Safety Edge SM

HMA Demonstration Projec

Jasper County, Iowa 

t 

Field Report 

June 6, 2011 
FOREWORD 

The purpose of this field report is to provide a summary of the observations and field 

measurements made during the hot mix asphalt (HMA) Safety EdgeSM project located 50 

miles east of Des Moines in Jasper County on route F62 between the villages of Sully and 

Lynnville, Iowa. These observations and data are to be used with similar information from 

other Safety EdgeSM projects to facilitate the development of standards and guidance for 

Safety EdgeSM construction and long term performance. 

All field and laboratory test results, HMA mixture design information and data, observations 

made during paving, and comments provided by construction personnel are included in the 

Field Evaluation Form that is provided as a separate document to this field report. This field 

report is a summary of the observations and field data collected during construction on 

August 5 and 6, 2010 to evaluate the use of the Safety EdgeSM during paving, compare Safety 

EdgeSM and non-Safety EdgeSM portions along the project, determine the slope of the Safety 

EdgeSM, recommend adjustments to the Safety EdgeSM design if found to be needed, and 

identify benefits and complications with the use of the Safety EdgeSM device. 
1. Report No. 2. Government Accession No 3. Recipient’s Catalog No 

3. Title and Subtitle 

Safety EdgeSM HMA Demonstration Project, Jasper County, Iowa. 

5. Report Date 

 June 6. 2011 

6. Performing Organization Code 

7. Authors 

Paul Littleton and Jagannath Mallela 

8. Performing Organization Report No. 

9. Performing Organization Name and Address 

 Applied Research Associates, Inc. 

 100 Trade Centre Drive, Suite 200 

 Champaign, IL 61820 

10. Work Unit No. 

11. Contract or Grant No. 

12. Sponsoring Agency Name and Address 

 Office of Infrastructure 

 Federal Highway Administration 

 1200 New Jersey Avenue, SE 

 Washington, DC 20590 

15. Supplementary Notes 

 Contracting Officer’s Technical Representative: Byron Lord and Mary Huie

Contracting Officer’s Technical Manager: Andy Mergenmeier

13. Type of Report and Period Covered 

 Field Report 

 July 2010–June 2011

14. Sponsoring Agency Code

16. Abstract 

In a coordinated effort with highway authorities and industry leaders, the Every Day Counts initiative serves as a catalyst to 

identify and promote cost effective innovations to bring about rapid change to increase safety of our nations highway 

system, decrease project delivery time, and protect our environment. The Safety EdgeSM concept is an example of one such 

initiative in which the edge of the road is beveled during construction for the purpose of helping drivers who migrate off the 

roadways to more easily return to the road without over correcting and running into the path of oncoming traffic or running 

off the other side of the roadway. 

This field report documents the observations made on the construction of Safety EdgeSM on a two lane highway hot mix 

asphalt (HMA) overlay project route F62 between the villages of Sully and Lynnville, Iowa. The TransTech Shoulder 

Wedge Maker was demonstrated during this project. Details regarding the performance of the device along with the shape 

and physical properties of the finished Safety EdgeSM are presented for the purpose of understanding what processes and 

techniques were most successful in forming the Safety EdgeSM. 

The findings from this overlay project and other similar ongoing projects form the basis for understanding the construction 

process and material performance necessary to bring this innovation into common highway practice and make our Nation’s 

highways safer. 

17. Key Words 

Safety EdgeSM, Slope, TransTech Shoulder Wedge 

Maker 

18. Distribution Statement 

No restriction. 

19. Security Classif.(of this report) 

Unclassified 

20. Security Classif. (of this page) 

Unclassified 

21. No. of Pages 

15 

22. Price 

Form DOT F 1700.7 (8-72)
iii

SI* (MODERN METRIC) CONVERSION FACTORS 

APPROXIMATE CONVERSIONS TO SI UNITS 

Symbol When You Know Multiply By To Find Symbol 

LENGTH 

(none) mil 25.4 micrometers μm

in inches 25.4 millimeters mm

ft feet 0.305 meters m 

yd yards 0.914 meters m 

mi miles 1.61 kilometers km

AREA 

in2square inches 645.2 square millimeters mm2

ft2square feet 0.093 square meters m

2

yd2square yards 0.836 square meters m

2

ac acres 0.405 hectares ha

mi2square miles 2.59 square kilometers km2

VOLUME 

fl oz fluid ounces 29.57 millimeters mL 

gal gallons 3.785 liters L 

ft3cubic feet 0.028 cubic meters m

3

yd3cubic yards 0.765 cubic meters m

3

NOTE: volumes greater than 1000 L shall be shown in m3

MASS 

oz ounces 28.35 grams g 

lb pounds 0.454 kilograms kg 

T short tons (2000 lb) 0.907 megagrams (or "metric ton") Mg (or "t") 

TEMPERATURE (exact degrees) 

