I-25 GAP Safety and Mobility - Douglas County, Colorado...Maximizing Safety and Mobility on ... I-25 GAP Coalition Presentation - June 2017. DiExSys, LLC Diagnostic Expert Systems

Maximizing Safety and Mobility onI-25 between

Monument and Plum Creek Interchanges………………………………………………………………………………………………………………………………………………………………………………………….…………

DiExSys, LLCJake Kononov, PE, PhD

Bryan Allery, PE

I-25 GAP Coalition Presentation - June 2017

DiExSys, LLCDiagnostic Expert Systems

We had our First Consulting Job in 2006We are focused with Laser-Like Intensity on Road SafetyWe provide Safety Analysis Services in:


• Wyoming• Montana• Louisiana• New Mexico• Oklahoma• Colorado

• Department of Transportation• Counties: Douglas, Jefferson, Adams• Cities: Lakewood, Denver, Aurora,

Arvada, Federal Heights• PPACG

• Arizona• Alabama• Italy

What is the Magnitude of the Safety Problem within Study Limits?

and

What is its Nature?

How Susceptible is it to Correction?


Segment 1MP 160.00 to 163.32

Segment 2MP 163.33 to 179.27

Segment 3MP 179.28 to 181.00


Crash Summary I-25 MP 160.00-181.00 1/1/2011-12/31/20151,969 Crashes (1,296 PDO, 667 INJ, 6 FAT)


Segment 1MP 160.00 to 163.32


I-25 MP 160.00 - 163.32 Crash Frequency


I-25 MP 160.00 - 163.32 Crash Severity


Segment 2MP 163.33 to 179.27






Segment 3MP 179.28 to 181.00






History of Speed Limits• Today speed limits on freeways are established by computing 85th

percentile speed during free-flow (Off Peak) period

• … but what is the speed limit when freeway is congested???

• What is the meaning of the speed limit established off-peak for the peak period conditions?

• This methodology was developed over 50 years ago by Solomon (USDOT, 1964)

• In retrospect, it appears that Solomon (Accidents on Main Rural Highways Related to Speed, USDOT, 1964) may not have been as wise as King Solomon (971 - 931 BC , Jerusalem, Israel)

• In fact we will show that the speed limit established during the Off Peak period using 85th percentile free-flow speed is sometimes detrimental to safety

• We will prove it by using common sense, fundamental traffic flow theory and empirical evidence collected in the field


Fundamental Relationship BetweenFreeway Speed and Flow from HCM



US6 - WO Federal - Westbound

LaneVolume0 400 800 1200 1600 2000 2400

85th

%S

peed

20

30

40

50

60

70

80


1 S1 = 70 mphV1 = 600 pc/h/ln

S2 = 68 mphV2 = 1750 pc/h/ln

∆S ≈ 3%∆V & ∆density ≈ 190%

R1 < R2




Simulation

High Speed

Low Density

High Speed

High Density

C470 from Santa Fe to Quebec


C470 from Santa Fe to Quebec PM Period

Cra

sh R

ate

C470 - PM (Lane Volume)R^2 = 0.783

Lane Volume600 1000 1400 1800

Cra

shR

ate

(Tot

al)

0.4

0.6

0.8

1

1.2

1.4


C470 from Santa Fe to Quebec All DayC470 - All Day (Lane Volume)

R^2 = 0.697

Lane Volume500 900 1300 1700

Cra

shR

ate

(Tot

al)

0.4

0.6

0.8

1

1.2

1.4


I-270 From I-76 to I-70


I-270 From I-76 to I-70 – AM PeriodI-270 - AM (Lane Volume)

R^2 = 0.961

Lane Volume850 1100 1350 1600

Cra

shR

ate

(Tot

al)

0.5

0.6

0.7

0.8

0.9

1


I-270 From I-76 to I-70 – PM PeriodI-270 - PM (Lane Volume)

R^2 = 0.914

Lane Volume700 1000 1300 1600

Cra

shR

ate

(Tot

al)

0.4

0.5

0.6

0.7

0.8

0.9

1


I-270 From I-76 to I-70 - All DayI-270 - All Day (Lane Volume)

R^2 = 0.873

Lane Volume700 1000 1300 1600

Cra

shR

ate

(Tot

al)

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1


I-70 From Georgetown to Twin Tunnels


I-70 From Georgetown to Twin TunnelsWeekend Winter Eastbound

I-70 - Weekend Winter (EB Flow)

EB Flow (vphpl)600 900 1200 1500

EB

Cra

shR

ate

(Acc

/MVM

T)

