst hazard.
The forecast information provided on the 9 February 2014 indicated a minimum road surface temperature of +0.6 C on the A465.
What factors you would use to determine the works necessary on a highway (o reduce the risks of ice forming on the carriageway?
Decisions in relation to presalting action requirements are based on forecast information provided hy MeteoGroup and are made in accordance with the guidance contained within the decision guide and treatment matrices provided in the SWTRA Adverse Weather Plan (2013/14) in accordance with WGOTRMM Part 5 Adverse Weather (02/07/12).
in consideration of the forecast provided on 9 February 2014 a decision was made to undertake presalting on the A465 at the time and rate of spread instructed in accordance with the decision guide and treatment matrices.
A copy of the Decision Matrix Guide and Treatment Matrix Guide is attached. Are the surfaces dctermined by a risk assessment or other recognised advice?
The road surface material is considered within the WGTRMM Part 5 Adverse Weather (02/07/12) auidance in so far as perous er open textured asphalts are treated at a higher spread rate than other read surface types. Furthermore where there ave known areas of water seepage onto the carriageway this is aiso treated ai a higher spread rate. This location was not a known seepage area.
How does the substance used on the carriageway react with the surface conditions,
to prevent the formation of ice or frost or to melt existing snow, salt must
first form a brine solution (dissolution). Therefore, after spreading the salt, there is a time lag before it becomes effective. The length of the lime required is dependent upon a number of factors fe.g. the size of the salt grains, availability of moisture, humidity and vehicle traffic running on treated surfaces). Treatment limes are considered to allow, where practicable, the required time for this dissolution to take place in order to increase the effectiveness of the treatment.
What visual evidence can be expected to be seen for persons viewing the carriageway surface?
Visual evidence is dependant on the rate of spread undertaken and the prevailing road conditions. During the time lag before the sait enters in to solution, the salt grains ave subject to the effects of wind and traffic whereby evidence of sali may be more prevalent in the channels and non trafficked areas, such as lay-bys, rather than on the main carriageway running lanes where salt has fornied a brine solution due partly to vehicle traffic on treated surfaces.
I trust that this information answers your enquiry however if you require further details please do not hesilale to contact me.
v8
Head of South Wales Trank Road Agent
Encs
SOUTH WALES TRUNK ROAD AGENT Asiant Cefnffyrdd De Cymru
Ye gweithio ar pan 4 et iipaodraeth Cymra f Working on behalf af the
Weish Government
Unit 12, Llandarcy House, The Courtyard, Llandarcy, Neath. SA10 GEJ
‘wet
Foun: NMF033
Edition: 03 a Created veomeantetiiateys ose .
om 13/42f12
NOTIFICATION OF. PROPOSED:TREATMENTS
::| Sunday Sth February 2014
af the 24 hour period started at 12:00. hrs 6
Scattered showers and bright speils this afternoon. The odd squaily hail shower possible with sleet or wet snow failing above 350m. The showers wili become isclated this evening as clear spells develop but then more widespread showers will spread in from the north-west after labe evening, again wintry on high ground, reaching many places by 02-03h. RSTs below zero for a time, exact timing variable from place to place - iow confidence especially on zero crossing times. Clearer later in the night. Occasional showers tomorrow morning, wintry on his.
2 Minimum Air Temperature Minimum RST Action Required: YESINO 020
SWTRA °°
: : Service Provider Route No, © 7
hid, 124 to J26, A4SMt
Ad, Ad49 slip rorde
LFOt LFG2
EFOS
A465, A470 North of Cefn Coed 47.00 & 04.00 cNo1 M4, J28 - 332, A422 Ne Action Cardiff C.C. = 4232 No Action |e
South Fast Watos Partnership
17.00 & 04.08
M4, 32 bo 034, Ad 70 No Actlon ru
fo A470 Tafis Well lo Abaroynon | NoAction | aa M4, 434 10.138 NoAcion | nia =| BICC _ na
N4, 335 to JI?
