UNPAVED ROAD CONDITION ASSESSMENT METHODS

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PROPOSED WEB BASED APPLICATION FOR NEW IMPROVED UNPAVED ROAD

CONDITION ASSESSMENT METHOD

a. Objective

The length of unpaved roads in the United States account for approximately 34.68 % of

the total road network (CIA, 2012) which is particularly important for the agricultural economy

by connecting farms to processing facilities and end markets. With increased traffic and heavy

designs of agricultural equipment these roads are facing challenges. Regular maintenance and

improvement of these roads is important for continued good rural economic performance.

County engineers constantly assess road conditions in order to initiate the maintenance work.

With limited budget and current assessment tools, decision making for fund allocation to roads is

mostly done on an ad hoc basis. To assist clear decision making and effective prioritizing of

roads for maintenance, reliable assessment tools should be developed. This paper proposes a new

improved condition assessment format for unpaved roads and further proposes a web based

application that will help organize, analyze and synthesize road performance assessment data.

b. Literature Review

There are many methods for assessing unpaved road conditions. All compared them with

an emphasis on examining reliability and accuracy. Most of the visual assessments are subjective

or qualitative in nature but are cost effective whereas advanced methods which use equipment

are precise but are more expensive comparatively. The focus will be to propose improved and

more reliable road condition assessment methods.

The assessment methods can be classified into the following categories: visual,

combination (visual and direct measurement), and indirect data acquisition with specialized

equipment (Brooks C., 2011).

1. Gravel PASER Manual

PASER is a completely visual method with a rating scale from 1 to 5, addresses almost

all aspects of the road condition. Further suggests measures to be taken for distresses present

respectively. Visual assessment is a good method to save a considerable amount of labor and

money in many cases where a long length of road is to be assessed. Table 1 is from the PASER

gravel road manual (D., 2002) which explains how the assessment is performed and what is

recommended for decision making. Evaluation of the crown, drainage, gravel layer, surface

deformation (wash boarding potholes and ruts) and Surface defect (Dust and Loose aggregate)

are included.

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Table 1 : Rating table from PASER gravel road Manual (D., 2002)

Surface

Rating

Visible Distress* General Conditions/

Treatment Measures

5

Excellent

No distress.

Dust controlled.

Excellent surface condition and ride.

New construction—or total

Reconstruction. Excellent

drainage.

Little or no maintenance

needed.

4

Good

Dust under dry conditions.

Moderate loose aggregate.

Slight wash boarding.

Recently regarded. Good

crown and drainage

throughout. Adequate

Gravel for traffic. Routine

grading and dust control

may be needed.

3

Fair

Dust under dry conditions.

Moderate loose aggregate.

Slight wash boarding.

Shows traffic effects.

Regarding (reworking)

necessary to maintain. Will

require some ditch

improvement and culvert

maintenance. Some areas

may need additional gravel.

2

Poor

Little or no roadway crown (less than 3”).

Adequate ditches on less than 50% of roadway.

Portions of the ditches may be filled, over grown

and/or show erosion. Some areas (25%) with little

or no aggregate. Culverts partially full of debris.

Moderate to severe wash boarding (over 3” deep)

over 25% of area. Moderate rutting (1”-3”),

over10%-25% of area. Moderate potholes (2”-4”)

over 10%-25% of area. Severe loose aggregate

(over 4”).

Travel at slow speeds (less

than 25 mph) is required.

Needs additional new

aggregate. Major ditch

construction and culvert

Maintenance also required.

1

Failed

No roadway crown or road is bowl shaped with

extensive ponding. Little if any ditching. Filled or

damaged culverts. Severe rutting (over 3” deep),

over 25% of the area. Severe potholes (over 4”

deep), over 25% of area. Many areas (over 25%)

with little or no aggregate.

Travel is difficult and road

may be closed at times.

Needs complete rebuilding

and/or new culverts.

* Individual road sections will not have all of the types of distress listed for any particular

rating. They may have only one or two types.

2. RSMS (Road Surface Management System)

This method addresses seven indices for unpaved road condition based on visual

evaluation. RSMS assigns a severity scale with rough percentage of distress visually assessed.

Four indexes are assigned percentage distress (Table 2) and three indexes have three scales good,

fair and poor (Table 3). This assessment method is completely visual and no measurement with

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any type of instrument is required. Also the use of a decision tree as shown in

Figure 1 is suggested to aid users of this method.

