Research, Development, and Technology

Turner-Fairbank Highway Research Center

6300 Georgetown Pike

McLean, VA 22101-2296

PUBLICATION NO. FHWA-HRT-23-052 MAY 2023 

Safety Evaluations of Innovative 

Intersection Designs for Pedestrians 

and Bicyclists
FOREWORD

The research documented in this report was conducted as part of the Federal Highway 

Administration’s (FHWA’s) Evaluation of Low-Cost Safety Improvements Pooled Fund Study 

(ELCSI-PFS). FHWA established this Pooled Fund Study (PFS) in 2005 to conduct research on 

the effectiveness of safety improvements identified by the National Cooperative Highway 

Research Program Report 500 guides as part of the implementation of the American Association 

of State Highway and Transportation Officials’ Strategic Highway Safety Plan. ELCSI-PFS 

studies provide a crash modification factor and benefit–cost economic analysis for each targeted 

safety strategy identified as a priority by member States of the PFS.

The objective of this FHWA project was to investigate the operational and safety improvements 

of innovative intersection retrofitting designs that benefit pedestrians and bicyclists, while 

maintaining a reasonable service to motor vehicles. These designs are also called protected 

intersections, and that is the term used in this document. The project summarizes previous 

research efforts, develops three design types, identifies potential study sites (both before-after

and comparison-existing pairs), and collects in-field operational behaviors of the users. This 

report details the method and results of this study. 

This report may be of interest to transportation practitioners, those conducting transportation 

safety research, industry professionals, and those working to improve transportation safety. 

Brian P. Cronin, P.E. 

Director, Office of Safety and Operations

Research and Development

Notice

This document is disseminated under the sponsorship of the U.S. Department of Transportation 

(USDOT) in the interest of information exchange. The U.S. Government assumes no liability for 

the use of the information contained in this document.

The U.S. Government does not endorse products or manufacturers. Trademarks or 

manufacturers’ names appear in this report only because they are considered essential to the 

objective of the document. 

Quality Assurance Statement

The Federal Highway Administration (FHWA) provides high-quality information to serve 

Government, industry, and the public in a manner that promotes public understanding. Standards 

and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its 

information. FHWA periodically reviews quality issues and adjusts its programs and processes to 

ensure continuous quality improvement. 
TECHNICAL REPORT DOCUMENTATION PAGE

1. Report No.

FHWA-HRT-23-052

2. Government Accession No. 3. Recipient’s Catalog No.

4. Title and Subtitle

Safety Evaluations of Innovative Intersection Designs for 

Pedestrians and Bicyclists

5. Report Date

May 2023

6. Performing Organization Code:

7. Author(s)

Kay Fitzpatrick (ORCID Number: 0000-0002-1863-5106), 

Maryam Shirinzad (ORCID Number: 0000-0002-2061-2771), 

Jeff Whitacre (ORCID Number: 0000-0000-0000-0000)

8. Performing Organization Report No.

9. Performing Organization Name and Address

Texas A&M Transportation Institute

The Texas A&M University System

College Station, TX 77843-3135

10. Work Unit No.

11. Contract or Grant No.

DTFH6116D00039L/693JJ319F000377/P00002

12. Sponsoring Agency Name and Address

Office of Safety Research and Development

Federal Highway Administration

6300 Georgetown Pike

McLean, VA 22101-2296

13. Type of Report and Period Covered

Final Report, October 2019–November 2022

14. Sponsoring Agency Code

HRSO-10

15. Supplementary Notes

The contracting officer’s representative was Wei Zhang (HRSO-10; ORCID: 0000-0002-5175-7527). Panel 

members were Jeffery Shaw, Brook Struve, and Roya Amjadi.

16. Abstract

The protected intersection is a type of innovative intersection design. Traffic professionals are exploring protected 

intersections to determine if they can successfully accommodate multimodal transportation by reducing conflicts 

between moving vehicles and vulnerable users (VU) or by lowering the impact force (reducing the vehicle speed 

and changing the collision angle in the event of a collision). For this Federal Highway Administration project, data 

were collected at 6 intersections both before and after the treatment was installed (for 12 site periods), at 14 

intersections where the treatment was present (representing 14 site periods), and at 4 intersections where the 

treatment was not present (termed comparison sites and representing 4 site periods). Technicians recorded 

behaviors for 23,505 VU at these 30 site periods. Drivers yielded to bicyclists and pedestrians more at the treated 

sites compared to the untreated sites. For bicyclist crossings, 38 percent of the crossings for treated sites compared 

to 34 percent for untreated sites involved a vehicle yielding to the bicyclist. For pedestrian crossings, the 

comparison is 23 percent for treated sites compared to 16 percent for untreated sites. The protected intersection 

treatment is designed to slow turning vehicles and provide drivers additional opportunity to see the crossing VU. 

The addition of the treatment at three of the before-after sites with traffic control signals resulted in more frequent 

yielding by drivers to pedestrians (41 percent in the before period to 47 percent in the after period). Right-turn 

speeds are higher at a larger corner radius. Reducing the corner radius with the installation of the treatment 

resulted in a decrease in the speed of right-turning vehicles. Prediction equations were generated, and for a corner 

changed from a 60-ft radius to a 25-ft radius, a decrease in speed of about 2.6 mph is predicted. Including truck 

aprons can facilitate the turning of large vehicles while also encouraging smaller radius turns for right-turning 

vehicles.

17. Key Words

Innovative intersections, protected intersections, 

corner islands, bicyclists, pedestrians, corner radius, 

right-turn speed

18. Distribution Statement

No restrictions. This document is available to the public 

through the National Technical Information Service, 

Springfield, VA 22161.

http://www.ntis.gov

19. Security Classif. (of this report)

Unclassified

20. Security Classif. (of this page)

Unclassified

21. No. of Pages

103 

22. Price

N/A

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized.
ii

 

 

 

 

 

 

 
iii

TABLE OF CONTENTS

CHAPTER 1. INTRODUCTION ................................................................................................ 1

Background ............................................................................................................................. 1

Project Objective ..................................................................................................................... 2

Study Approach ...................................................................................................................... 2

CHAPTER 2. LITERATURE ..................................................................................................... 3

Terms ....................................................................................................................................... 3

Overview of the Protected Intersection Concept ................................................................. 4

Key Reference Documents ..................................................................................................... 4

Specific Features ..................................................................................................................... 6

Corner Island ....................................................................................................................... 6

Bicycle Queue Area ............................................................................................................ 6

Bicycle Yield Line for Pedestrians Crossing Bicycle Lane ................................................ 6

Leading Island (Also Called Channelized Island, Pedestrian Island, and Street Buffer) ... 6

No Stopping or No Standing Zone...................................................................................... 6

Bicycle Lane Extension Lines and Green Pavement Markings (Also Known as Crossbike, 

Conflict, or Intersection Crossing Markings) ..................................................................... 7

Bikeway Setback ................................................................................................................. 7

Motorist Waiting Zone/Motorist Yield Zone...................................................................... 8

Pedestrian Curb Ramp ........................................................................................................ 8

Signal Operations ................................................................................................................ 8

Alternative for Intersection with Geometric Constraints .................................................... 8

Relevant Features .................................................................................................................... 9

Mixing Zone and Split-Phase Signals ................................................................................. 9

Bicycle Box and ASL ....................................................................................................... 10

Two-Stage Crossing .......................................................................................................... 11

Pedestrian Refuge Island................................................................................................... 11

Signing and Pavement Markings ...................................................................................... 12

Corner Radius and Right-Turn Speed ............................................................................... 12

Bend-Out and Bend-In ...................................................................................................... 14

Crosswalk Design ............................................................................................................. 15

Curb Extensions ................................................................................................................ 15

Shared Space and Pedestrian Plazas ................................................................................. 15

Bicycle Lane Designs ....................................................................................................... 16

Intersection Characteristics for Cars That May Help Pedestrians .................................... 16

Key Takeaways...................................................................................................................... 17

CHAPTER 3. IDENTIFY CANDIDATE SITES ..................................................................... 19

Creating Initial Requests for Information .......................................................................... 19

Identifying Potential Study Sites ......................................................................................... 19

Creating Three Typical Designs .......................................................................................... 19

Site Selection .......................................................................................................................... 25

CHAPTER 4. DATA COLLECTION....................................................................................... 27

Overview of Data collection ................................................................................................. 27
iv

Video from Cameras Installed for Study .......................................................................... 28

Video from Rooftop Camera ............................................................................................ 28

Video from Drone ............................................................................................................. 29

Sample Camera Views for Each Site ................................................................................ 30

Overview of Data Reduction ................................................................................................ 47

CHAPTER 5. OBSERVATIONS .............................................................................................. 51

Vulnerable Users ................................................................................................................... 51

Yielding Behaviors AND Potential Conflicts...................................................................... 54

Typical Travel Paths—Bicyclists ......................................................................................... 57

Bicyclists Travel Paths for Before-After Sites .................................................................. 57

Bicyclists’ Travel Paths for Existing and Comparison Sites ............................................ 59

Bicyclists’ Travel Paths by Movement Type .................................................................... 60

Bicyclists Behaviors With Regard to Corner Islands ........................................................ 61

Waiting Locations ................................................................................................................. 63

Motorists Right-Turn Behaviors ......................................................................................... 64

Speeds at Available Before-After Sites ............................................................................ 64

Sites with Apron Markings or Pylons ............................................................................... 75

Motorists Turning on Bicycle Queue Area ....................................................................... 81

CHAPTER 6. CONCLUSIONS ................................................................................................. 83

Summary ................................................................................................................................ 83

Key Observations .................................................................................................................. 83

Future Research Needs ......................................................................................................... 85

ACKNOWLEDGMENTS .......................................................................................................... 87

REFERENCES ............................................................................................................................ 89
v 

LIST OF FIGURES

Figure 1. Photo. Terms associated with the features of a protected intersection. ........................... 3

Figure 2. Illustration. Proposed revision to MUTCD.(9) ................................................................. 5

Figure 3. Illustration. MassDOT graphic on right-turning motorist and through bicyclist 

yielding behavior in the approach clear space.(10) ................................................................. 7

Figure 4. Illustration. Basic geometric elements and key dimensions of a protected 

intersection.(12) ..................................................................................................................... 14

Figure 5. Illustration. Large intersection with medians and bicycle lanes on all approaches. ...... 21

Figure 6. Illustration. Small intersection with bicycle lanes on all approaches............................ 22

Figure 7. Illustration. Small intersection with bicycle lanes on major approaches only. ............. 23

Figure 8. Photo. Example of video view for one of the cameras at DC‒WAS‒03‒Aft. .............. 28

Figure 9. Photo. Example of view for rooftop camera at MD‒SSP‒02‒Aft. ............................... 29

Figure 10. Photo. Example of view from the drone camera of CA‒FRE‒11‒Aft........................ 29

Figure 11. Photo. View from the video of CA‒BER‒01‒Exi. ..................................................... 31

Figure 12. Photo. View from the video of CA‒FRE‒01‒Exi. ...................................................... 31

Figure 13. Photo. View from the video of CA‒FRE‒02‒Exi. ...................................................... 32

Figure 14. Photo. View from the video of CA‒FRE‒03‒Exi. ...................................................... 32

Figure 15. Photo. View from the video of CA‒FRE‒04‒Exi. ...................................................... 33

Figure 16. Photo. View from the video of CA‒FRE‒05‒Com. .................................................... 33

Figure 17. Photo. View from the video of CA‒FRE‒05‒Exi. ...................................................... 34

Figure 18. Photo. View from the video of CA‒FRE‒06‒Exi. ...................................................... 34

Figure 19. Photo. View from the video of CA‒FRE‒07‒Com. .................................................... 35

Figure 20. Photo. View from the video of CA‒FRE‒07‒Exi. ...................................................... 35

Figure 21. Photo. View from the video of CA‒FRE‒09‒Exi. ...................................................... 36

Figure 22. Photo. View from the video of CA‒FRE‒11‒Bef. ...................................................... 36

Figure 23. Photo. View from the video of CA‒FRE‒11‒Aft. ...................................................... 37

Figure 24. Photo. View from the video of CA‒FRE‒12‒Bef. ...................................................... 37

Figure 25. Photo. View from the video of CA‒FRE‒12‒Aft. ...................................................... 38

Figure 26. Photo. View from the video of DC‒WAS‒01‒Bef, northbound................................. 38

Figure 27. Photo. View from the video of DC‒WAS‒01‒Aft, northbound. ................................ 39

Figure 28. Photo. View from the video of DC‒WAS‒02‒Bef, northbound................................. 39

Figure 29. Photo. View from the video of DC‒WAS‒02‒Aft, northbound. ................................ 40

Figure 30. Photo. View from the video of DC‒WAS‒03‒Bef, westbound. ................................. 40

Figure 31. Photo. View from the video of DC‒WAS‒03‒Aft, westbound. ................................. 41

Figure 32. Photo. DC‒WAS‒03‒Bef............................................................................................ 41

Figure 33. Photo. DC‒WAS‒03‒Aft. ........................................................................................... 42

Figure 34. Photo. View from the video of MD‒SSP‒01‒Exi. ...................................................... 42

Figure 35. Photo. View from the video of MD‒SSP‒02‒Bef. ..................................................... 43

Figure 36. Photo. View from the video of MD‒SSP‒02‒Aft. ...................................................... 43

Figure 37. Photo. View from the video of TX‒AUS‒16‒Com. ................................................... 44

Figure 38. Photo. View from the video of TX‒AUS‒16‒Exi. ..................................................... 44

Figure 39. Photo. TX‒CST‒01‒Exi.............................................................................................. 45

Figure 40. Photo. View from the video of TX‒CST‒01‒Exi. ...................................................... 45

Figure 41. Photo. View from the video of UT‒SLC‒01‒Exi. ...................................................... 46

Figure 42. Photo. View from the video of UT‒SLC‒01‒Com. .................................................... 46
vi 

Figure 43. Photo. View from the video of UT‒SLC‒03‒Exi. ...................................................... 47

Figure 44. Photo. CA‒FRE‒11 before-period gates. .................................................................... 65

Figure 45. Photo. CA‒FRE‒11 after-period gates. ....................................................................... 65

Figure 46. Photo. CA‒FRE‒12 before-period gates. .................................................................... 66

Figure 47. Photo. CA‒FRE‒12 after-period gates. ....................................................................... 66

Figure 48. Photo. Receiving lane names. ...................................................................................... 67

Figure 49. Photo. Measuring turning radius using Google Earth Pro. .......................................... 68

Figure 50. Graph. Entry, corner, and exit right-turn speeds for vehicles turning on a green 

signal indication, based on turning radius and receiving lane, for the before period. ......... 71

Figure 51. Graph. Entry, corner, and exit right-turn speeds for vehicles turning on a green 

signal indication, based on turning radius and receiving lane, for the after period............. 71

Figure 52. Graph. Vehicle speeds at each intersection corner for study sites during before 

and after conditions. ............................................................................................................ 72

Figure 53. Equation. Median right-turn speed functional form. ................................................... 73

Figure 54. Equation. Median right-turn speed functional form with coefficients. ....................... 73

Figure 55. Graph. Comparison of findings between this current study and the Fitzpatrick et 

al. 2022 study.(36) ................................................................................................................. 74

Figure 56. Photo. Trajectories of all vehicles for a 4-min, 47-s interval at CA‒FRE‒06‒

Exi. ...................................................................................................................................... 76

Figure 57. Photo. Trajectories of all vehicles for a 4-min, 47-s interval at CA‒FRE‒07‒

Exi. ...................................................................................................................................... 77

Figure 58. Photo. Trajectories of all vehicles for a 5-min, 01-s interval at MD‒SSP‒02‒

Aft........................................................................................................................................ 77

Figure 59. Photo. Trajectories of all vehicles for a 4-min, 47-s interval showing some 

vehicles driving inside the bottom left pylons (on the bicycle area) in UT‒SLC‒03‒

Exi study site. ...................................................................................................................... 78

Figure 60. Photo. Trajectories of all vehicles for a 4-min, 47-s interval showing some 

vehicles driving inside the raised pavement markers and solid white line for the truck 

apron at CA–BER–01–Exi. ................................................................................................. 79

Figure 61. Photo. Example of a city bus turning right at the southwest corner at 

MD–SSP–01–Exi. ............................................................................................................... 80

Figure 62. Photo. Right-turning car (white) entering the green marked bicycle queue area 

at UT‒SLC‒03‒Exi. ............................................................................................................ 82

Figure 63. Photo. Right-turning car (white) leaving the green marked bicycle queue area at 

UT‒SLC‒03‒Exi. ................................................................................................................ 82
vii 

LIST OF TABLES

Table 1. Study sites selected for the project. ................................................................................ 25

Table 2. PSL by approach for each study site. .............................................................................. 26

Table 3. Dates data collected at each study site. ........................................................................... 27

Table 4. User behavior measures collected at the study sites. ...................................................... 48

Table 5. Data collected from the video. ........................................................................................ 49

Table 6. Number of VU observed at each site. ............................................................................. 52

Table 7. Number of VU per hour observed at each site................................................................ 53

Table 8. Comparison of pedestrians, bicyclists, and scooters per hour for before-after sites. ..... 54

Table 9. Number of potential conflicts between VU and other traffic. ........................................ 55

Table 10. Number of interactions between the VU and a vehicle or bicyclist that enters the 

crossing, arranged by treatment presence and who yielded during the interaction. ............ 55

