Bicycle Network Planning That
Incorporates Bicyclist Behavior
Jon D. Fricker and Michael Klobucar
Purdue University and JTRP
June 2006 and continuing
Bicycle Network Analysis Tool
• Are bicycle
facilities in your
community
adequate?
• Where should
the next
improvements
be made?
2
Existing Network
TNL (mi)
58.7
TNPSL (smi)
210619.2
TNPTL (mi)
91950.6
INT
576
TNPSL/TNL
3588.0
TNPSL/INT
365.7
ABLL (mi)
-
∆TNPSL (smi)
-
∆TNPSL/ABLL
TT
ATL (mi)
∆ATL (mi)
51518.3
1.78
-
3
BNAT: Help Investment Decisions
BNAT based on how bicyclists choose routes
 Minimize distance
 Maximize perceived safety
4
Measuring Perceived Safety
• Bicycle Compatibility
Index (BCI) or Bicycle
LOS?
• Observe choices of
ROW Cross-Section
Component?
5
Bicyclists and the ROW
•
•
•
•
Lanes for motor vehicles (usu. 12’)
Parking lanes? (usu. 8’-10’)
Lanes or paths for bicyclists (>5’)
Sidewalks?
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BCI and BLOS
• Bicycle Compatibility
Index




Peak hour volume
85th percentile speed
Curb lane
Presence of bike
lane/shoulder
• Bicycle Level of
Service






Peak hour volume
Speed limit
Effective lane width
Pavement conditions
Trip generation
Driveways
1. Are equations transferable?
2. Are input data available?
7
Bicycle Level of Service
–
–
–
–
–
–
BLOS = perceived hazard of the
shared-roadway environment,
Vol15 = volume of directional traffic in
15-min time period,
L = total number of through lanes,
SPDp = posted speed limit (a surrogate
for average running speed),
HV = percentage of heavy vehicles (as
defined in the Highway Capacity
Manual),
NCA = effective frequency per mile of
uncontrolled vehicular access (e.g.,
driveways and on-street parking
spaces),
–
–
–
COM15 = trip generation intensity of
the land use adjoining the road
segment (stratified to a commercial trip
generation of 15, multiplied by the
percentage of the segment with
adjoining commercial land
development),
PC5 = FHWA’s 5-point pavement
surface condition rating, and
We = average effective width of outside
through lane (We = Wt + Wl – Wr, where
Wt = total width of outside lane (and
shoulder) pavement, Wl = width of
paving between the outside lane stripe
and the edge of pavement, and Wr =
effective width (reduction) due to
encroachments in the outside lane.)
BLOS = a1ln(Vol15/L)+a2ln[SPDp(1+HV%)]+a3ln(COM15*NCA)+a4(PC5)-2+a5(We)2+C
8
Bicycle Level of Service
LOS Designation
BLOS Range
A
≤ 1.5
B
1.5 - 2.5
C
2.5 – 3.5
D
3.5 – 4.5
E
4.5 – 5.5
F
> 5.5
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Bicycle Compatibility Index
– BL = Presence of a Bicycle
Lane or Paved Shoulder
– BLW = Bicycle Lane or
Paved Shoulder Width
– CLW = Curb Lane Width
– CLV = Curb Lane Volume
– OLV = Other Lane Volume
– SPD = 85th Percentile
Speed of Traffic
– PKG = Presence of a Parking
Lane With More Than 30%
Occupancy
– AREA = Presence of
Residential Roadside
Development
– AF = ft+fp+fn
– ft = Adjustment Factor for
Truck Volumes
– fp = Adjustment Factor for
Parking Turnover
– fn = Adjustment Factor for
Right Turn Volumes
BCI = C–a1BL-a2*BLW-a3CLW+a4CLV+a5OLV+a6SPD+a7PKG-a8AREA+AF
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Bicycle Compatibility Index
LOS Designation
BCI Range
A
≤ 1.50
B
1.51- 2.30
C
2.31 – 3.40
D
3.41 – 4.40
E
4.41 – 5.30
F
> 5.30
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Bicycle Route Choice
• Assumes Cyclist Makes Route Choice
Based on Two Factors
– Link Length
– Perceived Safety (BCI)
– Link “Cost” = BCI * Length
– Link “Cost” is called Safe Length
– Cyclist chooses route that minimizes Safe
Length
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Bicycle Route Choice
B
A
13
Bicycle Route Choice
4
1
Bike Lane
Length = 0.5 mi
Length = 0.3 mi
3
2
Safe Length
BCI ==3.8
1.90 smi
BCI = 5.2
Length = 0.3 mi
Length = 0.4 mi
6
5
Safe Length
BCI = 4.9
= 1.47 smi
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Salisbury Ave.
• Bike lane SB
• Lane ends!
15
Stadium Ave. WB
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Stadium Ave. WB (2)
• 1 block from
campus
• Parking on N
side
• Moderate
vehicle
speeds and
flow rate
17
Northwestern Avenue SB
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Northwestern Avenue SB (2)
• Approaching Purdue campus
• High vehicle
speeds and flows
• No bicycle lane
• Sidewalks both
sides
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Northwestern Avenue SB (3)
• 7 cyclists
used street
• 16 used
sidewalk
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Northwestern Avenue SB (4)
ROW characteristics
• Widths of
– Vehicle lanes
– Bicycle lanes or
paths
– Sidewalks
• Vehicle
– Speeds
– Flow rate
• Grade
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Northwestern Avenue SB (5)
Bicyclist characteristics
• 7 who used street:
 5 used helmet
 Average age ca. 35
years
• 16 who used sidewalk:
 8 used helmet
 Average age 27 years
 Only female: age 20, no helmet
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Bicyclist ROW Observations
• More than 300 bicyclists observed on
dozens of road sections
•  ROW component choice as f(ROW,
bicyclist, conditions)
• Link-based vs. path-based
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Survey Bicyclists about
Routes Used
•
•
•
•
Origin
Links on path
Where street not used
Observe bicyclist
characteristics
• n < 40 off-campus paths
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Example of Bicyclist Path
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• Need more
paths in
survey.
• Develop
“model” to
explain path
and ROW
component
choices.
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Summary
1. BNAT can provide
rational basis for
investments in bicycle
facilities.
2. ROW observations
can explain bicyclist
perceptions of safety.
3. Path surveys can
form basis for
improved BNAT.
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