Research Report: Street Lighting for 

Pedestrian Safety

FHWA Safety Program

http://safety.fhwa.dot.gov
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TECHNICAL REPORT DOCUMENTATION PAGE

1. Report No.

FHWA-SA-20-062

2. Government Accession No.

No.

3. Recipient’s Catalog No.

4. Title and Subtitle

Research Report: Street Lighting for Pedestrian Safety

5. Report Date

December 2020

6. Performing Organization Code:

7. Author(s)

Travis Terry

Ronald Gibbons

Andrew Kassing

Rajaram Bhagavathula

Charlotte Lowdermilk

Paul Lutkevich, WSP

8. Performing Organization Report No.

9. Performing Organization Name and Address

Virginia Tech Transportation Institute

3500 Transportation Research Plaza

Blacksburg, VA 24060

10. Work Unit No.

11. Contract or Grant No.

DTFH6116D00004L

12. Sponsoring Agency Name and Address

Office of Safety

Federal Highway Administration

6300 Georgetown Pike

McLean, VA 22101-2296

13. Type of Report and Period Covered

Technical Report

9/19/2018 - 12/18/2020

14. Sponsoring Agency Code

15. Supplementary Notes

The Contracting Officer’s Representatives were Joseph Cheung, Tamara Redmon and Wesley Blount, Office of

Safety

16. Abstract

This document details three separate experiments that coalesce to form pedestrian lighting recommendations that

consider the visibility needs of both children and adults. In the first study, participant drivers were evaluated on

their ability to detect the presence of child-sized pedestrians under variations of luminaire type (2200 K, 4000 K,

and 5000 K), mounting height (road scale and ped scale), as well as variations in luminance and illuminance of the

visual target. A second experiment evaluated the ability for walking pedestrians (adults and children) to detect

hazards in their path under the same lighting conditions used in the first experiment. The final experiment

evaluated the abilities of adults and children to determine when it would be no longer safe to cross a mid-block

crosswalk as vehicles approach under varying lighting conditions. The outcomes of this research are presented as

recommendations for crosswalk lighting design to include considerations for children, depending on pedestrian

volume and road class.

17. Key Words

Pedestrians, lighting, safety, lighting

recommendations, children

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 22. Price

N/A

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

TABLE OF CONTENTS

EXECUTIVE SUMMARY .................................................................................................... XI

INTRODUCTION.....................................................................................................................1

PEDESTRIAN SAFETY..............................................................................................................1

SAFE ROUTES TO SCHOOL ......................................................................................................4

OBJECTIVE OF RESEARCH.......................................................................................................5

REVIEW OF EXISTING LITERATURE...............................................................................7

PEDESTRIAN VISIBILITY .........................................................................................................7

Hazards for the Pedestrian — Slips, Trips, and Falls........................................................7

PEDESTRIAN LIGHTING AT INTERSECTIONS .............................................................................9

SAFETY EFFECTS OF LIGHTING AT MIDBLOCK CROSSWALKS .................................................10

URBAN VERSUS RURAL CONSIDERATIONS..............................................................................12

SPECIAL PEDESTRIAN LIGHTING FOR CHILDREN....................................................................12

LITERATURE SUMMARY .......................................................................................................13

RESEARCH METHOD..........................................................................................................14

DRIVING AND DETECTION EXPERIMENT (DRIVER EXPERIMENT) ............................................14

Driver Experiment Procedure ........................................................................................15

PEDESTRIAN WALKING AND DETECTION EXPERIMENT (WALKER EXPERIMENT).....................17

Walker Experimental Design and Procedure..................................................................18

Walker Experiment Procedure .......................................................................................18

PEDESTRIAN CROSSWALK GAP ACCEPTANCE EXPERIMENT (GAP EXPERIMENT).....................19

Gap Acceptance Experimental Design and Procedure....................................................19

Gap Experiment Procedure ............................................................................................20

RESULTS DISCUSSION IN BRIEF......................................................................................22

SEMI-CYLINDRICAL AND VERTICAL ILLUMINANCE................................................................22

DRIVER EXPERIMENT ...........................................................................................................22

WALKER EXPERIMENT .........................................................................................................26

GAP ACCEPTANCE EXPERIMENT ...........................................................................................27

LIGHTING RECOMMENDATIONS ...................................................................................30

LIGHTING FOR PEDESTRIAN AREAS.......................................................................................30

CROSSWALK LIGHTING.........................................................................................................30

LUMINAIRE HEIGHT .............................................................................................................30

RECOMMENDATIONS ............................................................................................................31

OTHER CONSIDERATIONS .....................................................................................................31

DESIGN AND VERIFICATION APPROACH ................................................................................32

CONCLUSION .......................................................................................................................33

REFERENCES........................................................................................................................34

APPENDICES.........................................................................................................................39

APPENDIX A: LIGHTING DESIGN METRICS ............................................................................39

Illuminance....................................................................................................................39

Luminance.....................................................................................................................40
vi

Contrast.........................................................................................................................41

APPENDIX B: INDEPENDENT VARIABLES ...............................................................................43

Driver Experiment Independent Variables.....................................................................43

Walker Experiment Independent Variables....................................................................46

Gap Acceptance Independent Variables.........................................................................48

APPENDIX C: VEHICLES AND EXPERIMENTAL AREA ..............................................................49

Vehicles ........................................................................................................................49

Experimental Area.........................................................................................................49

APPENDIX D: ANALYSIS AND DISCUSSION OF EXPERIMENTAL RESULTS.................................51

Semi-cylindrical versus Vertical Illuminance.................................................................51

Driver Experiment Results.............................................................................................53

Walker Experiment Results ...........................................................................................57

Gap Experiment Results ................................................................................................61

APPENDIX E: LIGHTING DESIGN EXAMPLES ..........................................................................63

Example A: Low/Medium Pedestrian Volume...............................................................63

Example B: High Pedestrian Volume / School Zone (Rural-Suburban)..........................65

Example C: High Pedestrian Volume / School Zone (Urban).........................................67

Example D: Urban Roadway .........................................................................................69

APPENDIX F: FIGURE SOURCE LIST.......................................................................................71
vii

LIST OF FIGURES

Figure 1. Example of a SRTS traffic improvement project as reported by Commission 

Internationale de l'Éclairage (2010)................................................................................5

Figure 2. Top six occupational injuries in the United States in 2017 (National Safety 

Council, 2017)...................................................................................................................8

Figure 3. Wheel stop in a parking lot (Bhagavathula and Gibbons, 2019) .............................9

Figure 4. Increase in detection distance with increase in vertical illuminance on the 

pedestrians as reported by C. Edwards and Gibbons (2008).......................................11

Figure 5. Diagram of driver experiment procedure ..............................................................16

Figure 6. Cylindrical tube and child-sized mannequin..........................................................17

Figure 7. Walker experiment method ....................................................................................19

Figure 8. Gap experiment setup .............................................................................................21

Figure 9. Age by detection distance per lap ...........................................................................23

Figure 10. Detection distance by semi-cylindrical illuminance for each light type (ped 

scale, road scale).............................................................................................................24

Figure 11. Luminance (cd/m2) and illuminance (lux) across detection distance (m) ...........25

Figure 12. Detection distance for rural highway by light type and luminance.....................26

Figure 13. Detection distance by light type and luminance ...................................................27

Figure 14. Crossing acceptance distance for gap experiment by age and light type ............28

Figure 15. Crossing acceptance distance for gap experiment by age group .........................29

Figure 16. Calculation and Verification Grid Layout............................................................32

Figure 17. Illuminance measurement diagram ......................................................................40

Figure 18. Negative and positive and contrast (Gibbons, Edwards et al. 2008)....................42

Figure 19. View of child-sized mannequin under each SPD..................................................43

Figure 20. Spectral Power Distribution of luminaires; relative irradiance spectral 

content normalized for 6.27 lux.....................................................................................44

Figure 21. Urban environment for driver experiment (mannequin highlighted with 

green outline) .................................................................................................................45

Figure 22. Comparison of pedestrian- and road-scale mounting heights .............................46

Figure 23. Tripping hazards...................................................................................................47

Figure 24. Diagram of Walker Experiment lanes and target positions.................................48

Figure 25. Smart Road test area.............................................................................................50

Figure 26. Comparison of illuminance methods (Konica Minolta T-10 versus Everfine 

Photo-2000EZ Semi-Cylindrical). .................................................................................51
viii

Figure 27. Detection distance by illuminance per measurement method..............................52

Figure 28. Spatial comparison of illuminance methods (vertical illuminance versus 

semi-cylindrical illuminance) ........................................................................................53

Figure 29. Detection distance by semi-cylindrical illuminance for each light type 

(2200 K, 4000 K, 5000 K LEDs).....................................................................................54

Figure 30. Detection distance by luminance (cd/m2) per lap for first two laps of the 

driver experiment ..........................................................................................................55

Figure 31. Detection distance by illuminance per measurement method for laps 1 and 

2 ......................................................................................................................................56

Figure 32. Detection distance for urban environment by light type and luminance ............57

Figure 33. Horizontal and vertical illuminance (lux) and detection distance (m) by 

luminance level (cd\m2).................................................................................................58

Figure 34. Detection distance for age by light type and luminance (cd/m2).........................59

Figure 35. Detection distance by light type ............................................................................59

Figure 36. Detection distance by luminance...........................................................................60

Figure 37. Detection distance by number of trials for each age group 9...............................61

Figure 38. Crossing acceptance distance for gap experiment by age group .........................62

Figure 39. Simplified grid and values for Low/Medium pedestrian traffic in rural 

area design......................................................................................................................64

Figure 40. Illustration for low pedestrian traffic design........................................................64

Figure 41. Simplified grid and values for School Zone in a Suburban Area ........................66

Figure 42. Illustration for high pedestrian traffic in rural or suburban area design...........66

Figure 43. Simplified grid and values for High Pedestrian traffic School Zone in 

Urban Area Design ........................................................................................................68

Figure 44. Illustration for high pedestrian traffic school zone in urban area design ...........68

Figure 45. Simplified grid and values for high pedestrian traffic in urban area design ......70

Figure 46. Illustration for high pedestrian traffic in urban area design...............................70
ix

LIST OF TABLES

Table 1: Pedestrian Fatalities and injuries as a Percentage of Total Fatalities and 

injuries in traffic crashes (2009 t0 2018) (excerpted from FARS 2009-2017 

National Center for Statistics and Analysis. (2020). Pedestrians: 2018 data. DOT 

HS 812 850) ......................................................................................................................2

Table 2: Total and Pedestrians Killed or Injured in Traffic Crashes, by Age Group, 

2018 (National Center for Statistics and Analysis, 2020) ...............................................3

Table 3: Comparison of crosswalk lighting methods and illuminances................................12

Table 4. Independent variables and levels for driver experiment.........................................15

Table 5. Walker experiment design........................................................................................18

Table 6. Gap acceptance experiment design ..........................................................................20

Table 7. Recommended Light Level Criteria for Pedestrian Facilities.................................31

Table 8. Values for low pedestrian traffic design...................................................................64

Table 9. Values for high pedestrian traffic in rural or suburban area design......................67

Table 10. values for high pedestrian traffic school zone in urban area design.....................68

Table 11. Values for high pedestrian traffic in urban area design........................................70
x

LIST OF ABBREVIATIONS

AASHTO American Association of State Highway and Transportation Officials

ANSI American National Standards Institute

CCT Correlated Color Temperature

CIE Commission Internationale de L'Eclairage

FHWA Federal Highway Administration

IES Illumination Engineering Society

K Kelvin

LED Light Emitting Diode

NSC National Safety Council

Ped Pedestrian

SPD Spectral Power Distribution

SRTS Safe Routes to School

SSD Stopping Sight Distance
xi

EXECUTIVE SUMMARY

Current research and design guidance for pedestrian lighting has centered on the ability of adult 

drivers to detect adult pedestrians but ignore the needs for children. This research considered the 

visibility needs of pedestrians, both adult and child, and evaluated the ability of drivers to detect 

children as pedestrians. The Safe Routes to School initiative (SRTS) is a program with the goal 

of increasing the safety of children on their daily routes to school through interventions that 

improve their visibility and well-being. A product of this research is a set of lighting 

recommendations that can serve as an intervention for improving the visibility of pedestrians at 

night, specifically children. The project objectives were: 1) to evaluate the visibility of childsized pedestrians alongside a lighted roadway at night (Driver Experiment), 2) to evaluate the 

visibility of trip hazards in a lighted crosswalk at night (Walker Experiment) and 3) to assess the 

impact of roadway lighting on the decision to cross a roadway (Gap Acceptance Experiment).

The results found that the 2200 K LED light type does not produce the same level of visibility as 

the 4000 K LED or the 5000 K LED which could be related to the light distribution. 

When considering urban versus rural environments, two different lighting designs may be 

necessary. The results indicated that with more visual clutter as is typical in an urban 

environment, increased luminance levels may be necessary (2 cd/m2) while a rural environment 

can maintain safe visibility with 1 cd/m2luminance level. These luminance levels combined with 

the established minimum illuminance of 9 to 10 lux form a recommended guideline for 

illuminating pedestrian areas. 

The second human factors study evaluated participants; children and adults, acting as walking 

pedestrians for potential trip hazards while walking at night. The results showed that the lighting 

systems had a minimal impact on the visibility of trip hazards in the forward view of participants 

as a majority of detections occurred from at least 40 meters.

The third evaluation sought to determine the impact of various light levels on the decisionmaking ability of both children and adults when crossing a crosswalk. 

Neither light level nor light scale affected the responses of children and adults in regard to when 

they would no longer attempt to cross a roadway; however, it was determined that the presence 

of roadway lighting may inform an adult’s perception of depth more accurately. 

The results also indicated that children underestimate the acceptable crossing period compared to 

adults. Adults were more conservative by an average of 30 m (98 ft.) or a range of 2 to 3 seconds 

with vehicle speeds of 35 and 25 mi/h, respectively. 

In addition to the human factors experiments, this research also evaluated vertical and semicylindrical methods of illuminance measurement. Vertical illuminance is commonly used as a 

specification in design guides for roadway lighting; however, semi-cylindrical illuminance, 

which considers light from a wider angle and may be more applicable in certain scenarios. It was 

determined that face-height semi-cylindrical illuminances below approximately 9 lux yielded 

shorter detection distances indicating that at least 9 lux of semi-cylindrical illuminance at face 

height is warranted for visibility of pedestrians. The results also indicate that beyond 9 lux 

vertical there was minimal benefit. 
xii

Based on these results, the recommended lighting levels are a minimum 2 lux vertical 

illuminance in areas where pedestrian volumes are low (0-100 pedestrians per hour). Higher 

pedestrian areas (>100 pedestrians per hour) are recommended to be 10 lux semi-cylindrical. The 

luminance recommendations for low volume pedestrian zones is 1 cd/m2in urban areas. For high 

volume urban areas, 2 cd/m2is recommended and rural areas are recommended to maintain 1 

cd/m2. The color temperature of the light source should be 3000 K are higher. Pedestrian 

crosswalks should have a minimum of 20 lux vertical as current guidelines suggest.
1

INTRODUCTION

The design of lighting for pedestrians is critical for the implementation of outdoor and street 

lighting. In the past, efforts have focused primarily on crosswalk lighting, as crosswalks are 

typically where pedestrians and vehicles occupy the same space on the roadway. However, 

sidewalks, non-crosswalk areas used to cross the road, and areas not connected to the road are 

also in need of lighting design guidelines. Research in this area has been lacking and the current 

guidelines remain consensus based.