°F Fahrenheit 5 (F-32)/9 

or (F-32)/1.8 

Celsius °C

ILLUMINATION 

fc foot-candles 10.76 lux lx

fl foot-Lamberts 3.426 candela per square meter cd/m2

FORCE and PRESSURE or STRESS 

lbf poundforce 4.45 Newtons N 

lbf/in2 (psi) poundforce per square inch 6.89 kiloPascals kPa 

k/in2 (ksi) kips per square inch 6.89 megaPascals MPa 

DENSITY 

lb/ft3 (pcf) pounds per cubic foot 16.02 kilograms per cubic meter kg/m3

APPROXIMATE CONVERSIONS FROM SI UNITS 

Symbol When You Know Multiply By To Find Symbol 

LENGTH

μm micrometers 0.039 mil (none) 

mm millimeters 0.039 inches in

m meters 3.28 feet ft

m meters 1.09 yards yd

km kilometers 0.621 miles mi

AREA 

mm2square millimeters 0.0016 square inches in2

m

2

square meters 10.764 square feet ft2

m

2

square meters 1.195 square yards yd2

ha hectares 2.47 acres ac

km2square kilometers 0.386 square miles mi2

VOLUME 

mL milliliters 0.034 fluid ounces fl oz 

L liters 0.264 gallons gal 

m

3

cubic meters 35.314 cubic feet ft3

m

3

cubic meters 1.307 cubic yards yd3

MASS 

g grams 0.035 ounces oz 

kg kilograms 2.202 pounds lb

Mg (or "t") megagrams (or "metric ton") 1.103 short tons (2000 lb) T 

TEMPERATURE 

°C Celsius 1.8C+32 Fahrenheit °F

ILLUMINATION 

lx lux 0.0929 foot-candles fc

cd/m2candela per square meter 0.2919 foot-Lamberts fl

FORCE and PRESSURE or STRESS 

N Newtons 0.225 poundforce lbf 

kPA kiloPascals 0.145 poundforce per square inch lbf/in2 (psi) 

MPa megaPascals 0.145 kips per square inch k/in2 (ksi) 

*SI is the symbol for the International System of Units. Appropriate rounding should be made to comply with Section 4 of ASTM E380. (Revised March 

2003) 
iv

Table of Contents 

Topic Page 

FOREWORD................................................................................................................................. 1

SUMMARY OF OBSERVATIONS ............................................................................................ 1

Overall Opinion of the Safety EdgeSM ..................................................................................... 1

Slope of Safety EdgeSM ............................................................................................................ 1

Edge Preparation .................................................................................................................... 1

Construction/ Compaction ...................................................................................................... 1

HMA Mixture .......................................................................................................................... 2

Future Considerations or Material Enhancements to Improve Performance ........................ 2

EVALUATION OF HMA OVERLAY WITH SAFETY EDGESM .......................................... 3

INTRODUCTION ............................................................................................................................... 3

PAVEMENT STRUCTURE AND PROJECT CONDITIONS .................................................................... 4

FIELD EVALUATION TESTS ............................................................................................................ 4

Slope Measurements ............................................................................................................... 5

Cores....................................................................................................................................... 6

Nuclear Density Results .......................................................................................................... 8

OBSERVATIONS MADE DURING PAVING WITH THE SAFETY EDGESM ........................................ 10

Preparatory Work ................................................................................................................. 10

Placement/Paving Operations.............................................................................................. 10

Compaction Operations ........................................................................................................ 12

Shoulder edge backing .......................................................................................................... 14

FINDINGS AND CONCLUSIONS ...................................................................................................... 15

APPENDIX A. DATA TABLES FROM FIELD MEASUREMENTS ................................ A-1
1

SUMMARY OF OBSERVATIONS 

This section of the report provides a summary of important observations made during the 

paving operations, interviews with paving personnel, and findings from the field 

measurements taken during paving that are expected to have a significant impact on the 

performance of the Safety EdgeSM. 

Overall Opinion of the Safety EdgeSM

 The paving operation was not noticeably slowed or otherwise inconvenienced by 

incorporating the Safety EdgeSM. However, the average slope of the completed Safety 

EdgeSM was greater than the targeted 30° and the density at the edge may affect the 

long-term pavement performance. These issues and other issues are noted in the 

following bulleted items. 

Slope of Safety EdgeSM

 The slope of the Safety EdgeSM varied throughout the project. The average slope 

measurement was 38°. 

 The sloped face of the Safety EdgeSM had a well formed but had a coarse/open texture

Large aggregates in the slope face could be removed by hand without much difficulty,

which was the same observation for the non-Safety EdgeSM sections. 

. 

 The Safety EdgeSM was incorporated into all three lifts in some sections of the road 

increasing the amount of HMA placed on this project. The lower lifts extended out 

slightly farther to accommodate the lifts above resulting in more HMA used to build 

the edge. 

Edge Preparation 

 Overall, the project was well suited for the Safety EdgeSM given that the base for the 

shoulders was well constructed and wide enough to accommodate the Safety EdgeSM. 

Edge clearance was not an issue which allowed the endplate of the paving screed and 

the Safety EdgeSM device to operate freely. 

Construction/ Compaction 

 The Safety EdgeSM was formed using the TransTech Shoulder Wedge Maker attached 

to the paving screed. The device was hand operated and required some elevation 

adjustments by the screed operator when approaching turnouts and cross roads. The 

demonstration project had many long tangents so making adjustments occurred only 

periodically. 

 In an effort to maintain the slope of the Safety EdgeSM, the breakdown roller and 

intermediate roller were kept from overhanging the edge and applying the maximum 

compactive force. It was observed that by overhanging the edge of the mat the edge 

would shift and increase the slope of the Safety EdgeSM. Therefore, the contractor 
2

decided to make only one pass at the edge of the mat with the finish roller in static 

mode. 

 The non-Safety EdgeSM test sections of this project received a typical rolling pattern 

that covered the edge of the mat with passes made by the breakdown and intermediate 

rollers. As a consequence of the different rolling patterns, the average density adjacent 

to the edge of the mat was 6 percent less for the Safety EdgeSM compared to the nonSafety EdgeSM test sections. 

 The air voids adjacent to the Safety EdgeSM were high (average of 13.6 percent). The 

air void content is higher than desirable for long term pavement performance. 

HMA Mixture 

 The mat did not appear to be overly tender during compaction. However, horizontal 

displacement was observed at the edge of the mat under the breakdown roller. 