Table 2 : RSMS - Severity and Extent (H., 1994)

Distress Severity Extent

Corrugations Low

Medium

High

Low : <10%

Medium : 10% - 30%

High : >30%

Potholes Low

Medium

High

Low : <10%

Medium : 10% - 30%

High : >30%

Rutting Low

Medium

High

Low : <10%

Medium : 10% - 30%

High : >30%

Loose Aggregate Low

Medium

High

Low : <10%

Medium : 10% - 30%

High : >30%

Table 3 : RSMS - Condition (H., 1994)

Distress Condition

Cross- section Good

Fair

Poor

Drainage Good

Fair

Poor

Dust Light

Medium

Heavy

Figure 1 : Decision tree RSMS (H., 1994)

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3. Objective Rating System - Central Federal Lands Highway Division

The Impacts of stabilizing products were studied in the Buenos Aires National Wildlife

Refuge and Seedskadee National Wildlife Refuge by the Central Federal Lands Highway

Division of the USDOT FHWA. Five indices for road conditions were assessed. All five

distresses were physically measured using with a defined scale chart for each index. Each index

has 10 scales with physical measurement differences except dust. Whereas Wash boarding,

raveling, rutting & potholes varied from >60 mm deep to <5mm to not visible from 0 to 10 rating

scale respectively. Table 4 provides an example about below how the rating was given for

various indexes.

Table 4 : Objective rating for field Measurements (Surdahl R. W., 2005)

4. Unsurfaced road condition Index (URCI)

Developed by Unites States Army Corps of Engineers unsurfaced road condition Index

(URCI) addresses 7 indexes. All of these indexes have to be measured physically except dust

which is addressed subjectively. Also the severity of each index is noted in an example of a

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completed inspection sheet ( Figure 2). The density for each distress is calculated with

respect to the area of a sample unit into a percentage.

Figure 2 : Example of completed inspection sheet – URCI (Army, 1995)

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c. Definition & explanation of the primary project management topic addressed in the

report.

This paper primarily addresses the issue of the maintenance which is a prominent topic

given the long length of unpaved roads in the country. Assessment of such roads is necessary in

order to carry out maintenance activity. As various road condition assessment methods for

unpaved roads have been reviewed, next, they will be compared and possible improvements will

be considered. And further will suggest decision making based on the method.

A comparison amongst assessment methods in the Table 5 showing key indices is given,

which are important for evaluating road conditions. All methods have their pros and cons, but

each of the methods lacks objectivity. An important index such as dust completely visually or

subjectively evaluated, questions are raised on the reliability of the road condition assessment as

a whole. Indexes such as sub-grade and ride quality should be addressed in road assessment as

these are also important indexes for overall road condition evaluation. Table 5 compares various

assessment methods based on important indexes which play a vital role in road condition

evaluation.

Table 5: Comparison between assessment methods on different Indexes

Indexes of

road

characteristics

and Distresses

PASER

Gravel

Roads

RSMS Objective

Rating

UCRI Remarks

Sub-Grade Not

addressed

Not

addressed

Not

addressed

Not addressed Sub-grade

plays a

important role

in the overall

condition of

roads and

should be

addressed in a

objective

manner

Cross Section Height and

condition of

crown slope

of road

visually

evaluated

Visually

assessed

with

ambiguous

severity split

in three

conditions

Not

addressed

Density of

distress is

calculated by

measuring it

with respect to

area of sample

area and then to

a percentage

Few methods

measure

crown and

slope of the

road cross

section. But a

more

objective

measurement

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should be

done.

Drainage Roadside

ditches and

under-road

culverts

visually

evaluated

Visually

assessed

with

ambiguous

severity split

in three

conditions

Not

addressed

Density of

distress is

calculated by

measuring it

with respect to

area of sample

area and then to

a percentage

Just one

method

addresses it

with a

physical

measurement.

Gravel

thickness

Thickness

and quality

of gravel

visually

evaluated

Visually

assessed

with

severity

extend

Not

addressed

Not Addressed Thickness of

the gravel

should be

measured

physically

across the

cross section.

Corrugations Visually

evaluated

Visually

assessed

with

ambiguous

severity split

in three

conditions

Scale from 0

to 10 based

on physical

measurement

of >60 mm

to < to 5mm

to not

measureable

Density of

distress is

calculated by

measuring it

with respect to

area of sample

area and then to

a percentage

Corrugations

are assessed

in a

measurable

manner by

two methods.