Correctly applied and effective lighting addresses the issues (primarily that of darkness) and 

safety concerns of both adult and child pedestrians. Research has shown lighting is essential not 

only for the driver to see pedestrians, but for pedestrians to see their surroundings, with glare 

control, comfort, ability to detect trip and fall hazards, and promote perceptions of safety and 

security. 

The final consideration is the development of lighting technology. As luminaires and light 

sources evolve, existing guidelines may become obsolete. For example, solid-state lighting 

(LED) fixtures have a controlled optical output than traditional sources and as a result, light that 

was typically emitted to light crosswalks and sidewalks may be limited. Now, recommendations 

for a suitable pedestrian lighting level are needed for application to pedestrian areas like 

sidewalks and crosswalks.

Pedestrian Safety

According to a National Center for Statistics and Analysis (2020) fact sheet, the percent of total 

fatalities involving pedestrians increased from 2009 to 2018 by five percent, as shown in the 

Percentage of Total Fatalities Column of Table 1. During this time period, there was also an 

approximate increase of 16,000 injuries. In 2018, 74% of all pedestrian fatalities occurred at nonintersections and 10% occurred on roadsides, shoulders, parking lanes, bicycle lanes, sidewalks, 

mid-block crosswalks, among other sites. Three-fourths of all pedestrian related fatalities 

occurred during periods of darkness (76%). 
2

Table 1: Pedestrian Fatalities and injuries as a Percentage of Total Fatalities and injuries

in traffic crashes (2009 t0 2018) (excerpted from FARS 2009-2017 National Center for 

Statistics and Analysis. (2020). Pedestrians: 2018 data. DOT HS 812 850)

Year Total 

Fatalities

Pedestrian 

Fatalities

Percentage of 

Total 

Fatalities

Total Injured Pedestrian 

Injured

Percenta

ge of 

Total 

Injured

2009 33,883.00 4,109.00 12% 2,224,000.00 59,000.00 3%

2010 32,999.00 4,302.00 13% 2,248,000.00 70,000.00 3%

2011 32,479.00 4,457.00 14% 2,227,000.00 69,000.00 3%

2012 33,782.00 4,818.00 14% 2,369,000.00 76,000.00 3%

2013 32,893.00 4,779.00 15% 2,319,000.00 66,000.00 3%

2014 32,744.00 4,910.00 15% 2,343,000.00 65,000.00 3%

2015 35,484.00 5,494.00 15% 2,455,000.00 70,000.00 3%

2016 37,806.00 6,080.00 16% 3,062,000.00 86,000.00 3%

2017 37,473.00 6,075.00 16% 2,745,000.00 71,000.00 3%

2018 36,560.00 6,283.00 17% 2,710,000.00 75,000.00 3%

The age groups of pedestrians killed or injured in traffic crashes in 2018 are shown in Table 3. 

Children are designated as ages 14 and younger and 17% of all child fatalities and 3% of all 

injuries were as pedestrians (National Center for Statistics and Analysis, 2020).
3

Table 2: Total and Pedestrians Killed or Injured in Traffic Crashes, by Age Group, 2018 

(National Center for Statistics and Analysis, 2020)

Age Group Total 

Fatalities

Pedestrian 

Fatalities

Percentage 

of Total 

Fatalities

Total 

Injured

Pedestrian 

Injured

Percentage 

of Total 

Injured

<5 344 63 18% 50,000 1,000 2%

5–9 331 58 18% 64,000 3,000 4%

10–14 363 60 17% 76,000 5,000 6%

Children <= 14 1,038 181 17% 190,000 9,000 5%

15–19 2,318 227 10% 254,000 6,000 3%

20–24 3,927 431 11% 334,000 7,000 2%

25–29 3,688 482 13% 310,000 7,000 2%

30–34 3,045 485 16% 244,000 7,000 3%

35–39 2,690 501 19% 219,000 6,000 3%

40–44 2,299 423 18% 191,000 5,000 2%

45–49 2,548 485 19% 190,000 4,000 2%

50–54 2,588 553 21% 183,000 5,000 3%

55–59 2,889 608 21% 170,000 6,000 4%

60–64 2,491 558 22% 149,000 5,000 3%

65–69 1,934 385 20% 102,000 3,000 3%

70–74 1,579 291 18% 77,000 3,000 3%

75–79 1,304 238 18% 46,000 2,000 3%

80+ 2,090 361 17% 51,000 1,000 3%

Ages 65+ 6,907 1,275 18% 276,000 9,000 3%

Total 36,428 6,209 17% 2,710,000 76,000 3%

A specific focus of pedestrian safety is school-age children as they are travelling to school. These 

children travel at twilight in both morning and afternoon, creating unique issues. Children are 

especially vulnerable to traffic. In addition to being small and easily distracted, it is difficult for 

children to judge the direction of sounds, estimate the speed and distance of oncoming vehicles, 

and anticipate driver behaviors. In a recent virtual reality simulation, six-year-old children were 

struck 8% of the time when crossing busy one-lane streets, while the crash rates for eight-, 10-, 

and 12-year-old children were 6%, 5%, and 2%, respectively. Children’s limited ability to judge 

the available gap at a young age primarily attributes to this difficulty in crossing streets. Younger 

children also take more time to take the first step in crossing the street, shortening the available 

gap. However, children’s crossing speeds do not differ from those of adults (O’Neal et al, 2018).

When considering all pedestrians in addition to children, one of the factors contributing to the 

fatality rate at night is lack of lighting. The International Commission on Illumination (CIE) 

states that the reason roadway fatalities are higher during periods of darkness is mainly due to 
4

reduced visibility (National Center for Statistics and Analysis, 2018). Since approximately 90% 

of the information drivers use to navigate the roads is visual (Hills, 1980), seeing and avoiding 

pedestrians crossing the street or at an intersection becomes more challenging with less light. In 

fact, roadway fatalities during periods of darkness are approximately three times greater than 

those during daylight (National Highway Traffic Safety Administration, 2015).

Nationally, on average about 75% of pedestrian fatalities occur after dark (National Center for 

Statistics and Analysis, 2018). However, this statistic is more compelling when considering the 

fact that only about 25% of all traffic volume occurs after dark (Commission Internationale de 

l'Éclairage, 2010). This means that during the time of day when the least number of vehicles are 

on the road, the greatest number of pedestrians are killed in crashes. Furthermore, as mentioned 

earlier, pedestrian fatalities are the only category of traffic deaths that are increasing. This shows 

a heightened need to add or improve safety measures to protect areas of roadway traffic with 

high pedestrian volume, especially after dark. Adding lighting to roadways has been shown to be 

an effective countermeasure against crashes at night (Wortman et al, 1972; Elvik, 1995; 

Isebrands et al, 2010; Donnell, Porter, & Shankar, 2010; Sasidharan & Donnell, 2013). 

Safe Routes to School

SRTS is an international approach using engineering, enforcement, safety education, and 

incentives to encourage children to walk and bike to school. Engineering approaches broadly 

incorporate design, implementation, operation, and maintenance of infrastructure improvements 

like traffic control devices or physical devices. Enforcement approaches encompass strategies to 

stop unsafe behaviors in drivers, pedestrians, and bicyclists. Enforcement strategies also 

encourage all road users to obey all traffic safety rules and share the road with other road users. 

Education approaches involve teaching road users the benefits of SRTS and creating awareness 

about them. Encouragement approaches closely follow education approaches. Their aim is to 

promote walking and bicycling by getting road users interested in those means of transportation. 

The U.S. Congress created the Federal-Aid SRTS Program in 2005, providing funding for the 

implementation of SRTS programs to improve safety and levels of physical activity for students 

in the form of active transportation to school. These programs can be implemented by a state 

department of transportation, metropolitan planning organization, local government, school 

district, or even a school (Terry, Brimley, Gibbons, & Carlson, 2016).

Many studies on the various implementations of SRTS have overwhelmingly concluded that it 

offers positive benefits. It has been established that the program has been successful in its 

primary goal and that there has been an increase in the number of children walking and biking to 

school. A cross-sectional evaluation examined the relationship between urban form changes 

(SRTS projects such as sidewalks, traffic lights, pedestrian crossing improvements, and bicycle 

paths; see (Figure 1) and walking and biking to school (Commission Internationale de 

l'Éclairage, 2010). Surveys were distributed to parents of third through fifth graders at 10 schools 

near a project with aforementioned features. Subjects were categorized into one of two groups 

depending on whether or not their children traveled passed the location of an SRTS project on 

their way to school. Based on responses, children whose travel path utilized some of the features 

provided through the SRTS project were more likely to show increases in walking or biking than 

the children who did not travel passed the SRTS project (15% vs. 4%). Governors Highway 

Safety Association (2017) assessed changes in the rates of active school travel after SRTS 
5

projects were implemented. They looked at 48 implementations and the 53 schools affected by 

them in Florida, Mississippi, Washington, and Wisconsin. A before-and-after analysis concluded 

that there were significant increases in active school transportation after SRTS projects were 

implemented. Specifically, walking increased from 9.8% to 14.2% and biking from 2.5% to 3%. 

Figure 1. Example of a SRTS traffic improvement project as reported by Commission 

Internationale de l'Éclairage (2010)

Roadway and pathway lighting focusing on the visibility of children at night can serve as an 

SRTS intervention as current lighting guidelines focus primarily on the visibility of adult 

pedestrians. Recommendations for lighting in areas common to children who walk to school, in 

both rural and urban areas, are provided based on the results of this research. A careful 

consideration to the characteristics of urban and rural environments must be given as contrast, 

visual clutter, and multiple light sources impact a pedestrian’s visibility. The scope of this 

research not only includes the visibility of children as pedestrians from the point of view of the 

driver but also the ability of pedestrians, children, and adults, to detect hazards in their walking 

path under the same lighting conditions. This method ensures that any recommendation for 

lighting that benefits the visual performance of a driver also considers the visual performance of 

pedestrians of all ages.

Objective of Research

The objective of this research was to provide recommendations for lighting for pedestrian safety 

including lighting methods for improving safe routes to school for children. Lighting 

recommendations for improving the visibility of pedestrians, both adult and child, from a 

driver’s point of view were developed as a result. Pedestrian visibility, from the pedestrian’s 

point of view, in detecting hazards on walkways and crosswalks are factored into the research 

method and recommendations.

The findings of the literature review under section 2 reveals the need to develop a luminance

standard that would result in optimal visibility for all road users: adult and child pedestrians on 

sidewalks and in crosswalks, as well as drivers. The luminance standard thus must include both 

optimal visibility of pedestrians by drivers and the level and type of lighting needed for safe 
6

pedestrian travel. A secondary objective is the determination of differences in luminance

requirements for adult versus child pedestrians in terms of maintaining good visual performance

and perceptions of visibility, comfort, and safety.

The researchers also sought to evaluate the possibility of developing a lighting metric that 

enhances pedestrian safety per the outcomes of these objectives.
7

REVIEW OF EXISTING LITERATURE

During the course of this research effort, a literature review considering the visibility needs both 

for and of the pedestrians was considered. The topics considered in this effort include pedestrian 

lighting at crosswalks and intersections, urban and rural issues and visibility needs in general. A 

summary is provided at the end of the review.

Pedestrian Visibility

Studies have shown a positive correlation between well-lit pathways and physical activity, such 

as running, walking, and bicycling. Through surveys and literature reviews, Lopez and Hynes 

(2006) concluded that the installation of sidewalk lighting in residential areas encourages 

physical activity. The same study also noted that comparable research on the relationship of the 

built environment and health is needed for urban, especially inner city, neighborhoods, as well as 

for rural areas. Balfour and Kaplan (2002) suggest that the neighborhood environment, including 

pathway lighting, may influence functional health at an older age. Their study consisted of 

surveying 883 functionally healthy participants 55 years or older in Alameda County, California, 

for one year. To determine functional loss, they were asked to rate the severity of neighborhood 

problems and the difficulty of certain physical everyday tasks. The study found an increased risk 

to overall functional health in residents who reported living in multiple-problem neighborhoods, 

where those problems consisted of traffic, noise, crime, trash and litter, poor lighting, and 

inadequate public transportation, compared to those in non-problem neighborhoods. The study 

also concluded that neighborhood problems associated with the largest increased risk were heavy 

traffic, excess noise, and inadequate lighting. Inadequate pathway lighting was not studied as a 

lone factor, however. In a survey that examined associations between perceived neighborhood 

characteristics and leisure-time physical activity, Huston et al. (2003) reported that streetlights 

were positively associated with engaging in leisure or physical activity, but path lighting was not 

studied specifically.

Hazards for the Pedestrian — Slips, Trips, and Falls

Pedestrian safety hazards are commonly encountered on sidewalks and neighborhood pathways 

and walkways. A walkway profile survey done in Palo Alto, California, found 50 potential trip 

points in a 1-mile (0.6-km) stretch (Ayres & Kelkar, 2006). The minimum change in elevation 

required to be identified as a potential trip point was 0.5 inches (1.3 cm). Based on the walkway 

profiles, Ayres and Kelkar (2006) concluded that abrupt rises large enough to destabilize a 

pedestrian appear to be common in residential sidewalks. Potential trip and fall obstacles consist 

of uneven pavement, holes (in pavement), construction barriers, bicycle racks, and lighting posts, 

among others (Fotios & Cheal, 2009).