Table 11. Who yields to a pedestrian at before-after sites in California or Maryland.................. 56

Table 12. Who yields to pedestrian at before-after sites in Washington, DC. .............................. 57

Table 13. Bicycle paths at six before-after sites. .......................................................................... 58

Table 14. Bicyclists use of crossbike or crosswalk markings at before-after sites (Did 

bicyclists stay within the crossbike or crosswalk area?). .................................................... 59

Table 15. Bicyclists starting position at before-after sites, subdivided by the type of 

intersection control. ............................................................................................................. 59

Table 16. Bicyclists starting and ending positions at existing and comparison sites. .................. 60

Table 17. Start of bicyclist path for treated and untreated sites. ................................................... 60

Table 18. Start of bicyclist path by movement type for treated and untreated sites. .................... 61

Table 19. Bicyclist paths with respect to the corner island for sites with raised islands or a 

mix of raised islands and pylons. ........................................................................................ 62

Table 20. Bicyclist paths with respect to the corner island for sites with pylons. ........................ 62

Table 21. Waiting area for bicyclists in before and after periods for CA–FRE–11 and 

CA–FRE–12. ....................................................................................................................... 63

Table 22. Waiting area for pedestrians in before and after periods for CA‒FRE‒11 and 

CA‒FRE‒12. ....................................................................................................................... 64

Table 23. Turning radii for intersection corners. .......................................................................... 68

Table 24. Count of right-turning cars for study intersections. ...................................................... 69

Table 25. Average right-turn speed for before and after periods. ................................................. 70

Table 26. Distribution of right-turning vehicles by signal indication. .......................................... 70

Table 27. Count (or percent) of cars by site, period, and receiving lane. ..................................... 72

Table 28. Linear regression parameters. ....................................................................................... 73

Table 29. Characteristics of sites with truck apron or pylons with drone video available. .......... 75

Table 30. Percentage of vehicles on the truck apron. ................................................................... 76

Table 31. Number or percentage of right-turning vehicles using the truck apron at 

MD–SSP–03–Exi. ............................................................................................................... 80

Table 32. Number of vehicles observed on marked bicyclist waiting area. ................................. 81
viii

LIST OF ABBREVIATIONS

ASL advanced stop line 

AUS Austin

BER Berkeley

CB crossbike 

CST College Station

CW crosswalk

ELCSI-PFS Evaluation of Low-Cost Safety Improvements Pooled Fund Study 

e-scooter electronic scooter

FHWA Federal Highway Administration

FRE Fremont 

MassDOT Massachusetts Department of Transportation

MUTCD Manual on Uniform Traffic Control Devices for Streets and Highways

NACTO National Association of City Transportation Officials

NCHRP National Cooperative Highway Research Program 

NPA Notice of Proposed Amendments 

PFS pooled fund study

PSL posted speed limit 

RBL receiving bicycle lane

RPL receiving parking lane 

RVL1 receiving vehicle inside lane 

RVL2 receiving vehicle middle lane 

RVL3 receiving vehicle outside lane 

SLC Salt Lake City

SSP Silver Spring

Veh vehicle

VU vulnerable users 

WAS Washington, DC 
1 

CHAPTER 1. INTRODUCTION

BACKGROUND

Many transportation agencies are increasing their emphasis on improving pedestrian and 

bicyclist safety and reducing the risk of a fatality or serious injury to these users. A wide variety 

of treatments and countermeasures have been conceived and implemented across the country in 

recent years. Some of them, such as the pedestrian hybrid beacon and median refuge islands, 

have had documented benefits so positive that they have been included in the Federal Highway 

Administration’s (FHWA’s) Proven Safety Countermeasures.

(1) However, not all treatments are 

associated with such comprehensive results, and many have not had a thorough evaluation with 

respect to safety.

Recently, traffic professionals have conceived and implemented certain innovative intersection 

designs aimed at accommodating multimodal transportation, reducing conflicts between moving 

vehicles and vulnerable users (VU), and lowering the impact force (reducing vehicle speed and 

changing collision angle in the event of collision). In concept, these designs should improve 

conditions for pedestrians and bicyclists; however, studies that document the changes and 

potential benefits are not yet available. The goal of this FHWA project is to address this gap. 

At intersections, roadway design elements have long sought to minimize delay to motorized 

traffic. However, to minimize exposure and improve safety for VU, a paradigm shift in roadway 

design is required, where features emphasize slower speeds and improved visibility between the 

motorist and VU. Traffic professionals are developing a variety of potential innovative 

intersection treatments that accomplish this paradigm shift, and have recently installed those 

treatments or planned for their installation. The number of intersections with existing or planned 

installations of these features presents an opportunity to investigate the benefits and tradeoffs of

these designs. Assessments of these treatments should consider the specific intersection’s

geometric configuration, the approach cross section (e.g., number of lanes, presence and width of 

median, presence of onstreet parking, bicyclist lane width, presence of bicyclist lane buffer), 

changes in user demand, and interaction among pedestrians, bicyclists, and motor vehicles at 

intersecting points.

The evolving pedestrian- and bicyclist-centered infrastructure improvements have typically 

originated in urban centers seeking to encourage nonmotorized transportation to reduce 

congestion and emissions as well as encourage active lifestyles for citizens. These designs can be 

characterized by the level of exposure for the VU, such as the following categories used in the 

FHWA bikeway selection guide:(2)

• High exposure level: Conventional bicycle lanes and shared lanes.

• High-to-medium exposure level: Separated bicycle lanes with mixing zones. 

• Medium-to-low exposure level: Separated bicycle lanes through roundabouts.

• Low exposure level: Protected intersections.
2 

Even where progress toward improving safety for VU along a corridor has occurred, the benefits 

of those treatments along the corridor may not be fully realized when discontinued at 

intersections. Therefore, traffic professionals are developing, installing, and refining treatments 

to continue the benefits through the intersection. As an example, traffic professionals are 

modifying corner islands and turning paths to force vehicles further into an intersection before 

making a turning maneuver. This treatment has recently been incorporated into an FHWA 

university course module for intersection design.

(3)

Several names are used for these types of intersections, including the term innovative 

intersections. In the broad category of innovative intersections are designs and concepts being 

used and discussed in other documents. For example, the National Association of City 

Transportation Officials (NACTO) is using the terms protected intersection and dedicated 

intersections.

(4) In some international literature, these intersections are referred to as Dutch 

intersections or Dutch-style junctions. In all cases, the design attempts to establish and enhance 

physical separation between pedestrians, bicyclists, and motorists through the intersection. This 

report uses the term protected intersection.

PROJECT OBJECTIVE

The objective of this FHWA project was to investigate the operational and safety improvements 

of innovative intersection retrofitting designs that benefit pedestrians and bicyclists while 

maintaining a reasonable level of service to motor vehicles.

STUDY APPROACH

The approach used in this study included the following steps: 

• Conduct a synthesis of the innovative intersection retrofitting designs that benefit 

pedestrians and bicyclists while maintaining a reasonable level of service to motor 

vehicles.

• Select two to three designs for formal evaluations and develop design templates for these 

designs. 

• Identify State and local agencies that are planning to install such designs and conduct 

in-field before-after data collection.

• Identify existing and comparison sites—when sufficient before-after sites are not 

available due to timing of this study—and gather in-field operational behaviors of the 

users.

• Develop a half-day training course for the evaluated designs, and conduct an 

instructor-led pilot training for a class of 25 or more participants from Federal, State, and 

local agencies.
3 

CHAPTER 2. LITERATURE

TERMS

Several terms are used to describe treatments added at intersections that benefit pedestrians and 

bicyclists while also maintaining a level of service to motor vehicles. FHWA used the term 

innovative intersections to cover several novel intersection designs, including the designs studied 

in this project. NACTO uses the terms protected intersection or dedicated intersection, while 

others use the term Dutch intersection or Dutch-style junction. This report uses the term 

protected intersection.

Figure 1 summarizes some of the terms used for features associated with the protected 

intersections studied in this project. The following sections use terms commonly found in the 

literature or terms identified by the research team. 

Source: FHWA.

Figure 1. Photo. Terms associated with the features of a protected intersection.
4 

OVERVIEW OF THE PROTECTED INTERSECTION CONCEPT

Protected intersections include features to separate bicyclists from motor vehicle traffic for a 

portion of the intersection, using physical elements (e.g., raised curbs, bollards, pylons). Because 

of the newness of this design concept, only a few studies in the literature have focused on the 

design. More studies are available that focus on features being incorporated into the protected 

intersection. In this literature review chapter, the term used to describe the intersection or feature 

will be the term provided by the authors; however, this report will also provide alternative terms.

In 2020, Lyons et al. documented a before-after case study of a protected intersection in Salt 

Lake City, UT.

(5)

 They collected data in 2015 (before) and 2016 and 2018 (two after periods). 

The intersection was completed in late 2015 and represented one of the first examples of a 

protected intersection design in North America. They found that active transportation usage 

increased, with most of the growth attributed to electronic scooter (e-scooter) users. The authors 

identified nonoptimal behaviors, such as disobeying a signal or crossing outside of the 

crosswalk, and found a minimal change in the rates of nonoptimal behaviors by pedestrians and a 

decreased rate for bicyclists. E-scooter users, however, demonstrated nonoptimal behaviors at 

very high rates compared with other active transportation modes.

KEY REFERENCE DOCUMENTS

The Manual on Uniform Traffic Control Devices for Streets and Highways (MUTCD) is the key 

reference document for signing and markings for bicyclist treatments.(6) The current edition of 

the MUTCD is the 11th edition. A comprehensive update to the 11th edition of the MUTCD is 

ongoing at the time of the writing of this report. The Notice of Proposed Amendments (NPA) 

was released on December 14, 2020, and public comments were allowed. In developing the 

NPA, FHWA considered the results of official experiments, official interpretations, interim 

approvals, and other research. The NPA closed public comment in the Federal Register on 

May 14, 2021, after receiving more than 17,000 entries comprising over 35,000 individual 

comments.

(7) The update to the MUTCD may contain several changes for bicycle facilities, 

including green colored pavement to add conspicuity to bicycle-only facilities.

In an FHWA memorandum released on January 5, 2017, the following information was provided 

regarding bicycle lane extension markings through intersections: 

Extensions of bicycle lanes are compliant with the MUTCD and can be marked as would 

be an extension of any other lane. The provisions of [MUTCD] Section 3B.08 - 

Extensions Through Intersections or Interchanges - apply to bicycle lanes. Among other 

guidance, Section 3B.08 states that "Where highway design or reduced visibility 

conditions make it desirable to provide control or to guide vehicles through an 

intersection or interchange... dotted line extension markings consisting of 2-ft line 

segments and 2- to 6-ft gaps should be used to extend longitudinal line markings through 

an intersection or interchange area." It should be noted that chevron markings are not 

permitted to be used in bicycle lanes or bicycle lane extensions, nor are shared-lane 

markings. Bicycle lane extensions through intersections can include standard bicycle lane 

arrows, bicycle symbols, or pavement word markings. Additionally, green-colored 
5 

pavement can be used to enhance conspicuity if the installing jurisdiction has received 

approval under Interim Approval 14.(8)

The proposed revision to the MUTCD includes several anticipated changes to bicyclist signing 

and markings.(9) One of the changes includes examples of lane markings for separated bicycle 

lanes. Figure 2 is one example. The markings in the intersection are labeled as “green-colored 

pavement (optional)” in figure 2 and are known as bicycle lane extension lines and green 

pavement markings. They are also called crossbike, conflict, or intersection crossing markings. 

Source: FHWA.

Figure 2. Illustration. Proposed revision to MUTCD.(9)

Several other key pieces of literature in the United States discuss protected intersections, 

including on the public side the NACTO document entitled Don’t Give Up at the Intersection, 

the Massachusetts Department of Transportation (MassDOT) document Separated Bike Lane 

Planning & Design Guide, and the Seattle Right-Of-Way Improvement Manual section on Bike 

Intersection Design.

(4,10,11)

 One of the major contributions from the private side is the document 

Lessons Learned: Evolution of the Protected Intersection.

(12,13) Collectively, these documents 

identify 11 features of protected intersections, overlapping on several. 

NACTO discusses two intersection design types: protected intersections and dedicated 

intersections. Their document, Don’t Give Up at the Intersection, provides illustrations of these 

two intersection forms.(4)

Key features of a protected intersection are illustrated in figure 1 and are described in the 

following section. 
6 

SPECIFIC FEATURES

The following sections discuss features of the protected intersection.

Corner Island

The corner island (sometimes referred to as a corner refuge island) is a raised area that separates 

the bicycle lane from the motor vehicle lane and is the defining feature of the innovative 

(protected) intersection concept, without which the other elements could not be used.(4,6) For 

example, the pedestrian islands, bikeway setback, and bicycle queuing area are only possible due 

to the presence of the corner island. If necessary, the corner island can be coupled with a corner 

apron to accommodate off-tracking by larger vehicles.(12,14)

Bicycle Queue Area

Bicyclists queue adjacent to the corner island and pedestrian refuge island, closer to the 

intersection. A forward stop bar is located near the curb to indicate to bicyclists where to wait to 

cross the intersection.

(12) The design reduces bicyclists’ crossing distance and creates a physical 

leading interval for bicyclists and pedestrians.(15)

Bicycle Yield Line for Pedestrians Crossing Bicycle Lane

The intersection design calls for separate facilities for pedestrians, bicyclists, and motorized 

traffic. Consequently, conflict points for the nonmotorized traffic modes exist. NACTO indicates 

that bicycle yield markings are optional, depending on local policy.(4) MassDOT echoes this 

guidance, stating on page 71 of the Separated Bike Lane Planning & Design Guide that, “Yield 

lines in the bicycle lane in advance of the pedestrian crosswalk are typically used to emphasize 

pedestrian priority.”(10)

Leading Island (Also Called Channelized Island, Pedestrian Island, and Street Buffer)

The distance from the edge of the bicycle lane to the edge of the motor vehicle traveled way 

defined by the corner island creates a buffer. The area where the pedestrian crosswalk intersects 

this buffer area provides space for pedestrians (sometimes called a pedestrian island or leading 

island). This space shortens the pedestrian crossing distance.

(4,10,13)

No Stopping or No Standing Zone

MassDOT refers to space where there should not be any parking or drop-off zones because 

stopped vehicles would block the sight lines between motorists in the travel lane and bicyclists in 

the bicycle lane as a “decision zone.” This space is part of a larger segment of the roadway called 

the “approach clear space.” Prohibiting traffic from stopping in the area near the intersection 

(generally about 20 to 30 ft) is relatively common; however, MassDOT notes that the distance 

should reflect the multimodal nature of the intersection when the design is used.(10)

 By keeping 

this area free of parked vehicles, the bicyclists and motorists are provided with time to see one 

another and make modifications to their speed or yielding behavior that is necessary to facilitate 

both road users safely navigating the intersection. 
7 

Public domain illustration courtesy of MassDOT, 2015.

Figure 3. Illustration. MassDOT graphic on right-turning motorist and through bicyclist 

yielding behavior in the approach clear space.(10)

Bicycle Lane Extension Lines and Green Pavement Markings (Also Known as Crossbike, 

Conflict, or Intersection Crossing Markings) 

The bicycle lane extension lines and green pavement markings serve the purpose of delineating 

bicycle space through the area of the intersection used by motor vehicles. These markings have 

also been referred to as crossbike markings in NACTO’s Don’t Give Up at the Intersection.

(4)

According to the NACTO Urban Bikeway Design Guide, the bicycle lanes should typically use 

solid white lines except in areas of conflict with motor vehicles, where dashed lines are used.

(16)

These markings can be supplemented with solid color in the conflict area, dashed color in the 

conflict area, or solid color outside of the conflict area.

Bikeway Setback

The bikeway setback is used to make it easier for drivers to see bicyclists and pedestrians.(4) The 

use of an approach taper has been identified in the existing literature, though not explicitly 

identified as a key feature in several documents.(12) NACTO describes the feature as a variation 

to the design.(4) Effectively, this treatment creates a bend-out and bend-in as the bicycle lanes 

approach and depart the intersection and was observed by the research team during a review of 

existing sites. This bend-out, bend-in technique, which is discussed as a general treatment in the 

Bend-Out Bend-In section, creates an alignment change as bicyclists approach the intersection. 

This alignment change can be used to separate a bicycle lane from motor vehicle traffic at the 
8 

intersection, which facilitates the use of the intersection concept, particularly the bikeway 

setback, on bicycle lanes that are not separated at the corridor level. Another potential beneficial 

application of this technique is to create a speed calming effect, reducing bicyclist speed in areas 

of potential conflict with pedestrians.

Motorist Waiting Zone/Motorist Yield Zone

In this intersection design, the corner island causes the bicycle lane extension lines (also known 

as crossbike) and crosswalk locations to be offset from parallel vehicle traffic. This area of the 

intersection immediately adjacent to the corner island where right-turning motorists must wait 

for crossing bicyclists and pedestrians is called the motorist waiting zone.(4,10) MassDOT’s 

Separated Bike Lane Planning & Design Guide points to literature that indicates a setback of 

6 to 16 ft can have crash reduction benefits.

(10)

Pedestrian Curb Ramp

The ultimate goal of the protected intersection design is to prioritize the safety and mobility of 

nonmotorized users. To this end, MassDOT indicates that ramps and detectable warning surfaces 

that are compliant with the Americans with Disabilities Act of 1990 should be used when 

transitioning from the sidewalk elevation to the roadway elevation.