No Action South Centeal Wates Ma, J07 to dda, Add Partnership
M4, 538 to d45, Aaa
No Action nia on ne NPTCBC M4, £45 to 349 Ne Action nia
ViNOt PIRH YGO3
SOUTH WALES TRUNK ROAD AGENT |
Asiant Cefnffyrdd De Cymru te gacithia ean Working on behalf of the Unit 12, Llandarcy House, Welsh Government The Courtyard,
Llandarcy, Neath. SA70 GEJ Form: NMF/033
Creaied on: 13/42/42
South West Waies Partnership
Delay treatment if raining
Actioned by: [ | | Verified by: Date & Time: 09/02/74 at 13.45 Date & Fire:
69/02/14 at 13.15
~ South Wales Trunk Road Agent
Ya quverttlo ae san
Asiant Cefnffyrdd De Cymru YR Liywadraeth Cynara Working on behatt of the Unit 12, Liandarcy House, Welsh Government The Courtyard,
Created on: 8°" Nov. 2012
_. Uandarcy, Neath. SA10 6E]
To: South Wales Traffic Management Gentre (SWTRA) Fax. 017$2 325805 E-mait : w.maintenance@southwaies-tra.gov.uk
. DAILY OPERATIONAL REPORT for SWTRA _Actions undertaken b
Anetruction issued (Time/Date) SUNDAY 9 | SUNDAY OMFEBRUARY 2014 5014 “Actual Treatment
Commenis
YJE0 BXH
CN61 DDK
cne1 oDu
ae a A
Additional Comments, problems encountered, plant defects
Please note that these salting records are for a 24hr period irom 42:00pm on the date of action.
Page loft
Arlvesse tfeather Phan 2013-14
Decision Matrix Guide
Predicted Road Conditions
Road Surface +o ge Wet Tempasrature 7 Precipitation etc. Wet Patches Dry No rain May fall below +4°C No hoar frost sallbelore | No action likely, fete perenne oe No rain Salt (See note moniter wealher No hear frost before A) (See note A} No fog Ernected fog |__| Satt before frost (See note B) Expected rain . BEFORE freezing __ Salt afler rain stops Expected rain Salt beiore frost and after rain stops
Expected to fall DURING freezing (See note C}
below +7°C Possible rain Moni th Possible hoar frost Sait before frost _ weaner Possible fog _ conditions
‘Expected snow Sait before snow fall
Before rain Salt before rainfait (See note C
During rain i i
om memenen ef:
Salt during rainfall (See note ¢
wae ae |
Freezing rain After rain Salt after rainfall (See note C}
A Partiouiar attention shouid be given to any possibility of water running across carriageways and such locations should be monitored and treated as required,
8B When a weather warning contains reference to expected hoar frost considerable deposits of frost are likely to occur and close moniforing will be required. Particular attention should be given fo the timing of precautionary treatments due fo the possibility that salt deposited on a dry road may be dispersed before it can become effective.
G Under these circumstances rain will freeze on contact with running surfaces and full pre-treatment should be provided even on dry roads. This is a most serious condition and should be monitored closely and continuously throughout the danger period.
NriNelwork Manaacment\Nctwork Coatral Conte Advenn: 34 Weather - WATE 314-WaAttS\ed 13.7 Severe Weather
PlantWarking CopySWTRA Adverse Weather Pian 13-14
{text only}.des
Adverse Wealber Plan 3073-14
Treatment Matrix Guide {im accordance wi P/GTRIMM 2072 Part:5.8 Application of Sal}
“Teaatmant Matrix (2012-2013)
Weather Conditions Air Dry Sa iting” | Road Surface Conditions Temp tain?)
Road Surface Femperature(RST}
(MARGINAL CONDITIONS}
Frest or forecast frost, RST ator 10
above -2°C and dry or damp raad
conditions. (Porous / open textured {42}
surfacing, see Note 4). ee es
Frost or forecast frost, RST at or
above -2°C and wet road conditions 190
(see Note 3 if wet and lightly
trafficked}. (Poraus / open textured {45}
surfacing, see Note 4).
