illinois interchange · 2020-02-28 · the rwd clearly detects changes in pavement structure....

This November, the U.S. willlikely have new guidelines by whichtraffic signs, signals and pavementmarkings are designed, installed andmaintained. Sign “minimum reflectivity”standards will be included in the nextMUTCD (Manual on Uniform ControlDevices) and should also be introducedin November. The Federal HighwayAdministration (FHWA) states that thechange “seeks to improve the nightvisibility of traffic signs by requiringagencies to replace all signs that donot meet driver needs.”

How do we know whether a sign “meets driver needs?”

A sign’s nighttime visibility ismeasured by “retroreflectivity” whichis a scientific term that describes howwell the sign bounces light from avehicle’s headlamps back to the driver’seyes. FHWA has published minimumretroreflectivity values that each signmust meet. In addition, signs degradeover time. We must continuouslymonitor retroreflectivity to make suresigns stay in compliance and replace

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IllinoisInterchange

I l l i n o i s T e c h n o l o g y T r a n s f e r C e n t e r

Vol. 15 No. 3 Fall Issue 2007

Please pass this on to otherinterested parties in your office.

INSIDE:From the Desk of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

NLTAPA Silver Sponsor . . . . . . . . . . . . . . . . . . . . . . 2

NLTAPA Platinum Sponsor . . . . . . . . . . . . 3

NLTAPA Gold Sponsor. . . . . . . . . . . . . . . . . . . . . . . . . 3

Rolling Wheel Deflectometer. . . . . . 4

Pavement Management . . . . . . . . . . . . . . . . . . . . 6

NLTAPA Photos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Highway Safety Initiatives. . . . . . . . . . . 10

BRIGHTER SIGNS FOR BETTER ROADWAY SAFETYBy Leo Rickertsen, Freelance Transportation Writer

FROM THE DESK OF...

Illinois Interchange2 Fall 2007

The Local Technology AssistanceProgram (LTAP) is a nationwide effortprimarily financed by the FederalHighway Administration, individualstate departments of transportation, anduniversities. Its purpose is to foster asafe, efficient, and environmentallysound surface transportation system byimproving the skills and increasingthe knowledge of the transportationwork force and decision makers. TheIllinois Technology Transfer Center isone of the 58 LTAP Centers in theUnited States.

Across the country, 38,000 localagencies - small and large cities, ruraland urban counties, and tribal gov-ernments - maintain nearly three mil-lion miles of roads and some 29,000

bridges. LTAP is a direct, hands-onmethod for moving innovative trans-portation technologies out of the lab,off the shelf, and into the hands ofthe people who maintain our localstreets and roads:• public works directors and staff • city and county engineers • local highway safety officers • transportation planners • street and road maintenance

superintendents and staff • certified technicians • skilled roadway laborers

As an LTAP Center, Illinois host-ed the National Local TechnologyAssistance Program Association’s(NLTAPA) 25th Annual Conferencein Chicago, IL from July 23 – July26, 2007. NLTAPA’s main objectivesare to build awareness about LTAP inthe transportation community, assistFHWA with developing strategies forthe program, and strengthen thecapacity of each center to best meetthe needs of its customers. This con-ference provides an opportunity forLTAP Centers to discuss commonconcerns, learn from others’ successes

and failures, and interact with peersand partner organizations.

The conference was highlightedby the opening remarks of Joe Toole,FHWA’s Associate Administrator forProfessional and CorporateDevelopment and a keynote addressby Professor Bruce Seely, the SocialSciences Chair of MichiganTechnological University. Numerousspecial sessions dealt with a varietyof training, management, operations,and communications topics. The con-ference concluded with a banquet andfireworks display on Navy Pier.

Thank you to all of the nationalsponsors and special thanks to theIllinois Association of CountyEngineers, the Illinois AsphaltPavement Association, and IllinoisChapter of the American PublicWorks Association for their sponsor-ship of this event.

Kevin Burke III, P.E.T2 Program Manager

NLTAPA CONFERENCE SILVER SPONSORThe American Public Works Association is an international educational and professional association

of public agencies, private sector companies, and individuals dedicated to providing high quality public works goods and services. APWA provides a forum in which public works professionals can exchange

ideas, improve professional competency, increase the performance of their agencies and companies, andbring important public works-related topics to public attention in local, state and federal arenas.

The Illinois Chapter membership is composed of public works officials throughout Illinois. For more information, please visit their website at www.illinois.apwa.net.

Illinois InterchangeFall 2007 3

NLTAPA CONFERENCE PLATINUM SPONSORThe Illinois Association of County Engineers is the collective forum of the 102 appointed county officials in

direct charge of county highway transportation in Illinois. Since 1914, the Association has served to provide forthe exchange of ideas and information aimed at improving the county highway engineering profession and coun-

ty highway engineering services to the public.

County Engineers, as provided by Illinois law, are appointed by the various county boards and approved by theIllinois Department of Transportation (IDOT). They must be graduate, licensed professional engineers experi-

enced in highway transportation. The County Engineer's responsibilities include the administration of the countyroad agency, coordination of funding for the township road agencies in the county and representation of the

county's interests with IDOT. They are responsible for the construction, maintenance, and safe operation of the16,571 miles of designated county highways in Illinois.

For more information, please visit IACE’s website at www.iaceng.org.