(10)

Signal Operations

Traffic signal operations are specifically called out by Gilpin et al. as one of the critical elements 

of protected intersection design.

(12) The report by Gilpin et al. also emphasizes three principals of 

signalization previously outlined in NACTO’s Urban Street Design Guide: short cycle lengths, a 

minimal number of phases, and bicycle-compatible signal progression.(17)

Alternative for Intersection with Geometric Constraints

NACTO discusses a design called a dedicated intersection that can be used when geometric 

constraints prevent a bicycle lane at an intersection from being set back as much as for the 

protected intersection design.

(4) Like the NACTO protected intersection design, the crux of the 

dedicated intersection is the reduction of vehicle turning speeds. An overview of a dedicated 

intersection is shown in NACTO’s Don’t Give Up at the Intersection.

(4)

Corner Wedge and Speed Bump

A corner wedge rather than a corner island is applied at a smaller scale in the dedicated 

intersection as opposed to the protected intersection. The use of a modular speed bump extends 

the curb further into the intersection, preventing high-speed turns and increasing driver 

yielding.

(4)

Crosswalk Separator 

The crosswalk separator is placed to discourage motorists from trying to cut through the 

pedestrian and bicyclist space created by the corner wedge.

(4) Its functionality is similar to the 

pedestrian island (also called a leading island in figure 1) used in the protected intersection.
9 

Centerline Hardening

Modular curbs are used with or without post-mounted delineators. Similar to the corner wedge, 

this design element is intended to force vehicles further into the intersection before beginning 

their turn so they make their turn at a lower speed.

(4)

Bicycle lane Line Extensions (Also Known as Crossbike) 

The pavement markings through the intersection are similar in concept to those of the protected 

intersection. The most notable difference is that bicyclists queue before crossing the pedestrian 

crosswalk rather than after crossing it.

(4)

Buffer or Curb

The buffer or curb is similar in purpose to the pedestrian island (also called a leading island in 

figure 1) in the protected intersection. This design feature allows pedestrians to prepare to cross 

the intersection near the curb and separates bicyclists from motor vehicle traffic on the 

approach.(4)

RELEVANT FEATURES

A significant amount of literature, including FHWA’s Separated Bike Lane Planning and Design 

Guide, presents designs and principles that can be used as standalone treatments at intersections, 

or in concert with a suite of other treatments at protected intersections.(18)

 An overview of the 

application and effectiveness of these treatments as standalone treatments is provided in the 

following section. 

Mixing Zone and Fully Split-Phase Signals 

Mixing zones and split-phase signals represent two distinct treatments. This section compares

and contrasts the two designs. A mixing zone is formed when a dedicated bicycle lane stops 

(typically 110 ft from the crosswalk), forcing bicyclists and right-turning vehicles to share the 

same lane.

(18)

 A fully split-phase signal requires dedicated space and signal time for motor 

vehicles and for bicycles.

(19)

 Dedicated signals have been shown to be preferred to a number of 

other treatments.

(16)

On the pedestrian side, Zhang et al. found that at exclusive phasing intersections, pedestrians 

crossing on the walk signal experienced lower interaction severity compared to those crossing at 

sites with concurrent phasing.

(20)

 Additionally, pedestrians crossing concurrently when dedicated 

crossing time was available experienced higher interaction severity.

(20) Intersections with 

concurrent phasing have fewer total pedestrian crashes than those with exclusive phasing (but the 

crashes that do occur tend to be more severe.)(20)

 The authors of the study felt that exclusive 

pedestrian signal time was only beneficial when pedestrians actually wait for the walk signal, 

and they recommended that dedicated pedestrian phasing be used only where compliance was 

high. 
10 

A paper by Sundstrom, Quinn, and Weld investigated the safety performance of mixing zones 

relative to fully split-phase signal treatments on protected bicycle lanes in New York, NY.

(19)

The results of that analysis indicated that shorter mixing zones are more effective than fully splitphase signal treatments at high-turn-volume locations, that mixing zones are equally effective at 

reducing bicycle crashes as fully split-phase signal treatments at low-turn-volume intersections, 

and that shorter mixing zones are more effective than longer mixing zones across all 

intersections.

(19)

Monsere et al. examined the use of mixing zones on protected bicycle lanes.(21) The research 

team found a clear benefit to the restricted entry of vehicles into the turning lane based on 

87-percent compliance of motorists and 91-percent compliance of bicyclists. Furthermore, the 

researchers found that mixing zones with yield markings had 93-percent turning vehicle 

compliance but only 63 percent of bicyclists correctly used the mixing zone when a car was 

present, indicating that bicyclists may benefit from a through bicycle lane or hatching.(21) Finally, 

Monsere et al. found that 1 percent to 18 percent of turning vehicles at mixing zones turn from 

the wrong lane.(21)

Research in Japan by Rahimi, Kojima, and Kubota examined five intersection safety treatments 

for safety and comfort: mixed traffic with left-turning motorist, left-turn in the intersection for 

motorist, bicycle signal, advanced stop lines (ASLs), and bicycle boxes.

(22) Using a closed-course 

study, the researchers found that mixed traffic with left-turning motorists (i.e., a mixing zone) 

was the safest in terms of conflicts and in terms of the number of bicyclists entering the 

intersection from the blind spot of a motorist, while bicycle signals are the most comfortable 

design for bicyclists.

Bicycle Box and ASL

The aforementioned study by Rahimi, Kojima, and Kubota examined additional intersection 

treatments beyond the signal and mixing zone that were previously discussed.(22)

 Two of those 

treatments include the ASL and the bicycle box. A bicycle box is a designated area at the head of 

a traffic lane providing a safe, visible area for bicyclists ahead of queuing traffic.

(16) An ASL 

positions the stop bar for motor vehicles further from the intersection than the stop bar for

bicyclists, thus allowing the bicyclist to be positioned in view of the motorist and get a head start 

on crossing the street.

(22)

Ohlms and Kweon found that bicycle boxes installed on two legs of an intersection in 

Charlottesville, VA, had proper use rates of 46 and 24 percent and improper use rates of 

40 and 10 percent.(23)

 A Portland, OR, study by Dill, Monsere, and McNeil found that 73 percent 

of stopping vehicles did not encroach on the box.(24) Additionally, the researchers found 

decreased encroachment of the pedestrian crosswalk by motorists and bicyclists, mixed results 

on motorist encroachment into the bicycle lane, and decreased conflicts observed as the volume 

of turning motorists and bicyclists increased. Both drivers and bicyclists perceived the treatment 

as making an intersection safer.

In a United Kingdom-based report, Wall, Davies, and Crabtree found that moving the motor 

vehicle stop line back did not impact intersection capacity or require signal retiming and was

perceived favorably by survey respondents.(25) Moreover, the study found that bicyclist behavior 
11 

at study locations (which the researchers noted had low bicyclist volume) did not impact 

intersection capacity. The study termed the design sites as ASLs, but since bicyclists queuing 

was allowed directly in front of the motor vehicles, the design seems to be more of a bicycle 

box.(25)

Additional research in the United Kingdom by Allen, Bygrave, and Harper looked at ASLs in the 

London metro area.(26) Again, the study uses ASL to describe what appears to be a bicycle box, 

potentially pointing to the evolving nature of treatment terminology. The researchers found that 

only 1 percent of bicyclists were involved in conflicts, and only 0.1 percent were involved in 

serious conflicts. Proper behavior of bicyclists and motorists was not always observed. For 

example, bicyclists were obstructed 1 percent to 10 percent of the time.

(26)

 On the bicyclist side,

bicyclists waited in the correct spot 38 percent of the time. The study examined the effect of the 

placement of feeder lanes to allow bicyclists to reach the ASL (bicycle box). Curbside feeder 

lanes were used 87 percent of the time, while bicyclists were observed riding curbside 77 percent 

of the time when no feeder lane was present, and feeder lane use dipped to 52 percent when the 

lane was centrally located.

(26) The study team observed that bicyclists positioned themselves in 

front of motor vehicle traffic 78 percent of the time at treatment sites, versus 54 percent of the 

time at control sites.(26) One adverse effect of the treatment was that 17 percent of bicyclists 

violated red lights at ASL sites versus 13 percent at non-ASL sites. Another London study, this 

one by Atkins Services, found that relatively few bicyclists used the bicycle boxes in the 

intended manner, with about only 25 percent waiting in the bicycle box during the red signal and 

the rest crossing the intersection during the red phase.(27)

A bicycle box in Eugene, OR, on a one-way street with a left-side feeder lane was studied by 

Hunter.(28) After passing through the intersection, bicyclists could move to either a left-side or a 

right-side bicycle lane on the far side. The installation of the bicycle box reduced the proportion 

of bicyclists who would cross the intersection on the left side and then weave through traffic to 

get to the right lane from 53 to 35 percent.

Two-Stage Crossing

The two-stage crossing provides bicyclists the opportunity to make left turns at multilane 

intersections from a right-side bicycle lane by locating a queue box in front of far-side crossing 

traffic.

(16) However, evidence in the literature suggests that the design may be confusing or 

inconvenient for bicyclists. Ohlms and Kweon studied the use of the design in Charlottesville, 

VA, and found that the design was improperly used 57–100 percent of the time and associated 

with a 290-percent increase in prohibited left turns.

(23)

Pedestrian Refuge Island

The technique of using multiple stages to provide a crossing can also be applied to pedestrians’ 

through movements on boulevards where median islands provide a pedestrian refuge. A study by 

Kang in New York, NY, found pedestrian refuge islands to be effective at reducing the rate of 

postproject pedestrian collisions.

(29)

 A Chinese study by Cao, Ni, and Li found that the 

perception of safety by pedestrians is increased with the presence of a refuge island and that the 

perception increased as the width of the refuge island increased. However, this perceived safety 

may influence pedestrians to violate a traffic signal to complete the first part of the crossing.

(30)
12 

Hummer et al. found that a two-stage Barnes Dance is an effective pedestrian crossing design for 

high-volume superstreet intersections.

(31)

 Furth and Wang indicated that more than two stages 

can be used if enough pedestrian refuge islands are present.

(32)

Despite the advantages, challenges exist due to climatic issues. For example, Li and Fernie 

conducted an observational study in Toronto, Canada, and found that mean walking speed 

increases as temperature decreases in winter and pedestrians are more likely to walk against 

flashing or steady Don’t Walk signals in uncomfortable weather.(33) Consequently, pedestrian 

compliance at two-stage crossing signals dropped from 13 to 3 percent when the weather was 

cold and snowing. 

Signing and Pavement Markings

Signing and pavement markings play an important role in conveying the proper way for all road 

users to navigate an intersection. Many aspects of signs and markings have been studied for 

pedestrian and bicyclist considerations at intersections.

Boudart et al. examined MUTCD sign 9C-7 (which is intended to tell bicyclists where to wait to 

be detected for a green signal) and found that text explaining the sign was shown to improve 

comprehension through intercept surveys and video observations, while blue light feedback 

telling bicyclists that they have been detected had a nonsignificant reduction of red light 

running.(34) Warner et al. found that through intersection markings improved visual search and 

crash avoidance.

(14) Interestingly, despite the common association of green pavement markings 

with bicycle facilities, the researchers found that a single or double dotted white bicycle line with 

bicycle stencil should be considered because those markings were more effective than green 

markings.

(14)

The NACTO Urban Bikeway Design Guide provides guidance on several aspects of pavement 

markings on bicycle facilities.(16) The guide states that crossing striping shall be 6 inches wide, 

dotted lines should be 2 ft long with 2- to 6-ft spacing, white, skid resistant, and retroreflective. 

The NACTO guide also suggests other markings, such as shark teeth for crossing driveways and 

alleyways, colored pavement to increase visibility in conflict areas or entire intersections, and 

square markings as an alternative to a dotted line.

(16)

Iasmin, Kojima, and Kubota indicated that color and brick pavements have been shown to be 

associated with a decreased likelihood of small-gap acceptance by drivers, as well as decreased 

incidence of high-severity conflicts (where driver action is taken at the last minute to avoid a 

collision) when drivers are turning (right- or left-hook collisions).(35)

Corner Radius and Right-Turn Speed

A recent FHWA study explored the relationship between observed right-turn vehicle speeds and 

roadway geometrics, especially corner radius, at signalized intersections.(36) The selection of a 

large radius for a corner permits higher turning vehicle speeds in free-flow situations. While the 

potential increased vehicle speed through the right-turn lane is more efficient for the driver, 

trade-offs exist for this design. Increased vehicle speeds create more challenges for pedestrians 

attempting to cross the roadway. The analysis included a total of 31 sites with a range of radii 

varying between 15 and 70 ft. Other geometric variables considered included the type of 
13 

right-turn lane, the number of right-turn lanes, the length of the right-turn lane, the distance to 

the nearest upstream and downstream driveways, the number of lanes on the receiving leg, and 

the speed limit. No bicycle or parking lanes were present on the approach or the receiving leg for 

any of the sites. All sites were at a signalized intersection. The right-turn speed measurement 

methodology involved collecting video footage at signalized intersection approaches and 

post-processing the footage to extract speed measurements, along with headway between the 

turning vehicle and the preceding vehicle. This study allowed the inclusion of variables that 

described conditions present when the subject vehicle was turning right, including the signal 

indication (steady circular green indication or steady circular yellow indication), type of turning 

vehicle (car or truck), and characteristics of the vehicle immediately preceding the turning 

vehicle (straight or turning right). The conditions during the specific right turn (e.g., headway, 

signal indication) are more influential than the site characteristics, except for corner radius. 

The analysis found convincing evidence that right-turn speeds are a function of corner radius, 

with the range of increases in turning speed for corner radii between 15 and 70 ft being about 

4 mph. The larger the radius, the higher the turning speeds. The FHWA study generated a model 

that can be used to predict turning speeds. The model is available in the FHWA report.

(36) It 

includes the following variables: corner radius (range of 15 to 70 ft), headway to preceding 

vehicle, signal indication (yellow or green), vehicle type (truck or passenger car), and preceding 

vehicle movement (straight or turning). For example, assuming the preceding vehicle goes 

straight through the intersection with a 6-s headway to a passenger car that is turning right on a 

yellow indication, the range of median turning speed is 13.1 mph for a 15-ft corner radius to 

16.8 mph for a 70-ft corner radius. The range of 85th percentile speed with these assumptions is 

16.0 mph to 20.4 mph for corner radii of 15 to 70 ft.

Granitto in 2016 summarized the protected (innovative) treatment as having a design that 

prioritizes comfortable pedestrian and bicycle movement instead of fast car turning.

(37)

Summala et al. found that drivers’ visual scanning strategies when turning right are based on 

identifying vehicles coming from the left.(38)

 They compared their findings to the typical designs 

used at protected (innovative) intersection and noted that the corner islands create a bicycle 

queue area and place the bicyclists further forward in a more obvious position to drivers, while 

pedestrian islands provide some of the benefits of curb extensions. Bicyclists are not forced to 

merge into mixed traffic, have a dedicated path through the intersection, and have the 

right-of-way over the right-turn vehicles. Modifications to the design for large vehicles include 

mountable truck aprons with a separate corner radius.

(38)

 In 2021, Deliali, Christofa, and Knodler 

reported on a simulator study that examined right-turn driver performance with various bicycle 

infrastructure treatments.(39)

 They found a correlation between the presence of the protected 

(innovative) intersection elements and a higher rate of right glances at the intersection before the 

right turn.

Several driving simulators have been used to study protected intersections in general and corner 

islands specifically. Christofa et al. used a driving simulator to determine that forcing drivers 

further into the intersection causes slow turning by motor vehicles.(40) Warner et al. used a 

simulator to illustrate that smaller curb radii (10 ft versus 30 ft) positively influence crash 

avoidance and decrease potential crash severity by affecting motorist behavior through a

decrease in mean vehicle speed and reduction in speed variation.

(14)

 The study also found that the 

addition of green pavement markings was not shown to be consistently effective at positively 
14 

influencing driver behavior, while the presence of a bicyclist was associated with slower motorist 

speeds at protected intersections. Gilpin et al. recommend designing corners such that passenger 

car turning speeds are between 5 and 10 mph, using a corner radius of 20 ft (or larger depending 

on design vehicle) augmented with an apron that renders the effective radius to be 10–20 ft.(12) 

Bend-Out and Bend-In

The bend-out design moves the bicycle lane away from adjacent traffic at the intersection using a 

pedestrian refuge island, a key component of the protected intersection concept.(4) Figure 4

illustrates the shifting of the bicycle lane. The design can also be used in reverse to move 

bicyclists closer to motor vehicles at an intersection where such positioning provides added 

conspicuity for the bicyclists or where geometric constraints exist.

© 2015 Alta Planning + Design.

Figure 4. Illustration. Basic geometric elements and key dimensions of a protected 

intersection.(12) 
15 

Crosswalk Design

One modification to crosswalks at intersections to facilitate pedestrian safety is raising the 

crosswalk, effectively creating a speed hump. A case study by Candappa et al. found zebra 

markings on speed humps at a modified roundabout resulted in a speed reduction from 32.7 km/h 

to 30.7 km/h 30 m before the intersection and 17.6 km/h to 14.7 km/h 5 m from the intersection 

on weekdays (20.6 km/h to 17.9 km/h on weekends).

(41)

 Mohammadipour et al. found that the 

vehicle speed change from the approach to the crosswalk is larger on wider streets, and that the 

raised crosswalk is more effective when the difference between the road grade and crosswalk 

ramp grade is 4 percent or greater.

