1. Low Stress Bicycling and Network
Low Stress Bicycling and Network
Connectivity
y
Peter G. Furth, Northeastern University
Maaza Mekuria Axum Design & Engineering
Mekuria, Axum Design & Engineering

2. Most of the Population has a Low
Tolerance for T ffi St
T l f Traffic Stress

3. Classifying the Population by
Tolerance for T ffi St
T l f Traffic Stress
Strong &
Fearless Enthused &
< 1% Confident (7%)
C fid
Interested but Concerned No Way, No Source: Roger Geller,
(60%) How (33%) City of Portland
Classifying Network Elements by
Level of Traffic Stress (LTS)
LTS 1: for children LTS 3: for “Enthused &
LTS 2: for traffic intolerant Confident”
adult LTS 4: highest stress

4. What Is the “Bicycle Network” to an
Individual?
d d l
1. All the streets and paths where one may
1 All the streets and paths where one may
legally ride
2. Inventory of designated / improved bike
2 Inventory of designated / improved bike
facilities
3. Set of preferred or suggested routes
3 S f f d d
4. The set of streets and paths that don’t exceed
his / her level of tolerance for traffic stress

5. Connectivity : Can You Get from A to B
without exceeding a specified level of traffic stress?
h d f d l l f ff ?
San Jose (south central), Stress Level 1

6. Level of Traffic Stress 1 (LTS 1) Islands
6

7. SJSU Rooted Tree LTS 2
7

8. Level of Traffic Stress 2 (LTS 2) Islands
8

9. Connectivity : Can You Get from A to B
without exceeding a specified level of traffic stress?
h d f d l l f ff ?
without undue detour?
San Jose (south central), Stress Level 1

10. Detour Criterion
Detour Criterion
Low‐stress route should not be more than
25% longer than the shortest route
OR (for short trips)
OR (f h t t i )
0.33 mi longer than the shortest route
0 33 mi longer than the shortest route

11. Criteria for Level of Traffic Stress
Criteria for Level of Traffic Stress
• Bicycle Level of Service (BLOS 1997)
Bicycle Level of Service (BLOS, 1997)
– Black‐box formula yields A‐F rating
– Data hungry
Data hungry
– Doesn’t model intersections well
• Bi l C
Bicycle Compatibility Index (BCI, 1996)
tibilit I d (BCI 1996)
• Bikeway design criteria in places that have
succeeded in attracting the mainstream
population

12. New Set of Criteria
New Set of Criteria
LTS 1: suitable for children
LTS 2: acceptable to traffic Based on Dutch
intolerant adult
criteria
LTS 3: OK for “enthused &
Confident”
LTS 4 hi h t stress
4: highest t
• Segments
Segments
• Intersection Approaches
• Crossings

13. Weakest Link Principle of
Weakest Link Principle of
Aggregation
gg g
The stress of a route = stress of its most
The stress of a route stress of its most
stressful link
• Different from summing or averaging
1 1 1 4 1 1

14. Segments
Segment Type Level of Traffic Stress
Stand‐alone paths LTS = 1
Segregated paths
S d h LTS = 1
LTS 1
(sidepaths, cycle tracks)
Bike lanes LTS can vary from 1 to 4
Mixed traffic
Mi ed traffic LTS can vary from 1 to 4
LTS can ar from 1 to 4

