Maintenance Decision Support System

• Intersection I-15Intersection I-15

and I-70 in Utahand I-70 in Utah

• Point intervalsPoint intervals

along corridoralong corridor

ranging from 1ranging from 1

to 3 milesto 3 miles

• Intersection I-15Intersection I-15

and I-70 in Utahand I-70 in Utah

• Point intervalsPoint intervals

along corridoralong corridor

ranging from 1ranging from 1

to 3 milesto 3 miles

GIS Display of Jurisdiction AreaGIS Display of Jurisdiction Area

Snow Rain Mixed

MidnightWednesday

MidnightTuesday

MidnightThursday

0.00

0.10

0.20

0.30

0.40

Pre

cip

ita

tio

n R

ate

(SW

E)

(in

/hr)

Two-Day Precipitation Rate HistoryPrediction Point #3

3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48

Time Since Awareness (hrs)

0

0.05

0.15

0.25

0.35

5

10

15

20

25

30

35

40

Tem

per

atu

re (

deg

F)

3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48

Time Since Awareness (hrs)

0

0

Two-Day Temperature HistoryPrediction Point #3

MidnightWednesday

MidnightTuesday

MidnightThursday

Pavement Temperature

Air Temperature

MidnightWednesday

MidnightTuesday

MidnightThursday

Two-Day Snow Depth HistoryWithout TreatmentPrediction Point #3

2

4

6

8

10

12

14

16

Sn

ow

Dep

th (

in)

3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48

Time Since Awareness (hrs)

0

0

Snow Depth with No Maintenance Efforts

MidnightWednesday

MidnightTuesday

MidnightThursday

Two-Day Chemical Concentration HistoryWithout TreatmentPrediction Point #3

Co

nce

ntr

ati

on

(%

by

wei

gh

t)

5

10

15

20

25

3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48

Time Since Awareness (hrs)

0

0

Concentration of NaCl (no treatment)

MidnightWednesday

MidnightTuesday

MidnightThursday

Two-Day Friction Coefficient HistoryWithout TreatmentPrediction Point #3

Fri

ctio

n C

oef

fici

ent

3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48

Time Since Awareness (hrs)

0

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1Friction Coefficient with No Maintenance Efforts

What ? When ?How ?

Decisions Supported by MDSS

2.1 become aware of weather threat2.2 monitor weather threat2.3 identify weather threat occurance

2.4 assess sufficiency of equip. & consumables2.6 check readiness of equip. & consumables

2.10 assign minimum staff to monitor and manage2.13 disseminate important weather info to field staff2.14 forward-place equipment and stocks2.16 alert supervisory staff to monitor/prepare2.18 alert crews

Decisions Supported by MDSS

2.21 select treatment expendables2.5 replenish consumable stocks2.7 mix expendables

2.11 select event-treatment strategy2.17 confirm strategy-plan in place

2.12 assign crews to shifts, schedules

2.22 dress and load equipment

2.19 split crew shifts

2.25 dispatch crews to treat (anti-ice)

Decisions Supported by MDSS

2.24 dispatch crews to wait at routes

2.27 dispatch crews to treat (plow/spread)

2.28 dispatch crews to treat (plow cake, de-ice)2.30 dispatch crews to treat (ice-spot treat)2.42 re-evaluate storm intensity and duration2.44 determine the LOS goal is reached2.39 close roads2.41 rest crews

Decisions Supported by MDSS

2.29 dispatch crews to treat (bulk removal)2.31 dispatch crews to treat (drifting)2.47 dispatch crews to clean up

2.43 identify threat end2.48 open roads

Pre-Defined Levels Of ServicePre-Defined Levels Of Service

● DOT road classifications based on number of vehicles/day● Level of Service standards

• Bare Pavement• Full-width• 50%-75% width• Left-wheel• Passing Lane• None

• Time• 4, 6, 16, 24 hours after storm ends• Or as soon as practical and as weather permits

● “Provide reasonable traveling conditions for the prudent driver during storm, depending on location, time of day”

Current Pavement Temperature (F)