(42) Further study of raised crosswalks by Pratelli, Pratali, and 

Rossi found that the device was more effective at reducing speed as height increases, as well as 

when used in series rather than in isolation. They noted that the raised crosswalks are used in 

Italy at intersections and along corridors similar to speed humps.(43) Additionally, Gitelman et al.

found them to be associated with positive road-user behavior, particularly for motorists, when 

used on segments in conjunction with preceding speed humps.(44)

Another unique crosswalk design is to set back the crosswalks in a manner similar to the setback 

of bikeways, or have a bend-out and bend-in treatment. This design results in crosswalks that are

positioned approximately 20 ft back from the curb.(45) This positioning provides more space for 

vehicles that are turning and can reduce pedestrian conflicts with off-tracking vehicles and 

vehicles turning left against traffic. One downside of the design is that the path is less direct for 

pedestrians, so there may be a need for landscaping or a railing to guide pedestrians, and 

increased clearance time for vehicles needs to be provided. 

Curb Extensions

Conventional curb extensions are a recommended feature where there is onstreet parking, but the 

term defines a category of treatments including midblock pinch points, gateways to minor 

streets, chicanes (curb-based lateral alignment changes), and bus bulbs.(17) The category is also 

sometimes referred to as bulb-out or nubs.

(46) Fitzpatrick et al. stated that nubs permit buses to 

stop in a traffic lane without weaving around parked cars and provides additional waiting area 

for patrons.(46) Johnson conducted a case study and found that fewer vehicles pass a waiting 

pedestrian at uncontrolled intersections when curb extensions are present.(47) A study by Kang in 

New York, NY, found curb extensions to be effective at reducing the rate of pedestrian collisions 

after collision rates were adjusted for vehicle traffic volume.

(29) These extensions can impact 

drainage at a given location. Consequently, they can be designed as edge islands with a 

1- to 2-ft gap where drainage would be adversely impacted.

(17)

Shared Space and Pedestrian Plazas

As municipalities continue to emphasize nonmotorized road users, several ideas are emerging 

and gaining traction among traffic professionals. For example, rather than use pavement 

markings to dictate which road users should operate in specific areas, shared space intersections 

are designed with little to no lane markings and signing guidance to create traffic calming 

through ambiguity in mode assignment.(48) Another example of a novel idea is the pedestrian 

plaza, where areas formerly used by motor vehicles for travel and parking are converted into 

pedestrian space.

(49)

 Kang conducted a study of such facilities in New York, NY, and found 
16 

pedestrian plazas to be effective at reducing the rate of pedestrian collisions after collision rates 

were adjusted for vehicle traffic.

(29)

Bicycle Lane Designs

Several unique iterations of the bicycle lane have been developed at intersections to facilitate 

safe and efficient movement. Through bicycle lanes shift the bicycle lane between through and 

right-turning traffic at the intersection (as opposed to curbside). This treatment is also referred to 

as keyway and pocket (between the through and vehicle turn lane). NACTO noted that the 

presence of through bicycle lanes is associated with correct lane use rates of 87 percent for 

turning vehicles and 91 percent for bicyclists when turning vehicles have limited entry into the 

turning lane.

(16)

Combined bicycle lanes and turn lanes are similar to the through bicycle lanes but use less space. 

Right-turning vehicles and bicyclists queue and operate in the same space.

(16)

In wide curb lanes the lane nearest the curb is wider than a standard lane and provides space for 

motor vehicles and bicycles to share the lane.

(50)

 Hunter et al found that differences in signal 

compliance were less than 1 percent between bicycle lanes and wide curb lanes, while 

compliance at stop signs was much lower (80.6 percent of bicyclists obeyed stop signs at 

intersections with bicycle lanes versus 55.2 percent at wide curb lanes).(50)

Intersection Characteristics for Cars That May Help Pedestrians

Channelized right turn lanes are an intersection feature that uses a channelizing island to separate 

right-turning vehicles from through vehicles. Al-Kaisy and Roefaro examined why this device 

was used and the perceptions of its effectiveness through a survey.

(51)

 The researchers found that 

the device is primarily installed (and traffic control type determined) based on national and State 

guidelines and engineering judgment; the device is used to improve operations at locations with 

high right-turn volume. Additionally, mixed responses to surveys indicated that various survey 

respondents felt that they both improve and decrease pedestrian and motorist safety but are 

generally thought to improve both when used at signals.(51)

The continuous flow intersection, or more appropriately the displaced left turn intersection, is 

primarily designed for improving the safety and efficiency of motor vehicle travel. However, 

various documents have highlighted the ways it can be modified to improve pedestrian 

friendliness. For example, Bai and Li recommend that pedestrian refuge islands and signal 

optimization can provide superior service for pedestrians and vehicles, while a unique 

X-crossing design helps pedestrians at the expense of motorists.(52) Bonneson, Pratt, and 

Songchitruska documented the disadvantages of this design when pedestrians are present, noting 

a 20- to 40-percent increase in delay for vehicles at locations with low pedestrian volumes and a 

40- to 80-percent delay for intersections with high pedestrian volumes.(53)
17 

KEY TAKEAWAYS

The protected intersection is a combination of a suite of treatments, many of which have been 

examined as standalone safety features in the existing literature. However, the amount of 

literature dedicated to examining how these features function as a cohesive intersection design is 

limited. Additionally, although the protected (and dedicated) intersection is defined by the 

treatments used to reduce the curb radius, the effect of the islands and the bicycle lane taper on 

the approach as a chicane-like traffic calming feature for bicyclists has not been thoroughly 

examined.

The publication Lessons Learned: Evolution of the Protected Intersection recommends 

dimensions for various aspects of the protected intersection, including those shown in 

figure 4.

(12)

19 

CHAPTER 3. IDENTIFY CANDIDATE SITES

An initial effort in the project was to identify candidate treatments and study sites.

CREATING INITIAL REQUESTS FOR INFORMATION

With the relative newness of the protected intersection design in mind, the research team used 

several approaches to identify potential study sites, including: 

• Announcing the FHWA study at professional meetings and requesting leads on locations. 

• Using research team members’ and FHWA staff’s knowledge.

• Making calls to those regions with extensive bicycle networks. 

• Searching the internet for news articles that talked about the installation of bicycle 

treatments. Those leads were followed with emails or phone calls to the identified 

potential sites. 

IDENTIFYING POTENTIAL STUDY SITES

With the goal of conducting 15 before-after evaluations, a key component to choosing sites was 

to identify the study site before the treatment had been installed so that before data could be 

collected. The study was also bound by a fixed end date, so the installation of the treatment had 

to occur in sufficient time to permit adequate time to collect the after data, to conduct the 

analysis, and to complete the required study documentation before the end date of the contract. 

With these restrictions, a limited number of study sites were identified where both before data 

and after data could be collected in the contract limits. The remaining sites were either sites with 

existing treatments or sites that could serve as a comparison to nearby sites with existing 

treatments. 

CREATING THREE TYPICAL DESIGNS

Combining the findings from the literature with information provided by those installing relevant 

treatments resulted in the creation of three typical designs. Protected intersection designs provide 

dedicated paths through the intersection for pedestrians and bicyclists. The bikeway is set back 

from the parallel motor vehicle traffic, which makes bicyclists more visible to turning drivers 

than in a conventional intersection. Corner islands are a key feature of the design. They create a 

bicycle queue area after the crosswalk and provide a place for bicyclists to wait. The three 

scenarios developed in this study using protected intersection design concepts are provided in the 

following figures: 

• Figure 5, large intersection. 

• Figure 6, small intersection.

• Figure 7, quick build. 

21 

Source: FHWA.

Figure 5. Illustration. Large intersection with medians and bicycle lanes on all approaches.
22 

Source: FHWA.

Figure 6. Illustration. Small intersection with bicycle lanes on all approaches. 
23 

Source: FHWA.

Figure 7. Illustration. Small intersection with bicycle lanes on major approaches only. 

25 

SITE SELECTION

All of the identified sites where the implementation of protected intersection features was 

planned and where construction would be completed by the fall of 2021 were initially selected 

for study. These sites included two sites in Fremont (FRE), CA; one site in Silver Spring (SSP), 

MD; three sites in Washington (WAS), DC; and four sites in Austin (AUS), TX. Unfortunately, 

the start date for the construction at the four sites in Austin, TX, was shifted to the point where 

those sites were no longer viable for study. 

Since less than 15 sites were planned for changes in the period, the research team was instructed 

to identify sites with existing treatments along with nearby comparison sites. These sites were in 

Berkeley (BER), CA; Fremont, CA; College Station (CST), TX; and Salt Lake City (SLC), UT. 

The sites with existing treatments were assigned to one of the three typical design categories. 

Sites were removed from consideration or were given a lower priority if a two-way bicycle lane

was present, if the vehicle speed limit was low, or if a corner island was not present for all 

corners. The sites for study were selected during a panel meeting of the research team and 

FHWA. Table 1 lists the sites included in this project and involved 6 before-after sites (for 

12 site periods), 4 comparison sites (i.e., untreated intersections), and 12 existing (or treated) 

intersections. In most cases, the intersection traffic control was a signal with only 4 of the 

24 intersections having all-way stop control. All but one of the intersections had four legs. 

Table 1. Study sites selected for the project.

Site‒Period Condition Type Legs Control

CA‒BER‒01‒Exi Existing Traditional 4 Signal

CA‒FRE‒02‒Exi Existing Large 4 Signal

CA‒FRE‒03‒Exi Existing Large 4 Signal

CA‒FRE‒04‒Exi Existing Large 4 Signal

CA‒FRE‒05‒Com Compare Large 4 Signal

CA‒FRE‒05‒Exi Existing Large 4 Signal

CA‒FRE‒06‒Exi Existing Quick build 4 Signal

CA‒FRE‒07‒Com Compare Large 4 Signal

CA‒FRE‒07‒Exi Existing Quick build 3 Signal

CA‒FRE‒09‒Exi Existing Large 4 Signal

CA‒FRE‒11‒Bef or Aft Before-after Large 4 Signal

CA‒FRE‒12‒Bef or Aft Before-after Large 4 Signal

DC‒WAS‒01‒Bef or Aft Before-after Quick build 4 All-way stop

DC‒WAS‒02‒Bef or Aft Before-after Quick build 4 All-way stop

DC‒WAS‒03‒Bef or Aft Before-after Quick build 4 Signal

MD‒SSP‒01‒Exi Existing Traditional 4 Signal

MD‒SSP‒02‒Bef or Aft Before-after Traditional 4 Signal

TX‒AUS‒16‒Com Compare Large 4 Signal

TX‒AUS‒16‒Exi Existing Large 4 Signal

TX‒CST‒01‒Exi Existing Traditional 4 All-way stop

UT‒SLC‒01‒Com Compare Large 4 Signal

UT‒SLC‒01‒Exi Existing Traditional 4 Signal

UT‒SLC‒03‒Exi Existing Quick build 4 All-way stop

Bef = before; Aft = after; Exi = existing; Com = compare.
26 

Table 2 provides the posted speed limit (PSL) by approach for each study site. When the PSL

sign could not be identified, the value that was assumed based on State or city code is provided. 

The school speed limit value is also provided when present on the approach. All of the 

Washington, DC, sites, one Maryland site, and two California sites had PSLs of 25 mph on all 

approaches. Two of the Utah sites and one of the Texas sites had between 20 and 25 or 30 mph 

PSLs. Seven of the 24 sites had approaches with PSLs of 40 or 45 mph. 

Table 2. PSL by approach for each study site.

Site PSL-NB (mph) PSL-SB (mph) PSL-EB (mph) PSL-WB (mph)

CA‒BER‒01 25 25 25 25 

CA‒FRE‒01 25 30 (25 school) 35 (25 school) 35 

CA‒FRE‒02 30 30 35 35 

CA‒FRE‒03 25 25 35 35 

CA‒FRE‒04 25 (assumed) 25 (assumed) 25 25 

CA‒FRE‒05 35 35 30 30 

CA‒FRE‒05 35 35 35 30 

CA‒FRE‒06 35 Leg not present 40 45 

CA‒FRE‒07 35 Driveway 40 45 

CA‒FRE‒07 40 40 Ramp 45 

CA‒FRE‒09 25 (assumed) 25 40 40 

CA‒FRE‒11 35 40 35 35 

CA‒FRE‒12 35 40 35 35 

DC‒WAS‒01 25 (assumed) 25 25 (assumed) 25 (assumed)

DC‒WAS‒02 25 (assumed) 25 25 (assumed) 25 (assumed)

DC‒WAS‒03 25 (assumed) 25 (assumed) 25 25 (assumed)

MD‒SSP‒01 25 30 25 30 

MD‒SSP‒02 25 (assumed) 25 (assumed) 25 25 (assumed)

TX‒AUS‒16 35 35 35 (20 school) 35 (20 school) 

TX‒AUS‒16 40 (25 school) 40 (25 school) 40 35 

TX‒CST‒01 25 Driveway 30 20 

UT‒SLC‒01 25 25 (assumed) 20 20 

UT‒SLC‒01 25 25 20 20 

UT‒SLC‒03 30 25 25 25 

NB = northbound; SB = southbound; EB = eastbound; WB = westbound.
27 

CHAPTER 4. DATA COLLECTION

OVERVIEW OF DATA COLLECTION

A total of 24 unique site periods were studied with before-after data available for six of the 

24 intersections. Table 3 provides the data collection dates for each site period. 

Table 3. Dates data collected at each study site.

Site‒Period Intersection

Data Collection 

Date

CA‒BER‒01‒Exi Alameda Drive and Hopkins Avenue 8/31/21

CA‒FRE‒01‒Exi Walnut Avenue and Gallaudet Drive 9/1/21

CA‒FRE‒02‒Exi Walnut Avenue and Guardino Drive 8/30/21

CA‒FRE‒03‒Exi Walnut Avenue and Civic Center Drive 8/23/21

CA‒FRE‒04‒Exi Civic Center Drive and Bart Way 8/27/21

CA‒FRE‒05‒Com Walnut Avenue and Fremont Boulevard 8/24/21

CA‒FRE‒05‒Exi Walnut Avenue and Paseo Padre Parkway 8/25/21

CA‒FRE‒06‒Exi Cushing Parkway and Northport Loop W 8/18/21

CA‒FRE‒07‒Com Cushing Parkway and Fremont Boulevard 8/19/21

CA‒FRE‒07‒Exi Cushing Parkway and Northport Loop E 8/17/21

CA‒FRE‒09‒Exi Grimmer Boulevard and Wisdom Road 11/21/21

CA‒FRE‒11‒Aft Fremont Boulevard and Mowry Avenue 11/22/21

CA‒FRE‒11‒Bef Fremont Boulevard and Mowry Avenue 12/15/20

CA‒FRE‒12‒Aft Fremont Boulevard and Stevenson Boulevard 11/20/21

CA‒FRE‒12‒Bef Fremont Boulevard and Stevenson Boulevard 12/15/20

DC‒WAS‒01‒Aft 1st Street SE/Potomac Avenue and L Street 10/13/21

DC‒WAS‒01‒Bef 1st Street SE/Potomac Avenue and L Street 10/13/20

DC‒WAS‒02‒Aft 1st Street SE/Potomac Avenue and K Street 10/13/21

DC‒WAS‒02‒Bef 1st Street SE/Potomac Avenue and K Street 10/14/20

DC‒WAS‒03‒Aft K Street NE/NW and 5th Street 10/12/21

DC‒WAS‒03‒Bef K Street NE/NW and 5th Street 10/15/20

MD‒SSP‒01‒Exi Spring Street and 2nd Avenue 12/10/20

MD‒SSP‒02‒Aft Fenton Street and Cameron Street 6/7/22

MD‒SSP‒02‒Bef Fenton Street and Cameron Street 12/10/20

TX‒AUS‒16‒Com Escarpment Boulevard and Davis Street 6/21/21

TX‒AUS‒16‒Exi Escarpment Boulevard and La Crosse Avenue 6/21/21

TX‒CST‒01‒Exi Bizzell Street and Ross Street 1/26/22

UT‒SLC‒01‒Com Temple Street and Broadway Avenue 11/18/21

UT‒SLC‒01‒Exi Broadway Avenue (also known as 300 South) and 

200 West

11/17/21

UT‒SLC‒03‒Exi 700 South and 300 East 11/19/21

SE = southeast; NE = northeast; NW = northwest.
28 

Video from Cameras Installed for Study

For the Washington, DC, sites, the research team installed four video cameras on street light 

poles on either October 12 or October 13, 2020, to capture the before-modification condition. 

The installations occurred from October 20 to 22, 2021, for the after condition. Each camera 

covered one crosswalk at the intersection. Figure 8 shows the video from one of the cameras. 

Because one camera was needed for each approach, the number of hours of video data for 

Washington, DC, was much larger than for the sites with drone video data.

Source: FHWA. 

Figure 8. Photo. Example of video view for one of the cameras at DC‒WAS‒03‒Aft. 

Video from Rooftop Camera 

For the College Station, TX, site, a camera used to monitor traffic conditions on campus was 

used to collect the video data. The video for MD‒SSP‒02 used a mix of video taken by a drone 

and video recorded from the top story of a parking garage. Figure 9 provides an example of the 

video view from the rooftop camera.
29 

Source: FHWA. 

Figure 9. Photo. Example of view for rooftop camera at MD‒SSP‒02‒Aft. 