The National Safety Council (NSC) categorizes slip, trip, and fall accidents four different ways: 

slips and trips without falling, falling on the same level (i.e., tripping on a sidewalk), falling to a 

lower level (i.e., collapsing structures, falling from ladders or roofs), and jumping to a lower 

level (i.e., controlled and voluntary movement from one level to another). During 2017, slip, trip, 

and fall incidents occurred in the United States at a rate of 23.1 per 10,000 full-time workers, 

accounting for 227,760 occupational injuries (National Safety Council, 2017) and are among the 

top three occupational injuries (see Figure 2).
8

Figure 2. Top six occupational injuries in the United States in 2017 (National Safety 

Council, 2017)

As reported by the NSC, the demographic most at risk of a slip, trip, or fall accident is people 

aged 55 or greater. Falls were the leading cause of unintentional-injury death for the elderly in 

2013 (National Safety Council, 2013). Fotios and Cheal (2009) found significant differences in 

performance between young (18–45) and old (60+) participants at low illuminance (0.2 lux). The 

data showed a significant difference at low illuminance levels; however, the difference decreased 

in magnitude at higher illuminances, suggesting that obstacle detection ability increases with 

higher illuminance. The results of this study are bolstered by another study conducted by 

Bhagavathula and Gibbons (2019), which assessed the detection rates of wheel stops in parking 

lots and garages). Six different colors of wheel stops were tested: white, blue, gray, yellow, 

black, and black with yellow stripes. The results of this study showed that increased light levels 

resulted in higher detection rates of wheel stops (Figure 3). Plateaus in the detection performance 

(light level where improvement in detection rate was not observed with increasing light level) 

were observed at the 2-lux average light level in parking lots and 10-lux average light level in 

parking garages.
9

Figure 3. Wheel stop in a parking lot (Bhagavathula and Gibbons, 2019)

Pedestrian Lighting at Intersections

Lighting is a significant safety consideration for intersections, a primary road-crossing point for 

child and adult pedestrians. Pedestrians awaiting to cross at an unsignalized crosswalk must be 

aware of motorists approaching from multiple directions and understand the concept of time, 

speed, and distance. Even at signalized crossings, pedestrians must be aware of vehicles turning 

into one of the lanes they are crossing. Visibility requirements for effectively crossing a roadway 

hinge on the ability of pedestrians to detect approaching traffic as well as clearly see their 

pathway across and destination on the other side. Roadway lighting increases visibility, 

augments vehicle headlamps, and provides more information about the surrounding area for all 

road users, and consequently can be a contributing factor to reducing automobile crashes (Li, et 

al, 2020, Hasson & Lutkevich, 2002).

To determine the appropriate light level at intersections, a new systems-level approach to 

intersection lighting design was introduced by Bhagavathula, Gibbons, and Nussbaum (2018). In 

this study, three intersection lighting designs were evaluated. This evaluation was based on an 

evaluation of drivers’ nighttime visibility using both objective as well as subjective measures. 

For the objective measure the detection distances of small targets that were placed at the 

entrances, exits, and middle of pedestrian crosswalks was measured. The subjective ratings 

measured drivers’ perceptions of visibility, safety, and comfort. The results indicated that the 

design illuminating the intersection box offered better visual performance and had fewest missed 

target detections with visual performance plateauing between 7 and 10 lux of average 

intersection illuminance. 

A study by Minoshima et al. (2006) also examined the effect of intersection lighting design on 

subjective ratings of visibility. Subjective ratings of visibility were obtained from drivers 

exposed to three different intersection lighting layouts (or configurations), each with three levels 
10

of illumination (5, 10, and 15 lux). The three intersection layouts were based on the part of the 

intersection that was illuminated, and used the following three configurations: approach, corner 

(or box), and both approach and corner. Drivers rated five statements—visibility, danger to 

pedestrian, ease of driving, brightness, and safety—on Likert-type scales (1 to 5). With 1 being 

least favorable and 5 being most favorable with 3 being neutral. A mean rating higher than 3 (or 

the neutral anchor) was used as a measure of effectiveness of an intersection’s lighting design. In 

this study, increases in illuminance levels resulted in higher subjective ratings of visibility. With 

illuminance levels higher than 10 lux, mean ratings of pedestrian visibility were higher than 3 on 

the Likert-type scale in all three layouts. Minoshima et al. (2006) also found that ratings (all 

statements including pedestrian visibility) depended on illuminance level. At the 15-lux 

illuminance level, the lighting configuration illuminating the approach and corner was rated 

highest. At the 10-lux and 5-lux illuminance levels, the configuration illuminating the approach 

was rated the highest. The authors concluded that the approach lighting layout should be used to 

maintain a mean roadway surface luminance of 10 lux, but if a higher level of average roadway 

illuminance is needed, then both approach and corner illumination should be used. This study 

also analyzed the optical properties of intersections where crashes occurred frequently. The 

results indicate that a uniformity ratio of illuminance (ratio of minimum to average illuminance) 

of 0.4 makes intersections safer.

The safety effects of lighting at intersections have been given special consideration by both the 

Illumination Engineering Society (IES) and the Commission Internationale d’Eclairage (CIE). 

These organizations recommend minimum lighting levels for intersections, with specific levels 

depending on a number of factors, such as roadway classification, speed, traffic volume, and

traffic composition. The light levels recommended for intersections, though, differ substantially 

from those recommended for roadways. In addition to IES and CIE, other information sources 

are available for lighting roadways from the Federal Highway Administration (FHWA) and the 

American Association of State Highway and Transportation Officials (AASHTO). The 

intersection lighting guidance and warrants described by these agencies do not obligate state or 

local governments to provide lighting but do give important insight on when to investigate 

lighting and how to improve safety at an intersection. 

Safety Effects of Lighting at Midblock Crosswalks

Very few studies have been conducted on the topic of crosswalk lighting and pedestrian 

visibility. One of the earliest studies on pedestrian visibility at intersection crosswalks was by 

Freedman, et al. (1975), who reported that increasing the intensity of light resulted in an increase 

in the time available for drivers to respond, and recommended an average horizontal illuminance 

of 75 lux for crosswalks. This value however is extremely high and is not representative of 

current technology or responsible lighting practice.

Pedestrian visibility studies conducted in Switzerland showed that rendering pedestrians in 

positive contrast (i.e., pedestrians are illuminated from the approach side, rendering them 

brighter than the background), reduced pedestrian-vehicle crashes by two-thirds (Wilken et al., 

2001). Pedestrians can be rendered in positive contrast by increasing the vertical illuminance on 

them. The lighting design that rendered the pedestrians in positive contrast was compared to 

existing design in a field test (Hasson & Lutkevich., 2002), which showed that the crosswalk 

lighting design that rendered the pedestrians in positive contrast provided significant benefits 
11

over the conventional one. The benefits of positive contrast on pedestrians were also reported in 

research conducted in realistic nighttime environments. Edwards and Gibbons (2008) measured 

detection distances of pedestrians under different levels of vertical illuminance and reported that 

increasing the vertical illuminance on pedestrians increases the distance at which drivers can 

detect them (Figure 4).

Figure 4. Increase in detection distance with increase in vertical illuminance on the 

pedestrians as reported by C. Edwards and Gibbons (2008)

The above-mentioned research used fixed overhead lighting to illuminate pedestrian crosswalks; 

however, some recent research in pedestrian visibility has used bollard-type lights to illuminate 

pedestrian crosswalks. Bullough et al. (2009) reported a study exploring different ways to 

illuminate crosswalks for potential improvements in pedestrian visibility and safety. The study 

consisted of photometric simulations of various crosswalk lighting and a survey of individuals 

with expertise in the fields of transportation, transit operations, and public safety specifically to 

analyze the visual performance, glare, and economic impacts of each lighting system. The 

responses concluded that the bollard-based lighting for crosswalks increased pedestrian 

illuminance and reduced costs.

Some differences in light levels recommended for optimum pedestrian visibility in crosswalks 

depend on the approach used for the lighting of pedestrians in crosswalks. Edwards and Gibbons 

(2008) used conventional overhead lighting for illuminating crosswalks. They reported that a 

vertical illuminance level of 20 lux at a height of 1.5 meters (5 feet) from the road surface 

resulted in good driver visual performance at midblock crosswalks (for speeds up to 35 mi/h). 

Bullough and Skinner (2015), who used a bollard lighting system to illuminate a crosswalk, 

found that a vertical illuminance of at least 10 lux at a height of 0.9 m (3 ft) on the pedestrian is 

required to increase contrast and thereby visibility (speeds of the vehicles were not mentioned in 

the study).
12

Table 3: Comparison of crosswalk lighting methods and illuminances

Authors Light Type Vertical Illuminance Measurement 

Height (m)

Edwards and Gibbons 

(2008)

Overhead Lighting 20 lux 1.5

Bullough and Skinner 

(2015)

Bollards 10 lux 0.9

It is important to note that pedestrian visibility in bollard-based lighting has never been directly 

compared to overhead lighting in realistic roadway conditions where the drivers approached the 

crosswalk in a moving vehicle. Further, bollard-based lighting might increase transient glare for 

drivers approaching the crosswalk; however, glare control could be improved through use of 

louvers or baffles (Bullough et al., 2009). Demonstration projects were undertaken with 

acceptance by surveyed pedestrians in most aspects of the installations however drivers were not 

surveyed (Christoff, 2013). Another disadvantage of bollard-based lighting is that it involves 

placing additional fixed objects adjacent to the roadway.

Urban versus rural considerations

Over half of all traffic related fatalities occur in urban areas (53%); however, according to the 

Census Bureau, 80% of the U.S. population resides in urban areas. Rural fatalities account for 

45% of total fatalities with only 19% of the population residing there. These figures reveal that 

crashes that occur in rural areas are more likely to be fatal, likely due to higher posted speeds and 

variable terrain, compared to urban areas. In 2018, 79% of pedestrian deaths occurred in urban 

areas and 18% in rural (3% unknown), despite the higher rate of pedestrians in urban areas (US 

Department of Transportation, 2015). 

Compared to urban, rural related pedestrian fatalities and safety factors are more difficult to 

quantify due to inconsistencies in data regarding shoulder placement, road classes, sidewalk 

availability (Boarnet, Anderson, Day, McMillan, & Alfonzo, 2005), and lighting (Stewart, 

Moudon, & Claybrooke, 2014).

Special Pedestrian Lighting for Children

A study conducted by Wazana et al. (1997) that reviewed risk factors for child pedestrian 

injuries reported that children are 2.3 times more likely to be injured during darkness than during 

the day. Loukaitou-Sideris, Liggett, and Sung (2007) reported that to promote safe walking at 

night, it is important to increase pedestrian visibility by providing lighting. Safety interventions 

or countermeasures specifically tailored to children could significantly reduce these injuries. 

Installing special pedestrian interventions such as additional lighting, can promote the use of 

existing effective transportation safety interventions such as bicycle lanes or sidewalks for 

children. No specific lighting guidelines to improve the visibility of children currently exist, 

however, and this research endeavors to inform future guidelines with recommendations based 

on these empirical findings. Further, almost all the lighting evaluations for current design guides 

have been conducted from the adult point of view.
13

Literature Summary

Through the literature review, it was determined that urban and rural zones possess unique 

characteristics in terms of environmental lighting, pedestrian and vehicle volume, and driver 

expectation. These are important considerations for pedestrian lighting recommendations for 

contributing to the body of work under the Safe Routes to School program. Previous research has 

evaluated pedestrian lighting at intersections and mid-block crosswalks, and design guidelines 

for those scenarios are specific to pedestrians at adult height. The visibility of children, 

unaccompanied by an adult, in low-light conditions is a research gap that this multi-evaluation 

effort serves to fill.

The literature review has shown that the following areas need to be addressed for comprehensive

recommendations for lighting midblock crosswalks and intersections to be developed:

· There is a need to develop a light level that results in optimal visibility for all road users 

(pedestrians and drivers).

· There is a need to understand if there are differences in light level requirements for adult 

versus child pedestrians in terms of maintaining good visual performance.

· The existing recommended light levels are based on consensus and are not backed by 

empirical research. Specification of light levels should be backed my empirical research 

that accounts for all road users (pedestrians and drivers).

· Specifications of light levels and luminaire pole placements for crosswalks at midblock 

and intersections should be available so that departments of transportation can easily 

adopt them. 

· Finally, there is no universal metric for assessing the safety of a pedestrian. Several 

metrics have been proposed, such as vertical illuminance (at a specified height - 1.5 m, 

0.9 m etc.), semi-cylindrical illuminance, etc. For a lighting designer to be able to 

optimize a lighting design, a metric that represents pedestrian safety must be developed. 

This metric can then be used in a design method that can then compare designs and allow 

for luminaire and layout optimization.
14

RESEARCH METHOD

The pedestrian lighting study that forms the basis for this report incorporated three human 

factors-based experiments to achieve the project objectives. The project objectives were: 1) to 

evaluate the visibility of child-sized pedestrians alongside a lighted roadway at night (Driver 

Experiment), 2) to evaluate the visibility of trip hazards in a lighted crosswalk at night (Walker 

Experiment) and 3) to assess the impact of roadway lighting on the decision of when to cross a 

roadway (Gap Acceptance Experiment). Each of the evaluations compared different light types 

and mounting heights, and the two pedestrian experiments (Walker and Gap Acceptance) 

included children as participants. The output of this project is a set of lighting recommendations 

that consider the visibility of pedestrians (child and adult) to drivers as well as the visibility of 

drivers and trip hazards to pedestrians. The three experiments are described in greater detail 

below.

Driving and Detection Experiment (Driver Experiment)

In this experiment, the research team considered the visual needs of the driver with the goal of 

determining the lighting levels necessary to detect and identify a child-sized pedestrian offset 

from the roadway in a sidewalk or crosswalk simulation scenario. Metrics considered include 

vertical illuminance, semi-cylindrical illuminance, and roadway luminance. The environment 

was also a special consideration; the test trials included a rural setting with only a guardrail 

behind the pedestrian and a second setting with more visual clutter, as would be common in an 

urban environment.

Table 4 summarizes the independent variables of the driver experiment. The vertical illuminance 

levels varied due to the differences in spectral power distribution (SPD) of the light types and the 

luminance levels selected; however, the vertical illuminance levels were matched across light 

types and luminance levels. A high, medium, and low area of illuminance was selected under 

each condition. Along the route were four locations where a child-sized pedestrian (mannequin) 

could appear in a rural setting and one location in the urban setting.
15

Table 4. Independent variables and levels for driver experiment

Independent variable Rural environment Urban environment

Light spectral power distribution 

(SPD)

2200 K LED

4000 K LED

5000 K LED

4000 K LED

Road Luminance

High (2 cd/m2)

Medium (1 cd/m2)

Low (0.5 cd/m2)

High (2 cd/m2)

Medium (1 cd/m2)

Low (0.5 cd/m2)

Semi-cylindrical illuminance on 

pedestrian (dependent on SPD 

and luminance)

High 13–17 lux

Med. 10–13 lux

Low 7–10 lux

High 6–40 lux

Low 3–22 lux

Visual background Highway setting 

(guardrails) Street setting (clutter)

Light source scale (height) Highway scale 50 ft (15.2 

m) 

Road scale 30 ft (9.1 m)

Ped scale 18 ft (5.4 m)

Age Young (25 to 45 years), 

old (65 and older)

Young (25 to 45 years), old 

(65 and older)

Each of the three experiments used a repeated measures design to assess the effects of light 

spectral power distribution (SPD), luminance, and surround ratio on driver and pedestrian visual 

performance. Descriptions of each independent variable for this experiment can be found in 

Appendix B: Independent Variables.