Anticipated Pavement Temperature Change

Precipitation Type* / Severity

Salt Application Rate ** (lbs per two-lane mile) Comments

Above 32

25 to 32

20 to 25

15 to 20

15 or Below

Higher

Lower

Higher

Higher

Lower

Lower

Higher

Higher

Lower

Lower

Higher

Higher

Lower

Lower

R, SL, WS / Light

R, SL, WS / Mod. - Heavy

FR, SL, DS, WS / Light

FR, SL, DS, WS / Mod. – Heavy

FR, SL, DS, WS / Light

FR, SL, DS, WS / Mod. - Heavy

SL, DS, WS / Light

SL, DS, WS / Mod. – Heavy

SL, DS, WS / Light

SL, DS, WS / Mod. - Heavy

SL, DS / Light

SL, DS / Mod. – Heavy

SL, DS / Light

SL, DS / Mod. - Heavy

100 to 200

200 to 300

200 to 300

200 to 400

200 to 400

300 to 500

300 to 500

400 to 600

400 to 600

500 to 700

500 to 700

700 to 800

700 to 800

No Salt. Apply Sand

and Plow as Needed.

Use Pre-Wet System

Pre-Wet: 6 Gallons/Ton

Pre-Wet: 6 Gallons/Ton

Pre-Wet: 6 Gallons/Ton

Pre-Wet: 6 Gallons/Ton

Pre-Wet: 8 Gallons/Ton

Pre-Wet: 8 Gallons/Ton

Pre-Wet: 8 Gallons/Ton

Pre-Wet: 8 Gallons/Ton

Pre-Wet: 10 Gallons/Ton

Pre-Wet: 10 Gallons/Ton

Pre-Wet: 10 Gallons/Ton

Pre-Wet: 10 Gallons/Ton

Monitor Pavement Temp.

Switch to Salt if Rising Above

15F

* R=Rain, FR=Freezing Rain, SL=Sleet, WS=Wet Snow, DS=Dry Snow

If snow is blowing off roadway and no hard-pack exists, do not apply chemicals or abrasives.

** Initial application. Plow and re-apply salt at half-rate if surface becomes mealy or slushy, or full rate if glazed or packed.

Maine DOT Application Rate MatrixMaine DOT Application Rate Matrix

0 6 12 18 24 30 36 42 48

T IM E, H O U R S

0

5

10

15

20

25

30

35

SA

LT C

ON

CE

NT

RA

TIO

N, P

ER

CE

NT

BY

WE

IGH

T

0

10

20

30

40

PA

VE

ME

NT

TE

MP

ER

AT

UR

E, D

EG

RE

E F

AH

RE

NH

EIT

R a in

Snow

O ne tim e 400 lb /lane m i

100 lb /lane m i @ 3 hrs

250 lb /lane m i @ 6 hrs

400 lb /ln m i and 100 @ 3hrsFully Satura ted Solu tion

Ice-So lutionPhase L ine

Pavem ent Tem pera ture

Snow Rain Mixed

Ideal Time ForChemical Application

Ideal Time ForPlowing Effort

MidnightWednesday

MidnightTuesday

MidnightThursday

0.00

0.10

0.20

0.30

0.40

Pre

cip

ita

tio

n R

ate

(SW

E)

(in

/hr)

Two-Day Decision Support HistoryRecommended Treatments

Prediction Point #3

3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48

Time Since Awareness (hrs)

0

0.05

0.15

0.25

0.35

MidnightWednesday

MidnightTuesday

MidnightThursday

Two-Day Snow Depth HistoryWith and Without Treatment

Prediction Point #3

2

4

6

8

10

12

14

16

Sn

ow

Dep

th (

in)

3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48

Time Since Awareness (hrs)

0

0

Snow Depth with No Maintenance Efforts

Snow Depth with Recommended Maintenance Efforts

MidnightWednesday

MidnightTuesday

MidnightThursday

Two-Day Chemical Concentration HistoryWith and Without Treatment

Prediction Point #3

Co

nce

ntr

ati

on

(%

by

wei

gh

t)

5

10

15

20

25

3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48

Time Since Awareness (hrs)

0

0

Concentration of NaCl (no treatment)

Concentration of NaCl (with treatment)

MidnightWednesday

MidnightTuesday

MidnightThursday

Two-Day Friction Coefficient HistoryWith and Without Treatment

Prediction Point #3

Fri

ctio

n C

oef

fici

ent

3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48

Time Since Awareness (hrs)

0

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1Friction Coefficient with No Maintenance Efforts

Friction Coefficient with Recommended Maintenance Efforts

LOS 1

What A

Tool !