Video from Drone

For the remaining study site, video data were collected using a drone-mounted video camera.

The drone-enabled camera permitted the collection of all crosswalk data in one view. Figure 10

shows an example.

Source: FHWA. 

Figure 10. Photo. Example of view from the drone camera of CA‒FRE‒11‒Aft. 
30 

Sample Camera Views for Each Site

The following figures show the views from the video or a Google® EarthTM view when the angle 

of the video is such that an overview of the intersection is not presented:(54)

• Figure 11 provides a view from the video of CA‒BER‒01‒Exi.

• Figure 12 provides a view from the video of CA‒FRE‒01‒Exi.

• Figure 13 provides a view from the video of CA‒FRE‒02‒Exi.

• Figure 14 provides a view from the video of CA‒FRE‒03‒Exi.

• Figure 15 provides a view from the video of CA‒FRE‒04‒Exi. 

• Figure 16 provides a view from the video of CA‒FRE‒05‒Com.

• Figure 17 provides a view from the video of CA‒FRE‒05‒Exi.

• Figure 18 provides a view from the video of CA‒FRE‒06‒Exi.

• Figure 19 provides a view from the video of CA‒FRE‒07‒Com.

• Figure 20 provides a view from the video of CA‒FRE‒07‒Exi.

• Figure 21 provides a view from the video of CA‒FRE‒09‒Exi.

• Figure 22 provides a view from the video of CA‒FRE‒11‒Bef.

• Figure 23 provides a view from the video of CA‒FRE‒11‒Aft.

• Figure 24 provides a view from the video of CA‒FRE‒12‒Bef.

• Figure 25 provides a view from the video of CA‒FRE‒12‒Aft.

• Figure 26 provides a view from the video of DC‒WAS‒01‒Bef.

• Figure 27 provides a view from the video of DC‒WAS‒01‒Aft.

• Figure 28 provides a view from the video of DC‒WAS‒02‒Bef.

• Figure 29 provides a view from the video of DC‒WAS‒02‒Aft.

• Figure 30 provides a view from the video of DC‒WAS‒03‒Bef.

• Figure 31 provides a view from the video of DC‒WAS‒03‒Aft.

• Figure 32 provides a Google Earth aerial view of DC‒WAS‒03‒Bef.

• Figure 33 provides a Google Earth aerial view of DC‒WAS‒03‒Aft.

• Figure 34 provides a view from the video of MD‒SSP‒01‒Exi.

• Figure 35 provides a view from the video of MD‒SSP‒02‒Bef.

• Figure 36 provides a view from the video of MD‒SSP‒02‒Aft.

• Figure 37 provides a view from the video of TX‒AUS‒16‒Com.

• Figure 38 provides a view from the video of TX‒AUS‒16‒Exi.

• Figure 39 provides a Google Earth aerial view of TX‒CST‒01‒Exi.

• Figure 40 provides a view from the video of TX‒CST‒01‒Exi.

• Figure 41 provides a view from the video of UT‒SLC‒01‒Exi.

• Figure 42 provides a view from the video of UT‒SLC‒01‒Com.

• Figure 43 provides a view from the video of UT‒SLC‒03‒Exi.
31 

Source: FHWA. 

Figure 11. Photo. View from the video of CA‒BER‒01‒Exi. 

Source: FHWA. 

Figure 12. Photo. View from the video of CA‒FRE‒01‒Exi. 
32 

Source: FHWA. 

Figure 13. Photo. View from the video of CA‒FRE‒02‒Exi. 

Source: FHWA. 

Figure 14. Photo. View from the video of CA‒FRE‒03‒Exi. 
33 

Source: FHWA. 

Figure 15. Photo. View from the video of CA‒FRE‒04‒Exi. 

Source: FHWA. 

Figure 16. Photo. View from the video of CA‒FRE‒05‒Com. 
34 

Source: FHWA. 

Figure 17. Photo. View from the video of CA‒FRE‒05‒Exi. 

Source: FHWA. 

Figure 18. Photo. View from the video of CA‒FRE‒06‒Exi. 
35 

Source: FHWA. 

Figure 19. Photo. View from the video of CA‒FRE‒07‒Com. 

Source: FHWA. 

Figure 20. Photo. View from the video of CA‒FRE‒07‒Exi. 
36 

Source: FHWA. 

Figure 21. Photo. View from the video of CA‒FRE‒09‒Exi. 

Source: FHWA. 

Figure 22. Photo. View from the video of CA‒FRE‒11‒Bef. 
37 

Source: FHWA. 

Figure 23. Photo. View from the video of CA‒FRE‒11‒Aft. 

Source: FHWA. 

Figure 24. Photo. View from the video of CA‒FRE‒12‒Bef. 
38 

Source: FHWA. 

Figure 25. Photo. View from the video of CA‒FRE‒12‒Aft. 

Source: FHWA. 

Figure 26. Photo. View from the video of DC‒WAS‒01‒Bef, northbound.
39 

Source: FHWA. 

Figure 27. Photo. View from the video of DC‒WAS‒01‒Aft, northbound.

Source: FHWA. 

Figure 28. Photo. View from the video of DC‒WAS‒02‒Bef, northbound.
40 

Source: FHWA. 

Figure 29. Photo. View from the video of DC‒WAS‒02‒Aft, northbound.

Source: FHWA. 

Figure 30. Photo. View from the video of DC‒WAS‒03‒Bef, westbound.
41 

Source: FHWA. 

Figure 31. Photo. View from the video of DC‒WAS‒03‒Aft, westbound.

Original map: © 2019 Google® EarthTM.(54)

Note: Google Earth photo date is October 2019. 

Figure 32. Photo. DC‒WAS‒03‒Bef. 
42 

Original map: © 2022 Google® EarthTM.(54)

Note: Google Earth photo date is July 2022. 

Figure 33. Photo. DC‒WAS‒03‒Aft. 

Source: FHWA. 

Figure 34. Photo. View from the video of MD‒SSP‒01‒Exi. 
43 

Source: FHWA. 

Figure 35. Photo. View from the video of MD‒SSP‒02‒Bef. 

Source: FHWA. 

Figure 36. Photo. View from the video of MD‒SSP‒02‒Aft. 
44 

Source: FHWA. 

Figure 37. Photo. View from the video of TX‒AUS‒16‒Com. 

Source: FHWA. 

Figure 38. Photo. View from the video of TX‒AUS‒16‒Exi. 
45 

Original map: © 2022 Google® EarthTM.(54)

Note: Google Earth photo date is March 2022. 

Figure 39. Photo. TX‒CST‒01‒Exi. 

Source: FHWA. 

Figure 40. Photo. View from the video of TX‒CST‒01‒Exi. 
46 

Source: FHWA. 

Figure 41. Photo. View from the video of UT‒SLC‒01‒Exi. 

Source: FHWA. 

Figure 42. Photo. View from the video of UT‒SLC‒01‒Com. 
47 

Source: FHWA. 

Figure 43. Photo. View from the video of UT‒SLC‒03‒Exi. 

OVERVIEW OF DATA REDUCTION

Based on the review of the literature along with the engineering judgment of the research team 

and FHWA panel, the measures listed in table 4 were to be obtained from the videos.

Considering the measures shown in table 4, the research team developed a protocol for the data 

reduction. The technicians would watch each video and obtain the data listed in table 5 for each 

VU. Over 149 h of video (about 5 h per site period) were reduced.

Additional data reduction efforts used video analytics software to obtain details on right-turning 

speed and vehicle path for selected site periods. Details on those efforts are included in chapter 5. 
48 

Table 4. User behavior measures collected at the study sites.

Measure Measuring

Before-After 

Analysis

Comparison 

Analysis

Throughput (for 

bicyclists)

Number of bicyclists 

on the approach 

Did number of 

bicyclists increase 

from the before 

period to the after 

period?

Number of bicyclists 

per hour 

Driver yielding 

behaviors 

Driver yielding to 

crossing bicyclist or 

pedestrian

Change in percentage 

of driver yielding Descriptive statistics

Bicyclist yielding 

behaviors

Bicyclist yielding to 

pedestrian

Change in percentage 

of bicyclist yielding Descriptive statistics

Conflicts Conflicts between 

users Descriptive statistics Descriptive statistics

Typical pedestrians 

and bicyclists travel 

path

Number of users 

along specified travel 

path

Descriptive statistics Descriptive statistics

Where are 

pedestrians and 

bicyclists waiting?

Number of users 

waiting in specified 

locations

Descriptive statistics Descriptive statistics
49 

Table 5. Data collected from the video.

Heading Description of Data

Site Full site name.

Period What is the period type: Existing, Comparison, Before, or After?

File Name Video file name.

VU-TimeStamp Time VU appeared in video.

VU-CWLeg What leg was the VU crossing: North, South, East, or West?

VU Type What is the VU type: Pedestrian, Bicyclist, or Other (expand this list 

if skateboard or e-scooters are common for the intersection)?

VU-FromWhere Where was the VU when entering the field of view: Sidewalk, 

BikeLane, Street, CornerRefugeIsland, or Other?

VU-WaitArea Where did the VU wait: Sidewalk, Pedestrian Ramp, etc. (expand list 

as needed for site characteristics)?

VU-MoveType What was the VU movement: Through, Left, or Right?

VU-ToWhere Where did the VU go at end of crossing: Sidewalk, BikeLane, Street, 

or CornerRefugeIsland?

VU-StayInCWorCB 

Did the VU stay within the marked crosswalk or crossbike markings? 

Yes, Most, or No (use “Most” when the VU was not on the markings 

for a portion of the crossing)?

VehBikeEnterCWVUCrossingDid a vehicle or bicyclist enter the crossing during the VU crossing: 

No, Yes (Vehicle), or Yes (Bike)?

ConflictVehMan

If a vehicle or bicyclist enters the crossing during the VU crossing, 

what is the type of maneuver for entering vehicle or bicycle: 

Through, Left, or Right?

WhoYield 

If a vehicle or bicyclist enters the crossing during the VU crossing, 

who yielded: Pedestrian, Bicyclist, Veh, Both, Neither (e.g., the 

vehicle entered the crossing after the pedestrian has cleared the area), 

or Ped Should (use when the VU was crossing during the steady 

upraised hand phase)?

Conflict

Was there a conflict: Yes or No? (A conflict could be present if a 

user reacted to another user, e.g., a pedestrian stepped back because 

of an approaching bicyclist or vehicle. If yes, describe briefly in 

comment column.)

Comment Add comments that you want to bring to the attention of the rest of 

the team.

CW = crosswalk; CB = crossbike; Veh = vehicle.

51 

CHAPTER 5. OBSERVATIONS

VULNERABLE USERS

The research team collected data at a total of 30 site periods. The number of VU observed at 

each site is shown in table 6. More than 20,600 pedestrians and 2,454 bicyclists were observed. 

In addition, data for 332 scooters and 79 skateboards were gathered. The remaining 38 VU

observed were grouped into the other category and included pedestrians on roller skates, in a 

wheelchair, or on an e-scooter. The other category also included a lawn mower and mopeds. 

Because the number of minutes reduced per site varied, table 7 provides the number of 

VU per hour observed at the site period. A few sites had a very high number of pedestrians, with 

more than 300 per hour. The site with the highest number of bicycles per hour (TX–CST–01) 

was on a college campus.
52 

Table 6. Number of VU observed at each site. 

Site‒Period Pedestrians Bicycles Scooters Skateboards Other Total

CA‒BER‒01‒Exi 257 119 0 0 0 376

CA‒FRE‒01‒Exi 60 49 2 0 0 111

CA‒FRE‒02‒Exi 140 28 1 0 0 169

CA‒FRE‒03‒Exi 171 40 2 4 0 217

CA‒FRE‒04‒Exi 147 8 0 0 0 155

CA‒FRE‒05‒Com 106 55 1 0 0 162

CA‒FRE‒05‒Exi 183 82 3 0 0 268

CA‒FRE‒06‒Exi 85 24 0 0 0 109

CA‒FRE‒07‒Com 54 16 0 0 0 70

CA‒FRE‒07‒Exi 38 8 0 0 0 46

CA‒FRE‒09‒Exi 9 24 1 1 0 35

CA‒FRE‒11‒Bef 385 91 2 5 0 483

CA‒FRE‒11‒Aft 183 74 0 10 0 267

CA‒FRE‒12‒Bef 72 85 0 0 0 157

CA‒FRE‒12‒Aft 75 45 7 2 0 129

DC‒WAS‒01‒Bef 1,594 145 35 7 2 1,783

DC‒WAS‒01‒Aft 1,982 68 27 2 4 2,083

DC‒WAS‒02‒Bef 1,450 108 20 2 0 1,580

DC‒WAS‒02‒Aft 2,062 119 33 0 6 2,220

DC‒WAS‒03‒Bef 3,029 275 61 6 4 3,375

DC‒WAS‒03‒Aft 2,914 257 94 4 17 3,286

MD‒SSP‒01‒Exi 222 32 2 0 0 256

MD‒SSP‒02‒Bef 1,806 27 0 0 0 1,833

MD‒SSP‒02‒Aft 1,273 20 2 0 0 1,295

TX‒AUS‒16‒Com 184 52 0 0 1 237

TX‒AUS‒16‒Exi 106 140 0 0 0 246

TX‒CST‒01‒Exi 1,209 307 29 28 0 1,573

UT‒SLC‒01‒Com 332 59 4 1 4 400

UT‒SLC‒01‒Exi 358 54 5 6 0 423

UT‒SLC‒03‒Exi 116 43 1 1 0 161

Total 20,602 2,454 332 79 38 23,505
53 

Table 7. Number of VU per hour observed at each site.

Site‒Period

Reduced

(h)

Pedestrians 

(per h)

Bicycles

(per h)

Scooters

(per h)

Skateboards

(per h)

Other

(per h)

CA‒BER‒01‒Exi 4.2 61.4 28.4 0.0 0.0 0.0

CA‒FRE‒01‒Exi 4.2 14.3 11.7 0.5 0.0 0.0

CA‒FRE‒02‒Exi 4.7 30.0 6.0 0.2 0.0 0.0

CA‒FRE‒03‒Exi 4.0 43.0 10.1 0.5 1.0 0.0

CA‒FRE‒04‒Exi 5.3 27.9 1.5 0.0 0.0 0.0

CA‒FRE‒05‒Com 4.0 26.2 13.6 0.2 0.0 0.0

CA‒FRE‒05‒Exi 4.0 45.2 20.3 0.7 0.0 0.0

CA‒FRE‒06‒Exi 4.0 21.0 5.9 0.0 0.0 0.0

CA‒FRE‒07‒Com 4.4 12.2 3.6 0.0 0.0 0.0

CA‒FRE‒07‒Exi 4.0 9.4 2.0 0.0 0.0 0.0

CA‒FRE‒09‒Exi 4.0 2.2 6.0 0.2 0.2 0.0

CA‒FRE‒11‒Bef 7.1 53.9 12.7 0.3 0.7 0.0

CA‒FRE‒11‒Aft 4.2 43.9 17.7 0.0 2.4 0.0

CA‒FRE‒12‒Bef 5.3 13.7 16.1 0.0 0.0 0.0

CA‒FRE‒12‒Aft 4.1 18.1 10.9 1.7 0.5 0.0

DC‒WAS‒01‒Bef 6.8 236.0 21.5 5.2 1.0 0.3

DC‒WAS‒01‒Aft 6.9 288.4 9.9 3.9 0.3 0.6

DC‒WAS‒02‒Bef 6.8 214.7 16.0 3.0 0.3 0.0

DC‒WAS‒02‒Aft 7.6 271.4 15.7 4.3 0.0 0.8

DC‒WAS‒03‒Bef 6.4 475.3 43.2 9.6 0.9 0.6

DC‒WAS‒03‒Aft 6.2 467.4 41.2 15.1 0.6 2.7

MD‒SSP‒01‒Exi 4.7 47.7 6.9 0.4 0.0 0.0

MD‒SSP‒02‒Bef 5.3 340.1 5.1 0.0 0.0 0.0

MD‒SSP‒02‒Aft 4.1 313.5 4.9 0.5 0.0 0.0

TX‒AUS‒16‒Com 4.5 40.7 11.5 0.0 0.0 0.2

TX‒AUS‒16‒Exi 6.4 16.6 22.0 0.0 0.0 0.0

TX‒CST‒01‒Exi 4.0 302.3 76.8 7.3 7.0 0.0

UT‒SLC‒01‒Com 4.0 82.9 14.7 1.0 0.2 1.0

UT‒SLC‒01‒Exi 4.4 81.1 12.2 1.1 1.4 0.0

UT‒SLC‒03‒Exi 3.5 32.8 12.2 0.3 0.3 0.0

Table 8 shows the change in VU rates for the sites where before and after data are available. In 

addition to improving safety, convenience, and comfort for VU, it may be that, over time, the 

installation of the protected intersection treatments will encourage greater use and higher 

volumes of VU. Overall, pedestrians per hour between the two periods was similar. There was a 

slight decrease in the number of bicyclists and a slight increase in the number of scooters

between the two periods. For the two California sites, one experienced an increase in bicycle 

usage, while the other experienced a decrease in bicyclists per hour. The lack of a sizable 

increase in use may be influenced by only having a few months between the end of construction 

and the collection of after data. Also, the data represent an hourly basis, and daily, weekly, or 

annual use may possibly be higher. The attractiveness of the treatment may not yet be realized by 

the VU in the area.
54 

Table 8. Comparison of pedestrians, bicyclists, and scooters per hour for before-after sites.

