HCM 2010 WITHIN SYNCHRO 8
ITE Traffic Engineering Workshop & Transportation Planning Forum
April 22, 2015
Jeff Knudson, P.E., PTOE
SRF Consulting Group
901 Deming Way, Suite 101, Madison, WI 53717
Ph: (608) 298-5407 | Email: [email protected]
Alex Thornburg, EIT
SRF Consulting Group
11270 West Park Place, Suite 220, Milwaukee, WI 53224
Ph: (414) 269-5004| Email: [email protected]
OUTLINE
•
•
•
•
Background
HCM General Methodology
HCM in Synchro
-Volume
-Capacity
Delay & Level of Service (LOS)
Along the way:
-Limitations & Sensitivities
-Tips & Tricks
TIP
BACKGROUND
What is HCM 2010?
• Highway Capacity Manual
2010
• Transportation Research
Board (TRB)
Software
• Synchro 8 (Trafficware)
•
Build 806
HCS (McTrans)
BACKGROUND
3 Modules
1.
Auto
•
•
•
•
Signals
AWSC
TWSC
Roundabouts
2. Pedestrian
3. Bicycle
HCM GENERAL METHODOLOGY
Provides Levels of
Service for:
• Approaches
• Lane Groups
Lane Groups
Approach
HCM GENERAL METHODOLOGY
1) Volume
2) Capacity
3) Delay
4) Level of Service (LOS)
HCM GENERAL METHODOLOGY
1) Volume
2) Capacity
TIP
Volume
Demand Flow Rate
Capacity
Affected by:
• # of Lanes
• Saturation Flow Rate (Default 1900 veh/hr/ln)
-
•
Geometry
Heavy Vehicle %
Environmental/weather
Traffic/driver type
Signal Timings
Lane Geometries
•
•
•
Lane Width
-10’ to 12’ Lanes  Same
# of Lanes
Lane Group Configurations
-
No Storage Lengths (No Lane Starvation)
No Triple Lefts or Rights
No Exclusive Turns with a Shared Turn/Thru Lane
•
Synchro Creates HCM De Facto Lane
OR
Heavy Vehicle %
Only affects delay when v/c approaches 1.0
Delay (s) vs. Heavy Vehicle %
65
60
55
50
Delay (s)
•
45
High v/c
Low v/c
40
35
30
25
20
15
0
5
10
15
Heavy Vehicle %
20
25
TIP
Capacity
Affected by:
• # of Lanes
• Saturation Flow Rate (Default 1900 veh/hr/ln)
-
•
Geometry
Heavy Vehicle %
Environmental/weather
Traffic/driver type
Signal Timings
Signal Timings
Primary capacity-affecting:
• Type of signal
• Phasing/timing/cycle
Interesting Applications
• Diamond TTI phasing (overlaps)
• Vehicle detection (advance detection)
• Dallas Phasing (flashing yellow )
Diamond TTI phasing (overlaps)
Diamond TTI phasing (overlaps)
Diamond TTI phasing (overlaps)
Diamond TTI phasing (overlaps)
2 Changes
• Progression
• Pre-Timed
Assume perfect
progression
Diamond TTI phasing (overlaps)
Lane Group Delay (s/veh)
EBT
EBR
WBL
WBT
SBL
SBT
SBR
HCM 2010
Pretimed
48
24
12
1
27
27
22
HCM 2000
55
24
4
1
23
23
19
Synchro
60
8
6
1
27
27
5
HCM 2010 Actuated
18
12
21
1
21
21
17
RTOR
Handled
Differently
Diamond TTI phasing (overlaps)
Lane Group Delay (s/veh)
EBT
EBR
WBL
WBT
SBL
SBT
SBR
HCM 2010
Pretimed
48
24
12
1
27
27
22
HCM 2010 Actuated
18
12
21
1
21
21
17
Actuated single intersection does not
account for influence of other side
Vehicle Detection
Vehicle Detection
Vehicle Detection
Vehicle Detection
Vehicle Detection
Vehicle Detection
Vehicle Detection
Vehicle Detection
Vehicle Detection
Vehicle Detection
Detection Takeaways
•
Delay not sensitive
Detection Takeaways
•
Phase duration not sensitive
Detector Template
TIP
Detector Template
TIP
Dallas Phasing
Aerial photo compliments of Google Earth
Dallas Phasing
Dallas Phasing
Phase 2 Traditional Permissive
Phase 6 Dallas Permissive
Dallas Phasing
RTOR – Right Turn On Red (veh/hr)
•
•
•
•
Several factors affect this value
-
Sight Distance
-
Conflicts with Pedestrians
-
Conflicts with opposing Left Turns
Measure in field when possible
HCM assumes 0 vph (Conservative)
SE Region Method:
-
Uncheck RTOR box in Lane Settings
Change Growth Factor in HCM Module
• Single RT Lane = 0.50 Growth Factor
• Dual RT Lane = 0.70 Growth Factor
• Triple RT Lane = 0.80 Growth Factor
CAPACITY
•
•
DELAY
LOS
Capacity =
Delay = Uniform + Incremental + Initial
Queue
-
What do these mean? You don’t want to know.
•
Common Factor
•
Level Of Service
(g/C) aka Signal Timings
OVERVIEW OF LIMITATIONS - Signals
Overall Intersection
• Intersections with three (3) or four (4) approaches
• Isolated from nearby intersections. Adjustments
for actuated-coordinated networks only
• Phasing must adhere strictly to standard NEMA
phasing
OVERVIEW OF LIMITATIONS - Signals
Auto Mode
• Lane starvation & queue spillbacks
• Exclusive left/right turn with a shared left/right turn /
through lane
• Turn movements served by more than two exclusive
lanes
• RTOR
• NEMA phasing (2-ring, 8-phase)
• Multiple advance detectors per travel lane
• Phase overlaps (i.e. typical diamond interchange
phasing)
LESSONS LEARNED
•
•
•
•
HCM is v/c
HCM limitations are numerous but workarounds
are adequate
Do not commit to a presentation without knowing
the material very well
The researchers of HCM are much smarter than
we are
THANKS!
Questions?
Alex and Jeff will be signing autographs at the
Water Street Brewery in Delafield
immediately following the conference.