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

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

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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

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Stress Level 1

10

Level of Traffic Stress 1 (LTS 1) Islands

11


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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31

Slate of Possible Improvements

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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

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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.)

Documents

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