Driver Experiment Procedure

In the driver experiment, participants drove a vehicle through a course and detected child-sized 

mannequins on the shoulder of the roadway by saying “kid” or “child” aloud when a mannequin 

is spotted. Participants were instructed to scan and search for child-sized pedestrians on their 

route and announce when they could detect them. An in-vehicle experimenter pressed a handheld 

button after the participant’s verbalization to flag the moment in the data stream. Using the 

vehicle’s data acquisition system, which captures audio, video, and experimenter input, and 

continuous differential GPS, the exact moment of detection was pinpointed during data reduction 

procedures. The distance from the point of detection to the mannequin is considered the 

detection distance. Figure 5 illustrates this concept in greater detail.
16

Figure 5. Diagram of driver experiment procedure

The dependent variable is detection distance (i.e., the distance between the driver and the target

object at which the driver detects the object). Detection distance is commonly used as a measure 

of visual performance in nighttime roadway visibility studies (Bhagavathula & Gibbons, 2013; 

Bhagavathula, Gibbons, & Nussbaum, 2017; Mayeur, Bremond, & Bastien, 2010; Shinar, 1985). 

Detection distance of a visual target can also be directly compared to the stopping sight distance 

(SSD), which is used as a design standard for sight distance in road design by the American 

Association of State Highway and Transportation Officials (2011). SSD is the minimum distance 

required for a driver travelling at the design speed to come to a complete stop. If the detection 

distance is lower than the SSD, the driver will not be able to avoid a collision with the object

under the given conditions.

The study incorporated the use of cylindrical cardboard tubes (Figure 6) as catch trials to 

encourage participants to announce only they had seen a child-sized mannequin 45 in (1.14 m) 

tall when they were sure. This height correlates with the average height of a 6-year-old, an age 

on the lower end of ages of children walking to school. In a nighttime setting, both the 

mannequins and the tubes appear as silhouettes from a distance beyond approximately 246 ft (75 

m), the distance headlamps typically reach. At this distance, the tubes and mannequins could 

appear similar. Participants were encouraged to announce a detection only when they were sure 

it was a mannequin and not a tube.

Figure 6 also illustrates where the vertical illuminance measurement was taken on the 

mannequin. This measurement was taken to ensure each position along the test course was 

matched for vertical illuminance. Three vertical illuminance levels (high, medium, and low) 

were used for the rural road test, and two high and low), for the urban road test.
17

Figure 6. Cylindrical tube and child-sized mannequin

The mannequins were positioned approximately 5 to 7 ft (1.5 to 2 m) to the right of the driving 

lane. This distance coincides with the positioning of a sidewalk where roadway lighting would 

be required to also illuminate a sidewalk. Distances closer to the roadway are more illuminated; 

therefore, an offset distance represents a worst-case scenario.

It can be argued that detecting a pedestrian at a high degree offset (5 to 7 ft (1.5 to 2 m), is not 

always important to the driving task; however, the behaviors and decision making of children are 

not predictable. The safety of a child in proximity to a roadway increases when the driver is 

aware of the child. Researchers placed the mannequins in relation to the luminaire to establish a 

variety of vertical and semi-cylindrical illuminance conditions for detection.

Pedestrian Walking and Detection Experiment (Walker Experiment)

This experiment explored the visibility needs of pedestrians at roadway-scale and pedestrianscale street lighting. In this case, the visibility needs under consideration were those of the 

pedestrians to walk and move safely. Pedestrian participants were exposed to a visual 

environment where they were tasked with identifying a potential trip-and-fall hazard in their path 

ahead. For the experiment, the experimental variables included lighting metrics such as vertical 
18

and horizontal illuminance, roadway uniformity, luminance, contrast, and surround ratio were

recorded and described in Appendix B: Independent Variables..

Walker Experimental Design and Procedure

Table 5 shows the variables, levels, and classifications for the walker experiment. Many of these 

variables and levels remain consistent from the driver experiment, including luminance and light 

type. The differences include the visual target types (tripping hazards) and vertical illuminance at 

ground level for the targets.

Table 5. Walker experiment design

Independent variable Levels

Light spectral power distribution 

(SPD) 4000 K LED

Surface Luminance

High (2 cd/m2)

Medium (1 cd/m2)

Low (0.5 cd/m2)

Vertical illuminance on tripping 

hazard

High: (Ped 22–24 lux; Road 19-22 lux)

Medium: (Ped 10–13 lux; Road 6-9 lux)

Low: (Ped 6–7 lux; Road 3-5 lux)

Tripping hazard height 0.5 inch

1 inch

Age

Old (65 and older)

Young (25 to 45 years)

Child (8 to 12 years)

Light Type Road scale (Overhead)

Ped scale

Lane Furthest from roadside lighting

Nearest to roadside lighting

Walker Experiment Procedure

For the walker experiment, two participants observed targets placed inside their own lane on the 

surface of an intersection ahead (Figure 7). The participants started 61 meters (200 feet) from the 

intersection and began walking toward the intersection. When they could detect an object in their 

lane within the intersection, they stopped walking and the distance was measured to determine 

from which they could detect the object. The detection distance was the dependent variable for 

this experiment.
19

Figure 7. Walker experiment method

Pedestrian Crosswalk Gap Acceptance Experiment (Gap Experiment)

The third experiment was a gap acceptance scenario in which a child and adult (sometimes the 

child’s parent) each indicated separately at what point they would still consider crossing the

street as a vehicle approached at various speeds and in different lanes.

Gap Acceptance Experimental Design and Procedure

Table 6 shows the variables and levels for the gap experiment. Many of these variables and 

levels remain consistent from the walker experiment, including luminance, light type, and age. 

The differences are the lanes of travel and the speeds of the vehicles operating in the trials. 

Descriptions of these independent variables are in Appendix B: Independent Variables..
20

Table 6. Gap acceptance experiment design

Independent Variable Levels

Light spectral power 

distribution (SPD)

4000 K LED

Surface Luminance

High (2 cd/m2)

Medium (1 cd/m2)

Low (0.5 cd/m2)

Lane Nearest: (3.6 m (12 ft) from participants)

Furthest: (10.9 m (33 ft) from participants)

Speed 25 mph (40 km/h)

35 mph (56 km/h)

Age

Old (65 and older)

Young (25 to 45 years)

Child (8 to 12 years)

Light type Road scale

Ped Scale

Gap Experiment Procedure

The walker and gap experiments were conducted on the same nights with the same participants. 

After the completion of the walker experiment, participants moved behind the jersey barriers 

indicated in Figure 8. Participants were each provided a handheld button they could press with 

their thumbs. Participants were instructed to press their button at the moment they would no 

longer feel safe attempting to cross the road. It was emphasized that to cross the roadway, they 

would be walking and not running, and that they needed to make it all the way across the road 

before a vehicle reached the crosswalk.
21

Figure 8. Gap experiment setup

A total of 28 trials that included combinations of each light scale (ped and road), each luminance 

(high, medium, and low), each lane (near and far), and each speed (25 mph and 35 mph). There 

were four trials when no roadway or pedestrian lighting was on.

The dependent variable for this task is the distance between the vehicle and the participant at the 

instant when participants pressed the button. This data would indicate the position just beyond 

the last accepted point a participant would consider crossing the road.
22

RESULTS DISCUSSION IN BRIEF

This chapter will provide a brief summary of findings from the analysis of the three experiments. 

For the full analysis, including charts and descriptions of interaction effects, refer to Appendix 

D: Analysis and Discussion of Experimental Results.

Semi-Cylindrical and Vertical Illuminance

Comparisons of semi-cylindrical and vertical illuminance measurement methods showed a strong 

correlation. Due to the wider angle of the semi-cylindrical measurement instrument, light from 

multiple sources can contribute to the illuminance values. Due to this, the research team believes 

the use of semi-cylindrical in an urban environment where more light sources are present is an 

appropriate measurement method. For rural environments where there are not light sources in 

addition to the roadway or pedestrian lighting, the vertical illuminance method can be used as a 

wider-angle consideration is not necessary.

For semi-cylindrical illuminance, there appears to be a shift at approximately 9 to 10 lux where 

detection distance begins to plateau (as shown in Figure 27 in Appendix D: Analysis and 

Discussion of Experimental Results). This was especially apparent for the road- and pedestrianscale lighting systems. As this area was an urban environment, and therefore a worse-case 

scenario for contrast in terms of the visibility level of an object, the researchers believe that this 

range where the shift occurs is a minimum lighting requirement for semi-cylindrical illuminance 

at face height.

Driver Experiment

A learning effect was determined through analysis where participants’ performance improved 

after the first two laps and plateaued for the remaining eight laps. Due to this, and because the 

study’s design was balanced across participants for the configurations they would experience 

first, the results are broken into expected versus unexpected detections.

During the trials, when participants were unsure of when to expect a pedestrian, the results were 

truer to reality. After two laps, the repetition increased familiarity with the course and where the 

mannequins might appear despite balancing the experiment and including catch trials. Most 

“unexpected” detections occurred between 45 and 65 m (148 and 213 ft) from the pedestrian. At 

a speed of 45 mph (72 km/h), that is a range of 2.2 and 3.2 seconds compared to the 3.4 to 4.7

seconds of detection during later laps in the experiment.

The data shown in Figure 9 highlights the concept of unexpected versus expected appearance of 

objects. Each participant drove one practice with mannequins or objects of detection presented 

before driving the ten experimental laps. The data here shows that on the first two experimental 

laps, when participants were first exposed to the mannequins, their detection distances were 

shorter. On the third lap and beyond, a learning effect is shown to plateau the detection distances, 

across all lighting configurations and scenarios, most likely due to expectancy. This highlights a 

potential for weighted importance of the data from the first two laps, as an ordinary driver on any 

highway would come across a pedestrian unexpectedly. The data also shows that younger drivers 

detected the child pedestrian consistently from a greater distance than older drivers, even during 
23

the first two laps before familiarity with the experimental trials improves their awareness of 

mannequin placement.

Figure 9. Age by detection distance per lap

Ped scale and road scale lighting comparisons may indicate that semi-cylindrical illuminance 

levels below 8 lux have shorter detection distances than when semi-cylindrical illuminance is 

greater than 20 and as high as 40 lux (Figure 10). But between 10 and 20 lux, no discernible 

difference is found either for the two scales of lighting compared here or the three light types 

(2200 K, 4000 K, or 5000 K). Based on these results, there is a visual plateau at approximately 

10 lux.
24

Figure 10. Detection distance by semi-cylindrical illuminance for each light type (ped scale, 

road scale)

Figure 11 shows the relationship between the luminance level (cd/m2

), semi-cylindrical 

illuminance (lux), and detection distance (m). The average illuminance correlates to each 

luminance level, as expected, and the trend is apparent in the detection distance as well. In 

general, higher light levels result in longer detection distances.
25

Figure 11. Luminance (cd/m2) and illuminance (lux) across detection distance (m)

A correlation was found between luminance level and detection distance for the first lap when 

the general location of the mannequins was completely unfamiliar to participants. As this 

scenario captures the truest response from drivers, a weighted emphasis is placed on this result. 

Thus, the 2 cd/m2luminance level was the most preferred as during the first lap participants were 

able to detect the child-sized mannequins an estimated 7 m (22 ft) further than at 1 cd/m2 and 17 

m (56 ft) further than at 0.5 cd/m2(as shown in Figure 9 in Appendix D: Analysis and 

Discussion of Experimental Results).

In the rural highway locations, researchers compared three light types consisting of 2200 K 

LEDs, 4000 K LEDs, and 5000 K LEDs. The 2200 K LEDs could not achieve the higher 

luminance of 2 cd/m2, as did the other two light types. Results determined the detection distances 

under the 2200 K LEDs for both luminance levels (0.5 and 1 cd/m2) were significantly shorter 

than 4000 K and 5000 K under the same luminance levels (Figure 12). 
26

Figure 12. Detection distance for rural highway by light type and luminance

When compared to the 4000 K and 5000 K light types, the 2200 K produced much lower 

detection distances by approximately 20 m (66 ft), but luminance (cd/m2) had no impact on 

detection for highway lighting. When comparing the ped-scale and road-scale lighting (urban 

environment), however, the higher luminance produced a greater detection distance.

This may be explained by the complexity of the environment. Again, the 2200 K, 4000 K, and 

5000 K light types were on the rural highway section of the course and the Ped Scale and Road 

Scale were on the urban section with visual clutter positioned in the vicinity of the mannequin. 

When comparing the rural and urban environments, the mannequins placed in the rural locations 

were detected further for each luminance. Results indicate a higher luminance may be necessary 

in environments with visual clutter (signs, light poles, and other common street-side objects) for 

drivers to discern a child-sized person from their background. In rural environments where the 

background is a guardrail or consistent darkness, there is less impact of luminance level.

Walker Experiment

The results of this experiment showed that pedestrians could detect small objects from 

significantly further away under ped-scale lighting than road scale by an estimated average of 7 

m (22 ft). While all participants identified the obstacle in their path well before it would become 

a threat to their safety, this difference does indicate that ped-scale lighting positively impacted 

visual performance.
27

Results indicated that for both light types (ped scale and road scale) the higher luminance (2 

cd/m2) produced longer detection distances. Again, while the distances at which participants 

recognized and identified hazards were much longer than necessary for a real-world trip and fall 

scenario, it does show that acuity is improved under higher luminance levels. While the task for 

this study was to identify a small object several meters ahead, visual acuity may be necessary for 

more immediate threats not considered in this experiment.

Figure 13 shows the two-way interaction between light type and luminance for ped scale 

lighting. There is an expected trend downward from higher luminance levels (2 cd/m2) to 

medium (1 cd/m2) to low (0.5 cd/m2). For road scale, the higher luminance produced longer 

detection distances as expected, but low and medium averages were not significantly different.

Significant differences in detection distance exist between ped scale 2.0 cd/m2and ped scale 0.5 

cd/m2 (adjusted p-value = <0.0001) of approximately 10 meters (32.8 ft). Road scale 2 cd/m2 was 

significantly different from both 1 cd/m2(adjusted p-value=0.0008) and 0.5 cd/m2 (adjusted pvalue = 0.0395).

Figure 13. Detection distance by light type and luminance

Gap Acceptance Experiment

Due to differences in adult and child walking speeds, it is difficult to determine if the responses 

provided by participants, were safe choices. In most cases, crossing the road would be 

considered a safe decision if after a person crossed a roadway, the next vehicle did not reach the 

crosswalk until several seconds later. The task was for participants to indicate when they would 

no longer consider walking across, however, so their answers cannot be based on if the decision 

was a safe choice. Rather, all decisions made by the participants should be considered as “just 
28

unsafe” and cannot be compared to a correct “safe” answer. Therefore, the responses only 

indicate how conservative (or not) participants were with estimations of danger.

In terms of safe stopping distance, the responses provided by participants were more than 

adequate. Assuming a vehicle traveling 25 mph (40 km/h) began to stop immediately as a 

pedestrian entered the crosswalk, that vehicle would come to a complete stop within 

approximately 17 meters (82 ft). At 35 mph (56 km/h) this distance increases to 29 m (95 ft). In 

either case, 17 m (82 ft) and 29 m (95 ft) are far less than the average distance vehicles were in 

the responses, which were approximately 97 m (318 ft) for children and 127 m (417 ft) for 

adults.