Frost or forecast frost, RST balow
-2°C and above -5°C and dry ar damp road conditions (see Note 3 if dainp and lightly trafficked}. (Porous / open lexturad surfacing, see Note 4}.
Frost oF forecast frost, RST below
-2°C and above -5°C and wel road conditions (see Note 3 ifiightly - trafficked). (Porous / open textured surfacing, sve Nate 4).
Frosl or forecast frost, RST at ar betow -5°C and above -10°C and dry or damp road candillons {see Note 3 if damp and lighty aificked}. (Poraus f open textured surfacing, see Note 4}. . Frosl or forecast frost, RST at or below -5°C and above -10°C and wet road conditions (existing or anticipaled) (see Note 3 if lighliy frafficked}. (Porous / opan textured surfacing or particularly low temperatures at jower end of
temperature band, see Note 4}. “Light snow forecast (<?0mm).
Na
Modiumfheavy snow or freezing
_taln forecast.
“Freazing rain failing.
Aftar freezing rain. (euccessive as sequired)
Ice formed Tce formed (minor accumatations). accumulations}. SC 20
NANetwork Manigement\Netwark Contre] CenteclAdverse Weather - WMALI14-WiESVWM 13.7 Severe Weather PlantWorking CoppiSWiIRA Adverse Weather Plan 13-T4 (text only).doc
Treatment _ Pra-Weited Pre-Coated | Ploughing Salting Salting (gin’} igfm’) |__ {see Note 1 19 10 {12} (18)
12 See Note 2 Below
20 See Note 2 Below
25
(2x15)
10-20 See | _Noie 2 Below
See Note 2
Below 16 No
See Note 2 : Below 6 _ No 345
tn wo awe samen 8A
Boe en a
ns mettre re ciennee te
Pia:
Adiverse VWoather Pia 2013-14 g } ‘
— ——_—_———— _. . ee Ch _.. at or lee formed. | below | 2x 20 2 See Note 2 | 2x15 | No “°C Ow
‘Treaimant Matrix (2032-2073) (continued)
Weather Conditions Pre-Wetted | Pre-Coated Road Surface Conditlons Salting Saiting Road Surface Temperature(RST} ites”) (gim’}
—... _ see Note 1) | _ Snow covering exceeding 30mm. See Nole 2 10-45 . _ (successive) _ Below _|_ {successive} Hard packed snow/ice. 20 See Note 2 45 _ (successive) Below {successive} . Saltlabrasive Sees Note 2 Saltfabrasive Hard packed snow/ice. (successive) Below {successive}
Rates of spread for precautionary treatments may be adjusted to take account of residual salt or surface indisture. Refer to mare detailed Advice and Guidance Nofes.
if the indicated spread rafe can not he accurately applied due to limitations of the equipment or calibration difficulties, the next higher spread rate shauid be used. (For example: when indicated f2gin*
use 15g/m*}.
Equipment shail be calibrated and adjusted to ensure that the required spread rates throughout the salting route {with varying loads} does not fali below the minimum rate specified, this is particularly important for the jower spread rates indleoted.
Where double traaiment Is necessary the initial first treatment shall be af the highest spread reafe possible within the limitations of the spreader for the route length. For example 2xt5g/m’ applied as 4n26 gin + dxt0 gin’.
