Low Traffic Stress Bicycling Networks
Peter G. Furth, Northeastern University
What Is the “Bicycle Network” to an Individual?
1. Legal2. Inventory3. The set of streets and paths that don’t exceed
his / her level of tolerance for traffic stress
Most of the Population has a Low Tolerance for Traffic Stress
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
Distribution of Segment Miles by Level 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%
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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
Home-Work Trip ConnectivityTrip 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% 100.0% 100.0% 100.0%Total trips 78,673 136,652 189,439 292,396
Trip Length < 4 mi < 6 mi < 8 mi AllLTS 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
Before
After
Criteria for Level of Traffic Stress and
Data Needs to Support the Analysis
• Segments• Intersection Approaches• Unsignalized Crossings
SegmentsSegment Type Level of Traffic Stress
Stand-alone paths LTS = 1
Segregated paths (sidepaths, cycle tracks)
LTS = 1
Bike lanes LTS can vary from 1 to 4
Mixed traffic LTS can vary from 1 to 4
LTS > 1 LTS > 2 LTS > 3 LTS > 4
Street width (thru lanes per direction)
1 (n.a.) 2 or more (n.a.)
Sum of bike lane and parking lane width
15 ft or more
14 or 14.5 fta
13.5 ft or less
(n.a.)
Speed limit or prevailing speed
25 mph or less
30 mph 35 mph 40 mph or more
Bike lane blockage rare (n.a.) frequent (n.a.)
Criteria for Bike Lanes Alongside a Parking Lane
Dimensions aggregate using Weakest Link logic
Criteria for Mixed Traffic
Street Width
Speed Limit2-3 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 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 fewer than 3 lanes; use higher value otherwise.
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 Bike lane or cycle track
Bike lane or cycle trackc
Four lanes (2 + 2) or more
any (Does not exist)
Cycle track or low-speed service road
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.
Traffic Stress on Intersection Approaches – “Pocket Bike Lanes”
Criteria for Pocket Bike Lanes
ConfigurationLevel 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.
LTS > 3
Single RT lane with any other configuration; dual RT lanes; or RT lane plus option (through-right) lane
LTS = 4
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Stress at Crossings – Apparent Safe Routes Crossing Winchester Avenue
Crossing Winchester at Rosemary
Criteria for CrossingsNO 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
WITH MEDIAN REFUGEWidth of street being crossed
Speed Limit Up to 3 lanes 4 - 5 lanes 6+ lanesUp to 25 mph LTS 1 LTS 1 LTS 230 mph LTS 1 LTS 2 LTS 335 mph LTS 2 LTS 3 LTS 440+ LTS 3 LTS 4 LTS 4
25ADEC CalGIS 2012 Sacramento, CA
For an arterial to not be a barrier, it needs a low-stress crossing COMBINED WITH a low-stress approach
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What are the Barriers?
A Measure of Connectivity
Percent Trips Connected, by Level of Traffic Stress
• Trip Table for Home-to-Work TripsNumber of people traveling from zone i to zone jWhich zone pairs are connected at a given LTS?TAZ (traffic analysis zone) = standard geographic
unit
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?
Detour Criterion
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
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Level of Traffic Stress 2 (LTS 2) Islands
31
Slate of Possible Improvements
32
Resulting Network for LTS < 2
Home-Work Trip ConnectivityTrip 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% 100.0% 100.0% 100.0%Total trips 78,673 136,652 189,439 292,396
Trip Length < 4 mi < 6 mi < 8 mi AllLTS 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
Before
After
0.7% of home-work
pairs connected
HarborW
alk
Charles River Paths
Mud
dy R
iver P
ath
SW C
orrid
or P
ath
MinutemanBikeway
Neponset River Greenway
51% of home-work
pairs connected
71% of population within 1 km
37
Acknowledgement
• Co-researcher Maaza Mekuria, PhD, Axum Engineering & Design
• Support from the Mineta Transportation Institute
• Inspiration from Rails to Trails Conservancy
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 (n.a.) (n.a.)
Speed limit or prevailing speed
30 mph or less
(n.a.) 35 mph 40 mph or more
Bike lane blockage rare (n.a.) frequent (n.a.)