 Only slight segregation was observed sporadically at the longitudinal joint and at the 

edge of the mat. 

 The planned HMA thickness was 1.5 inches for the intermediate course from which 

measurements were made. The thickness of the cores from this lift varied from 1.2 to 

2.4 inches along the outside edge of the project. 

 The slope of the Safety EdgeSM tended to increase with increased lift thickness. 

Future Considerations or Material Enhancements to Improve Performance 

 Automatic adjustment to the vertical profile of the Safety EdgeSM device would be of 

benefit to the operator. 

 Currently the angle of the Safety EdgeSM device shoe is not adjustable. It would be 

beneficial to be able to decrease the angle of the device when using HMA mixtures for 

which the slope angle tends to increase when compacted. 

This Safety EdgeSM project should be monitored to determine its long-term performance and 

the frequency of any required maintenance operations, as well as the life cycle cost of the 

Safety EdgeSM and its effectiveness over time. 
3

EVALUATION OF HMA OVERLAY WITH SAFETY EDGESM

Introduction 

A series of field tests were carried out to assess the placement and condition of the HMA 

along route F62 with and without the use of the Safety EdgeSM device. The objective or 

purpose of this field study was to evaluate the quality of the in-place HMA material and 

Safety EdgeSM by investigating three issues or features. 

1. Correct use of the Safety EdgeSM device during paving. 

2. Safety EdgeSM versus non-Safety EdgeSM portions of project. 

3. Slope of the Safety EdgeSM. 

st Project stationing began at Station 22+00 (west project limit) at the intersection of 1 Street 

and route F62 in Sully and extends to the Jasper/Poweshiek County line east of Lynnville 

(east project limit), refer to Figure 1. The maximum posted speed on this roadway was 55 

mph. The contractor, Manatt's Inc., used the TransTech Shoulder Wedge Maker for this 

demonstration. 

West project 

limit. East project 

limit.

Figure 1. Site location. 
4

Pavement Structure and Project Conditions 

The project consisted of a 5-inch cold in-place recycling of the existing asphalt pavement then 

placement of a 2-inch HMA base course, a 1.5-inch HMA intermediate course, and a 1.5-inch

HMA surface course. All three HMA layers were comprised of the same 19.0 mm mix, the 

only exception was the base course contained RAP. Earthwork was not required on this 

project as the original width of the pavement and shoulders matched the new cross section 

plan. Figure 2 shows the typical pavement cross section. 

Figure 2. Typical pavement cross section. 

At the time of the site visit, the contractor had placed the base and intermediate courses, both 

with the Safety EdgeSM, from Sully to Lynnville. The section east of Lynnville had the base, 

intermediate, and the westbound surface course paved without the Safety EdgeSM. 

Field Evaluation Tests 

Four Safety EdgeSM and two non-Safety EdgeSM test sections were established, all on the 

intermediate course. In an effort to maximize the number of test sites and reduce the amount 

of coring, the test sections were located where the County had previously cut QA cores at

approximately 3 ft. from the edge or near the center of the lane. The cores from the County 

together with cores cut adjacent the Safety EdgeSM (and some cores cut from 3 ft. from the 

edge) during the current testing would have served to calibrate the nuclear density tests taken

in each test section. Unfortunately, the laboratory test results from the County were 

unavailable, nevertheless, the cores taken at the time of the field evaluation were used for 

calibration. 
5

The four Safety EdgeSM test sections were located between Sully and Lynnville. The two 

non-Safety EdgeSMs sections were located east of Lynnville and serve as control sections for 

comparison. The following summarizes the six test sections included in this field study: 

1. Section #1, Safety EdgeSM, westbound lane, tangent section , centered at Sta 150+75 at 

a field entrance across from the "welcome to Lynnville" sign on the west side of the 

village. 

2. Section #2, Safety EdgeSM, westbound lane, curved section, centered at Sta 116+15 

across from a "No Passing Sign" between the gravel drives to residence address 

numbers 13848 and 13808. 

3. Section #3, Safety EdgeSM, westbound lane, curved section, centered at Sta 81+27 and 

150 ft. east of the center of the gravel drive to residence/farm address number 13288. 

Section #4, Safety EdgeSM; westbound lane, curve section, centered at Sta 69+82 at the 

intersection with East 132nd Street. 

4.

5. Section #5, non-Safety EdgeSM, eastbound, tangent section, centered at Sta 254+92 at 

525 ft. east of the centerline of gravel drive to residential address number 15686. 

6. Section #6, non-Safety EdgeSM, eastbound, tangent section, centered at Sta 251+08 at 

300 ft. west of the centerline of gravel drive to residential address number 15686. 

At the time of the site visit mechanical difficulties with the asphalt plant delayed paving until 

later in the day, ultimately shortening the amount of surface course paved. However, the 

intermediate course from previous paving had been paved with the Safety EdgeSM and was 

suitable for testing. Therefore, all tests and edge slope measurements were conducted on the 

intermediate course. 

Slope Measurements 

Slope measurements were taken at 25-ft. intervals (spacing was adjusted for field/driveway 

entrances) using a straight-edge and tape measure to determine the horizontal and vertical 

dimensions of the Safety EdgeSM on the intermediate course only. The Safety EdgeSM on the 

base course was ignored. 

The vertical measurement was also the thickness at the edge of the mat which is not always 

the case. For example when HMA is allowed to slide down the slope during paving the true 

edge thickness is obscured. Figure 3 shows the technique in measuring the edge slope. 
6

Figure 3. Slope measurement technique. 

The average slope of the Safety EdgeSM was calculated to be 38° from the width and thickness 

measurements. Slope measurements are listed in Table A-1 and Table A-2 in Appendix A. 