0.1

0.3

0.5

0.7

0.9

1.1

1.3 (r²) = 0.8514


I-70 - All Day Summer (EB Flow)

EB Flow (vphpl)400 650 900 1150

EB

Cra

shR

ate

(Acc

/MVM

T)

0.05

0.15

0.25

0.35

0.45

0.55

0.65

0.75

0.85(r²) = 0.5946

I-70 From Georgetown to Twin TunnelsWeekend Summer Eastbound


Regime 1 is characterized by low to moderate density and high speeds, where drivers are becoming more focused on the driving task and are still able to compensate for increasing density. This increased focus on the driving task may possibly explain the fact that during Regime-1 the crash rate remains stable despite increase in density.

Regime 2 is characterized by high densities without notable speed reduction where many more near misses become crashes, thus a sharp rise in crash rate.


Freeway Flow Crash Potential Index (FFCPI)FFCPI = dS2

Crash Rate vs. Freeway Flow Relationship

Observed Speed

Recommended Speed Limit

70 6569 6067 5562 50

FFCPIcr

Metro Denver Freeway

Freeway dS2

dS2


ATM in Europe


Colorado I-70 Concepts


ATM in Europe


NormalCardiogram

Medical Analogy

Onset ofHeart Attack

Full-BlownHeart Attack

Heart Damage

Need Cardiac Rehab!


Timely Intervention

NormalCardiograph

Onset ofHeart Attack

Back toNormal

Intervention

Clot Buster Drugs and/or Angioplasty


Active Traffic Management

Is like taking a Cardiogram of the Highway and Responding

in Time


Variable Speed Limit Decision Support Analysis


Variable Speed Limit Decision Support AnalysisTime of DayReal Time Inputs

PM

Real Time Input:(Volume) V(Speed) S(density) dRoad/Weather Conditions

AM




Corridor-Specific Safety Performance Curves

Road/Weather Conditions

Time of DayReal Time Inputs

PM

Real Time Input:(Volume) V(Speed) S(density) dRoad/Weather Conditions

AMdS2 (FFCPI)

AdverseIcy/Snowy

Wet

AdverseIcy/Snowy

Wet

dS2

dS2

dS2

dS2

Fair Weather Dry Pavement

Cra

sh R

ate

Cra

sh R

ate

Cra

sh R

ate

Cra

sh R

ate

Fair Weather Dry Pavement

FFCPI = Freeway Flow Crash Potential Index

dS2 (FFCPI)

dS2 (FFCPI)

dS2 (FFCPI)



Typical Annual Savings in Crash PreventionFatalities

6

Injuries 667

PDO1,296

1040 Injured

5 Years Crash Data


Savings in Crash Prevention from VSL over 5 Years

20% Reduction 30% Reduction 1,296 PDO (20%) ($10,200) = $2,643,8401,040 INJ (20%) ($96,100) = $19,988,800

6 FAT (20%) ($1,688,400) = $2,026,080==========

$ 24,658,720

1,296 PDO (30%) ($10,200) = $3,965,7601,040 INJ (30%) ($96,100) = $29,983,200

6 FAT (30%) ($1,688,400) = $3,039,120==========

$ 36,988,080

Expected Range of Crash Prevention 20% – 30%

Current CDOT Numbers:PDO = $10,200INJ = $96,100

FAT = $1,688,400


Fatalities6

Injuries 667

PDO1,296

1040 Injured

Savings in Delay Reduction from VSL over 5 Years

1,969 Total Accidents 20% Reduction 30% Reduction

1,969 (20%) (3,500) ($10) = $13,783,000==========

$ 13,783,000

1,969 (30%) (3,500) ($10) = $20,674,500==========

$ 20,674,500

Expected Range of Crash Prevention 20% – 30%

On Average 1 Crash Delays 3,500 Vehicles for

1/2 hour @ $20/hr


Fatalities6

Injuries 667

PDO1,296

1040 Injured

Safety and Mobility Benefits Combined

20% Reduction 30% Reduction

$ 38,441,720 $ 57,662,580


Fatalities6

Injuries 667

PDO1,296

1040 Injured

TRB


Maximizing Safety and Mobility onI-25 between

Monument and Plum Creek Interchanges………………………………………………………………………………………………………………………………………………………………………………………….…………

DiExSys, LLCJake Kononov, PE, PhD

Bryan Allery, PE


Documents

I-25 GAP Safety and Mobility - Douglas County, Colorado...Maximizing Safety and Mobility on ... I-25 GAP Coalition Presentation - June 2017. DiExSys, LLC Diagnostic Expert Systems