15. Dutch Criteria (CROW 2007)
Lane
L Daily traffic
D il t ffi Street type and speed limit
St t t d d li it
configuration (vehicles/day)
Urban local Urban Rural local Fast traffic
street through street road road
30 km/h (19
30 k /h (19 50 km/h (31
50 k /h (31 60 km/h (37
60 k /h (37 70+ km/h
70 k /h
mph) mph) mph) (44+ mph)
Two‐way traffic <2500 Mixed traffica Bike laneb or Advisory bike Cycle track
with no cycletrackc laned or low‐
centerline 2000–3000 bike laneb or
bike lane or speed
speed
cycle tracke service road
3000–5000
>4000 Bike lane or Bike lane or
cycle track cycle trackc
Two lanes (1+1) any Bike lane or Bike lane or
cycle track cycle trackc
Four lanes (2 + any (Does not Cycle track or low‐speed service road
2) or more
2) exist)
i t)
aFor designated bike routes, a bike lane or advisory bike lane is optional.
bMay be an advisory bike lane on road sections with no centerline.
cCycle track is preferred if there is parking; cycle track is recommended for designated bike routes
track is preferred if there is parking; cycle track is recommended for designated bike routes.
dAlthough CROW (2007) gives “mixed traffic” for this cell, the default layout for roads in this category
is to mark advisory bike lanes.
eCycle track is preferred for designated bike routes.

16. Criteria for Bike Lanes Alongside a Parking
Lane
LTS > 1 LTS > 2 LTS > 3 LTS > 4
Street idth (thru
St t width (th 1 (n.a.)
( ) 2 or more (n.a.)
( )
lanes per direction)
Sum of bike lane and 15 ft or 14 or 14.5 13.5 ft or (n.a.)
parking lane width more fta less
Speed limit or 25 mph 30 mph 35 mph 40 mph or
prevailing speed or less more
Bike lane blockage rare (n.a.) frequent (n.a.)
Dimensions aggregate using Weakest Link logic

17. Criteria for Bike Lanes Not Alongside a
Parking Lane
Parking Lane
LTS > 1 LTS > 2 LTS > 3 LTS > 4
Street width (thru 1 2, if directions more than 2, (n.a.)
lanes per direction) are separated or 2 without a
by a raised separating
median median
Bike lane width 6 ft or 5.5 ft or less (n.a.) (n.a.)
more
Speed limit or 30 mph (n.a.) 35 mph 40 mph
prevailing speed or less or more
Bike lane blockage rare (n.a.) frequent (n.a.)

18. Criteria for Mixed Traffic
Street Width
2-3 lanes 4-5 lanes 6+ lanes
Speed Limit
Up to 25 mph LTS 1 a or 2 a LTS 3 LTS 4
30 mph LTS 2 a or 3 a LTS 4 LTS 4
35+ mph LTS 4 LTS 4 LTS 4
a. Use lower value for streets without marked centerlines or
classified as residential and with f
l ifi d id ti l d ith fewer th 3 l
than lanes; use hi h
higher
value otherwise.

19. Traffic Stress on Intersection
Approaches – “ k
h “Pocket Bike Lanes”
k ”
Dutch criteria
• RT lane must be
short
• RT lane must begin
abruptly
• Bik l
Bike lane must
t
continue straight
• Wide bike lane
• Intersection angle
keeps turning speed
to 15 km/h
to 15 km/h

20. Criteria for Pocket Bike Lanes
Criteria for Pocket Bike Lanes
Level of
Configuration
Traffic Stress
Single RT lane up to 150 ft long, starting abruptly while LTS > 2
the bik lane continues straight; i t
th bike l ti t i ht intersection angle
ti l
such that turning speed is < 15 mph.
Single RT lane longer than 150 ft ,starting abruptly LTS > 3
while the bike lane continues straight; intersection
angle such that turning speed is < 20 mph.
Single RT lane in which the bike lane shifts to the left, LTS > 3
but intersection angle and curb radius are such that
turning speed is < 15 mph.
Single RT lane with any other configuration; dual RT LTS = 4
lanes; or RT lane plus option (through-right) lane