oA ee eS ry
Notes
Spread rates for pre-wetted sait Is the combined weight of dry rock sait and brine combined at 70:30 proportion by weight respectively. Please see Guidance / Advice regarding the addillon of Agricultural by Pracucts (ABP’s} within the brine 10% by volume maximum} or use of pre-coated salt (3% by welghtofsali}), | When ice has formed or snow is lying, dry or pre-coated salting is the preferred freaiment unless the road is ciosed {fo lraffic whan pre-wetted salting may be used. Pre-welied and pre-coated salting is a more effective treatment in advance of such conditions. Pre coaise and Ory Sailing should be undertaken when roads are wet
Treatments See choc be carried out, whenever po possible, after fralfic has dispersed standing water. Successive normai or half rate treatinents (for pre-wetled, pre- coated and diy salt) may be considered, based on operational exparience for lighily trafficked roads at the iower end of ihe temperature bands indicated and climatic variations experienced. Where a surfacing is of an open texture and for por porous or surface water is evident the higher spread rafe (indicated in brackets} should be used. Where temperatures may reach the lower end of the temperature bands, fight traffic or a more caulious approach to ireatmant is required based on operational exparience, iocal knowiedgs, the higher spread rate Gindicated in brackets) may be used.
AL Wetwark Manayement\Nctwork Control CentreAdversa: 36 Weather - WMU3 14-Wil [SUV 23.7 Severe Weather
Plan\Working CopyS¥ TRA ddlverse Weatlter Phir 13-14
(text only}dac
a ne md
= ee
a sents,
1 refer fo your letter dated 13 Febreary 2014 regarding the fatal collision which occurred on the 10 February 2014 near Liangua and in particular the request for delails in relation to wintcr maintenance treatment undertaken prior to the collision.
In response te your request | haye outlined details as follows:
i, Date and times any road surface treatment may have been applied in relation lo the surface conditions prior to the reported collision.
Presaiting was instructed on Sunday 9 February 2014 commencing at L700hts at a spread rate of 20g/sqm. the record of instruction to Parinership Service Providers is attached with route highlighted in yellow.
2. What records are heid fo determinc that these works toak place together with the level of substance applied?
Foliowing the instruction South East Partnership returned a Daily Operational Report on ff February 2014 indicating treatment undertaken (attached with route highlighted in yellow).
wou Cecing 5 Read of Service - kr Wales Trunk Read Agent
F nena. 7 Pennaeth Gwasanaeth - Asiant Ceinftyrdd Be Cyrare $ easter : Unit 12, ttandarey House, The Courtyard. Liendarcy, Neath SATO bF} %, ooo taal a E-mail: enquizics@saunthwales-tra.govuk Fesscssarneo? Tel: 01792 325960, Eax: Of792 325902
wrew suunthwates-lra.govak Ps 3 ieg
What carriageway surface temperaiure equipment is availabic to you near this collision site, and what records of temperature were given during the night prior to this collision?
SWTRA obtain a route based forecasting service provided by the Welsh Government’s specialist ‘all Wales’ forecast provider, MeteoGroup, who consider a number of factors and use various sources of data to produce their weather forecast models.
This will include data from roadside weather sensors which record information such as read surface temperature and air temperature. One of these sensors is located on the A465 at Liangua.
A text based forecast for the 24 hours ahead is provided by 1300hrs each day and includes a cofour coded graphical representation of the predicted road surface temperatures across the network, a tabulated route schedule that indicates those routes likely to require treatment including minimum road surface temperatives and worst hazard.
The forecast information provided on the 9 February 2014 indicated a minimum road surface temperature of +0.6 C on the A465.
What factors you would use to determine the works necessary on a highway (o reduce the risks of ice forming on the carriageway?
Decisions in relation to presalting action requirements are based on forecast information provided hy MeteoGroup and are made in accordance with the guidance contained within the decision guide and treatment matrices provided in the SWTRA Adverse Weather Plan (2013/14) in accordance with WGOTRMM Part 5 Adverse Weather (02/07/12).
in consideration of the forecast provided on 9 February 2014 a decision was made to undertake presalting on the A465 at the time and rate of spread instructed in accordance with the decision guide and treatment matrices.
A copy of the Decision Matrix Guide and Treatment Matrix Guide is attached. Are the surfaces dctermined by a risk assessment or other recognised advice?