When broken down by light type, it was found that adults were more conservative with their 

responses when no roadway lighting was present (Figure 14). For adults, the no-lighting 

condition was statistically significant from both the ped scale (adjusted p-value= <0.0001) and 

road scale (adjusted p-value=0.0418). There were no significant differences between ped scale 

and road scale overall, even when the no-lighting condition was removed from the model.

Figure 14. Crossing acceptance distance for gap experiment by age and light type

Figure 15 shows data charted from a three-way model including age group and light type by 

luminance. There was no significance found between luminance levels, and aside from the 

differences determined in the age groups already highlighted, there are no notable or practical 

trends between luminance.
29

Figure 15. Crossing acceptance distance for gap experiment by age group

No significant effects determined for the speed of the vehicles. For each lighted condition, adults 

responded to each speed within three meters of the other speed. In general, the responses of 

children were more widely varied.

The results of the gap acceptance experiment primarily showed that children are less 

conservative than adults when judging when it is safe to cross a roadway with oncoming traffic. 

This finding was consistent across light types and luminance levels, indicating the lighting did 

not affect their decisions.

In the absence of light, however, adults were more conservative with crossing choices than on a 

lighted roadway, a phenomenon that could be attributed to the lack of certainty in relation to 

depth perception experienced in area with no roadway lighting. It is unclear if adults were 

choosing to cross sooner in the unlighted condition due to uncertainty with the vehicle’s location. 

If so, then perhaps the addition of lighting aided depth perception, resulting in a more confident 

and less conservative choice. In general, neither light type nor level influenced when people 

would choose not to cross. 
30

LIGHTING RECOMMENDATIONS

Lighting for Pedestrian Areas

The research results show a correlation between the lighting level on the roadway and visibility 

of pedestrians. The research indicates that at a level of 9 lux semi-cylindrical or 3 lux vertical 

illuminance, additional light does not increase visibility. A higher lighting level is needed for 

high visual clutter on a roadway, however, which seems to indicate that a luminance level of 2 

cd/m2 is required for visibility in urban settings. As there is a stronger link between the roadway 

luminance and the semi-cylindrical illuminance, it has been determined that the more stringent 

criteria for pedestrian lighting shall be used in the areas which have high pedestrian volumes and 

potential uncertainty in pedestrian behavior. These areas might include school zones or roadways 

with pedestrian levels of 100 pedestrians per hour which is drawn from existing Lighting design 

standards (IESNA RP-8-18, 2018).

A grid of calculation and measurement points aligned along the side of the roadway for adjacent 

sidewalks or along the pedestrian walkway for separated pedestrian paths should be illuminated 

to a minimum level based on a line of calculation points along the path and spaced at no more 

than 2 m (6.6 ft.).

Crosswalk Lighting

Current research shows that crosswalk light levels should be at 20 lux vertical illuminance or 

higher. Recognizing that this level is significantly higher than the levels recommended along the 

side of the roadway, these facilities are in the roadway and the path of the vehicle and as such a 

higher lighting level is recommended. Further research is being developed for these criteria.

In terms of lighting for pedestrians at crosswalks, results of this research indicated that neither 

light level nor light scale impacted the responses of children and adults in regard the point at 

which they would no longer attempt to cross a roadway; however, it was determined that the 

presence of roadway lighting may inform an adult’s perception of depth more accurately. Most 

crosswalks are lit for the primary purpose of allowing pedestrians to be seen. The results of this 

study also indicate a benefit to the pedestrian in being able to make a more confident decision 

regarding the vehicle’s distance from the crosswalk. The decision-making abilities of children 

are not improved with the addition of lighting, nor are they impacted by the lane positioning or 

speed of approaching vehicles.

Luminaire Height

On roadways, pedestrian lighting is typically provided by the roadway lighting system itself. 

However, pedestrian-scale lighting is used for some roadways and pathways. Typically, 

pedestrian scale lighting is mounted at a lower height and provides high levels of vertical 

illumination. Roadway lighting is mounted at a higher elevation and provides a higher level of 

horizontal illuminance. The other issue with a lower mounting height is that luminaires which 

direct vertical illuminance towards the pedestrian also typically have higher glare rating for both 

the person and vehicle drivers. As a result, the roadway luminance needs to increase to overcome 

the potential for disability glare.
31

Recommendations

Based on the research results above, the criteria in Table 7 are recommended for areas where the 

pedestrian lighting is provided by a roadway scale luminaire (6.5 m or 20 ft or higher). For 

pedestrian scale lighting (6.5m in height or lower) an additional 2 lux vertical and 0.5 cd/m2 are 

required to be added to the criteria to overcome the glare from the lower mounting height.

The average of the rural and urban recommendations can be considered for suburban areas.

Note that while these recommendations can be applied to any light source, the Color temperature 

recommendation typically applies to LED light sources only.

Table 7. Recommended Light Level Criteria for Pedestrian Facilities

Pedestrian facility 

characteristics

Pedestrian lighting 

minimum

Rural (Average 

Surface Luminance)

Urban (Average 

Surface Luminance)

Low/medium 

pedestrian volumes 

(0-100 Pedestrians 

per hour)

2 lux vertical No luminance 

recommendation; use 

the typical road 

luminance 

1 cd/m2

High pedestrian 

volume/ school zones 

(>100 Pedestrians per 

hour)

10 lux SC 1 cd/m22 cd/m2

Pedestrian crosswalk 20 lux vertical 

(minimum average)

No luminance 

recommendation; use 

the typical road 

luminance

No luminance 

recommendation; use 

the typical road 

luminance

The spectral characteristics of the light source are recommended to be 4000K CCT however 

other spectral contents can be considered if concerns for the surrounding areas are raised. This 

light source should be a minimum of 3000K CCT.

Other Considerations

Along with these design recommendations, other roadway lighting criteria must also be met. 

This includes consideration of both glare, surround ratio, light trespass, and environmental 

concerns.

Disability glare, which is intensity from a light source that limits a road user’s ability to see, and 

discomfort glare, where light from a luminaire causes discomfort for the driver and pedestrians, 

should be limited. IESNA RP-8-18, 2018 provides guidance for both of these. For disability 

glare adherence to a ratio of veiling luminance to the roadway lighting level is evaluated and 

must meet a design criterion. Similarly, recommendations for the selection and placement of 

luminaires for discomfort glare control are also provided.

Another consideration is that of surround ratio. Current research has shown that lighting at least 

one lane width outside of the roadway driving lanes at 0.8 of the lighting level in the driving 
32

lanes provides significant benefits for the detection of objects and pedestrians in both in and 

beside the roadway. Surround Ratio must be balanced with the needs of the areas adjacent the 

roadway and considered as light trespass. 

Light trespass is a term used to describe light leaving the roadway right of way (ROW) and 

falling on the adjoining properties. This should, whenever possible, be minimized and is 

typically evaluated based on a calculation of a vertical illuminance level at the edge of the ROW. 

For pedestrian lighting however, if the pedestrian way (sidewalk or path) is outside the ROW, 

there may be an exception where the light would leave the ROW to light the pedestrian facility.

The final consideration is areas where the environment must be considered. Certain plant species 

and most animal species are impacted by roadway lighting. Roadway lighting emitted outside of 

the roadway can has been shown to impact soybean crops, bird behavior, and even fish 

migration. This requires that a lighting design must balance the need to light the road and 

pedestrian areas while minimizing light trespass. The criteria might become more stringent in the 

areas of environmental sensitivity. The Lighting Environmental Zone provided in IESNA RP-8 

2018 can be used as guidance.

Design and Verification Approach

For the calculation and the verification of the lighting in the pedestrian sidewalks and areas, the 

calculation grid should be spaced between the luminaires and centered in the design area with a 

maximum spacing of 2 meters (6.6 ft) between grid points in each direction. This grid layout is 

shown in Figure 1

Verification of lighting levels should be made at the same location as in the calculation grid.

Figure 16. Calculation and Verification Grid Layout.
33

CONCLUSION

The objective of this research was to combine results of the three experiments to determine 

recommendations for lighting that benefit drivers and pedestrians. The following conclusions can 

be drawn from this research effort:

· A learning effect was determined for the driving experiment, leading researchers to add a 

weighted emphasis to the results of initial trials. Initial trials indicate that lighting level 

has an impact on visibility. Detection distance increased as light level increased in 

scenarios when the object being presented was unfamiliar. After the initial trials, 

detection distances plateaued regardless of the independent variables. The 

recommendations resulting from this effort focus on the detections recorded for each 

participant prior to when a learning effect was observed.

· It was determined that the optimal semi-cylindrical illuminance was 9 lux. Lighting 

levels below approximately 9 lux yielded shorter detection distances and beyond 9 lux 

there was limited benefit of the additional lighting.

· The results indicated that the 2200 K LED light type does not produce the same level of 

visibility for drivers detecting child-sized pedestrians offset from the roadway as the 4000 

K LED or the 5000 K LED, which could be related to light distribution. SRTS 

interventions that incorporate lighting should consider the use of LEDs of at least 3000K.

· Urban versus rural environments warrant two different lighting designs to enhance the 

visibility of pedestrians. The results indicated that increased luminance levels (2 cd/m2)

may be necessary in environments with visual clutter in a typical in an urban 

environment. Optimal visibility could be maintained in a rural environment with an 

average luminance of 1 cd/m2. These luminance levels combined with the established 

minimum vertical illuminance of 9 to 10 lux form a recommended guideline for 

illuminating pedestrian areas.

· Neither light level nor light scale influenced the responses of children and adults with

regard to the extent they would no longer attempt to cross a roadway; however, it was 

determined that the presence of roadway lighting may inform an adult pedestrian’s

perception of depth more accurately.

· The results offer a consideration for future SRTS interventions by indicating that children 

underestimate the acceptable crossing period compared to adults. Adults were more 

conservative than children by an average of 30 meters (100 feet) or a range of 2 to 3 

seconds with vehicle speeds of 35 and 25 mph (56 and 40 km/h), respectively. The 

provision of lighting seemed to provide greater depth perception which modified decision 

making of adults. Expectedly, the responses provided by children reinforced the need to 

focus on safety considerations with their decision-making and well-being as pedestrians.

· The results of the walking experiment indicated that participants of each age group could 

detect the presence of trip hazards from at least 50 meters across all variables. Therefore, 

the resulting recommendations of this document are not expected to compromise 

visibility of trip hazards of 0.5-inch thickness on a forward walking path.
34

REFERENCES

American Association of State Highway and Transportation Officials. (2011). A Policy on 

Geometric Design of Highways and Streets. ISBN: 1560515082, 9781560515081.

American National Standards Institute/Illuminating Engineering Society. (2018). (ANSI/IES) 

RP-8-18, American National Standard Practice for Design and Maintenance of Roadway 

and Parking Facility Lighting.

Ayres, T. J., & Kelkar, R. (2006). Sidewalk potential trip points: A method for characterizing 

walkways. International Journal of Industrial Ergonomics, 36(12), 1031-1035. 

doi:https://doi.org/10.1016/j.ergon.2006.09.004

Balfour, J. L., & Kaplan, G. A. (2002). Neighborhood Environment and Loss of Physical 

Function in Older Adults: Evidence from the Alameda County Study. American Journal 

of Epidemiology, 155(6), 507-515. doi:10.1093/aje/155.6.507

Bhagavathula, R., & Gibbons, R. B. (2019). Light Levels for Parking Facilities Based on 

Empirical Evaluation of Visual Performance and User Perceptions. LEUKOS, 1-22. 

doi:10.1080/15502724.2018.1551724

Bhagavathula, R., Gibbons, R. B., & Nussbaum, M. A. (2018). Effects of Intersection Lighting 

Design on Nighttime Visual Performance of Drivers. LEUKOS, 14(1), 25-43.

Bhagavathula, R., Gibbons, R. B., Edwards, C. J. Relationship between Roadway Illuminance 

Level and Nighttime Rural Intersection Safety. Transportation Research Record: Journal 

of the Transportation Research Board, 2015. 2485: 8–15.

Boarnet, M. G., Anderson, C. L., Day, K., McMillan, T., & Alfonzo, M. (2005). Evaluation of 

the California Safe Routes to School legislation: Urban form changes and children’s 

active transportation to school. American Journal of Preventive Medicine, 28(2, 

Supplement 2), 134-140. doi:https://doi.org/10.1016/j.amepre.2004.10.026

Boyce, P. (2009). Lighting for Driving: Roads, Vehicles, Signs, and Signals. Boca Raton: CRC 

Press

Bullough, J. D., & Skinner, N. P. (2015). Demonstrating urban outdoor lighting for pedestrian 

safety and security.

Bullough, J. D., Zhang, X., Skinner, N. P., & Rea, M. S. (2009). Design and evaluation of 

effective crosswalk illumination (FHWA-NJDOT-2009-003). Retrieved from Troy, NY: 

https://www.state.nj.us/transportation/refdata/research/reports/FHWA-NJ-2009-003.pdf

Castelli, D., Glowacki, E., Barcelona, J., Calvert, H., & Hwang, J. (2015). Active education: 

Growing evidence on physical activity and academic performance. Active Living 

Research, 1-5.
35

Christoff, T. A. (2013, December 2). Pedestrian Illumination and Street Lighting. 

[Memorandum] Aspen, CO Mayor and City Council. 

http://aspen.siretechnologies.com/sirepub/cache/2/4rcd0l0amx5ji1oimehlprza/141150629

2020012453467.PDF

CIE. (2010). CIE 115:2010 Lighting of Roads for Motor and Pedestrian Traffic: Commission 

Internationale de L'Eclairage.

CIE. (2019). CIE 140:2019 Road Lighting Calculations, 2nd Edition: Commission Internationale 

de L'Eclairage. (DOI 10.25039/TR.140.2019)

DiMaggio, C., & Li, G. (2013). Effectiveness of a Safe Routes to School Program in Preventing 

School-Aged Pedestrian Injury. Pediatrics, 131(2), 290-296. doi:10.1542/peds.2012-2182

Donnell, E. T., Porter, R. J., & Shankar, V. N. (2010). A framework for estimating the safety 

effects of roadway lighting at intersections. Safety science, 48(10), 1436-1444. 

Edwards, C., & Gibbons, R. (2008). Relationship of vertical illuminance to pedestrian visibility 

in crosswalks. Transportation Research Record: Journal of the Transportation Research 

Board (2056), 9-16.

Elvik, R. (1995). Meta-analysis of evaluations of public lighting as accident countermeasure. 

Transportation Research Record(1485), 112-123. 

Fotios, S., & Cheal, C. (2009). Obstacle detection: A pilot study investigating the effects of lamp 

type, illuminance and age. Lighting Research & Technology, 41(4), 321-342. 

doi:10.1177/1477153509102343

Freedman, M., Janoff, M., Koth, B., & McCunney, W. (1975). Fixed illumination for pedestrian 

protection. Retrieved from

Gallagher, E. M., & Scott, V. J. (1997). The STEPS Project: Participatory Action Research to 

Reduce Falls in Public Places Among Seniors and Persons with Disabilities. Canadian 

Journal of Public Health, 88(2), 129-133. doi:10.1007/bf03403876

Governors Highway Safety Association. (2017). Pedestrian Traffic Fatalates by State. Retrieved 

from https://www.ghsa.org/sites/default/files/2018-02/pedestrians18.pdf

Hasson, P., & Lutkevich, P. (2002). Roadway lighting revisited. Public roads, 65(6), 32-36.