Cores 

Cores were cut from the mid-point of each test section. These cores were taken to measure 

thickness and for laboratory testing. Table 3 in the Appendix provides a summary of the core 

thickness results. Figure 4 shows the location of the cores taken adjacent to the pavement 

edge and 3 ft. away from the edge. 

Figure 4. Safety EdgeSM section with cores cut adjacent to the edge and at 3 ft. from the edge. 

Horizontal

Dimension

Vertical

Dimension
7

Figure 5 compares the thickness of the intermediate course near the Safety EdgeSM and the 

slope of the Safety EdgeSM. As shown, the slope appears to increase with the thickness of the 

Safety EdgeSM. 

Figure 5. Comparison of slope and edge thickness. 

Figure 6 shows the comparison of the core densities taken adjacent to the edge and at 3 ft. 

from the edge for the Safety EdgeSM and non-Safety EdgeSM sections. As expected the 

densities away from the edge where the mat received full coverage of the roller passes are 

significantly higher than near the edge of the pavement. This result reflects the relatively low 

degree of compactive effort applied to the Safety EdgeSM in comparison to standard 

compaction given to the non-Safety EdgeSM section. 

65

60 se

55

regeD ,

50

epolS f

45

o elgnA

40

 egrae

35

vA

30

1 1.5 2 2.5 3 3.5 4

Thickness of the Edge of Mat, inches
8

Figure 6. Comparison of core densities adjacent to the edge and 3 ft. from the edge. 

Nuclear Density Results 

Density tests were conducted using a Troxler 3411 nuclear density gauge in backscatter mode 

for 60 second test durations. Nuclear density tests were conducted adjacent to the edge and 3 

ft. from the edge at 50-ft intervals for 200 ft. before and after the location of the cores. The 

actual test spacing was adjusted to avoid non-representative areas at field/driveway entrances. 

Adjustment factors were determined by correlating the nuclear density readings to the core 

laboratory test results of bulk specific gravity (saturated surface dry test condition) testing. 

The following summarizes the adjustment factors determined for this project. 

Location 

Adjacent to the edge 

3 ft. from the edge 

Adjustment Factor 

0.978

0.995

125

130

135

140

145

150

155

125 130 135 140 145 150 155

Core Densities, 3 ft from edge, pcf

Core Densities, Adjacent to Edge, pcf

Safety Edge Section Non-Safety Edge Section Line of Equality
9

Figure 7 shows a comparison of the nuclear densities and densities measured from the cores 

As shown, the value at 3 ft. from the edge was close to unity and the value adjacent to the 

edge is not as close to unity. The adjusted densities using the adjustment factors are also 

listed in Table A-4 in Appendix A. The factors were used to adjust the nuclear density gauge 

readings to be consistent with the densities that were measured in the laboratory. The nuclear 

density test results are listed in Table A-5 and A-6 in Appendix A. 

125.00

130.00

135.00

140.00

145.00

150.00

155.00

125 135 145 155

Density, Nuclear Gauge, pcf

Density of Core, pcf (Bulk Saturated Surface Dry)

Adjacent to Edge 3-feet From Edge Line of Equality

125.00

130.00

135.00

140.00

145.00

150.00

155.00

125 135 145 155

Density, Nuclear Gauge, pcf

Density of Core, pcf (Bulk Saturated Surface Dry)

Adjacent to Edge 3-feet From Edge Line of Equality

Figure 7. Comparison of the nuclear density readings and core densities. 

Figure 8 is a comparison of the adjusted nuclear density gauge readings taken adjacent to the 

edge and at 3 ft. from the edge. Figure 9 is a comparison of the HMA air voids between both 

areas. Generally, the two figures show densities were lower and the air voids were higher 
10

adjacent to the edge than away from the edge. The same correlation holds true for comparing 

the Safety EdgeSM sections to the non-Safety EdgeSM sections, and it is recognized that the 

non-Safety EdgeSM sections received greater compactive effort from the rolling procedures. 

Figure 8. Comparison of densities adjacent to the edge and 3 ft. from the edge. 

Figure 9. Comparison of air voids adjacent to the edge and 3 ft. from the edge. 

125.0

130.0

135.0

140.0

145.0

150.0

155.0

125.0 130.0 135.0 140.0 145.0 150.0 155.0

Nuclear Density Readings, 3 ft from edge, pcf

Nuclear Density Readings Adjacent to Edge, pcf

Safety Edge Sections Non-Safety Edge Sections Line of Equality

0

2

4

6

8

10

12

14

16

18

20

22

0 2 4 6 8 10 12 14 16 18 20 22

Air Voids, 3 ft from edge, %

Air Voids, Adjacent to Edge, %

Safety Edge Section Non-Safety Edge Section Line of Equality
11

Observations Made During Paving with the Safety EdgeSM

This section shares the observations made during the paving and rolling of the surface course 

starting in Sully and proceeding east toward Lynnville. 

Preparatory Work 

The base for the shoulders was well constructed and wide enough to accommodate the Safety 

EdgeSM. Edge work on the pavement or shoulders prior to paving was not observed. Edge 

clearance was not an issue which allowed the endplate of the paving screed and the Safety 

EdgeSM device to operate freely. 

Placement/Paving Operations 

The contractor utilized a windrow material transfer vehicle (MTV) together with a Blaw-Knox 

rubber tire paver equipped a Caterpillar Extend-A-Mat 10-20B screed (Figure 10). Figure 11 

and Figure 12 are images of the paving screed and the Safety EdgeSM device bolted to the 

screed. Vertical control of the Safety EdgeSM device was accomplished by hand cracking the 

device by the screed operator walking beside the paver. 