Dust Visually

evaluated

Visually

assessed

with

ambiguous

severity split

in three

conditions

Subjective

uneasiness at

driving 25

mph to a

scale of 0 to

10

No density

calculation

No method

quantifies

dust in a

measurable

manner for

evaluation

regarding

road

condition.

Potholes Visually

evaluated

Visually

assessed

with

ambiguous

severity split

in three

conditions

Scale from 0

to 10 based

on physical

measurement

of >60 mm

to < to 5mm

to not

measureable

Density of

distress is

calculated by

measuring it

with respect to

area of sample

area and then to

a percentage

Potholes are

assessed in a

measurable

manner by

two methods.

Ruts Visually

evaluated

Visually

assessed

with

ambiguous

Scale from 0

to 10 based

on physical

measurement

Density of

distress is

calculated by

measuring it

Ruts are

assessed in a

measurable

manner by

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severity split

in three

conditions

of >60 mm

to < to 5mm

to not

measureable

with respect to

area of sample

area and then to

a percentage

two methods.

Loose

Aggregates

Visually

evaluated

Visually

assessed

with

ambiguous

severity split

in three

conditions

Scale from 0

to 10 based

on physical

measurement

of >60 mm

to < to 5mm

to not

measureable

Density of

distress is

calculated by

measuring it

with respect to

area of sample

area and then to

a percentage

Two

assessment

methods

addressed it

and it should

be based on

more

objective

criteria.

Ride Quality Not

addressed

Not

addressed

Not

addressed

Not addressed Road quality

or ride quality

should be

included as

another key

index

The reason for introducing Sub-grade in the indexing system for road condition

assessment is due to the interconnection between the road conditions outcomes caused by

different in the soil types and sub-grade compaction that changes from section to section. The

thickness of the gravel is selected based on the sub-grade bearing capacity. Therefore a change in

the condition of the subgrade can directly affect the performance of the road above. Sub-grade

condition should be implied on the results of the earlier assessment methods and a relationship

between sub-grades to the road condition should be established.

The dust index has not been addressed in any of the previous reviewed assessment

method, in objective or quantified manner, so there is a need to measure dust in a more objective

manner with the use for dust measuring tool such as dustometer. Two types of reliable

dustometers which have been used for assessments are Colorado State University (CSU)

Dustometer & testing re-entrained aerosol kinetic emissions from roads (TRAKER). TRAKER is

a more precise and accurate dust measuring device having GPS and computer mounted under the

car; it has been used for several environmental studies (Etyemezian V., 2003). CSU Dustometer

is a straight forward assembly of vacuum pump and filter mounted in the back of a truck

(Morgan R. J., 2005). The measurements taken from this device is also precise and is more

economical in comparison to those of the TRACKER. The CSU Dustometer is more suited to

road assessment as a long stretch of road can be evaluated economically. CSU Dustometer,

which employs the filtration technique, is an improvement compared to previously developed

devices. Although the dustometer technique involves weighing of the filters in the laboratory, the

process can be executed quickly, and it enables large amounts of precise dust data to be gathered

in a short period of time (Sanders T.G., 2000). It will standardize and normalize the way in

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which road conditions are assessed. Dust directly depends on the moisture in the road. One

important factor is the interplay of moisture from rain and evaporation and another is the amount

of moisture beneath the road from sub grade due to capillary action. If the sub grade has moisture

content which can be maintained in the top surface by capillary action in summer and avoid

generation of dust, then that optimum moisture content that keeps road moist without losing

bearing capacity should be found and the surface layers should be designed with this in mind.

This again connects the dust index with subgrade. Also if the subgrade permanently loses its

bearing capacity due to full saturation or settles down due to sedimentation or failure, the

subgrade must be replaced or strengthen by various means.

Ride quality is another index that should be addressed in a more quantitative way using

instruments such as accelerometers which could establish a more reliable measuring tool in

context of speed of the vehicle. This can be economically performed by using iPhone and with

an appropriate software application. One such application has been developed by Diffraction

Limited Design is called Vibration. This software application takes advantage of the fact that the

iPhone has an inbuilt 3-axis accelerometer. It can measure up to plus/minus 2.0g and has a

sensitivity of about 0.02g. Those characteristics make it useful for measuring ride comfort. The

application can be set to sample at up to 100Hz (100 times a second) and the data can be

displayed as a series graphs. Furthermore, mathematical analysis of the data can be performed by

the software. You can also email screen shots and a .csv file of the collected data to other

platforms for later analysis. (J., 2013)

Another application called Roadroid is also very helpful to determine IRI indexes. This

application can be only used on android OS for smartphones. (www.roadroid.com)

In all it is clear that a more objective and standardized assessment method can be

developed in order to present a more reliable road condition report. It is clear that quantitative

assessment is more objective than quantitative assessment.