Hillman, C. H., Pontifex, M. B., Raine, L. B., Castelli, D. M., Hall, E. E., & Kramer, A. F. 

(2009). The effect of acute treadmill walking on cognitive control and academic 

achievement in preadolescent children. Neuroscience, 159(3), 1044-1054. 

doi:https://doi.org/10.1016/j.neuroscience.2009.01.057

Hills, B. L. (1980). Vision, visibility, and perception in driving. Perception, 9(2), 9. 
36

Huston, S. L., Evenson, K. R., Bors, P., & Gizlice, Z. (2003). Neighborhood Environment, 

Access to Places for Activity, and Leisure-Time Physical Activity in a Diverse North 

Carolina Population. American Journal of Health Promotion, 18(1), 58-69. 

doi:10.4278/0890-1171-18.1.58

IESNA. (2018). IES-RP8-2018: Roadway Lighting Recommended Practice. Illuminating 

Engineering Society, Wall Street, NY. 

Isebrands, H. N., Hallmark, S. L., Li, W., McDonald, T., Storm, R., & Preston, H. (2010). 

Roadway lighting shows safety benefits at rural intersections. Journal of Transportation 

Engineering, 136(11), 949-955. 

Jaschinski, W. (1982). Conditions of emergency lighting. Ergonomics, 25(5), 363-372. 

doi:10.1080/00140138208925002

Li, Yingfeng Eric; Bhagavathula, R., Terry, T. N., Gibbons, R. B, Medina, A. (2020). Safety 

Benefits and Best Practices of Intersection Lighting. Virginia Transportation Research 

Council, Charlottesville, VA. 

Lopez, R. P., & Hynes, H. P. (2006). Obesity, physical activity, and the urban environment: 

public health research needs. Environmental Health, 5(1), 25. doi:10.1186/1476-069x-5-

25

Loukaitou-Sideris, A., Liggett, R., & Sung, H.-G. (2007). Death on the Crosswalk: A Study of 

Pedestrian-Automobile Collisions in Los Angeles. Journal of Planning Education and 

Research, 26(3), 338-351. doi:10.1177/0739456x06297008

Lutkevich, P., R. Gibbons, R. Bhagavathula, and D. Mclean. (2019). Solid-State Roadway 

Lighting Design Guide: Volume 2: Research Overview. NCHRP Research Report 940. 

Transportation Research Board, Washington, D.C. 

Minoshima, O., Oka, K., Ikehara, K., & Inukai, N. (2006). Research on Accident Reduction by 

Intersection Lighting. Paper presented at the Road Engineering Association of Asia and 

Australasia (REAAA) Conference, Philippines.

National Center for Statistics and Analysis. (2020). Pedestrians: 2018 data. DOT HS 812 850 

Washington, DC: 

National Center for Statistics and Analysis. (2020). Rural/urban comparison of traffic fatalities: 

2018 data. Retrieved from Washington, DC: 

National Highway Traffic Safety Administration. (2015). Fatalities Analysis Reporting Systems 

(FARS). 

National Safety Council. (2017). Top Work-Related Injury Causes. Retrieved from 

https://injuryfacts.nsc.org/work/work-overview/top-work-related-injury-causes/
37

NCSS Statistical Software (2019). Chapter 222 – Mixed Models – Repeated Measures. Found 

online at (https://ncss-wpengine.netdna-ssl.com/wpcontent/themes/ncss/pdf/Procedures/NCSS/Mixed_Models-Repeated_Measures.pdf) 

[Accessed November 3, 2019]

O'Neal, E. E., Jiang, Y., Franzen, L. J., Rahimian, P., Yon, J. P., Kearney, J. K., & Plumert, J. M. 

(2018). Changes in perception–action tuning over long time scales: How children and 

adults perceive and act on dynamic affordances when crossing roads. Journal of

Experimental Psychology: Human Perception and Performance, 44(1), 18–26.

Orenstein, M. R., Gutierrez, N., Rice, T. M., Cooper, J. F., & Ragland, D. R. (2007). Safe Routes 

to School safety and mobility analysis.

Peli, E. (1990). Contrast in complex images. Journal of the Optical Society of America, 7(10), 

2032.

Pelli, D. G., & Bex, P. (2013). Measuring contrast sensitivity. Vision Research, 90, 10-14.

Polus, A., & Katz, A. (1978). An analysis of nighttime pedestrian accidents at specially 

illuminated crosswalks. Accident Analysis & Prevention, 10(3), 223-228. 

doi:https://doi.org/10.1016/0001-4575(78)90013-1

Sasidharan, L., & Donnell, E. T. (2013). Application of propensity scores and potential outcomes 

to estimate effectiveness of traffic safety countermeasures: Exploratory analysis using 

intersection lighting data. Accident Analysis & Prevention, 50, 539-553. 

doi:https://doi.org/10.1016/j.aap.2012.05.036

Stewart, O., Moudon, A. V., & Claybrooke, C. (2014). Multistate Evaluation of Safe Routes to 

School Programs. American Journal of Health Promotion, 28(3_suppl), S89-S96. 

doi:10.4278/ajhp.130430-QUAN-210

Terry, T., Brimley, B., Gibbons, R., & Carlson, P. J. (2016). Roadway Visibility Research Needs 

Assessment.

Trust for America’s Health. (2018). The State of Obesity: Better Policies for Healthier America 

2018. Retrieved from Washington, DC: https://stateofobesity.org/wpcontent/uploads/2018/09/stateofobesity2018.pdf

U.S. Department of Health and Human Services. (2018). Physical Activity Guidelines for 

Americans, 2nd edition. Retrieved from Washington, DC: 

https://health.gov/paguidelines/secondedition/pdf/Physical_Activity_Guidelines_2nd_edition.pdf

US Department of Transportation. (2015). Safe Routes to School Programs. Retrieved from 

https://www.transportation.gov/mission/health/Safe-Routes-to-School-Programs
38

Wilken et al. (2001). European Road Lighting Technologies, Report FHWA-PL-01-034, Office 

of Policy of International Porgrams, Federal Highway Administration, Washington, D.C. 

80pp. 

Wortman, R., Lipinski, M., Fricke, L., Grimwade, W., & Kyle, A. (1972). Development of 

warrants for rural at-grade intersection illumination.
39

APPENDICES

Appendix A: Lighting Design Metrics

Illuminance

Illuminance, the amount of luminous flux per unit area, in other words, a measure of incident 

light illuminating a surface. For roadway lighting it is measured primarily by three approaches: 

horizontally, vertically, and semi-cylindrically (shown in Figure 17).

Horizontal Illuminance

Illuminance on a surface is defined as the luminous intensity on the plane normal to the direction 

of propagation of light divided by square of the distance between the source and the surface (the 

inverse square law). Illuminance is measured on a road surface horizontally; an increase in 

vertical illuminance improves the accuracy and speed that information can be ascertained from 

the roadway environment. This method is supported by previous research (Boyce, 1973; 

Eloholma et al., 2006; Rea, 2000; Terry & Gibbons, 2015). Night crashes at intersections have 

also been mitigated by increasing horizontal illuminance level (Bhagavathula et al., 2015; 

Minoshima et al., 2006; Oya, Ando, & Kanoshima, 2002). 

Vertical Illuminance

For pedestrian visibility, studies have shown that a vertical illuminance level of 20 lux at height 

of 1.5 m (5 ft) from the road surface resulted in good driver visual performance at nighttime 

(Edwards & Gibbons, 2008). Vertical illuminance measurements are typically recorded at eye 

level of an observer oriented to their path of travel, whether driver or pedestrian. Generally, a 

height of 1.5 m (5 ft) from the ground is used for standards regarding a standing pedestrian.

Semi-cylindrical Illuminance

Semi-cylindrical illuminance, which has shown links to visual performance (Rombauts, 

Vandewyngaerde, & Maggetto, 1989), has gained interest as a metric since earlier crosswalkrelated works. Semi-cylindrical illuminance is a measure that considers the light falling on a 

semi-cylinder rather than on a flat surface. Because pedestrians are not flat, this metric may more 

accurately represent performance and allow for the three-dimensional aspect of the object 

(Figure 17).
40

Figure 17. Illuminance measurement diagram

Semi-cylindrical illuminance is measured in the same way as vertical illuminance but is done so 

using a type of equipment designed to incorporate lighting from 180-degrees to better represent 

human vision by incorporating the peripheral vision. 

It is notable that the semi-cylindrical illuminance provides an illuminance level that more closely 

represents actual lighting experience and gathers light from all directions within its 180-degree 

operational field. This metric seems to average measured illuminance, meaning that when an 

object is close to a luminaire, it receives light on its side face but when it is far away, it receives 

light on its front vertical face. This implies that while vertical illuminance varies widely, the 

semi-cylindrical does not.

As facial recognition is critical for the perception of safety and comfort for pedestrians (Castelli, 

Glowacki, Barcelona, Calvert, & Hwang, 2015; National Center for Statistics and Analysis, 

2020), semi-cylindrical illuminance may be a better metric for the pedestrian lighting 

requirements. 

Luminance

Luminance is the amount of light emitted from a surface in a specific direction per unit area. A 

luminance measure describes the amount of “brightness” of an object when viewed from a given 

direction. Research has shown that increasing the luminance of the roadway surface makes the 

objects on the roadway easier to detect (Economopoulos, 1978). At night, drivers can detect 

objects sooner as the average luminance of the roadway increases (Cuvalci & Ertas, 2000; 

Gibbons et al., 2015; He et al., 1997; Lewis, 1999).

Design criteria and recommended practices are guided by basic measures of luminance: such as 

average, minimum, and average-to-minimum ratios. ANSI/IES RP-8-18, a roadway lighting 

recommended practice guide, provide specifications for average luminance and average 

uniformity ratios for certain road classes. A street classified as major with a high pedestrian 

conflict should have an average luminance of 1.2 cd/m2(candela per square meter) and an 
41

average uniformity ratio of 3.0 Lavg/Lmin. A roadway classified as local with high pedestrian 

conflict is required to possess an average luminance of 0.6 cd/m2and an average uniformity ratio 

of 6.0 Lavg/Lmin. The difference between the two scenarios is the road class, which often involves 

differences in speed, lane width, and identifiable markings. The type of lighting system, 

mounting height of luminaires, or the color temperature of the lighting do not impact luminance 

metrics or recommendations for road classes and pedestrian zones (Illuminating Engineering 

Society, 2014).

Contrast

Contrast is the measurable visible difference between a target and the target’s background. There 

are two types of contrast: color and luminance. Color contrast is the measurable difference 

between two colors. Luminance contrast is the measurable monochromatic difference between a 

lighted target and its background.

Contrast sensitivity is a measure of a person’s ability to discern between different levels of 

luminance in a static environment. To test the contrast sensitivity of an individual, a visual target 

is placed in front of a uniform background. The contrast of the target to its background 

determines how visibly distinguishable it is. If the luminance of the background is changed, in 

either direction, it may make the target more difficult or easier to see. The ability of an individual 

to distinguish the background from the foreground is the standard deviation of pixels in an 

image. This method is commonly used to define the contrast of a single image so that two 

different images can be directly compared (Peli 1990).

Weber Contrast is the most commonly used metric and most applicable to night driving research. 

Weber Contrast incorporates the concept of absolute contrast or contrast polarity. This means 

both negative and positive contrasts are accounted for in the equation. In night driving, 

headlamps present a unique construct in that most objects within the span of headlamps contrast 

positively to their background even if that background is also lit by infrastructure lighting. This 

degree of positivity is affected by angle and distance.

Weber contrast is the difference in the highest and lowest luminance in each scene divided by the 

average luminance of its background. This value may result in a positive or negative number. 

With positive contrast, the target appears brighter than its background; with negative contrast, 

the target appears darker than its background (Figure 18) (Peli 1990, Gibbons, Edwards et al. 

2008, Pelli and Bex 2013).
42

Figure 18. Negative and positive and contrast (Gibbons, Edwards et al. 2008)

The environment, notably glare, plays an important role in visual acuity and contrast sensitivity. 
43

Appendix B: Independent Variables

Driver Experiment Independent Variables

Several variables were controlled for or manipulated during the study. The approximately 90-

minute duration of each experimental session experienced by participants, necessitated by the

need to control for numerous independent variables, had the potential to introduce confounding 

effects of learning, which were investigated during analysis.

Spectral Power Distribution of the Light.

In the absence of an established metric to distinguish the SPDs of luminaires, correlated color 

temperature (CCT) was used to evaluate the effect of SPDs on visual performance. The 2200 K 

and 5000 K CCT LED luminaires represent the minimum and the maximum CCTs currently 

available on the market. The 4000 K LED is widely used in roadway lighting. Figure 19 shows 

the visual differences between the three different light sources used in the driver experiment.

Figure 19. View of child-sized mannequin under each SPD

The Smart Road dimming system balances luminance on the roadway between each of the 

luminaire configurations. The SPDs of the luminaires is shown in Figure 20.
44

Figure 20. Spectral Power Distribution of luminaires; relative irradiance spectral content 

normalized for 6.27 lux

For the walker and gap acceptance experiments, 4000 K luminaires were mounted at two heights 

on poles within the Surface Street expansion. The two luminaire types chosen for the study were 

to represent a roadway lighting system and an urban/suburban lighting system, which are 

distinguished by mounting height. The first luminaire, pole-mounted at a height of 30 ft (9.1 m), 

was an overhead road-scale luminaire. The second, mounted at height of 15 ft (4.5 m) was posttop luminaire. 

Road Luminance and Vertical Illuminance.

Researchers examined the effect of three roadway luminance levels (2 cd/m2, 1 cd/m2, and 0.5 

cd/m2) on the effect of visual performance of objects in that surrounding area. These levels were 

achieved by adjusting the output of the lighting systems. The lighted test area was designed to 

achieve the specific roadway luminance using AGI-32 software and verified upon installation 

manually using a handheld LS-110 luminance meter. 

Positions along the test track that were used for placement of the child-sized mannequins were 

selected on the basis of vertical illuminance to control the amount of illuminance on the visual 

target and to ensure that variations of illuminance were evaluated across each variable 

combination of light type and luminance level.
45

Age

While younger drivers have better visual acuity, older drivers have more driving experience. 

Thus, by including age as an independent measure, a wide range of physiological capabilities and 

driving experiences were considered. To examine how these physiological changes in the eyes 

affect the visual performances of drivers and pedestrians, the driver experiment included 36

participants divided between two age groups: younger (25-45 years) and older (65 and older). 