Slight segregation was noticed at both the unconfined longitudinal centerline joint and at the 

free edge when compared to the center of the mat. The segregation was present in the Safety 

EdgeSM as well as the non-Safety EdgeSM sections of the project. Each course of HMA was 

offset during construction to accommodate the sloped Safety EdgeSM on the following lift of 

HMA. Consequently, more HMA was placed to obtain the planned pavement width than 

would otherwise be placed with a traditional pavement edge. Figure 13 shows the Safety 

EdgeSM and the offset placement of each pavement layer. 
12

Figure 10. Material transfer vehicle ahead of the paver. 

Figure 11. Blaw-Know paver with the Caterpillar screed. 
13

Figure 12. TransTech Shoulder Wedge Maker bolted to the paver screed. 

Figure 13. Offset HMA layers with Safety EdgeSM. 

Compaction Operations 

According to contractor personnel, all three courses with the Safety EdgeSM were constructed 

using identical compactive effort and rolling pattern. The compaction equipment consisted of 

a Caterpillar CB 654D 16-ton steel drum breakdown roller followed by a Bomag pneumatic 
14

rubber tire intermediate roller and finished with a Hamm HD12DHV 16-ton steel drum finish 

roller. The rollers are shown in Figure 14. 

The following rolling pattern was observed during the paving of the surface course on August 

5. The pavement received 2 coverages from the breakdown roller in vibratory mode (low 

amplitude and high frequency) and the middle portion of the lane received an additional third 

coverage in vibratory mode. The first pass of the breakdown roller overhung the centerline 

joint 2 to 4 inches and the next pass overhung 1 inch. The breakdown roller stayed 6 inches 

from the Safety EdgeSM. The intermediate roller made up to 9 passes with each part of the 

mat receiving 4 coverages except that the intermediate roller stayed away from the edge of the 

mat. The area near the Safety EdgeSM received no breakdown or intermediate roller coverages 

and only 1 coverage of the finish roller in static mode overhanging the edge by 2 inches. The 

finish roller made 5 passes over the rest of the mat to smooth the tire marks from the 

intermediate roller. 

Upon special request, the breakdown roller operator hung over the Safety EdgeSM of the mat 

about 2 inches on the first vibratory pass for a short section. Doing so caused the edge of the 

mat to displace horizontally and become steeper. This proved the slope of the Safety EdgeSM

was sensitive to the rollers position. The vibratory first pass at the longitudinal centerline 

joint caused the mat to move approximately 0.75 inches horizontally. 

Although paving and compaction operations were not observed for the non-Safety EdgeSM

portion of this project, discussions with the contractor indicated normal rolling was conducted 

in which the breakdown roller made passes overhanging the edge and generally both the 

breakdown and intermediate rollers made passes closer to the edge. Thus, greater compactive 

effort was applied to the non-Safety EdgeSM sections compared to the Safety EdgeSM sections. 
15

 

Figure 14. Compaction equipment. 

Shoulder edge backing 

Nearly all of the existing granular shoulder material was free of vegetation or any debris that 

might interfere with paving operations. At this point in construction before the surface course 

was paved, new granular shoulder material had not been placed in some areas exposing the 

Safety EdgeSM from the base course upward. The contractor was allowed an extended time 

frame to pull up the shoulder material because of the use of the Safety EdgeSM. Normally the 

shoulder material would need to be placed in conjunction with each day's mainline paving. 

Figure 15 is a typical view of the project east of Sully showing the shoulder and the exposed 

Safety EdgeSM of the base and intermediate courses. 

Breakdown Roller

Finish Roller

Intermediate Roller
16

Figure 15. Typical view showing the base and intermediate course with Safety EdgeSM and 

granular shoulder material. Image taken east of Sully. 

Findings and Conclusions 

The objective of this field study was to evaluate the quality of the in-place HMA material and 

Safety EdgeSM by investigating three features. 

1. Correct use of the Safety EdgeSM device during paving. 

2. Safety EdgeSM versus non-Safety EdgeSM portions of project. 

3. Slope of the Safety EdgeSM. 

This section of the field report summarizes some of the findings and conclusions made during 

the paving/compaction operations. 

 The contractor stayed away from the Safety EdgeSM in an effort to preserve the slope 

of the Safety EdgeSM. The Safety EdgeSM received only one pass of the finish roller in 

static mode. 

 As a consequence of preserving the slope of the Safety EdgeSM, the density test results 

at the Safety EdgeSM were lower and the air voids higher than the control sections 

where normal rolling (more compactive effort) was performed. 

 The design of the Safety EdgeSM device should be improved to achieve the desired 

slope and density. 

 A benefit of the Safety EdgeSM to this project is the extra time allowed for placing 

shoulder material. 
A-1

APPENDIX A. DATA TABLES FROM FIELD MEASUREMENTS 

This section of the field report provides a listing of the field measurements recorded during 

the paving operations. These data are also included in the detailed evaluation forms. 

Table A-1. Safety EdgeSM Slope Measurements. 