New improved assessment method

As shown below in Table 6, each index has been addressed with a objective rating scale

based on physical measurements by using instruments. Also relevant measures according to the

scale given are suggested.

Table 6 : Improved assessment method addressing road distress/ condition indexes

Indexes of

road

characteristics

and Distresses

Measurement

Instrument

Rating

method

Scale (10) Measures

Sub-Grade Proctor test for

Optimum

moisture

> -/+5%

+/- 0-5 %

OMC

0 – 5 for < or >

+/- 5%

5-10 for +/- 0-

Subgrade will be replaced or

strengthened as necessary

means according to scale.

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content. < -/+5% 5%

Cross Section Height and

condition of

crown slope of

road measured

physically or by

surveying.

Crown 6”

3-6”

<3”

No crown

Crown 6” - 10

3-6” – 7

<3” - 3

No crown – 0

Motor grader maintenance or

new construction based on the

scale.

Drainage Roadside

ditches and

under-road

culverts

measured

physically or by

surveying.

Blocked with

respect to

total area of

drainage in

percentage.

0 to100% - 0

to 10

Based on the blockage scale

decision to clean or replace

drainage will be made.

Gravel

thickness

Thickness and

quality of

gravel

measured

physically or by

surveying.

6”

3-6”

<3”

Not present

6” - 10

3-6” – 7

<3” - 3

No present - 0

Based on the scale virgin

aggregates will be mixed or

new construction will be

done.

Corrugations Corrugations

measured

physically or by

surveying.

>60 mm

deep to <5

mm to not

present

0 to 9 and 10

respectively.

Density of distress is

calculated by measuring it

with respect to area of sample

area and then to a percentage

Dust CSU

Dustometer is

used to weigh

dust for roads.

Per 2000 ft.

weekly test will

be taken

5 g

4 g

3 g

2 g

1 g

5 g – 0 to 2

4 g– 2 to 4

3 g – 4 to 6

2 g– 6 to 8

1 g– 8 to 10

Dust suppressants according

to the conditions.

Potholes Potholes

measured

physically or by

an instrument.

Average depth

in a area will be

measured.

not passable

to >100 mm

to

<5 mm to

not evident

0 to 1 to 9 and

10 respectively

Filling the potholes or

reconstruction according to

the severity of the scale will

be finalized.

Ruts Ruts measured

physically or by

an instrument.

>60 mm

deep to <5

mm to not

present

0 to 9 and 10

respectively.

Adequate measures will be

taken

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Loose

Aggregates

Loose

aggregates

measured

physically or by

an instrument

Not present

<20 mm

deep

20 to 40 mm

40 to 60 mm

>60 mm

Not present -0

<20 mm deep -

2

20 to 40 mm -

4

40 to 60 mm -

8

>60 mm - 10

Reclaiming the loose

aggregates or grading will be

done respectively.

Ride Quality Ride quality

will be

measured

physically by

an instrument

called

accelerometer.

A Constant

speed of 25

mph will be

kept.

Determine

car to be

used and

other factors

such as car

condition,

suspension

etc. Once

calibrated

and

benchmarked

readings can

be taken.

Scale will be

set according

to the

calibration and

benchmarking

form 0-10.

Grading or adequate measures

will be taken according to the

scale because of the waves

formed on the road surface.

Aerial Photography using Quad copters

Michigan Technological University is using quad copter for taking pictures of

unpaved roads. These pictures will be then analyzed and compared with the ground truth data.

Hence a process will be developed to calculate road width, road cross-section and potholes.

Web based application

Today in the age of cloud computing, prominent cloud platforms like Windows Azure,

Amazon Web services and The Rackspace cloud offer large and robust hardware backup to

promote use of cloud based web applications. Many Companies are creating construction apps

for mobile devices addressing accounting, estimating, invitation to bid, project management,

BIM, document management, information management, supply chain management, inventory

management, engineering software and many more.

Instead of running programs and data on an individual desktop computer, everything is

hosted in the “cloud”—a nebulous assemblage of computers and servers accessed via the

Internet. Cloud computing lets you access all your applications and documents from anywhere in

the world, freeing you from the confines of the desktop and making it easier for group members

in different locations to collaborate. (M., 2008)

Good examples of web based applications are google docs, salesforce.com which have

their own servers and applications which can be accessed from anywhere with just internet

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connection. In a way all the data of the assessment can be stored in software on a server and can

be accessed from anywhere.