VU Site

Before

(VU/h) 

After

(VU/h) 

Change

(VU/h) 

VU Increase

(percent)

Pedestrian CA‒FRE‒11 53.9 43.9 −10.0 −19 

Pedestrian CA‒FRE‒12 13.7 18.1 4.5 33 

Pedestrian DC‒WAS‒01 236.0 288.4 52.5 22 

Pedestrian DC‒WAS‒02 214.7 271.4 56.7 26 

Pedestrian DC‒WAS‒03 475.3 467.4 −7.9 −2 

Pedestrian MD‒SSP‒02 340.1 313.5 −26.6 −8 

Pedestrian All before-after sites 222.3 233.8 11.5 5 

Bicycle CA‒FRE‒11 12.7 17.7 5.0 39 

Bicycle CA‒FRE‒12 16.1 10.9 −5.2 −32 

Bicycle DC‒WAS‒01 21.5 9.9 −11.6 −54 

Bicycle DC‒WAS‒02 16.0 15.7 −0.3 −2 

Bicycle DC‒WAS‒03 43.2 41.2 −1.9 −4 

Bicycle MD‒SSP‒02 5.1 4.9 −0.2 −3 

Bicycle All before-after sites 19.1 16.7 −2.4 −12 

Scooters CA‒FRE‒11 0.3 0.0 −0.3 −100 

Scooters CA‒FRE‒12 0.0 1.7 1.7 NC

Scooters DC‒WAS‒01 5.2 3.9 −1.3 −24 

Scooters DC‒WAS‒02 3.0 4.3 1.4 47 

Scooters DC‒WAS‒03 9.6 15.1 5.5 58 

Scooters MD‒SSP‒02 0.0 0.5 0.5 NC

Scooters All before-after sites 3.0 4.3 1.3 42 

NC = not calculated as the before rate was 0.0 VU/h.

YIELDING BEHAVIORS AND POTENTIAL CONFLICTS

Overall, for this database, most of the VU did not have a vehicle enter their space during their 

crossing. As shown in table 9, 81 percent of the bicyclists and 67 percent of the pedestrians did 

not have a vehicle enter the crosswalk or crossbike marked area during their crossing. For all site

periods, pedestrians were more likely to interact with a vehicle (33 percent of the pedestrian 

crossings involved a vehicle) compared to bicyclists (19 percent of the bicyclist crossings).
55 

Table 9. Number of potential conflicts between VU and other traffic.

VU Type

Period 

Type 

VU 

Crossings 

without 

Vehicle or 

Bicyclist 

Entering

(count) 

VU 

Crossings 

without 

Vehicle or 

Bicyclist 

Entering

(percent)

VU 

Crossings 

with Vehicle 

or Bicyclist 

Entering

(count) 

VU 

Crossings 

with Vehicle 

or Bicyclist 

Entering

(percent) Total 

Bicyclist Compare 150 82 32 18 182

Bicyclist Before 585 80 146 20 731

Bicyclist After 768 80 190 20 958

Bicyclist Existing 483 83 100 17 583

Bicyclist Subtotal 1,986 81 468 19 2,454

Pedestrian Compare 439 65 237 35 676

Pedestrian Before 5,855 70 2,481 30 8,336

Pedestrian After 1,649 53 1,452 47 3,101

Pedestrian Existing 5,949 70 2,540 30 8,489

Pedestrian Subtotal 13,892 67 6,710 33 20,602

Both 

bicyclists and 

pedestrians

Grand 

total 15,878 69 7178 31 23,056

Table 10 provides the distribution of who yielded during the interaction between the VU and the 

vehicle or bicyclist that entered the crossing when the VU was crossing. In most cases the 

vehicle yielded to the pedestrian or bicyclist or neither yielded (situation occurred when the 

vehicle entered the crossing after the VU had departed that space). Another interpretation could 

be that the vehicle yielded to the pedestrian or bicyclist, in that the driver slowed or timed their 

passage to avoid the pedestrian or bicyclist. The technicians were instructed to use “Veh” for the 

“who yielded” field when the driver of the vehicle obviously yielded to the VU. 

Table 10. Number of interactions between the VU and a vehicle or bicyclist that enters the 

crossing, arranged by treatment presence and who yielded during the interaction.

VU Type

Who 

Yielded

Treated

(count) 

Treated

(percent) 

Untreated

(count) 

Untreated

(percent) 

Total 

(count) 

Total 

(percent) 

Bicyclist Bicyclist 34 12 7 4 41 9 

Bicyclist Both 15 5 29 16 44 9 

Bicyclist Neither 132 46 82 46 214 46

Bicyclist Veh 109 38 60 34 169 36

Bicyclist Subtotal 290 100 178 100 468 100

Pedestrian Both 286 7 339 12 625 9 

Pedestrian Neither 2,420 61 1,760 65 4,180 62

Pedestrian Pedestrian

should 238 6 131 5 369 5 

Pedestrian Pedestrian 125 3 55 2 180 3 

Pedestrian Veh 923 23 433 16 1,356 20

Pedestrian Subtotal 3,992 100 2,718 100 6,710 100
56 

The distribution was compared between the intersections with a protected intersection treatment 

(i.e., after condition and existing sites) and those intersections without (i.e., the before condition 

or the comparison sites). For treated sites, more vehicles yielded to bicyclists (38 percent for 

treated sites compared to 34 percent for untreated sites) and yielded to pedestrians (23 percent 

for treated sites compared to 16 percent for untreated sites).

The treatment is designed to slow turning vehicles and provide drivers additional opportunity to 

see the crossing VU. The addition of the treatment should result in more frequent yielding by 

drivers. For the before-after sites in Fremont, CA, and Silver Spring, MD, a greater percentage of 

the interactions did result in the vehicle yielding to the pedestrian. As shown in table 11, the 

percentage of vehicles that yielded to the crossing pedestrian increased for each of the signalized 

intersections (46 to 59 percent for CA‒FRE‒11, 48 to 57 percent for CA‒FRE‒12, and 

37 to 42 percent for MD‒SSP‒02). The number of pedestrians at the Silver Spring, MD, site was 

much higher and included several inappropriate crossings made outside of the crosswalk or 

during the steady upraised hand (do not walk) interval, resulting in situations where the 

pedestrian should have yielded. Overall, for these three signalized intersection sites, 41 percent 

of the pedestrian crossings in the before period involved the vehicle yielding, while an increase 

to 47 percent of the crossings in the after period involved the vehicle yielding to the pedestrian. 

Table 11. Who yields to a pedestrian at before-after sites in California or Maryland. 

Value Who Yields 

CA‒FRE‒11 CA‒FRE‒12 MD‒SSP‒02

All Three 

Sites

Before After Before After Before After Before After

Count Both 2 0 0 0 0 1 2 1 

Count Neither 128 48 21 24 150 66 299 138 

Count Pedestrian

should 8 6 2 1 98 161 45 15 

Count Pedestrian 6 0 0 1 39 14 108 168 

Count Veh 124 79 21 35 168 172 313 286 

Percent Both 1 0 0 0 0 0 0 0 

Percent Neither 48 36 48 39 33 16 39 23 

Percent Pedestrian

should 3 5 5 2 22 39 6 2 

Percent Pedestrian 2 0 0 2 9 3 14 28 

Percent Veh 46 59 48 57 37 42 41 47 

Count Total 268 133 44 61 455 414 767 608 

Table 12 shows the distribution of who yielded to the pedestrian at the Washington, DC, sites. 

These sites have lower speeds and heavy pedestrian and bicyclist activity. The DC‒WAS‒01 and 

‒02 sites are all-way stop control; therefore, with vehicles legally required to come to a complete 

stop before proceeding, logically there are fewer situations where a vehicle or a pedestrian would 

need to yield. In almost all cases, the technicians coded the interactions as having neither or both 

users yielding. An example of a scenario when neither yield is when a right-turning vehicle 
57 

enters the crosswalk after the pedestrian has cleared the area. DC‒WAS‒03 has a traffic control 

signal with only one observation where the pedestrian or vehicle obviously yielded to the other. 

Table 12. Who yields to pedestrian at before-after sites in Washington, DC. 

Value

Who 

Yields 

DC‒WAS‒01

All-Way Stop

DC‒WAS‒02

All-Way Stop

DC‒WAS‒03

Signal

All Three DC 

Sites

Before After Before After Before After Before After

Count Both 88 107 57 47 190 116 335 270 

Count Neither 301 619 253 427 822 610 1,376 1,656 

Count Pedestrian 2 5 1 0 0 0 3 5 

Count Veh 0 1 0 0 0 0 0 1 

Percent Both 23 15 18 10 19 16 20 14 

Percent Neither 77 85 81 90 81 84 80 86 

Percent Pedestrian 1 1 0 0 0 0 0 0 

Percent Veh 0 0 0 0 0 0 0 0 

Count Total 391 732 311 474 1,012 726 1,714 1,932 

TYPICAL TRAVEL PATHS—BICYCLISTS

The typical travel paths for bicyclists were identified at each site. These typical paths could start 

(or end) on the bicycle lane, the road (i.e., the portion of the street that was not the bicycle lane), 

or the sidewalk. 

Bicyclists Travel Paths for Before-After Sites

For the six before-after sites, most of the sites saw increased use of the bicycle lane-to-bicycle 

lane path from the before period to the after period, along with a decrease in the 

sidewalk-to-sidewalk path. See table 13 for specific numbers. The comparison included 1,314 

bicyclists. In the before period, only 13 percent of the observed bicyclists were riding from the 

bicycle lane to the bicycle lane. In the after period for these six sites, the percentage of bicyclists

riding from bicycle lane to bicycle lane increased to 52 percent. The percentage of the bicyclists 

moving from the sidewalk to the sidewalk decreased in the after period (from 21 percent of all 

bicyclists to only 12 percent in the after period). 
58 

Table 13. Bicycle paths at six before-after sites.

Value VU From Where VU To Where Before After

Count Bicycle lane Bicycle lane 95 303 

Count Bicycle lane Road 28 24 

Count Bicycle lane Sidewalk 11 47 

Count Road Bicycle lane 79 17 

Count Road Road 219 36 

Count Road Sidewalk 51 15 

Count Sidewalk Bicycle lane 35 61 

Count Sidewalk Road 58 11 

Count Sidewalk Sidewalk 155 69 

Percent Bicycle lane Bicycle lane 13 52 

Percent Bicycle lane Road 4 4 

Percent Bicycle lane Sidewalk 2 8 

Percent Road Bicycle lane 11 3 

Percent Road Road 30 6 

Percent Road Sidewalk 7 3 

Percent Sidewalk Bicycle lane 5 10 

Percent Sidewalk Road 8 2 

Percent Sidewalk Sidewalk 21 12 

Count All All 731 583 

Increased use of the crossbike or crosswalk markings is another way to identify the ways that 

bicyclists are using the space at the intersection. As shown in table 14, the use of the crossbike 

and crosswalk space increased at CA‒FRE‒11 (from 51 to 93 percent) and CA‒FRE‒12 (from 

18 to 84 percent). For the other two before-after signalized intersections (DC‒WAS‒03 and 

MD‒SSP‒02), bicyclists frequently either did not use the crossbike space or only used it for part 

of the crossing (coded as “most” for the question “did bicyclist stay within the crossbike or 

crosswalk area?”). For the two all-way stop controlled sites in Washington, DC (DC‒WAS‒01

and ‒02), the percentage of bicyclists who did not use the space available for bicyclists went 

from 74 or 81 percent no to only 18 or 13 percent no. In other words, bicyclists at the all-way 

stop-controlled intersections would more frequently use the crossbike marked area in the after 

condition. 
59 

Table 14. Bicyclists use of crossbike or crosswalk markings at before-after sites (Did 

bicyclists stay within the crossbike or crosswalk area?).

Site Period 

Type 

Yes 

(count) 

No 

(count) 

Most 

(count) 

Yes 

(percent)

No 

(percent)

Most 

(percent)

Total 

(count) 

CA‒FRE‒11 Before 46 23 22 51 25 24 91 

CA‒FRE‒11 After 69 1 4 93 1 5 74 

CA‒FRE‒12 Before 15 38 32 18 45 38 85 

CA‒FRE‒12 After 38 1 6 84 2 13 45 

DC‒WAS‒01 Before 10 107 28 7 74 19 145 

DC‒WAS‒01 After 24 12 32 35 18 47 68 

DC‒WAS‒02 Before 12 88 8 11 81 7 108 

DC‒WAS‒02 After 96 15 8 81 13 7 119 

DC‒WAS‒03 Before 133 94 48 48 34 17 275 

DC‒WAS‒03 After 69 95 93 27 37 36 257 

MD‒SSP‒02 Before 9 11 7 33 41 26 27 

MD‒SSP‒02 After 4 9 7 20 45 35 20 

Grand total Both 525 494 295 40 38 22 1,314 

The addition of the protected intersection treatment could encourage left-turning bicyclists to 

take advantage of the additional coverage provided by the corner islands. The number of 

left-turning bicyclists observed was small; therefore, conclusions on whether there were changes 

in paths cannot be made. For many of the before-after sites, several left-turning bicyclists were 

observed to start from the sidewalk even after the installation of the treatment. See table 15 for 

specific numbers. 

Table 15. Bicyclists starting position at before-after sites, subdivided by the type of 

intersection control. 

Value

From 

Where

All-Way 

Stop Before

All-Way 

Stop After

Signal

Before

Signal

After

Grand 

Total 

Count Bicycle lane 3 5 8 8 24 

Count Road 7 10 17 11 45 

Count Sidewalk 15 14 20 19 68 

Percent Bicycle lane 12 17 18 21 18 

Percent Road 28 34 38 29 33 

Percent Sidewalk 60 48 44 50 50 

Count All 25 29 45 38 137 

Bicyclists’ Travel Paths for Existing and Comparison Sites

Table 16 provides the distribution of the paths used by bicyclists at the existing and comparison 

sites, showing that bicyclists most often went from the bicycle lane to the bicycle lane, with a 

sizable number going from sidewalk to sidewalk (14 percent at existing sites and 19 percent at 

comparison sites).
60 

Table 16. Bicyclists starting and ending positions at existing and comparison sites.

Value From Where To Where Existing Compare Both

Count Bicycle lane Bicycle lane 506 102 608 

Count Bicycle lane Road 30 5 35 

Count Bicycle lane Sidewalk 76 11 87 

Count Road Bicycle lane 55 8 63 

Count Road Road 42 4 46 

Count Road Sidewalk 17 1 18 

Count Sidewalk Bicycle lane 81 15 96 

Count Sidewalk Road 19 1 20 

Count Sidewalk Sidewalk 132 35 167 

Percent Bicycle lane Bicycle lane 53 56 53 

Percent Bicycle lane Road 3 3 3 

Percent Bicycle lane Sidewalk 8 6 8 

Percent Road Bicycle lane 6 4 6 

Percent Road Road 4 2 4 

Percent Road Sidewalk 2 1 2 

Percent Sidewalk Bicycle lane 8 8 8 

Percent Sidewalk Road 2 1 2 

Percent Sidewalk Sidewalk 14 19 15 

Count All All 958 182 1,140 

Bicyclists’ Travel Paths by Movement Type 

The sites were regrouped to reflect whether the data represented whether the intersection was

treated (existing or after sites) or untreated (comparison or before sites). As shown in table 17, 

more bicyclists started their path from the bicycle lane when the intersection was treated

(64 percent) compared to untreated (28 percent). Table 18 provides the distribution by movement 

type. A greater proportion of each movement type started from the bicycle lane for the treated 

sites, with larger proportions being present for the right turns and through movements.

Table 17. Start of bicyclist path for treated and untreated sites.

Value From Untreated Treated Grand Total 

Count Bicycle lane 252 986 1,235 

Count Road 362 182 545 

Count Sidewalk 299 373 674 

Percent Bicycle lane 28 64 50 

Percent Road 40 12 22 

Percent Sidewalk 33 24 27 

Count All 913 1,541 2,454 
61 

Table 18. Start of bicyclist path by movement type for treated and untreated sites.

Value From

Left 

Untreated

Left 

Treated

Right

Untreated

Right

Treated

Through

Untreated

Through

Treated

Count Bicycle 

lane 16 77 8 15 228 891 

Count Road 30 58 7 3 325 122 

Count Sidewalk 40 58 7 7 252 310 

Percent Bicycle 

lane 19 40 36 60 28 67 

Percent Road 35 30 32 12 40 9 

Percent Sidewalk 47 30 32 28 31 23 

Count All 86 193 22 25 805 1,323 

BICYCLISTS BEHAVIORS WITH REGARD TO CORNER ISLANDS

A greater proportion of the bicyclist’s path through an intersection is separated from motorized 

vehicles with the presence of corner islands. At some sites, following the intended path results in 

longer travel time through the intersection, including having to slow to accommodate the 

bend-out and bend-in bicycle path that can be generated by the location of the corner island. 

Each bicyclist’s path with respect to the corner island was reviewed to determine if the bicyclists 

followed the intended path or if they bypassed the corner islands by moving into the travel lane. 

If the bicyclist was traveling in the opposite direction compared to the direction the bicyclists 

should be going in the neighboring bicycle lane, the bicyclist was coded as “Opp.” The 

remaining bicyclists were coded as either “To Left” or “To Right” with respect to the corner 

island. The path was coded as “To Left” when the bicyclist went to the left and bypassed the 

corner island. The path was coded as “To Right” when the bicyclist followed the marked 

crossbike area and went to the right of the corner island. 

