justify. methodology for measuring navigator its performance its georgia annual meeting 2010...
TRANSCRIPT
JUSTIFY
Methodology for Measuring NaviGAtor ITS Performance
ITS Georgia Annual Meeting 2010
Presented By:Prasoon Sinha, P.E, PTOE
Department Manager, ARCADIS
• Deficiencies in current practices
• Approach to estimating benefits of
NaviGAtor/ITS
• Approach to estimating secondary crashes and
ITS impact parameters
• How can we perform better?
• Summary
OutlineP
rese
nta
tion
Goa
ls
Back
grou
nd
• Do not segregate the benefits of ITS and geometric operational/safety improvements
Absence of traceability between problems and solutions
• Use national values of “ITS impact parameters” which may not be applicable to all areas
Analysis results do not reflect accurate benefits
• Do not identify the deficiencies in the existing ITS and roadway infrastructure to answer the question
“How can we perform better?”
Current Practices
Bene
fits
of IT
S/N
aviG
Ator
Sys
tem
Methodology
Benefits = Performance Without ITS - Performance WithITS
Three main ingredients to the methodology:• Traceability between various incident types and
applicable countermeasures/solutions
• Approach to estimation of secondary crashes
• Approach to estimation of area-specific “Without ITS Conditions” / “ITS Impact Parameters”
Traceability Between Problems and Solutions
Trig
ger E
vent
Queues
Severities (Fatalities, Injuries, PDO) Due to Primary Crashes
Recu
rrin
g Co
nges
tion
Queues
Secondary Crashes
Severities
QueuesDelay
EmissionThroughput
DelayEmission
Throughput
FatalitiesInjuries
PDO
FatalitiesInjuries
PDO
DelayEmission
Throughput
Tied to and Addressed by
ITS Deployments
Tied to and Addressed by Operational and Safety
Improv.
Cost of Severity
Cost of Severity
Value of Time
Value of Time
Value of Time
Queuing Eqn.
Queuing Eqn.
Queuing Eqn.
•Bad Weather
•Debris
•Stalled Vehicle
•Work Zones
•Special Events
•Primary Crashes
Demand >
Capacity
Bene
fits
of IT
S/N
aviG
Ator
Sys
tem
• Categorize current crash data by trigger events• Estimate queues due to all trigger events (using queuing theory
equations)• Estimate secondary crashes resulting from all trigger events
• Estimate severities due to primary crashes• Perform travel time comparisons (under “No trigger event”
condition) to quantify recurring congestion
Form Data Groups & Estimate Secondary Crashes
),*)(( ii TTrCVQMAX
Area of Influence (spatial & temporal coordinate)
Bene
fits
of IT
S/N
aviG
Ator
Sys
tem
Data Availability and ITS Impact Parameters
Not Available Available
Available Available
Without With
NaviGAtor/ITS
Operational & Safety Improv.
• Need to estimate “Without NaviGAtor/ITS” conditions data
-> Estimate Impact Parameters
• Define control corridors
Corridors having “Without ITS” and “With ITS” data
I-285 West wall (between I-75 and I-20)
SR 400 between I-285 and Old Milton Pkwy
I-85, South of Camp Creek Pkwy Control group corridors
(currently No ITS)
I-20 east of Panola Road
Bene
fits
of IT
S/N
aviG
Ator
Sys
tem
ITS Driven Congestion Benefits - All Trigger Events
iTrCVQMAX *)( MAX QUEUE LENGTH
DELAY FOR DURATION OF
INCIDENT 2
2
1
2
1iii TrCVTQD
Incident Clearance
Time
QUEUE CLEARANCE
TIME
VgC
QTg
VgC
TrCV
VgC
QTQD
i
gg
22
2
)(
)(22
1
DEL
AY C
OM
PON
ENTS
QUEUE CLEARANCE
TIME
DELAY DURING CLEARANCE
TIME
TOTAL DELAY (DT)DT = Di + Dg
V- Average Volume on the freewayC- Freeway Capacity at LOS Er- Capacity Reduction Factorg- Average flow rate during queue clearance time
CARS
TRUCKS
TRANSIT
Delay By Travel Mode
Del
ay S
avin
gs ($
)
Time Value of Money ($$$)
Fuel Consumption($)
Reduced Emission ($)
Total Congestion Benefits ($)
Congestion Before = Delay DT (Before) + Emission (Before) + Fuel Consumption (Before)
Congestion After = Delay DT (After) + Emission (After) + Fuel Consumption (After)
Congestion Benefit (CB-ITS)= Congestion Before - Congestion After
Bene
fits
of IT
S/N
aviG
Ator
Sys
tem
Benefit of ITS & Proportion of ITS Benefits
Benefits ITS Total = Congestion Benefit (CB-ITS) + Safety Benefit (SB-ITS)
Benefits Ops Total = Congestion Benefit (CB-Ops)+ Safety Benefit (SB-Ops)
BenefitsTotal = Congestion Benefit (CB-ITS) + Congestion Benefit (CB-Ops)+ Safety Benefit (SB-ITS) + Safety Benefit (SB-Ops)
Total
Total
Benefits
TS Benefits IsTS BenefitShare of I
Jus
tifica
tions
for F
utur
e IT
S D
eplo
ymen
tsHow Can We Perform Better?
• Categorize incident data by Trigger Events (GIS database, thematic maps)
• Conduct Hot-Spot Analysis• Query to identify highest secondary
crash locations (ITS) or high primary crashes (operational or safety improvements)
• Identify existing NaviGAtor coverage at Hot-Spot locations
• Identify the gaps in deployment and match it with problem type
• Fill the gaps in deployment• Deploy ITS that can address primary
crashes & recurring congestion
A robust methodology that:• Resides on a GIS platform which ties perfectly into the
NaviGAtor dashboard• Provides B/C ratios by corridors and by overall system – Provides equations for estimation of secondary
crashes and calculations of ITS benefits and costs– Provides approach to estimating region specific ITS
impacts• Categorizes the share of non-recurring congestion by
incident type• Provides ratio of ITS Benefits to Overall Benefits• Identifies existing system deficiencies, recommends
potential countermeasures and expected benefitsProvides Funding Justification for ITS
In Summary…..
QUESTIONS?
Contact Information:
Prasoon Sinha, PE, PTOE
(770)384-6604
Thank You!