A software or application should be created based on the new improved road condition

assessment method. This application should addresses all the points proposed and should be kept

on a cloud server, so that all the engineers can collaboratively access and analyze the data. Being

on the cloud it could be accessed from the field.

d. Advantages & Disadvantages to:

1. The Owner

Advantages: Owner with the new improved unpaved road condition assessment method

can have more precise input for making decisions on how to maintain roads. They will be able to

quantify and measure any adjustments that might be attempted in order to affect improvements.

The owner can easily compare the assessment results before and after the adjustments.

Disadvantages: Cost of comparing the adjustments using the proposed assessments will

be more than conventional methods. The owner has to understand and consider each assessment

result and monitor the measurements.

2. The Designer

Advantages: Designer can draw accurate performance data that will be available after the

assessments are conducted. Historic assessment for data of a region will help designers to design

improvements under similar condition with improved outcomes. This will lead to better

stakeholder satisfaction, better performance and greater effectiveness including sustainability.

Disadvantages: Added effect would be required for the designer to review assessment

outcomes and select treatments based on the review.

3. The Maintenance Operator

Advantages: Better estimates can be prepared for the maintenance work that is to be

undertaken. The results of the assessment will guide the operator, will have improved

information about what operations are most effective and will produce the most desirable

outcomes. In all, the operator has to follow the assessment measurements and quantify the work

to be carried out.

Disadvantages: If the most effective maintenance operator is better known, the

maintenance operator may have less latitude in choosing an operational approach.

e. Cost Implications

Due to the instruments and manpower assigned to carry out assessments the overall cost

will be more than conventional methods. This may lead to fund scarcity for other projects in the

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county. The cost of equipment, man power required to take measurements will be high and will

be a driving force in overall cost of the project. Implemented on a large project this method will

turn out to be feasible. Also due to more engineering and planning effort put in, there may be

savings in material to be used.

f. Conclusions and Recommendations

There is a need to assess road condition of unpaved roads in a more objective manner

given the importance to rural transportation networks. The assessment method purposed in this

paper requires greater effort in comparison to conventional methods, but will provide more

quantitatively rigorous results to the engineer so that more effective interventions can be

planned. The use of electronic data collection and web-applications will make the results

available to more stakeholders and encourage a more collaborative analysis, Interpolation of the

results leading to more collaborative implementation.

A more detailed research effort should be undertaken with regard to the proposed

assessment method after initial practical usage. An elaborated description of the web-based

application and the framework and function of the system should be undertaken. A relationship

between the various indices of road distress should be developed and a more integrated and

complete assessment method should be devised.

Other tools such as GPS and weather condition monitoring might be also employed

during the assessment to strengthen the reliability of the assessment outcomes by correlating

with the performance affecting attributes that are measured by the tools.

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h. Bibliography

Army, D. o. (1995). Unsurfaced Road Maintenance Management. Department of Army.

Brooks C., C. T. (2011). Cahracterization of Unpaved Road Condition Through the use of Remote sensing.

Michigan Tech Research Institute .

CIA. (2012). CIA Factbook. Retrieved from CIA Factbook: http://www.cia.gov/library/publications/the-

world-factbook/geos/us.html

D., W. (2002). Pavement Surface Evaluation and Rating - PASER gravel roads Manual. Transportation

Information Center.

Etyemezian V., K. H. (2003). Vehicle-based road dust emission measurement: I - methods and

calibiration. Atmospheric Environment.

H., G. a. (1994). Road Surface Management System.

J., E. (2013). Ride Quality Part 2. Retrieved from Autospeed:

http://www.autospeed.com/cms/article.html?&title=Ride-Quality-Part-2&A=112915

M., M. (2008). Cloud Computing: Web-based applications that change the way you work and collaborate

online. Que publishing.

Morgan R. J., S. V. (2005). Determination and Evaluation of Alternative Methods for Managing and

Controlling Highway - Related Dust, Phase II - Demonstration Project . IHRB.

Sanders T.G., a. A. (2000). Experimental road dust measurement device. Journal of transportation

engineering.

Surdahl R. W., W. J. (2005). Road Stabilizer Product Performance: Buenos Aires National Wildlife Refuge.

FHWA.

UNPAVED ROAD CONDITION ASSESSMENT METHODS

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