With regard to sites with raised islands (table 19), most of the bicyclists (66 percent) did follow 

the marked path and went to the right of the corner islands. Sites where more than 40 percent of 

the bicyclists bypassed the corner island and went to the left included CA–FRE–09, 

MD–SSP–01, and MD‒SSP‒02. The bicyclists appeared to be seeking the shortest path for many 

of these cases. A high percentage of the bicyclists at these sites (22 percent overall) were 

traveling the opposite direction with respect to the bicycle lanes. In many cases, these bicyclists 

came from or were going to the sidewalk, perhaps to access a nearby development, and used the 

crosswalk for part of their crossing.
62 

Table 19. Bicyclist paths with respect to the corner island for sites with raised islands or a 

mix of raised islands and pylons. 

Site Period

To 

Left

(count) 

To 

Right

(count) 

Opp

(count) 

To Left

(percent)

To Right

(percent)

Opp

(percent)

Total

(count) 

CA–BER–01 Existing 31 81 7 26 68 6 119 

CA–FRE–01 Existing 4 41 4 8 84 8 49 

CA–FRE–02 Existing 2 25 1 7 89 4 28 

CA–FRE–03 Existing 1 32 7 3 80 18 40 

CA–FRE–04 Existing 0 5 3 0 63 38 8 

CA–FRE–05 Existing 0 75 7 0 91 9 82 

CA–FRE–09 Existing 10 13 1 42 54 4 24 

CA‒FRE‒11 After 1 47 26 1 64 35 74 

CA‒FRE‒12 After 3 30 12 7 67 27 45 

MD–SSP–01 Existing 14 17 1 44 53 3 32 

MD‒SSP‒02 After 11 4 5 55 20 25 20 

TX–AUS–16 Existing 8 89 43 6 64 31 140 

TX–CST–01 Existing 26 187 94 8 61 31 307 

UT–SLC–01 Existing 7 33 14 13 61 26 54 

All All 118 679 225 12 66 22 1,022 

To Left = bicyclist rode to left of corner island; To Right = bicyclist rode to right of corner island; Opp = bicyclist 

rode in the opposite direction as compared to the neighboring one-way bicycle lane. 

Table 20 provides the bicyclist paths for those sites where the corner island was created using 

pylons. Again, most of the bicyclists (58 percent) followed the marked path and went to the right 

of the corner island. A sizable number (17 percent) traveled in the opposite direction with respect 

to the bicycle lane or rode through the pylons (19 percent). 

Table 20. Bicyclist paths with respect to the corner island for sites with pylons.

Site Period

Thru

(count) 

To 

Left 

(count) 

To 

Right

(count) 

Opp

(count) 

Thru

(%) 

To 

Left

(%) 

To 

Right

(%) 

Opp

(%) 

Total

(count) 

CA–FRE‒06 Existing 1 0 23 0 4 0 96 0 24

CA‒FRE‒07 Existing 2 0 6 0 25 0 75 0 8 

DC‒WAS‒01 After 1 6 37 24 1 9 54 35 68

DC‒WAS‒02 After 5 9 91 14 4 8 76 12 119

DC‒WAS‒03 After 78 15 114 50 30 6 44 19 257

UT–SLC–03 Existing 10 1 30 2 23 2 70 5 43

All Both 97 31 301 90 19 6 58 17 519

Thru = bicyclist rode through the pylons; To Left = bicyclist rode to left of corner island; To Right = bicyclist rode 

to right of corner island; Opp = bicyclist rode in the opposite direction as compared to the neighboring one-way 

bicycle lane. 
63 

WAITING LOCATIONS

The locations where pedestrians and bicyclists waited were identified. In most cases, the 

pedestrian or bicyclist did not have to wait before crossing, especially for the all-way stop 

intersections. For all-way stop intersections, 95 percent of the VU did not wait before entering 

the crossing. While the details of State laws vary, for all-way stops the general rule is first come 

first served; however, when pedestrians wish to cross the road, they take priority over vehicles. 

In Washington, DC: “When official traffic-control signals are not in place or not in operation, the 

driver of a vehicle shall stop and give the right-of-way to a pedestrian crossing the roadway 

within any marked crosswalk or unmarked crosswalk at an intersection.”(55)

For the signalized intersections included in this evaluation, overall, 54 percent of the VU did not 

wait. Of those who waited, 44 percent waited on the ramp, 30 percent on the sidewalk, and 

10 percent on the corner island.

The two intersections that converted the right-turn lane to the protected intersection treatment 

had similar trends (CA‒FRE‒11 and ‒12; see table 21 for specific numbers). Most of the 

pedestrians who waited on the channelizing island in the before condition were now waiting in 

the pedestrian ramp area in the after condition. These pedestrians did not have to weave through 

the moving right-turning motorized vehicles to reach the refuge area where they stood and 

waited before crossing the intersection. Bicyclists also shifted from waiting on the right-turn lane 

corner island to waiting either on the pedestrian ramp or the bicycle lane ramp.

Table 21. Waiting area for bicyclists in before and after periods for CA–FRE–11 and 

CA–FRE–12. 

Wait Area

CA‒FRE‒11 CA‒FRE‒12 CA‒FRE‒11 CA‒FRE‒12

Before

(count)

After

(count)

Before

(count)

After

(count)

Before

(percent)

After

(percent)

Before

(percent)

After

(percent)

Bicycle 

lane 4 26 14 15 4 35 16 33 

Bicycle 

waiting 0 0 0 1 0 0 0 2 

Island 54 0 29 0 59 0 34 0

NA 17 21 30 16 19 28 35 36

Other 0 2 0 0 0 3 0 0

Pedestrian

ramp

0 24 0 13 0 32 0 29 

Road or 

CW or CB 15 1 11 0 16 1 13 0 

Sidewalk 1 0 1 0 1 0 1 0

All 91 74 85 45 100 100 100 100

NA = not applicable.
64 

Table 22. Waiting area for pedestrians in before and after periods for CA‒FRE‒11 and 

CA‒FRE‒12. 

Wait Area

CA‒FRE‒11 CA‒FRE‒12 CA‒FRE‒11 CA‒FRE‒12

Before

(count) 

After 

(count) 

Before

(count) 

After 

(count) 

Before

(percent) 

After 

(percent) 

Before

(percent) 

After 

(percent) 

Bicycle lane 0 2 0 2 0 1 0 3 

Bicycle 

waiting 0 4 0 0 0 2 0 0 

Island 309 15 67 4 80 8 93 5 

NA 65 26 1 6 17 14 1 8 

Other 0 4 0 2 0 2 0 3 

Ramp 1 129 0 61 0 70 0 81 

Road or CW

or CB 2 1 2 0 1 1 3 0 

Sidewalk 8 2 2 0 2 1 3 0 

All 385 183 72 75 100 100 100 100 

MOTORISTS RIGHT-TURN BEHAVIORS

This section provides observations on motorists right-turn behaviors such as the speed used when 

turning right. 

Speeds at Available Before-After Sites

The following sections contain details about the right-turn speed study. 

Study Site Characteristics

While video was used to collect user behaviors at all sites, the video cameras installed near the 

intersection, such as on mast arms, are not positioned so that right-turn speed could be measured. 

However, when drones were used, the speeds of right-turning vehicles could be gathered. Two 

California sites used drones and can provide data for before and after the installation of the 

treatment. Right-turn speed data, along with the associated vehicle type and headway, were 

reviewed for the two before-after sites where the free-flow, right-turn lane was replaced with 

protected intersection elements. The study team placed “gates” in the following locations for 

each intersection corner:

• On the approach to the turn. 

• At the corner of the intersection.

• Where the turning movement was completed. 

In instances where the starting or completion points were not captured in the video, the closest 

captured locations were selected. The study team attempted to place the gates in similar locations 

for the before and after periods. 

Figure 44 and figure 45 show assigned gates for before and after periods for CA‒FRE‒11. 

Similarly, figure 46 and figure 47 show gates for before and after periods for CA–FRE–12. The 
65 

orientation of the drone videos for before and after conditions were not similar, and the research 

team assigned gate names according to their geographic location rather than the location relative 

to the captured pictured frame.

Source: FHWA. 

Figure 44. Photo. CA‒FRE‒11 before-period gates. 

Source: FHWA. 

Figure 45. Photo. CA‒FRE‒11 after-period gates. 
66 

Source: FHWA. 

Figure 46. Photo. CA‒FRE‒12 before-period gates. 

Source: FHWA. 

Figure 47. Photo. CA‒FRE‒12 after-period gates. 

The resulting database from image processing (including vehicle type, vehicle speed, and 

headway at the three gates) was postprocessed to acquire the receiving lane for the turning 

vehicle. Vehicles turning into the farthest lane have a larger effective turning radius and can have 

a larger turning speed. Figure 48 illustrates the receiving lanes that were considered and included 

the bicycle lane (RBL), the parking lane (RPL), the inside vehicle lane (RVL1), the middle 

vehicle lane (RVL2), or the outside vehicle lane (RVL3).
67 

Original map: © 2022 Google® EarthTM(54), modified by FHWA (see Acknowledgments). 

Figure 48. Photo. Receiving lane names.

The turning radii and turn angle were obtained using measuring tools in Google Earth. Because 

the current Google Earth aerial view only reflected the before condition, the research team added 

an image overlay using a frame of the captured video. The captured videos’ viewing angles could 

be slightly different from the Google Earth Pro’s viewing angle, but the error introduced by this 

difference was negligible. Figure 49 shows an example of measuring the turning radius and 

table 23 shows the radii and turn angle for the study corners. 
68 

Original map: © 2022 Google® EarthTM(54), modified by FHWA (see Acknowledgements).

Figure 49. Photo. Measuring turning radius using Google Earth Pro. 

Table 23. Turning radii for intersection corners.

Site Period

East 

Leg 

Entry 

Radius 

(ft)

East Leg 

Entry 

Turn 

Angle 

(degree) 

North

Leg 

Entry 

Radius 

(ft)

North

Leg 

Entry 

Turn 

Angle 

(degree) 

South

Leg 

Entry 

Radius 

(ft)

South

Leg 

Entry 

Turn 

Angle 

(degree) 

West

Leg 

Entry 

Radius 

(ft)

West

Leg 

Entry 

Turn 

Angle 

(degree) 

CA‒FRE‒11 After 25 90 25 90 25 90 25 90

CA‒FRE‒11 Before 65 90 65 90 65 90 65 90

CA‒FRE‒12 After 30 105 22 75 25 90 25 90

CA‒FRE‒12 Before 120 119 60 69 65 90 60 90

Vehicle Speed Data

Speed and headway information were collected with a goal of having at least 30 right-turning 

vehicles at each intersection corner for each period (before and after). Table 24 shows the 

number of right-turn movements for each intersection corner. Upon review of the data, the 

research team decided to remove vehicles that were not identified as being a car from the 

evaluation due to small sample sizes for the other categories. Cars that turned into the bicycle 

lane (one car) or parking lane (seven cars) were also removed. 
69 

Table 24. Count of right-turning cars for study intersections. 

Site Site Leg Before (count) After (count)

CA‒FRE‒11 East leg entry 77 38 

CA‒FRE‒11 North leg entry 48 38 

CA‒FRE‒11 South leg entry 109 54 

CA‒FRE‒11 West leg entry 108 66 

CA‒FRE‒11 Subtotal for site 342 196 

CA‒FRE‒12 East leg entry 101 61 

CA‒FRE‒12 North leg entry 29 31 

CA‒FRE‒12 South leg entry 97 114 

CA‒FRE‒12 West leg entry 78 83 

CA‒FRE‒12 Subtotal for site 305 289 

Both sites Grand total 647 485 

Additional review of a sample of the data revealed that the signal indication for the right-turning 

vehicle was needed. Each right-turning vehicle was coded as having one of the following 

conditions: 

• Green: The signal indication on the approach was green. 

• Red: The signal indication on the approach was red. 

• Red-no conflict: The signal indication on the approach was red; however, the movement 

with the green did not generate conflicting vehicles. For example, when the north and 

south approaches had green for the left-turn movements, right-turning vehicles on the 

east and west approach would have a red indication but no conflicting vehicles. In this 

scenario, the right-turning vehicles on the north and south approach would be coded as 

“Red” since they would conflict with the left-turning vehicles. The vehicle was also 

coded as “Red” if the right-turning speed was influenced by a U-turning vehicle. 

Table 25 shows that, overall, the average right-turn speed during a green signal indication for 

cars turning into a travel lane went from 16.0 mph in the before period down to 13.3 mph in the 

after period. Another interesting trend shown in table 26 is that fewer right-turning vehicles 

turned during the red indications after the treatment was installed. For CA‒FRE‒11, the 

proportion that turned during the red indications went from 52 percent in the before condition to 

16 percent in the after condition. For CA‒FRE‒12, the change was 58 percent to 29 percent.
70 

Table 25. Average right-turn speed for before and after periods.

Signal 

Indication Site

Before

(count) 

Before

(average 

corner speed 

in mph)

After

(count) 

After

(average 

corner speed 

in mph) Count

Green CA‒FRE‒11 162 14.8 164 13.2 326 

Green CA‒FRE‒12 126 17.6 205 13.5 331 

Green

Total or 

weighted 

average speed

288 16.0 369 13.4 657 

Red CA‒FRE‒11 141 7.5 15 10.6 156 

Red CA‒FRE‒12 139 8.9 38 12.3 177 

Red

Total or 

weighted 

average speed

280 8.2 53 11.8 333 

Red-no 

conflict CA‒FRE‒11 35 11.6 16 9.7 51 

Red-no 

conflict CA‒FRE‒12 37 10.7 46 12.3 83 

Red-no 

conflict 

Total or 

weighted 

average speed

72 11.1 62 11.6 134 

All

Total or 

weighted 

average speed

640 12.0 484 13.0 1,124 

Table 26. Distribution of right-turning vehicles by signal indication.

Signal 

Indication

CA‒

Fre‒11‒

Before

(count) 

CA‒

FRE‒11‒

Before

(percent) 

CA‒

FRE‒11‒

After

(count) 

CA‒

FRE‒11‒

After

(percent) 

CA‒

FRE‒12‒

Before

(count) 

CA‒

FRE‒12‒

Before

(percent) 

CA‒

FRE‒12‒

After

(count) 

CA‒

FRE‒12‒

After

(percent) 

Green 162 48 164 84 126 42 205 71

Red 141 42 15 8 139 46 38 13

Red-no 

conflict 35 10 16 8 37 12 46 16

Grand total 338 100 195 100 302 100 289 100

Right-Turn Speeds at Entry, Corner, and Exit 

The study team collected speed values at the beginning (or entry), corner, and end (or exit) of the 

right turn. Figure 50 and figure 51 show the average speed of cars during a green signal 

indication at the entry, corner, and exit points of the turning movement for different turning radii 

and receiving lanes for the before and after periods, respectively. As illustrated in these plots and 

as expected, the corner speeds, as opposed to the entry or exit speeds, were the lowest speed, 

regardless of the receiving lane or turning radius. 
71 

Source: FHWA. 

Figure 50. Graph. Entry, corner, and exit right-turn speeds for vehicles turning on a green 

signal indication, based on turning radius and receiving lane, for the before period.

Source: FHWA. 

Figure 51. Graph. Entry, corner, and exit right-turn speeds for vehicles turning on a green 

signal indication, based on turning radius and receiving lane, for the after period. 

Comparison of Right-Turn Corner Speeds

When drivers turn into a lane other than the one nearest to the curb, they are increasing their 

effective radius. Therefore, the effective radius, or the receiving lane, needs to be considered. 

Table 27 shows that 89 percent of the right turns were into the nearest vehicle lane in the before 

period for CA‒FRE‒11 (free-flow, right-turn lane is present) when only 26 percent of the right 

turns turned into that lane in the after period. When multiple receiving lanes are available, the 
72 

data for these two sites show that drivers are more likely to use a larger radius when making the 

right turn.

Table 27. Count (or percent) of cars by site, period, and receiving lane.

Receiving 

Lane

CA‒

FRE‒11‒

Before

(count) 

CA‒

FRE‒11‒

Before

(percent) 

CA‒

FRE‒11‒

After

(count) 

CA‒

FRE‒11‒

After

(percent) 

CA‒

FRE‒12‒

Before

(count) 

CA‒

FRE‒12‒

Before

(percent) 

CA‒

FRE‒12‒

After

(count) 

CA‒

FRE‒12‒

After

(percent) 

RVL1 149 89 44 26 103 80 23 11

RVL2 17 10 86 50 24 19 120 58

RVL3 1 1 42 24 2 2 63 31

Grand 

total 167 100 172 100 129 100 206 100

Figure 52 shows box plots of the measured speeds at each corner for both the before and after 

periods. This graph illustrates another potential characteristic of the protected intersection 

design. Not only did the average speed drop compared to the before conditions (with one 

exception in CA‒FRE‒11 west leg), the range of speed also dropped. The box plot represents the 

interquartile range of the data, in other words the data between the lower quartile and the upper 

quartile. The solid bar represents the median value. As shown in figure 52, the boxes for the after 

periods are smaller than the boxes for the before period (except CA‒FRE‒12 north leg), 

indicating that vehicles turn right not only more slowly, but also in a more uniform manner. 

Source: FHWA.