Section ID Station Type of Section Safety EdgeSM

Width of Taper, in Thickness of Taper, in Slope, deg 

1 148+75 Safety EdgeSM 2.4 1.8 37

1 149+00 Safety EdgeSM 2.1 1.8 41

1 149+25 Safety EdgeSM 2.4 1.8 37

1 149+50 Safety EdgeSM 2.0 1.9 44

1 149+75 Safety EdgeSM 2.1 1.7 39

1 150+00 Safety EdgeSM 2.2 1.9 41

1 150+25 Safety EdgeSM 2.6 1.8 35

1 150+50 Safety EdgeSM 1.9 1.5 38

1 150+75 Safety EdgeSM 1.6 1.4 41

1 151+25 Safety EdgeSM 2.3 1.4 31

1 151+50 Safety EdgeSM 1.8 1.6 42

1 151+75 Safety EdgeSM 2.1 1.7 39

1 152+00 Safety EdgeSM 1.9 1.6 40

1 152+25 Safety EdgeSM 2.2 1.7 38

1 152+50 Safety EdgeSM 2.2 1.7 38

1 152+75 Safety EdgeSM 2.0 1.6 39

2 114+15 Safety EdgeSM 2.2 1.3 31

2 114+40 Safety EdgeSM 2.8 1.7 31

2 114+65 Safety EdgeSM 2.4 1.6 34

2 114+90 Safety EdgeSM 2.8 1.5 28

2 115+15 Safety EdgeSM 2.1 1.6 37

2 116+15 Safety EdgeSM 3.0 1.8 31

2 116+40 Safety EdgeSM 3.2 2.1 33

2 117+40 Safety EdgeSM 3.0 2.1 35

2 117+65 Safety EdgeSM 3.2 2.1 33

2 117+90 Safety EdgeSM 3.0 2.3 37

2 118+15 Safety EdgeSM 2.6 2.1 39

2 118+40 Safety EdgeSM 2.3 1.9 40

2 118+65 Safety EdgeSM 2.6 1.6 32

2 118+90 Safety EdgeSM 2.5 1.9 37

3 78+27 Safety EdgeSM 4.0 3.375 40

3 78+52 Safety EdgeSM 3.375 3.0 42

3 78+77 Safety EdgeSM 5.25 2.5 25

3 79+02 Safety EdgeSM 2.75 2.75 45

3 79+27 Safety EdgeSM 2.75 2.75 45

3 79+52 Safety EdgeSM 2.375 2.75 49

3 79+77 Safety EdgeSM 2.25 2.75 51

3 81+02 Safety EdgeSM 3.0 2.75 43

3 81+27 Safety EdgeSM 2.875 2.875 45

3 81+52 Safety EdgeSM 2.25 2.625 49

3 81+77 Safety EdgeSM 1.5 2.875 62

3 82+02 Safety EdgeSM 2.875 3.25 49

3 82+27 Safety EdgeSM 3.25 2.75 40
A-2

Section ID Station Type of Section Safety EdgeSM

Width of Taper, in Thickness of Taper, in Slope, deg

3 82+52 Safety EdgeSM 2.875 2.5 41

3 82+77 Safety EdgeSM 2.25 2.5 48

3 83+02 Safety EdgeSM 2.5 3.0 50

3 83+27 Safety EdgeSM 2.5 2.75 48

4 67+82 Safety EdgeSM 3.75 2.0 28

4 68+07 Safety EdgeSM 3.75 2.75 36

4 68+32 Safety EdgeSM 3.25 2.0 32

4 68+57 Safety EdgeSM 3.5 2.25 33

4 68+82 Safety EdgeSM 3.0 2.0 34

4 69+07 Safety EdgeSM 3.5 2.0 30

4 69+32 Safety EdgeSM 3.0 2.0 34

4 69+57 Safety EdgeSM 3.0 2.0 34

4 69+82 Safety EdgeSM 2.75 1.875 34

4 71+32 Safety EdgeSM 3.375 2.125 32

4 71+57 Safety EdgeSM 3.25 2.0 32

4 71+82 Safety EdgeSM 3.0 1.75 30

4 72+07 Safety EdgeSM 2.0 1.5 37

4 72+32 Safety EdgeSM 3.25 1.875 30

4 72+57 Safety EdgeSM 3.375 1.875 29

4 72+82 Safety EdgeSM 3.25 2.25 35

4 73+07 Safety EdgeSM 3.5 2.25 33

4 73+32 Safety EdgeSM 3.375 2.125 32

Mean Value 2.7 2.1 38

Standard Deviation 0.6 0.5 6.8

Coefficient of Variation,% 23.7 23.7 18.1

Table 2. Non-Safety Edge Measurements. SM

Type of Section Safety EdgeSM

Section ID Station Width of 

Taper, in

Thickness of 

Taper, in Slope, deg

5 256+92 Non-Safety EdgeSM

5 256+67 Non-Safety EdgeSM

5 256+42 Non-Safety EdgeSM

5 256+17 Non-Safety EdgeSM

5 255+92 Non-Safety EdgeSM

5 255+67 Non-Safety EdgeSM

5 255+42 Non-Safety EdgeSM 2.75 2.5 42

5 255+17 Non-Safety EdgeSM

5 254+92 Non-Safety EdgeSM 2.0 2.625 53