The road surface material is considered within the WGTRMM Part 5 Adverse Weather (02/07/12) auidance in so far as perous er open textured asphalts are treated at a higher spread rate than other read surface types. Furthermore where there ave known areas of water seepage onto the carriageway this is aiso treated ai a higher spread rate. This location was not a known seepage area.
How does the substance used on the carriageway react with the surface conditions,
to prevent the formation of ice or frost or to melt existing snow, salt must
first form a brine solution (dissolution). Therefore, after spreading the salt, there is a time lag before it becomes effective. The length of the lime required is dependent upon a number of factors fe.g. the size of the salt grains, availability of moisture, humidity and vehicle traffic running on treated surfaces). Treatment limes are considered to allow, where practicable, the required time for this dissolution to take place in order to increase the effectiveness of the treatment.
What visual evidence can be expected to be seen for persons viewing the carriageway surface?
Visual evidence is dependant on the rate of spread undertaken and the prevailing road conditions. During the time lag before the sait enters in to solution, the salt grains ave subject to the effects of wind and traffic whereby evidence of sali may be more prevalent in the channels and non trafficked areas, such as lay-bys, rather than on the main carriageway running lanes where salt has fornied a brine solution due partly to vehicle traffic on treated surfaces.
I trust that this information answers your enquiry however if you require further details please do not hesilale to contact me.
v8
Head of South Wales Trank Road Agent
Encs
SOUTH WALES TRUNK ROAD AGENT Asiant Cefnffyrdd De Cymru
Ye gweithio ar pan 4 et iipaodraeth Cymra f Working on behalf af the
Weish Government
Unit 12, Llandarcy House, The Courtyard, Llandarcy, Neath. SA10 GEJ
‘wet
Foun: NMF033
Edition: 03 a Created veomeantetiiateys ose .
om 13/42f12
NOTIFICATION OF. PROPOSED:TREATMENTS
::| Sunday Sth February 2014
af the 24 hour period started at 12:00. hrs 6
Scattered showers and bright speils this afternoon. The odd squaily hail shower possible with sleet or wet snow failing above 350m. The showers wili become isclated this evening as clear spells develop but then more widespread showers will spread in from the north-west after labe evening, again wintry on high ground, reaching many places by 02-03h. RSTs below zero for a time, exact timing variable from place to place - iow confidence especially on zero crossing times. Clearer later in the night. Occasional showers tomorrow morning, wintry on his.
2 Minimum Air Temperature Minimum RST Action Required: YESINO 020
SWTRA °°
: : Service Provider Route No, © 7
hid, 124 to J26, A4SMt
Ad, Ad49 slip rorde
LFOt LFG2
EFOS
A465, A470 North of Cefn Coed 47.00 & 04.00 cNo1 M4, J28 - 332, A422 Ne Action Cardiff C.C. = 4232 No Action |e
South Fast Watos Partnership
17.00 & 04.08
M4, 32 bo 034, Ad 70 No Actlon ru
fo A470 Tafis Well lo Abaroynon | NoAction | aa M4, 434 10.138 NoAcion | nia =| BICC _ na
N4, 335 to JI?
No Action South Centeal Wates Ma, J07 to dda, Add Partnership
M4, 538 to d45, Aaa
No Action nia on ne NPTCBC M4, £45 to 349 Ne Action nia
ViNOt PIRH YGO3
SOUTH WALES TRUNK ROAD AGENT |
Asiant Cefnffyrdd De Cymru te gacithia ean Working on behalf of the Unit 12, Llandarcy House, Welsh Government The Courtyard,
Llandarcy, Neath. SA70 GEJ Form: NMF/033
Creaied on: 13/42/42
South West Waies Partnership
Delay treatment if raining
Actioned by: [ | | Verified by: Date & Time: 09/02/74 at 13.45 Date & Fire:
69/02/14 at 13.15
~ South Wales Trunk Road Agent
Ya quverttlo ae san
Asiant Cefnffyrdd De Cymru YR Liywadraeth Cynara Working on behatt of the Unit 12, Liandarcy House, Welsh Government The Courtyard,
Created on: 8°" Nov. 2012
_. Uandarcy, Neath. SA10 6E]
To: South Wales Traffic Management Gentre (SWTRA) Fax. 017$2 325805 E-mait : w.maintenance@southwaies-tra.gov.uk
. DAILY OPERATIONAL REPORT for SWTRA _Actions undertaken b
Anetruction issued (Time/Date) SUNDAY 9 | SUNDAY OMFEBRUARY 2014 5014 “Actual Treatment
Commenis
YJE0 BXH
CN61 DDK
cne1 oDu
ae a A
Additional Comments, problems encountered, plant defects
Please note that these salting records are for a 24hr period irom 42:00pm on the date of action.