Environment

Only one location on the route provided an environment simulating an urban setting. The urban 

environment included a sidewalk, light pole, bicycle, work zone sign, and trash can. A golf cart 

simulated a bus stop or structure behind the mannequin’s location (Figure 21). The mannequin 

was placed on the sidewalk during experimental trials. The precise location along the sidewalk 

was determined by vertical illuminance and light type. The remaining four locations on the route 

were rural settings with only a guardrail in the background of the mannequin. 

Figure 21. Urban environment for driver experiment (mannequin highlighted with green 

outline)

Light Source Scale

The three experiments compared the impact of different mounting heights. Road-scale lighting 

was mounted 30 ft (9.1 m) high, as is typical for most roadway lighting installments. The second 

mounting height, 18 ft (5.4 m), is considered street lighting or pedestrian-scale lighting, as it is 

designed for the benefit of pedestrians and is mounted lower than road scale lighting. This 

lighting design is typically found in urban environments where pedestrian traffic is greater in 
46

favor of the higher-mounted streetlights (Figure 22). The third lighting design, not shown here, is 

highway-scale luminaires mounted (50-ft [15.2m]) high.

Figure 22. Comparison of pedestrian- and road-scale mounting heights

Walker Experiment Independent Variables

Many of the variables for the walker experiment were the same as those for the driver 

experiment. The SPD, luminance, and light types remained largely the same.

The key differences include the illuminance on the tripping hazard. The illuminances were 

measured vertically, rather than semi-cylindrically. These measurements were taken at the 

ground (oriented vertically) facing the direction of the observer. Ped- and road-scale vertical 

illuminance levels were different because they required different levels of output for each to 

achieve the luminance levels. Due the luminaire’s shorter distance to the roadway and the angle 

of the light, the ped scale illuminance levels at the road’s surface were slightly higher than that of 

the road scale for each luminance.

In addition to the two adult age groups used for the driver experiment, this experiment added a 

child age group of age 8 to 12. This age range was chosen due to their ability to follow 

instructions and the amount of walking required for the protocol, so younger ages were excluded. 

There were 36 total participants: 18 children, 9 younger adult (25-45 years) and 9 older adults 

(65 years and older).
47

Trip Hazards

The objects depicted in Figure 23 were 30.4 x 30.4 cm (1 x 1 ft) plywood squares that were 

painted black and covered with gray shingle to disguise themselves to the roadway. Two 

different thicknesses were used to compare variations in trip hazards. Targets were 1.2-cm 

(0.5-inch) and 2.5-cm (1-inch) thick (Figure 23).

Figure 23. Tripping hazards

Lanes

Two targets were positioned in each lane. One position was 40 ft (12.2 m) further away than the 

other. Figure 24 diagrams the different lanes used and the position of the targets. On the left, the 

separation of lanes A and B are shown, and an individual is pictured walking toward the lighted 

intersection. On the right, the four circles represent the approximate location of the luminaires. 

Each square represents an area where a target could be positioned for each trial.
48

Figure 24. Diagram of Walker Experiment lanes and target positions

Gap Acceptance Independent Variables

The lanes were chosen for safety and due to time limitations of study length. To incorporate all 

four lanes of travel, or even three, would increase the number of trials and extend the study an 

amount of time that would make recruiting small children to participate more difficult. The 

nearest lane that could be chosen was the second lane (one lane separated from the jersey barriers 

for safety considerations). The furthest lane (lane four) was selected to observe a greater contrast 

in observations than the next lane (lane 3) would be expected to show.

The speeds of 25 mi/h (40 km/h) and 35 mph (56 km/h) were selected as typical speeds where 

crosswalks are common.
49

Appendix C: Vehicles and Experimental Area

Vehicles

For the driver experiment, the test vehicles driven by participants were two identical 2017 Ford 

Explorers. Each vehicle was equipped with a data acquisition system that captured four camera 

views inside and outside the vehicle, GPS data, and vehicle network data. In-vehicle 

experimenters denoted when a participant detected a mannequin with a button press. The press 

and recorded in-vehicle audio were used to determine when an experimental object was seen.

For the gap experiment, the same two vehicles traversed through the intersection.

Experimental Area

This project was conducted on the Virginia Smart Roads, a suite of testing facilities that includes 

2.5 m (4 km) of controlled-access roadway (Figure 25). The Smart Roads are equipped with a 

configurable roadway lighting system that includes 75 poles, each of which supports three 

luminaires. The lighting system can be configured to spacings of 40, 60, 80, and 120 m (131, 

197, 262, and 394 ft) between lights. With the remotely controlled lighting system, researchers 

can change luminaires, spacing, or luminance levels as needed. A speck of 80 m (262 ft) was 

used for the driver experiment.

The Surface Street Facility allows a reconfigurable visual environment in a controlled 

environment. This area allowed for the pedestrian and road scale luminaires to be implemented. 

Due to the flexibility of the testing area, the design of these lights could be tailored specifically 

to the experimental area and were movable via forklift.
50

Figure 25. Smart Road test area.
51

Appendix D: Analysis and Discussion of Experimental Results

This section will highlight the significant main effects, interactions, and relationships between 

the variables tested across the three experiments conducted for this research. Linear Mixed 

Modeling (LMM), ideal for repeated measures designs (NCSS Statistical Software, 2019) was 

used to examine the fixed effects of luminance, vertical illuminance, and light spectral power 

distribution on the detection distances. Post hoc analyses were performed on significant 

interactions using a difference of least squared means procedure adjusting for multiple 

comparisons. The significance level (a) was set at 0.05 for all statistical tests.

Semi-cylindrical versus Vertical Illuminance

A secondary objective of this research was to compare different methods of measuring 

illuminance: 

1. using an Everfine Photo-2000EZ semi-cylindrical illuminance meter and 

2. using a vertical Konica Minolta T-10 illuminance meter. 

The illuminance at locations used for the visual targets in the driving study was recorded using 

both methods and plotted in Figure 26. All vertical illuminance measurements were taken at the 

height of the child mannequin’s face (approximately 1.2 m (4 ft) from the ground) facing the 

direction participants would be observing them. The result is a linear relationship (R2=0.9142). 

As expected, the semi-cylindrical instrument resulted in higher illuminance values because it is 

designed to receive light from a wider angle.

Figure 26. Comparison of illuminance methods (Konica Minolta T-10 versus Everfine 

Photo-2000EZ Semi-Cylindrical).
52

Figure 27 shows the illuminance measured by detection distance via both the semi-cylindrical 

and vertical methods. The results of this experiment indicate that neither metric is a better 

predictor for visibility; however, semi-cylindrical was chosen to represent the measurements 

taken in this document due to its accounting for multiple angles of light similar in characteristic 

to a human face would. 

Figure 27. Detection distance by illuminance per measurement method

To further compare semi-cylindrical and vertical illuminance measurement methods, the research 

team plotted out a 25 x 4 grid marked at 5-ft (1.5-m) intervals with two parking lot luminaires 

spaced 105 ft (32 m) apart inside the grid (leaving a 1 x 4 end grid second behind the luminaries)

Using both methods, the team measured illuminance at every intersection of the grid at 5-foot 

(1.5-m) intervals, including in the end grids beyond the poles. Each measurement instrument was 

mounted on a 5-ft tripod oriented orthogonally toward the direction of the second luminaire. 

Figure 28 illustrates the lighting profile created by the two measurement types.
53

Figure 28. Spatial comparison of illuminance methods (vertical illuminance versus semicylindrical illuminance)

In this comparison, the semi-cylindrical measurements are higher under the luminaire than the 

vertical because the side of the meter detects the light, whereas the vertical is higher farther from 

the light where the luminaire throws light towards the measurement point.

Driver Experiment Results

Figure 29 shows the relationship between vertical illuminance measured with the semicylindrical illuminance meter and detection distance. In general, detections of mannequins under 

the 2200 K LED were lower than those of 4000 K and 5000 K LEDs. Additionally, no strong 

relationship is found between the amount of illumination at the face of the child-sized mannequin 

and the distance at which they could be detected for any light source.
54

Figure 29. Detection distance by semi-cylindrical illuminance for each light type (2200 K, 

4000 K, 5000 K LEDs)

Figure 30 isolates the detection distances of the first two laps when presentations of the 

mannequin were less expected by the participants. The first lap indicates the impact of luminance 

as detection distances stair-step upward by approximately 10 m (3.3 ft) for each luminance level. 

On lap 2, when participants have learned what to expect from the experiment, the 0.5 cd/m2

luminance level outperforms all luminance levels from the first lap. There is little difference 

between luminance levels on lap 2, indicating that the learning effect can supersede the

luminance required for vision, and that design guides should put a weighted emphasis on 

unexpected scenarios, such as the results of lap 1.
55

Figure 30. Detection distance by luminance (cd/m2) per lap for first two laps of the driver 

experiment

Detection distance by semi-cylindrical illuminance for laps one and two are shown in Figure 31. 

The low R-square value indicates that, unlike luminance, semi-cylindrical illuminance was not a 

factor in the visibility of the mannequins. However, it can be deduced that illuminances of 

approximately 9 semi-cylindrical lux and greater were able to produce longer detection distances 

than those less than 9 semi-cylindrical lux, perhaps indicating a minimum semi-cylindrical level 

for design considerations.
56

Figure 31. Detection distance by illuminance per measurement method for laps 1 and 2

For the mannequin placed in the urban environment, where the ped scale and road scale 

luminaires were positioned, luminance appears to have an impact on visibility. There was a 

significant difference found between within the ped scale-light type between 2 cd/m2 and 

0.5 cd/m2(adjusted p = 0.0101). For the road-scale light type, statistically significant differences 

were found between 2 cd/m2and each other luminance: 1 cd/m2 (adjusted p-value=0.0037) and 

0.5 cd/m2(adjusted p-value=0.0087) (Figure 32).
57

Figure 32. Detection distance for urban environment by light type and luminance

Walker Experiment Results

Figure 33 shows the relationship between horizontal and vertical illuminance of the trip hazard 

target (at the ground) for each luminance level. The right vertical axis corresponds to the average 

detection distance under each light level. Increase in the light level (both horizontal and vertical) 

resulted in longer detection distances.
58

Figure 33. Horizontal and vertical illuminance (lux) and detection distance (m) by

luminance level (cd\m2)

Results indicate there is no significant effect between any two light combinations (ped scale or 

road scale) and their lighting levels among child participants. There was only a significant 

difference between light type within an age group as ped scale-2 cd/m2and ped scale-0.5 cd/m2

(adjusted p-value = 0.0134) resulted significantly different distances among older adults. One 

noteworthy result is that older adults identified the presence of trip hazards approximately 6 m 

(20 ft) further under road scale 0.5 cd/m2compared to road scale 1 cd/m2.

From a practical detection standpoint, every light combination used in the experiment allowed 

pedestrians to visualize trip hazards as small as 12.7 cm (0.5 in) from at least approximately 40 

m (131 ft). This distance is more than ample for the detection of a potential trip hazard. It is 

important to note that this experiment was conducted on a closed road course and participants 

were instructed to look for an object in an intersection; therefore, the task required no saccades 

and attention was focused on trip hazard detection. Though not statistically significant, the mean 

detection distances shown in (Figure 34) indicate that the detection distances are affected by light 

level, as expected. There is a noticeable difference between ped scale and road scale distances 

for each light type within each age group of approximately 6 to 10 m (20 to 32 ft), but this 

difference was not determined to be statistically significant.
59

Figure 34. Detection distance for age by light type and luminance (cd/m2)

Statistical significance was found in the model comparing ped-scale lighting to road-scale 

lighting (Figure 35). The average detection distances for ped scale were estimated to 61.9 m (203 

ft); those for road scale were estimated at 54 m (178 ft) (adjusted p-value = 0.0001).

Figure 35. Detection distance by light type
60

Comparing the luminance levels produced by ped- and road-scale light types, participants 

identified trip hazards significantly further away under 2 cd/m2luminance compared to 1 cd/m2 

(adjusted p-value = 0.0004) and 0.5 cd/m2

(adjusted p-value = <0.0001) levels (Figure 36).

Figure 36. Detection distance by luminance

As in the driver experiment, the walker experiment saw the impact of a learning effect with age 

groups. Figure 37 shows the number of trials broken into three groups of five. During the 

experiment, the lighting condition changed every five laps, providing a natural break for this 

data. The children and young adults improved between the first and second five trials and then 

plateaued, indicating a subtle learning effect. Older adults improved between the first and second 

five trials, indicating a learning effect, but regressed for the third group of trials, perhaps 

indicating fatigue.
61

Figure 37. Detection distance by number of trials for each age group 9

Gap Experiment Results

The research team was interested in how the responses of children would differ from adults. 

Overall, adults were more conservative and indicated they were uncomfortable crossing much 

sooner than children by approximately 30 m (100 ft), a statistically significant difference 

(adjusted p-value = 0.0499) (Figure 38).
62

Figure 38. Crossing acceptance distance for gap experiment by age group
63

Appendix E: Lighting Design Examples 

Design examples included below show some typical areas for the various classes of pedestrian 

facilities. They are focused on areas where child pedestrians are expected which typically 

includes school zones, recreational facilities, sports, and community facilities, etc. It is also 

worth noting that the dark times of day when children use these types of facilities is limited and 

dependent on location and time of year. Consideration should be given for the use of adaptive 

lighting systems on new installations meeting the recommendations of this guideline in order to 

meet the safety intent of the recommendations but also limit control any lighting impacts to the 

surrounding areas. Methods for applying adaptive lighting technologies is included in ANSI/IES 

RP-8-18 as well as Solid-State Roadway Lighting Design Guide: Volume 2: Research Overview 

(Lutkevich et al., 2019).

Example A: Low/Medium Pedestrian Volume

Design Problem:

Lighting design for the selection and placement of Luminaire for both the roadway and the 

adjoining pedestrian facility.

Base Condition:

· A collector type of street with a medium pedestrian volume in a suburban area.

· The peak hourly pedestrian volumes occur before and after school hours as this street is 

used by some students living in the neighborhoods within walking distance of the school 

and sports facilities. 

· Volumes during peak hours on this street are approximately 50 pedestrians per hour.

Design Criteria:

Selection and placement of luminaire to provide an average vertical illuminance in the sidewalk 

area of 2 lux.

· No roadway light levels are recommended as part of this guideline, so levels advised by 

IES, AASHTO, or local criteria should be applied.

· The IES recommendations for the roadway lighting are 0.6 cd/m2per the table from 

ANSI/IES RP-8-18 for a collector roadway with medium pedestrian volumes.

Design Approach:

· As shown in Figure 39, Figure 40, and Table 8, a mounting height of 9.1 m (30 ft) was 

used for the LED roadway luminaires with pole located behind the sidewalk and spaced 

48 meters (160 feet) apart. A vertical illuminance grid is then placed on the sidewalk area 

at a height of 1.5 meters. Three rows of points are used in this example.
64

· The light levels on the roadway meet the IES recommended levels as well as uniformity 

and glare and the vertical illuminance levels recommended by this guideline are exceeded 

at 8.8 lux, meeting the needs identified in this research.