5 254+67 Non-Safety EdgeSM

5 254+42 Non-Safety EdgeSM 2.25 2.5 48

5 254+17 Non-Safety EdgeSM

5 253+92 Non-Safety EdgeSM

5 253+67 Non-Safety EdgeSM

5 253+42 Non-Safety EdgeSM

5 253+17 Non-Safety EdgeSM

5 252+92 Non-Safety EdgeSM

6 249+08 Non-Safety EdgeSM 1.25 1.75 54

6 249+33 Non-Safety EdgeSM 1.25 1.75 54

6 249+58 Non-Safety EdgeSM 1.25 1.75 54

6 249+83 Non-Safety EdgeSM 1.25 1.75 54

6 250+08 Non-Safety EdgeSM 1.25 1.625 52
A-3

Section ID Station 

Type of Section Safety EdgeSM

Width of 

Taper, in 

Thickness of 

Taper, in Slope, deg 

6 250+33 Non-Safety EdgeSM 1.25 1.75 54

6 250+58 Non-Safety EdgeSM 1.5 1.625 47

6 250+83 Non-Safety EdgeSM 1.5 1.875 51

6 251+08 Non-Safety EdgeSM 1.25 1.75 54

6 251+33 Non-Safety EdgeSM 1.25 1.75 54

6 251+58 Non-Safety EdgeSM 1.5 1.375 43

6 251+83 Non-Safety EdgeSM 1.5 1.75 49

6 252+08 Non-Safety EdgeSM 1.75 1.75 45

6 252+33 Non-Safety EdgeSM 1.75 1.75 45

6 252+58 Non-Safety EdgeSM

6 252+83 Non-Safety EdgeSM 1.25 2.375 62

6 253+08 Non-Safety EdgeSM 1.25 2.375 62

Mean Value 1.5 1.9 52

Standard Deviation 0.4 0.4 5.7 

Coefficient of Variation, % 27.2 18.9 11.0 

Table 3. Core Thickness Measurements. 

Table 4. Nuclear Density Adjustment Factors; Core Density/Nuclear Density. 

A – Adjacent 

to Edge

B – 3 feet 

from Edge

1 WB 150+75 Safety EdgeSM 1.25

2 WB 116+15 Safety EdgeSM 1.875

3 WB 81+27 Safety EdgeSM 2.5 2.25

4 WB 69+82 Safety EdgeSM 1.75

5 EB 254+92

Non-Safety 

EdgeSM

2.0 2.06

6 EB 251+08

Non-Safety 

EdgeSM

1.5 1.875

1.81 2.06

0.43 0.19

Coefficient of Variation, % 23.79 9.09

Section #

Mean, in. 

Area/Location

Standard Deviation, in. 

Station

Non-Safety Edge SM 

(control) test sections 

were located east of 

Lynnville.

Lane 

Dir.

Safety Edge SM test 

sections were between 

the villages of Sully and 

Lynnville.

Core Thickness, in

Type of Section

A – Adjacent 

to Edge

B – 3 feet 

from Edge

A – Adjacent

to Edge

A – Adjacent to 

Edge

B – 3 feet 

from Edge

1 WB 150+75 Safety EdgeSM 134.6

B – 3 feet from 

Edge

136.10 142.70 0.989

2 WB 116+15 Safety EdgeSM 133.3 135.10 142.50 0.987

3 WB 81+27 Safety EdgeSM 135.7 142.5 137.30 140.90 0.988 1.011

4 WB 69+82 Safety EdgeSM 132.6 140.80 151.60 0.942

5 EB 254+92

Non-Safety 

EdgeSM

141.7 148.00 152.20 0.957

6 EB 251+08

Non-Safety 

EdgeSM

139.1 143.4 138.80 146.60 1.002 0.978

136.2 143.0 139.4 146.1 0.978 0.995

3.54 0.64 4.69 4.88 0.02 0.02

2.60 0.45 3.37 3.34 2.34 2.36

Non-Safety Edge SM 

(control) test sections 

were located east of 

Lynnville.

Area/Location

Mean Value, pcf 

Standard Deviation, pcf 

Type of Section

Safety Edge SM test 

sections were between 

the villages of Sully and 

Lynnville.

Coefficient of Variation, % 

Adjustment Ratio

Section #

Lane 

Dir.

Station

Density of Cores Nuclear Density Values
A-4

Table 5. Safety EdgeSM Nuclear Gage Readings. 

2.471 Max. Density: 154.2

A = 0.978

B= 0.995

Maximum Specific Gravity of Mix (Gmm):

Adjustment Ratios for 

Nuclear Gauge:

