1. Low Traffic Stress Bicycling Networks
Peter G. Furth, Northeastern University

2. What Is the “Bicycle Network” to an Individual?
Legal
Inventory
The set of streets and paths that don’t exceed his / her level of tolerance for traffic stress

3. Most of the Population has a Low Tolerance for Traffic Stress

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

5. San Jose Street Network, All Levels of Stress

6. Distribution of Segment Miles by Level of Traffic Stress
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%

7. Stress Level 3 or Less

8. Stress Level 2 or Less

9. Stress Level 1

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

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

12. Slate of Possible Improvements

13. Resulting Network for LTS < 2

14. Home-Work Trip Connectivity
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%
LTS 3
22.6%
16.4%
13.2%
8.9%
LTS 4
100.0%
Total trips
78,673
136,652
189,439
292,396
Before After
Trip Length
< 4 mi
< 6 mi
< 8 mi
All
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%
Total trips
78,673
136,652
189,439
292,396

15. Criteria for Level of Traffic Stress and Data Needs to Support the Analysis
Segments
Intersection Approaches
Unsignalized Crossings

16. Segments Segment Type Level of Traffic Stress Stand-alone paths
LTS = 1
Segregated paths (sidepaths, cycle tracks)
Bike lanes
LTS can vary from 1 to 4
Mixed traffic
LTS can vary from 1 to 4

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

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

19. Dutch Criteria (CROW 2007) Lane configuration
Daily traffic (vehicles/day)
Street type and speed limit
Urban local street
Urban through street
Rural local road
Fast traffic road
30 km/h (19 mph)
50 km/h (31 mph)
60 km/h (37 mph)
70+ km/h (44+ mph)
Two-way traffic with no centerline
<2500
Mixed traffica
Bike laneb or cycletrackc
Advisory bike laned
Cycle track or low-speed service road
2000–3000
bike laneb or cycle tracke
3000–5000
>4000
Bike lane or cycle track
Bike lane or cycle trackc
Two lanes (1+1)
any
Four lanes (2 + 2) or more
(Does not exist)
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.
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.

20. Traffic Stress on Intersection Approaches – “Pocket Bike Lanes”

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

22. Stress at Crossings – Apparent Safe Routes Crossing Winchester Avenue

23. Crossing Winchester at Rosemary

24. 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
35 mph
LTS 3
40+
WITH 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
30 mph
LTS 3
35 mph
LTS 4
40+

25. For an arterial to not be a barrier, it needs a low-stress crossing COMBINED WITH a low-stress approach
ADEC
CalGIS 2012
Sacramento, CA

26. What are the Barriers?

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

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

29. Detour Criterion 25% longer than the shortest route
Low-stress route should not be more than
25% longer than the shortest route
OR (for short trips)
0.33 mi longer than the shortest route

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

31. Slate of Possible Improvements

32. Resulting Network for LTS < 2

33. Home-Work Trip Connectivity
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%
LTS 3
22.6%
16.4%
13.2%
8.9%
LTS 4
100.0%
Total trips
78,673
136,652
189,439
292,396
Before After
Trip Length
< 4 mi
< 6 mi
< 8 mi
All
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%
Total trips
78,673
136,652
189,439
292,396

34. 0.7% of home-work pairs connected MinutemanBikeway Charles River Paths
HarborWalk
Charles River Paths
Muddy River Path
SW Corridor Path
MinutemanBikeway
Neponset River Greenway
0.7% of home-work pairs
connected

36. 71% of population within 1 km
51% of home-work pairs
connected

37. Acknowledgement
Co-researcher Maaza Mekuria, PhD, Axum Engineering & Design
Support from the Mineta Transportation Institute
Inspiration from Rails to Trails Conservancy

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