Page loft
Arlvesse tfeather Phan 2013-14
Decision Matrix Guide
Predicted Road Conditions
Road Surface +o ge Wet Tempasrature 7 Precipitation etc. Wet Patches Dry No rain May fall below +4°C No hoar frost sallbelore | No action likely, fete perenne oe No rain Salt (See note moniter wealher No hear frost before A) (See note A} No fog Ernected fog |__| Satt before frost (See note B) Expected rain . BEFORE freezing __ Salt afler rain stops Expected rain Salt beiore frost and after rain stops
Expected to fall DURING freezing (See note C}
below +7°C Possible rain Moni th Possible hoar frost Sait before frost _ weaner Possible fog _ conditions
‘Expected snow Sait before snow fall
Before rain Salt before rainfait (See note C
During rain i i
om memenen ef:
Salt during rainfall (See note ¢
wae ae |
Freezing rain After rain Salt after rainfall (See note C}
A Partiouiar attention shouid be given to any possibility of water running across carriageways and such locations should be monitored and treated as required,
8B When a weather warning contains reference to expected hoar frost considerable deposits of frost are likely to occur and close moniforing will be required. Particular attention should be given fo the timing of precautionary treatments due fo the possibility that salt deposited on a dry road may be dispersed before it can become effective.
G Under these circumstances rain will freeze on contact with running surfaces and full pre-treatment should be provided even on dry roads. This is a most serious condition and should be monitored closely and continuously throughout the danger period.
NriNelwork Manaacment\Nctwork Coatral Conte Advenn: 34 Weather - WATE 314-WaAttS\ed 13.7 Severe Weather
PlantWarking CopySWTRA Adverse Weather Pian 13-14
{text only}.des
Adverse Wealber Plan 3073-14
Treatment Matrix Guide {im accordance wi P/GTRIMM 2072 Part:5.8 Application of Sal}
“Teaatmant Matrix (2012-2013)
Weather Conditions Air Dry Sa iting” | Road Surface Conditions Temp tain?)
Road Surface Femperature(RST}
(MARGINAL CONDITIONS}
Frest or forecast frost, RST ator 10
above -2°C and dry or damp raad
conditions. (Porous / open textured {42}
surfacing, see Note 4). ee es
Frost or forecast frost, RST at or
above -2°C and wet road conditions 190
(see Note 3 if wet and lightly
trafficked}. (Poraus / open textured {45}
surfacing, see Note 4).
Frost or forecast frost, RST balow
-2°C and above -5°C and dry ar damp road conditions (see Note 3 if dainp and lightly trafficked}. (Porous / open lexturad surfacing, see Note 4}.
Frost oF forecast frost, RST below
-2°C and above -5°C and wel road conditions (see Note 3 ifiightly - trafficked). (Porous / open textured surfacing, sve Nate 4).
Frosl or forecast frost, RST at ar betow -5°C and above -10°C and dry or damp road candillons {see Note 3 if damp and lighty aificked}. (Poraus f open textured surfacing, see Note 4}. . Frosl or forecast frost, RST at or below -5°C and above -10°C and wet road conditions (existing or anticipaled) (see Note 3 if lighliy frafficked}. (Porous / opan textured surfacing or particularly low temperatures at jower end of
temperature band, see Note 4}. “Light snow forecast (<?0mm).