A – Adjacent 

to Edge

B – 3 feet 

from Edge

A – Adjacent

to Edge

B – 3 feet 

from Edge

A – Adjacent 

to Edge

B – 3 feet 

from Edge

1 WB 148+75 Safety EdgeSM 132.2 145.6 129.29 144.87 1.8 16.15 6.04

1 WB 149+25 Safety EdgeSM 133.5 149.5 130.56 148.75 1.8 15.32 3.53

1 WB 149+75 Safety EdgeSM 123.5 149.3 120.78 148.55 1.7 21.67 3.66

1 WB 150+25 Safety EdgeSM 122.0 143.9 119.32 143.18 1.8 22.62 7.14

1 WB 150+75 Safety EdgeSM 136.1 142.7 133.11 141.99 1.4 13.67 7.91

1 WB 151+25 Safety EdgeSM 134.3 144.0 131.35 143.28 1.4 14.82 7.08

1 WB 151+75 Safety EdgeSM 133.2 144.7 130.27 143.98 1.7 15.51 6.62

1 WB 152+25 Safety EdgeSM 136.4 147.4 133.40 146.66 1.7 13.48 4.88

1 WB 152+75 Safety EdgeSM 135.0 142.0 132.03 141.29 1.6 14.37 8.37

2 WB 114+15 Safety EdgeSM 140.3 149.0 137.21 148.26 1.3 11.01 3.85

2 WB 114+65 Safety EdgeSM 131.8 141.7 128.90 140.99 1.6 16.40 8.56

2 WB 115+15 Safety EdgeSM 140.5 147.6 137.41 146.86 1.6 10.88 4.75

2 WB 116+15 Safety EdgeSM 135.1 142.5 132.13 141.79 1.8 14.31 8.04

2 WB 117+40 Safety EdgeSM 133.5 143.8 130.56 143.08 2.1 15.32 7.20

2 WB 117+90 Safety EdgeSM 133.3 143.7 130.37 142.98 2.3 15.45 7.27

2 WB 118+40 Safety EdgeSM 141.3 142.4 138.19 141.69 1.9 10.38 8.11

2 WB 118+90 Safety EdgeSM 140.2 145.0 137.12 144.28 1.9 11.07 6.43

3 WB 78+27 Safety EdgeSM 137.7 144.7 134.67 143.98 3.375 12.66 6.62

3 WB 78+77 Safety EdgeSM 138.0 143.9 134.96 143.18 2.5 12.47 7.14

3 WB 79+27 Safety EdgeSM 129.5 148.8 126.65 148.06 2.75 17.86 3.98

3 WB 79+77 Safety EdgeSM 134.9 143.0 131.93 142.29 2.75 14.44 7.72

3 WB 81+27 Safety EdgeSM 137.3 140.9 134.28 140.20 2.875 12.91 9.08

3 WB 81+77 Safety EdgeSM 136.8 144.9 133.79 144.18 2.875 13.23 6.50

3 WB 82+27 Safety EdgeSM 137.8 145.6 134.77 144.87 2.75 12.60 6.04

3 WB 82+77 Safety EdgeSM 138.8 145.9 135.75 145.17 2.5 11.96 5.85

3 WB 83+27 Safety EdgeSM 137.5 145.6 134.48 144.87 2.75 12.79 6.04

4 WB 67+82 Safety EdgeSM 129.3 152.9 126.46 152.14 2 17.99 1.33

4 WB 68+32 Safety EdgeSM 135.4 149.7 132.42 148.95 2 14.12 3.40

4 WB 68+82 Safety EdgeSM 143.2 145.0 140.05 144.28 2 9.17 6.43

4 WB 69+32 Safety EdgeSM 137.4 147.4 134.38 146.66 2 12.85 4.88

4 WB 69+82 Safety EdgeSM 140.8 151.6 137.70 150.84 1.875 10.69 2.17

4 WB 71+32 Safety EdgeSM 138.3 154.4 135.26 153.63 2.125 12.28 0.36

4 WB 71+82 Safety EdgeSM 144.5 152.5 141.32 151.74 1.75 8.35 1.59

4 WB 72+32 Safety EdgeSM 146.7 148.1 143.47 147.36 1.875 6.95 4.43

4 WB 72+82 Safety EdgeSM 138.4 153.4 135.36 152.63 2.25 12.22 1.01

4 WB 73+32 Safety EdgeSM 137.3 151.9 134.28 151.14 2.125 12.91 1.98

136.2 146.5 133.2 145.8 2.1 13.6 5.4

5.04 3.67 4.93 3.65 0.49 3.19 2.37

3.70 2.50 3.70 2.50 23.70 23.43 43.50

Station Adjusted Nuclear Values Air Voids, %

HMA 

Thickness, in.

Core Type of Section Nuclear Densities

Location

Lane 

Direction

Average Value

Standard Deviation

Coefficient of Variation
A-5

Table 6. Non-Safety EdgeSM Nuclear Gage Readings. 

A – Adjacent 

to Edge

B – 3 feet 

from Edge

A – Adjacent 

to Edge

B – 3 feet 

from Edge

A – Adjacent 

to Edge

B – 3 feet 

from Edge

5 EB 256+92 Non-Safety EdgeSM 143.6 145.1 140.44 144.37 8.92 6.37

5 EB 256+42 Non-Safety EdgeSM 140.9 143.9 137.80 143.18 10.63 7.14

5 EB 255+92 Non-Safety EdgeSM 152.9 144.4 149.54 143.68 3.02 6.82

5 EB 255+42 Non-Safety EdgeSM 143.5 152.0 140.34 151.24 2.5 8.98 1.91

5 EB 254+92 Non-Safety EdgeSM 148.0 152.2 144.74 151.44 2.625 6.13 1.78

5 EB 254+42 Non-Safety EdgeSM 137.0 151.5 133.99 150.74 2.5 13.10 2.24

5 EB 253+92 Non-Safety EdgeSM 146.5 149.5 143.28 148.75 7.08 3.53

5 EB 253+42 Non-Safety EdgeSM 140.8 143.9 137.70 143.18 10.69 7.14

5 EB 252+92 Non-Safety EdgeSM 138.2 149.3 135.16 148.55 12.34 3.66

6 EB 249+08 Non-Safety EdgeSM 150.8 146.3 147.48 145.57 1.75 4.35 5.59

6 EB 249+58 Non-Safety EdgeSM 140.8 153.5 137.70 152.73 1.75 10.69 0.95

6 EB 250+08 Non-Safety EdgeSM 142.4 148.8 139.27 148.06 1.625 9.68 3.98

6 EB 250+58 Non-Safety EdgeSM 137.5 150.0 134.48 149.25 1.625 12.79 3.20

6 EB 251+08 Non-Safety EdgeSM 138.8 146.6 135.75 145.87 1.75 11.96 5.40

6 EB 251+58 Non-Safety EdgeSM 150.4 147.3 147.09 146.56 1.375 4.60 4.95

6 EB 252+08 Non-Safety EdgeSM 144.6 143.7 141.42 142.98 1.75 8.28 7.27

6 EB 252+58 Non-Safety EdgeSM 139.6 150.2 136.53 149.45 11.45 3.08

6 EB 252+08 Non-Safety EdgeSM 143.3 144.2 140.15 143.48 2.375 9.11 6.95

143.3 147.9 140.2 147.2 2.0 9.1 4.6

4.76 3.28 4.66 3.26 0.44 3.02 2.12

3.32 2.22 3.32 2.22 22.41 33.18 46.47

Core Adjusted Nuclear Values

Location

Lane 

Direction

Station Type of Section

Average Value

Standard Deviation

Coefficient of Variation

HMA 

Thickness, in.

Nuclear Densities Air Voids, %