Figure 52. Graph. Vehicle speeds at each intersection corner for study sites during before 

and after conditions.
73 

Linear Regression of Right-Turn Corner Speeds

The research team conducted a regression analysis to determine how the corner speed was 

impacted by the vehicle headway, corner radius, and receiving lane. The study team added the 

period, receiving lane, turning radius, and corner headways as independent factors to the model. 

The model was done using only cars (no motorcycles or heavy vehicles) that had a green signal 

when they arrived at the intersection and turned into vehicle receiving lanes (vehicles that turned 

into parking lanes or bicycle lanes were eliminated). Table 28 shows the estimates, standard 

deviations, t values, and p values for the parameters in the simple linear regression model. Cars 

turning into RVL1 were the base for the model. This study clearly showed that while turning 

radius has a positive correlation with turning speed, the target lane choice also impacts 

right-turning speed. 

Table 28. Linear regression parameters. 

Parameter Estimate Standard Error t Value p Value

After 10.23 0.434771 23.529 <0.0001

Before 10.32 0.723572 14.269 <0.0001

RVL2 1.34 0.366833 3.643 0.0003

RVL3 1.69 0.480656 3.506 0.0005

Turning radius 0.07 0.009203 7.803 <0.0001

Corner headway 0.01 0.005019 2.703 0.0071

Residual standard error: 3.22 on 597 degrees of freedom; Multiple R-squared: 0.9544; Adjusted R-squared: 0.9539; 

F-statistic: 2081 on 6 and 597 degrees of freedom, p value: <0.0001. 

The equation for right-turn speed is given in figure 53. The coefficient values for the equation in 

figure 53 are shown in table 28. Figure 54 shows the model functional form with the 

corresponding coefficient estimate values.

Figure 53. Equation. Median right-turn speed functional form.

Where: 

vRT = predicted median right-turn speed for vehicle of interest (mph).

βi = calibration coefficients.

IA = indicator for after period (1.0 for after period, 0.0 otherwise). 

IB = indicator for before period (1.0 for before period, 0.0 otherwise). 

IRVL2 = indicator for vehicle turning into RVL2 (1.0, 0.0 otherwise). 

IRVL3 = indicator for vehicle turning into RVL3 (1.0, 0.0 otherwise). 

R = corner turning radius (ft).

CH = corner headway (s).

Figure 54. Equation. Median right-turn speed functional form with coefficients.

Fitzpatrick et al. previously studied right-turn speeds at 31 urban intersections in TX.(36)

 The path 

(i.e., the receiving lane) followed by the vehicle during the turn was used to calculate the vehicle 
74 

speed and not included in the modeling efforts. Most of the vehicles turned into the nearest lane 

to the curb in that study. From those 31 Texas intersections, the variables that impact right-turn 

speeds included turning radii, vehicle type (car or trucks), signal indication at the time of arrival

(yellow or green), whether the preceding vehicle was going straight or turning right, and vehicle 

headway. 

Figure 55 compares the findings between this study and the Fitzpatrick et al. work.(36)

 The range 

of radii included in the Fitzpatrick et al. work was 15 to 70 ft, while the range of radii included in 

this evaluation was 22 to 120 ft. As shown in figure 55, the plot of the equation from both studies 

shows similar trends. The current study provided the opportunity to illustrate the difference in 

speeds between vehicles turning into different receiving lanes. The RVL2 and the RVL3 had 

significantly higher turning speed values. 

This evaluation demonstrated that a protected intersection results in reduced turning speeds with 

the installation of smaller corner radii.

Source: FHWA. 

Note: Lines with squares, diamonds, and triangles are for the current study. Lines with circles are for the Fitzpatrick 

et al. 2022 study.

Figure 55. Graph. Comparison of findings between this current study and the Fitzpatrick 

et al. 2022 study.(36)
75 

Sites with Apron Markings or Pylons 

A few of the sites included truck aprons, had pavement markings to simulate a truck apron, or 

included pylons, to assist in informing the motorist of the edge of the corner. The research team 

observed that some of the right-turning vehicles drove on the truck apron, which was not 

unexpected because the truck apron is provided in situations where the additional space is 

needed. Additional review was conducted for those sites with an apron or pylons. Table 29

summarizes the corner characteristics for the sites included in this review. For the 

MD–SSP–01–Exi site, all right-turning vehicles were visually reviewed to determine whether the 

vehicle drove on the apron. The type of vehicle was also identified. For the other sites, the 

trajectories for a sample of the available videos, generally about 15 min, were reviewed to count 

the number of vehicles that drove in the marked area.

Table 29. Characteristics of sites with truck apron or pylons with drone video available.

Site‒Period

Presence of Raised 

Truck Apron

Other Corner 

Characteristics

Presence of 

Pylons

CA‒BER‒01‒Exi No. 

Pavement markings and 

buttons create a flush 

truck apron on all four 

corners.

No. 

CA‒FRE‒06‒Exi No. 

Pavement markings 

create a flush truck 

apron.

Yes.

CA‒FRE‒07‒Exi No. 

Pavement markings in 

NW corner create a small 

flush truck apron.

Yes, on NE and 

NW corners.

MD‒SSP‒01‒Exi

Yes, raised apron 

present on all four 

corners.

No additional comments. No. 

MD‒SSP‒02‒Aft Yes, raised on SW 

corner.

Yellow raised markings 

are included on NE and 

SE corner that create a 

flush truck apron. White 

markings are included on 

NW corner.

Yes, on NE and 

SE corners.

UT‒SLC‒03‒Exi No No additional comments Yes.

NW = northwest; NE = northeast; SW = southwest; SE = southeast.

Note: Shaded cells with italic type represent the cells of greatest interest for evaluation.

In most cases, only a few of the vehicles used the apron when turning. As shown in Table 30

none of the observed vehicles used the raised or flush aprons at CA‒FRE‒06‒Exi, 

CA–FRE–07–Exi, or MD‒SSP‒02‒Aft. A screen capture of the trajectories for these three sites 

are shown in figure 56, figure 57, and figure 58, respectively.
76 

Table 30. Percentage of vehicles on the truck apron.

Site‒Period

Corners 

Considered

Vehicles 

on Apron 

(No.) 

Vehicles 

Outside 

Apron (No.) 

Total 

Vehicles 

(No.) 

Vehicles on 

Apron 

(percent) 

CA‒BER‒01‒Exi All 4 18 19 37 4 

CA‒FRE‒06‒Exi NE, NW 0 23 23 0 

CA‒FRE‒07‒Exi NE, NW 0 15 15 0 

MD‒SSP‒01‒Exi All 4 97 448 545 18 

MD‒SSP‒02‒Aft All 4 0 11 11 0 

UT‒SLC‒03‒Exi All 4 4 16 20 20 

NE = northeast; NW = northwest.

Source: FHWA.

Figure 56. Photo. Trajectories of all vehicles for a 4-min, 47-s interval at CA‒FRE‒06‒Exi.
77 

Source: FHWA.

Figure 57. Photo. Trajectories of all vehicles for a 4-min, 47-s interval at CA‒FRE‒07‒Exi.

Source: FHWA.

Figure 58. Photo. Trajectories of all vehicles for a 5-min, 01-s interval at MD‒SSP‒02‒Aft.
78 

Several of the right-turning vehicles at UT‒SLC‒03‒Exi drove on the area of the intersection 

marked with green markings (the area located behind the island). For the period reviewed, 

approximately 20 percent of the vehicles drove either on the area with green markings or on the 

area marked as an island (area looks tan in the example shown in figure 59). 

Source: FHWA.

Figure 59. Photo. Trajectories of all vehicles for a 4-min, 47-s interval showing some 

vehicles driving inside the bottom left pylons (on the bicycle area) in UT‒SLC‒03‒Exi

study site. 

About half of the right-turning vehicles (18 of 37 right-turning vehicles) at CA‒BER‒01‒Exi

drove on the flush truck apron. Examples are shown in figure 60. 
79 

Source: FHWA. 

Figure 60. Photo. Trajectories of all vehicles for a 4-min, 47-s interval showing some 

vehicles driving inside the raised pavement markers and solid white line for the truck 

apron at CA–BER–01–Exi. 

The MD‒SSP‒01‒Exi site has raised truck aprons, and, overall, about 18 percent of the turning 

vehicles use the truck apron. Several large vehicles were present at the intersection with about 

half of these larger vehicles using the truck apron. Table 31 provides the number or percentage 

of right-turning vehicles using the truck apron at MD–SSP–03–Exi by vehicle type. Figure 61

shows an example of a city bus using the truck apron space during the right turn. The intersection 

was designed to accommodate the needs of these larger turning vehicles, including placing the 

stop bar further upstream of the intersection so that the larger vehicles have space to complete 

their turn.
80 

Table 31. Number or percentage of right-turning vehicles using the truck apron at 

MD–SSP–03–Exi. 

Vehicle Type

Vehicles 

Not Using 

Apron

(No.) 

Vehicles Not 

Using Apron

(percent) 

Vehicles 

Using Apron

(No.) 

Vehicles 

Using Apron

(percent) 

Total 

Vehicles 

(No.) 

Car, passenger 414 86 70 14 484 

City bus 24 73 9 27 33 

Concrete truck 1 25 3 75 4 

Garbage truck 0 0 2 100 2 

Large truck 0 0 2 100 2

Motorcycle 2 100 0 0 2 

Two-axle truck 7 39 11 61 18 

Grand total 448 82 97 18 545 

Source: FHWA. 

Figure 61. Photo. Example of a city bus turning right at the southwest corner at 

MD–SSP–01–Exi. 
81 

Motorists Turning on Bicycle Queue Area

A behavior of concern that was observed was motorized vehicles turning across the marked 

bicyclist queuing or waiting area. This behavior was observed at 4 intersections, with most of the 

observed behaviors (41 of 58) at a site with pylons rather than the sites with raised islands 

(table 32). All of these situations involved a vehicle turning right except in the site with pylons, 

where one of the occurrences involved a utility vehicle turning left.

Table 32. Number of vehicles observed on marked bicyclist waiting area. 

Site‒Period Treatment Car Van or Utility Vehicle Motorcycle Grand Total

CA‒BER‒01‒Exi Raised island 3 0 0 3

CA‒FRE‒11‒After Raised island 9 0 2 11

TX‒CST‒01‒Exi Raised island 0 0 3 3

UT‒SLC‒03‒Exi Pylons 33 8 0 41

Grand total Either 46 8 5 58

For the CA‒FRE‒11‒Aft site, the previous right-turn lanes were converted into space for VU. 

The observed drivers may still be adjusting to the new lane usage. The three drivers at 

CA‒BER‒01‒Exi moved into the space at low speeds, perhaps being confused as to where they 

needed to be to complete a right turn. All of the motor vehicles in the bicycle queue area at 

TX‒CST‒01‒Exi were motorcycles.

The UT‒SLC‒03‒Exi intersection has the onstreet parking lane next to the curb, with the bicycle 

lane between the onstreet parking lane and the travel lane (figure 62). Mixed messages may be 

present for drivers as to where they should be positioned during a right turn because drivers have 

to move through the bicycle lane to access the onstreet parking and because of the presence of 

no-parking markings. In addition, the width of the green marked area is wide enough for cars to 

enter. Figure 62 and figure 63 show an example of a white car entering and leaving, respectively, 

the marked bicyclist queue area.
82 

Source: FHWA. 

Figure 62. Photo. Right-turning car (white) entering the green marked bicycle queue area 

at UT‒SLC‒03‒Exi. 

Source: FHWA. 

Figure 63. Photo. Right-turning car (white) leaving the green marked bicycle queue area at 

UT‒SLC‒03‒Exi. 
83 

CHAPTER 6. CONCLUSIONS

SUMMARY

Traffic professionals are exploring innovative intersection designs to determine if they can 

successfully accommodate multimodal transportation by reducing conflicts between moving 

vehicles and VU or by lowering the impact force (reducing the vehicle speed and changing the 

collision angle in the event of a collision). The term protected intersection is used in this report. 

The objective of this FHWA project was to investigate the operational and safety improvements 

of innovative intersection retrofitting designs that benefit pedestrians and bicyclists while 

maintaining a reasonable service to motor vehicles. The project included summarizing previous 

research efforts, developing three design types, identifying potential study sites (both 

before-after and comparison-existing sets), and collecting in-field operational behaviors of the 

users.

With the goal of conducting 15 before-after evaluations, a key component was to identify the 

study sites before the treatment had been installed so that before data could be collected. The 

research study was also bound by a fixed end date, so the installation of the treatment had to 

occur in sufficient time to permit adequate time to collect the after data, to conduct the analysis, 

and to complete the required study documentation before the end date of the contract. With these 

restrictions, six study sites were identified where both before data and after data could be 

collected within the contract limits. These 6 sites represented 12 site periods, resulting in a need 

of 18 additional site periods. The remaining intersections to be selected either already had the 

treatment (14 intersections) or served as a comparison to nearby sites with existing treatments 

(4 intersections). For each site period, data were collected using video obtained either from 

installing cameras on a pole or on a rooftop at the site, or from drones. Because identifying VU

with software to process the video was not sufficiently accurate, technicians watched the video 

and recorded user behaviors. Behaviors for 23,505 users were recorded for the 30 site periods.

KEY OBSERVATIONS

The key observations from this research effort included the following: 

• Overall, pedestrians were more likely to interact with a vehicle (33 percent of the 

pedestrian crossings involved a vehicle) compared to bicyclists interacting with a vehicle 

(19 percent of bicyclist crossings).

• Drivers yielded to bicyclists and pedestrians more at the treated sites compared to the 

untreated sites. For bicyclist crossings, 38 percent of the crossings for treated sites 

compared to 34 percent for untreated sites involved a vehicle yielding to the bicyclist. For 

pedestrian crossings, the comparison is 23 percent for treated sites compared to 

16 percent for untreated sites.
84 

• The treatment is designed to slow turning vehicles and provide drivers additional 

opportunity to see the crossing VU. The addition of the treatment at three of the 

before-after sites with traffic control signals resulted in more frequent yielding by drivers 

to pedestrians (41 percent in the before period to 47 percent in the after period). 

• For the six before-after sites, the percentage of bicyclists riding from the bicycle lane to 

the bicycle lane increased from 13 percent to 52 percent, while the percent riding from 

the sidewalk to the sidewalk decreased from 21 percent to 12 percent. More of the 

bicyclists were in the space designed for their use after the treatment was installed.

• Corner islands separate a greater proportion of the bicyclist’s path through an intersection 

from motorized vehicles. At some sites, following the intended path results in longer 

travel time through the intersection, including slowing to accommodate the bend-out and 

bend-in bicycle path in that can be generated by the location of the corner island. With 

regard to sites with raised islands, most of the bicyclists (66 percent) did follow the 

marked path and went to the right of the corner islands. For those sites where the corner 

island was created using pylons, again, most of the bicyclists (58 percent) followed the 

marked path and went to the right of the corner island. However, a sizable number rode 

through the pylons (19 percent). 

• Bicyclists may want to go in the opposite direction along a street and appear to be doing 

so at protected intersections by using the sidewalks or crosswalks rather than the bicycle 

lane or green marked waiting area. 

• In some cases, bicyclists are leaving the bicycle lane and entering the sidewalk to use the 

pedestrian push button. 

• The two intersections that converted the right-turn lane to the protected intersection

treatment had similar trends. Most of the pedestrians who waited on the channelizing 

island in the before condition were now waiting in the pedestrian ramp area in the after 

condition. These pedestrians did not have to weave through the moving right-turning 

motorized vehicles to reach the refuge area where they waited before crossing the 

intersection.

• Right-turn speeds are higher at corners with a larger corner radius. The receiving lane for 

the right-turning vehicle also influences the right-turn speed, with drivers turning faster to 

the lane that is the furthest from the curb.
85 

• The right-turn speeds were compared before and after the installation of the protected 

intersection treatment at two California sites. The results are as follows: 

o With the decrease in corner radius from the before to the after period with the 

installation of the protected intersection, the average right-turn speeds decreased. For 

example, a corner being changed from a 60-ft radius to a 25-ft radius is predicted to 

have about a 2.6 mph decrease in speed. 

o In addition, the range of turning speeds in the period after the treatment was installed 

was smaller compared to the before period for most of the corners. In other words, the 

addition of the protected intersection treatment is also associated with fewer drivers 

turning at high right-turn speeds.

o The inclusion of truck aprons can facilitate the turning of large vehicles while also 

encouraging smaller radius turns for right-turning vehicles. 

FUTURE RESEARCH NEEDS

This research study investigated users’ behaviors while moving through a protected intersection. 

The following additional research could increase the profession’s understanding of the value of 

these types of intersection forms:

• Document the benefits in having a network of protected intersections, especially with 

respect to increased demand.

• Examine the types of crashes associated with these types of intersections, including the 

development of a crash modification factor once a sufficient sample size is available 

(number of sites and number of years of after data).

• Explore the influence of signal phasing and timing on yielding behaviors and conflicts. 

• Explore the use of bicycle signals with this type of treatment.

• Investigate the safety and operations of protected intersection elements with two-way 

bikeways. 

87 

ACKNOWLEDGMENTS

The original maps in figure 48 and figure 49 are the copyrighted property of Google® EarthTM 

and can be accessed from https://www.google.com/earth. Labels and arrows were added to 

figure 48. Lines showing the turning radius were added to figure 49. 

89 

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Recommended citation: Federal Highway Administration, 

Safety Evaluations of Innovative Intersection Designs for Pedestrians and Bicyclists 

(Washington, DC: 2023) https://doi.org/10.21949/1521997