Na
Modiumfheavy snow or freezing
_taln forecast.
“Freazing rain failing.
Aftar freezing rain. (euccessive as sequired)
Ice formed Tce formed (minor accumatations). accumulations}. SC 20
NANetwork Manigement\Netwark Contre] CenteclAdverse Weather - WMALI14-WiESVWM 13.7 Severe Weather PlantWorking CoppiSWiIRA Adverse Weather Plan 13-T4 (text only).doc
Treatment _ Pra-Weited Pre-Coated | Ploughing Salting Salting (gin’} igfm’) |__ {see Note 1 19 10 {12} (18)
12 See Note 2 Below
20 See Note 2 Below
25
(2x15)
10-20 See | _Noie 2 Below
See Note 2
Below 16 No
See Note 2 : Below 6 _ No 345
tn wo awe samen 8A
Boe en a
ns mettre re ciennee te
Pia:
Adiverse VWoather Pia 2013-14 g } ‘
— ——_—_———— _. . ee Ch _.. at or lee formed. | below | 2x 20 2 See Note 2 | 2x15 | No “°C Ow
‘Treaimant Matrix (2032-2073) (continued)
Weather Conditions Pre-Wetted | Pre-Coated Road Surface Conditlons Salting Saiting Road Surface Temperature(RST} ites”) (gim’}
—... _ see Note 1) | _ Snow covering exceeding 30mm. See Nole 2 10-45 . _ (successive) _ Below _|_ {successive} Hard packed snow/ice. 20 See Note 2 45 _ (successive) Below {successive} . Saltlabrasive Sees Note 2 Saltfabrasive Hard packed snow/ice. (successive) Below {successive}
Rates of spread for precautionary treatments may be adjusted to take account of residual salt or surface indisture. Refer to mare detailed Advice and Guidance Nofes.
if the indicated spread rafe can not he accurately applied due to limitations of the equipment or calibration difficulties, the next higher spread rate shauid be used. (For example: when indicated f2gin*
use 15g/m*}.
Equipment shail be calibrated and adjusted to ensure that the required spread rates throughout the salting route {with varying loads} does not fali below the minimum rate specified, this is particularly important for the jower spread rates indleoted.
Where double traaiment Is necessary the initial first treatment shall be af the highest spread reafe possible within the limitations of the spreader for the route length. For example 2xt5g/m’ applied as 4n26 gin + dxt0 gin’.
oA ee eS ry
Notes
Spread rates for pre-wetted sait Is the combined weight of dry rock sait and brine combined at 70:30 proportion by weight respectively. Please see Guidance / Advice regarding the addillon of Agricultural by Pracucts (ABP’s} within the brine 10% by volume maximum} or use of pre-coated salt (3% by welghtofsali}), | When ice has formed or snow is lying, dry or pre-coated salting is the preferred freaiment unless the road is ciosed {fo lraffic whan pre-wetted salting may be used. Pre-welied and pre-coated salting is a more effective treatment in advance of such conditions. Pre coaise and Ory Sailing should be undertaken when roads are wet
Treatments See choc be carried out, whenever po possible, after fralfic has dispersed standing water. Successive normai or half rate treatinents (for pre-wetled, pre- coated and diy salt) may be considered, based on operational exparience for lighily trafficked roads at the iower end of ihe temperature bands indicated and climatic variations experienced. Where a surfacing is of an open texture and for por porous or surface water is evident the higher spread rafe (indicated in brackets} should be used. Where temperatures may reach the lower end of the temperature bands, fight traffic or a more caulious approach to ireatmant is required based on operational exparience, iocal knowiedgs, the higher spread rate Gindicated in brackets) may be used.
AL Wetwark Manayement\Nctwork Control CentreAdversa: 36 Weather - WMU3 14-Wil [SUV 23.7 Severe Weather
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