Figure 39. Simplified grid and values for Low/Medium pedestrian traffic in rural area 

design

Figure 40. Illustration for low pedestrian traffic design

Table 8. Values for low pedestrian traffic design.

Label CalcType Units Avg Max Min Avg/Min Max/Min LVRatio

Road East_Luminance Luminance Cd/Sq.m 0.68 1.0 0.5 1.36 2.00 N.A.

Road East_Veil_Lum Veiling Luminance Cd/Sq.m 0.06 0.2 0.0 N.A. N.A. 0.29

Road West Luminance Luminance Cd/Sq.m 0.98 1.4 0.7 1.40 2.00 N.A.

Road West_Veil_Lum Veiling Luminance Cd/Sq.m 0.10 0.2 0.0 N.A. N.A. 0.20

Sidewalk_Vert_Illum Vertical Illum. Lux 8.81 31.0 0.1 88.10 310.00 N.A.
65

Example B: High Pedestrian Volume / School Zone (Rural-Suburban)

Design Problem: 

Lighting design for a pedestrian area on a suburban road within a school zone. 

Base Condition:

· Suburban road with Crosswalk in a School Zone

· During school hours or after school activities the pedestrian volumes in the area would 

also be classified as high.

Design Criteria:

· The recommendations are to provide 10 lux semi-cylindrical for the pedestrian/sidewalk 

areas and between 1 and 2 cd/m2on the roadway. 

· Because this roadway is considered a suburban area, a roadway lighting level of 1.5 

cd/m2is used for the roadway light level.

Design Approach:

· This example design uses 10.6 meter (35 ft) mounting height for the LED roadway 

luminaires with pole located behind the sidewalk and spaced 48 meters (160 ft) apart. 

· A semi-cylindrical illumnance grid is placed on the sidewalk area at a height of 1.5 

meters. The rows of points in this example are in accordance with the CIE:140 

methodology.

· The lighting levels on the roadway meet the 1.5 cd/m2roadway lighting level and 10 lux 

semi-cylindrical recommendations included in this guide. 

· It also meets IES recommended levels for uniformity and glare (Figure 41, Figure 42, and 

Table 9).).
66

Figure 41. Simplified grid and values for School Zone in a Suburban Area

Figure 42. Illustration for high pedestrian traffic in rural or suburban area design
67

Table 9. Values for high pedestrian traffic in rural or suburban area design

Label CalcType Units Avg Max Min Avg/Min Max/Mini LVRatio

Road North_Luminance Luminance Cd/Sq.m 1.52 2.0 1.0 1.52 2.00 N.A.

Road North_Veil_Lum Veiling Luminance Cd/Sq.m 0.18 0.4 0.0 N.A. N.A. 0.26

Road South Luminance Luminance Cd/Sq.m 2.59 3.4 1.8 1.44 1.89 N.A.

Road South_Veil_Lum Veiling Luminance Cd/Sq.m 0.22 0.4 0.0 N.A. N.A. 0.15

Sidewalk North Semi Ill Semicylindrical Illum. Lux 10.15 20.4 3.8 2.67 5.37 N.A.

Sidewalk North_Vert_Ill Vertical Illum. Lux 11.43 28.4 0.5 22.86 56.80 N.A.

Sidewalk South Semi Ill Semicylindrical Illum. Lux 12.76 35.5 0.3 42.53 118.33 N.A.

Sidewalk South_Vert_Ill Vertical Illum. Lux 19.62 53.8 0.4 49.05 134.50 N.A.

Example C: High Pedestrian Volume / School Zone (Urban)

Design Problem:

This example represents a school zone in an urban environment on a major road.

Base Conditions:

· School-related pedestrian volumes for this school is considered high and medium during 

non-school hours. 

· The roadway has parking along each side of the roadway and relatively wide sidewalk 

cross sections.

Design Criteria:

The recommendations are to provide 10 lux semi-cylindrical illuminance for the 

pedestrian/sidewalk areas and a luminance of 2 cd/m2on the roadway.

Design Approach:

· This example design (Figure 43, Figure 44, and Table 10) uses 9.1-m (30-ft) mounting

height for the LED roadway luminaires with poles located behind the face of curb for the 

sidewalk and spaced 36.5 m (120 feet) apart with an opposite pole layout arrangement 

and lumunaires on each side to the roadway. 

· A semi-cylindrical illumnance grid is placed on the sidewalk area at a height of 1.5 m (5 

ft). The rows of points in this example are in accordance with the CIE:140 methodology.

· The luminance on the roadway exceeds the 2 cd/m2roadway light level and meet the 10 

lux semi-cylindrical illuminance recommendations included in this guide. 

· Lighting levels meets IES recommended levels for uniformity and glare. 

Other Considerations:

· Because of the wide roadway cross section, light levels on the roadway are driven by the 

pedestrian lighting requirements. 

· An adaptive lighting control for this installation would be beneficial.
68

Figure 43. Simplified grid and values for High Pedestrian traffic School Zone in Urban 

Area Design

Figure 44. Illustration for high pedestrian traffic school zone in urban area design

Table 10. values for high pedestrian traffic school zone in urban area design

Label CalcType Units Avg Max Min Avg/Min Max/Min LVRatio

Road 1 Luminance Luminance Cd/Sq.m 3.45 4.2 2.8 1.23 1.50 N.A.

Road_1_Veil_Lum Veiling Luminance Cd/Sq.m 0.36 0.6 0.1 3.60 6.00 0.17

Road 2 Luminance Luminance Cd/Sq.m 3.43 4.0 2.9 1.18 1.38 N.A.

Road_2_Veil_Lum Veiling Luminance Cd/Sq.m 0.35 0.6 0.1 3.50 6.00 0.17

Sidewalk 1 Semu Illum Semicylindrical Illum. Lux 11.30 32.7 2.5 4.52 13.08 N.A.

Sidewalk_1_Vert_Illum Vertical Illum. Lux 15.93 49.4 1.2 13.28 41.17 N.A.

Sidewalk Semi Illum Semicylindrical Illum. Lux 10.10 30.4 2.7 3.74 11.26 N.A.

Sidewalk_Vert_Illum Vertical Illum. Lux 13.64 45.4 1.2 11.37 37.83 N.A.
69

Example D: Urban Roadway

Design Problem:

This is a roadway in an urban area with significant pedestrian volume, wide sidewalks, and 

residential buildings on each side of the roadway.

Base Conditions:

· The road is 5 lanes wide with a center turn lanes and parking on both sides of the 

roadway. 

· The sidewalks are 10 feet wide and separated from the roadway with an 8-foot paved 

median.

· Trees are located on each side of the roadway in front of mid level residential buildings

· There are high pedestrian volumes due to the residences and proximity to public

transport. 

Design Criteria:

The recommendations are to provide 10 lux semi-cylindrical illuminance for the 

pedestrian/sidewalk areas and a luminance of 2 cd/m2on the roadway.

Design Approach:

· The layout of the calculation grids is shown in Figure 45.

· This example design (Figure 45, Figure 46, and Table 11) uses 9.1-m (30-ft) mounting 

height for the LED roadway luminaires with poles located behind the face of curb for the 

sidewalk and spaced 21.3 m (70 feet) apart with an opposite pole layout arrangement and 

lumunaires on each side to the roadway. 

· A semi-cylindrical illumnance grid is placed on the sidewalk area at a height of 1.5 m (5 

ft). The rows of points in this example are in accordance with the CIE:140 methodology.

· The luminance on the roadway exceeds the 2 cd/m2roadway light level and meet the 10 

lux semi-cylindrical illuminance recommendations included in this guide. 

· Lighting levels meets IES recommended levels for uniformity and glare. 

Other Considerations:

An adaptive lighting control for this installation would be beneficial for times of low pedestrian 

volumes and during times when the residents in the adjacent apartment buildings are sleeping.
70

Figure 45. Simplified grid and values for high pedestrian traffic in urban area design

Figure 46. Illustration for high pedestrian traffic in urban area design

Table 11. Values for high pedestrian traffic in urban area design

Label CalcType Units Avg Max Min Avg/Min Max/Min

Road_1_Illum Illuminance Lux 35.53 39.5 32.0 1.11 1.23

Road_1_Luminance Luminance Cd/Sq.m 2.01 2.1 1.9 1.06 1.11

Road_1_Veil_Lum Veiling Luminance Cd/Sq.m 0.18 0.3 0.1 1.80 3.00

Road_1_Vis_Level Visibility Level N.A. N.A. N.A. N.A. N.A. N.A.

Road_1_Vis_Level_Bkgd_Lu Background Luminance Cd/Sq.m 1.98 2.1 1.9 1.04 1.11

Road_1_Vis_Level_Target_ Target Luminance Lux 3.59 4.3 2.7 1.33 1.59

Sidewalk_Illum Illuminance Lux 16.58 25.5 11.4 1.45 2.24

Sidewalk_Semi_Illum Semicylindrical Illum. Lux 10.52 15.1 7.3 1.44 2.07

Sidewalk_Surr_Illum_Off- Surround Illum. Lux 27.90 38.9 20.7 1.35 1.88

Sidewalk_Surr_Illum_Off- Surround Illum. Lux 11.35 14.9 9.3 1.22 1.60

Sidewalk_Surr_Illum_On-L Surround Illum. Lux 18.85 25.8 13.6 1.39 1.90

Sidewalk_Surr_Illum_On-R Surround Illum. Lux 14.29 19.0 11.3 1.26 1.68

Sidewalk_Vert_Illum Vertical Illum. Lux 10.12 17.2 4.8 2.11 3.58
71

Appendix F: Figure Source List

Figure 

Number

Description Page Figure Source

Cover – Left Lighted Virginia Smart Road with 

Pedestrians

C Ronald Gibbons, VTTI

Cover -

Upper Right

Example Pedestrian crossing in 

Massachusetts

C Paul Lutkevich, WSP

Cover -

Lower Right

Sidewalk Lighting in Cambridge 

Ma

C Paul Lutkevich, WSP

Figure 1. Example of a SRTS traffic 

improvement project as reported by 

Commission Internationale de 

l'Éclairage (2010)

16 Commission Internationale de 

I'Eclairage (2010)

Figure 2. Top six occupational injuries in the 

United States in 2017 (National 

Safety Council, 2017)

19 National Safety Council (2017)

Figure 3. Wheel stop in a parking lot 

(Bhagavathula and Gibbons, 2019)

20 Bhagavathula and Gibbons, 

VTTI

Figure 4. Increase in detection distance with 

increase in vertical illuminance on 

the pedestrians as reported by C. 

Edwards and Gibbons (2008)

22 Edwards and Gibbons, VTTI

Figure 5. Diagram of driver experiment 

procedure

27 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 6. Cylindrical tube and child-sized 

mannequin

28 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 7. Walker experiment method 30 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 8. Gap experiment setup 32 Figure was developed as part 

of the research effort for this 

contract. VTTI
72

Figure 

Number

Description Page Figure Source

Figure 9. Age by detection distance per lap 34 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 10. Detection distance by semicylindrical illuminance for each 

light type (ped scale, road scale)

35 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 11. Luminance (cd/m2) and 

illuminance (lux) across detection 

distance (m)

36 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 12. Detection distance for rural 

highway by light type and 

luminance

37 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 13. Detection distance by light type 

and luminance

38 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 14. Crossing acceptance distance for 

gap experiment by age and light 

type

39 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 15. Crossing acceptance distance for 

gap experiment by age group

40 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 16. Calculation and Verification Grid 

Layout.

43 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 17. Illuminance measurement diagram 50 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 18. Negative and positive and contrast 

(Gibbons, Edwards et al. 2008)

52 Gibbons, Edwards, et al, VTTI

Figure 19. View of child-sized mannequin 

under each SPD

53 Figure was developed as part 

of the research effort for this 

contract. VTTI
73

Figure 

Number

Description Page Figure Source

Figure 20. Spectral Power Distribution of 

luminaires; relative irradiance 

spectral content normalized for 

6.27 lux

54 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 21. Urban environment for driver 

experiment (mannequin 

highlighted with green outline)

55 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 22. Comparison of pedestrian- and 

road- scale mounting heights

56 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 23. Tripping hazards 57 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 24. Diagram of Walker Experiment 

lanes and target positions

58 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 25. Smart Road test area. 59 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 26. Comparison of illuminance 

methods (Konica Minolta T-10 

versus Everfine Photo-2000EZ 

Semi-Cylindrical).

60 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 27. Detection distance by illuminance 

per measurement method

61 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 28. Spatial comparison of illuminance 

methods (vertical illuminance 

versus semi-cylindrical 

illuminance)

62 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 29. Detection distance by semicylindrical illuminance for each 

light type (2200 K, 4000 K, 5000 K 

LEDs)

63 Figure was developed as part 

of the research effort for this 

contract. VTTI
74

Figure 

Number

Description Page Figure Source

Figure 30. Detection distance by luminance 

(cd/m2) per lap for first two laps of 

the driver experiment

64 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 31. Detection distance by illuminance 

per measurement method for laps 1 

and 2

65 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 32. Detection distance for urban 

environment by light type and 

luminance

66 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 33. Horizontal and vertical illuminance 

(lux) and detection distance (m) by 

luminance level (cd\m2)

67 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 34. Detection distance for age by light 

type and luminance (cd/m2)

68 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 35. Detection distance by light type 68 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 36. Detection distance by luminance 69 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 37. Detection distance by number of 

trials for each age group 9

70 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 38. Crossing acceptance distance for 

gap experiment by age group

71 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 39. Simplified grid and values for 

Low/Medium pedestrian traffic in 

rural area design

73 Figure was developed as part 

of the research effort for this 

contract. VTTI

Figure 40. Illustration and values for low 

pedestrian traffic design

73 Figure was developed as part 

of the research effort for this 

contract. WSP Software: 

AGI32
75

Figure 

Number

Description Page Figure Source

Figure 41. Simplified grid and values for 

School Zone in a Suburban Area

75 Figure was developed as part 

of the research effort for this 

contract. WSP Software: 

AGI32

Figure 42. Illustration and values for high 

pedestrian traffic in rural or 

suburban area design

76 Figure was developed as part 

of the research effort for this 

contract. WSP Software: 

AGI32

Figure 43. Simplified grid and values for High 

Pedestrian traffic School Zone in 

Urban Area Design

78 Figure was developed as part 

of the research effort for this 

contract. WSP Software: 

AGI32

Figure 44. Illustration and values for high 

pedestrian traffic school zone in 

urban area design

78 Figure was developed as part 

of the research effort for this 

contract. WSP Software: 

AGI32

Figure 45. Simplified grid and values for high 

pedestrian traffic in urban area 

design

80 Figure was developed as part 

of the research effort for this 

contract. WSP Software: 

AGI32

Figure 46. Illustration and values for high 

pedestrian traffic in urban area 

design

80 Figure was developed as part 

of the research effort for this 

contract. WSP Software: 

AGI32
For More Information:

https://safety.fhwa.dot.gov/

Point of Contact

Joseph Cheung

joseph.cheung@dot.gov

202-366-6994

FHWA-SA-20-062