21. Increased Traffic Stress on Widened
Approaches
h
Added
turn lanes
(Monroe
@ Stevens
Creek)

22. Widened Intersection Approaches
Interrupt Low‐Stress Paths
h

23. Stress at Crossings – Apparent Safe Routes
g
Crossing Winchester Avenue
23

24. Stress at Crossings
Stress at Crossings

25. Criteria for Crossings
Criteria for Crossings
NO MEDIAN REFUGE Width of Street Being Crossed
Speed Limit Up to 3 lanes 4 - 5 lanes 6+ lanes
Up to 25 mph LTS 1 LTS 2 LTS 4
30 mph LTS 1 LTS 2 LTS 4
35 mph LTS 2 LTS 3 LTS 4
40+ LTS 3 LTS 4 LTS 4
Width of street being crossed
WITH MEDIAN REFUGE
Speed Limit Up to 3 lanes 4 - 5 lanes 6+ lanes
Up to 25 mph LTS 1 LTS 1 LTS 2
30 mph LTS 1 LTS 2 LTS 3
35 mph LTS 2 LTS 3 LTS 4
40+ LTS 3 LTS 4 LTS 4

26. With Crossing Effect – Winchester becomes a
y g
barrier without any low‐stress crossing
CalGIS 2012
ADEC 26
Sacramento, CA

27. San Jose Street Network Stress Classification
CalGIS 2012
ADEC 27
Sacramento, CA

28. Distribution of Segment Miles by Level
g y
of Traffic Stress
Stress Level Miles Miles (percent)
Lowest 1 2131 64%
Low 2 115 3%
Medium 3 276 8%
High 4 678 20%
Prohibited 5 134 4%
Total 3334 100%

29. San Jose Street Network Stress Level 1
29

30. San Jose Street Network Stress Level 2
30

31. San Jose Street Network Stress Level 3
31

32. San Jose Street Network Stress Level 4
32

33. Barriers
• Natural (rivers mountains) RR Freeways:
Natural (rivers, mountains), RR, Freeways:
Crossings collect traffic, tend to be high stress
• Freeways: Added stress from on off ramps
Freeways: Added stress from on‐off ramps
• Arterials lacking low‐stress approaches with
low‐stress crossings
l i
• Parks and Campuses (!)
• Incomplete street grid, forcing traffic to use
arterials

34. Incomplete Street Grid as Barrier

35. Permeable Barriers Can Be a Key to
Connectivity and Low Stress
Downing Ave – Westfield Ave @ Hwy 17

36. Level of Traffic Stress 2 (LTS 2) Islands
36

37. Slate of Possible Improvements
37

38. Resulting Network for LTS < 2
38

39. A Measure of Connectivity
A Measure of Connectivity
Percent Trips Connected, by Level
of Traffic Stress
of Traffic Stress
• Trip Table for Home‐to‐Work Trips
Number of people traveling from zone i to zone j
p p g j
Which zone pairs are connected at a given LTS?
( y ) g g p
TAZ (traffic analysis zone) = standard geographic
unit

40. TAZ can be too coarse a geographic
unit to model bicycle access
unit to model bicycle access

41. Disaggregating Demand
from TAZs to Blocks
f l k
• Origins: in proportion to block population
Origins: in proportion to block population
• Destinations: in proportion to trip generation
factors

42. Linking Block Centroids to the Network
Linking Block Centroids to the Network
Block
centroid,
with
connectors
connectors
to
surrounding
vertices

43. Home‐Work Trip Connectivity
p y
Trip Length < 4 mi < 6 mi < 8 mi All
LTS 1 0.7% 0.4% 0.3% 0.2%
LTS 2 7.7% 4.7% 3.4% 2.2%
Before LTS 3 22.6% 16.4% 13.2% 8.9%
LTS 4 100.0% 100.0% 100.0% 100.0%
Total trips 78,673 136,652 189,439 292,396
Trip Length < 4 mi < 6 mi < 8 mi All
After LTS 1 1.7% 1.0% 0.8% 0.5%
LTS 2 14.9% 12.7% 11.1% 7.9%
LTS 3 27.4% 22.7% 20.0% 14.6%
LTS 4 100.0% 100.0% 100.0% 100.0%
Total trips 78,673 136,652 189,439 292,396

44. Acknowledgement
• Support from the
Mineta
Transportation
T i
Institute
• Inspiration from
Rails to Trails
Rails to Trails
Conservancy
• Cooperation of the
City of San Jose
y
44