NLTAPA CONFERENCE GOLD SPONSORIAPA, the ILLINOIS ASPHALT PAVEMENT ASSOCIATION, has been serving as an industry resource and a vital communications channel for those involved in virtually every facet of the

asphalt industry in Illinois, since our founding in 1938.

The MISSION of the Illinois Asphalt Pavement Association is to:• Promote the improvement and advancement of quality asphalt pavement construction in Illinois;• Provide assistance to members in the areas of research, technical specifications, environmental issues,

education, promotion, government relations, and other related areas; • Educate potential buyers and specifiers of asphalt pavements as to the pavement’s characteristics

and benefits.

IAPA also co-sponsors the Recycled Asphalt Pavement (RAP) training course offered through the Illinois Technology Transfer Center.

For more information, please visit IAPA’s website at www.il-asphalt.org.


BackgroundIllinois local road agencies are

responsible for maintaining severalthousand miles of highway pavement.Traditionally, highway engineershave used pavement visual conditionsto make roadway management deci-sions, such as which roads to programfor improvement and what types ofimprovements to make. While visualdistress surveys provide valuableinformation regarding a road’s condi-tion—such as the types cracking andtheir potential causes—they lack adirect measure of the pavement’sstructural condition. In the past, pave-ment structural response has beenmeasured with nondestructive deflec-tion devices, such as the BenkelmanBeam, Road Rater, and Falling WeightDeflectometer (FWD). While thesedevices have proved useful for proj-ect-level applications, they lack theproductivity and mobility required fornetwork-level assessment.

The RWD DeviceThe RWD is an innovative device

for the high-speed structural evaluationof highway pavements. It was devel-oped by Applied Research Associates(ARA), Inc. for the Federal HighwayAdministration (FHWA). The RWDis designed to collect continuousdeflection profiles at normal highwayspeeds, without the need for lane clo-sures (and the safety hazards thatcome with them). It uses four trian-gulation lasers (figure 1) mounted ona rigid beam beneath the RWD trailerto calculate the deflection producedby the trailer’s dual-tire, 18-kip singleaxle (see figure 2). Data is collectedin real-time by the RWD’s dataacquisition equipment located in thetruck’s cab, using proprietary hard-ware and software. The RWD hasundergone extensive field testing andis currently being deployed for useby highway agencies. It is intendedfor use in the network-level evalua-tion of highways for pavement man-agement purposes.

Field ResultsThe RWD has performed full-

scale demonstrations for several statehighway agencies, including Texas,Indiana, Minnesota, and Iowa.Locally, the RWD was recently usedin the implementation of a pavementmanagement system (PMS) forChampaign County. Field testing hasdemonstrated the RWD’s ability toefficiently and accurately measurepavement deflection due to an actualmoving wheel load, something thatprevious devices were not capable ofdoing. Figure 3 shows the results ofmultiple RWD passes on Texas FM-50, a low-volume, chip seal pavement.The high deflections (i.e., up to 50mils) reflect the low structural capacityof the thin pavement, and the multiplepasses show good repeatabilitybetween test runs.

Figure 4 shows data from IndianaSR 1, consisting of three distinctpavement sections on the same road.The RWD clearly shows the changein deflection—and therefore pave-

ROLLING WHEEL DEFLECTOMETER (RWD)An Innovative Device for Measuring Pavement Deflections at High-SpeedBy Doug Steele, Senior Engineer, Applied Research Associates, Inc. and

Bill Vavrik, Principal Engineer, Applied Research Associates, Inc.

Figure 1. One of the RWD’s four lasers used to measure deflection.

Figure 2. The RWD measures the deflection of an actual truck at moving speeds.


ment structural capacity—wherechanges in pavement thickness andcondition occur. As the pavementbecomes thinner and weaker, thepavement deflections increase andbecome more variable (e.g., betweenmile markers 75 and 85). In fact, thiswas also reflected in the pavement’ssurface condition, which presented ahigh degree of fatigue cracking.Pavements with good structuralcapacity and uniformity produce low,uniform deflections, such as the sec-tion from mile marker 65 to 75.

RWD Uses and BenefitsThe RWD was developed to pro-

vide never-before-available deflectiondata for network-level highway appli-cations. The end result to highwayagencies is better allocation of limitedhighway funds by identification ofpavement sections that are in need ofstructural improvement and the selec-tion of the most appropriate rehabilita-tion strategy, such as surface treatment,asphalt overlay, or reconstruction.

The specific benefits provided bythe RWD include:

• The RWD can operate over a broadrange of speeds—ranging from 10to 65 mph—allowing it to blend inwith the surrounding traffic stream.

• It does not require lane closures;thereby, increasing safety to fieldcrews and the traveling public,while eliminating lane closures tothat are inconvenient to highwayusers.

• The RWD is a nondestructive testand, therefore, does not damage thepavement’s structural integrity.

• It has good productivity—typicallytesting 100 to 200 miles per day—allowing for the testing of entirehighway networks in a matter ofdays.

• Data can be provided to highwayagencies in formats that are readilyusable in their pavement managementactivities, including linkage to Geo-graphical Information Systems (GIS).

For more information on theRWD, please contact Doug Steele at(217) 356-4500 or [email protected].

Figure 3. Multiple RWD passes show good repeatability—Texas FM-50.

Figure 4. The RWD clearly detects changes in pavement structure.

PAVEMENT MANAGEMENT SYSTEM SUCCESS STORY

CHAMPAIGN COUNTYJeff Blue, P.E., County Engineer, Champaign County Highway Department


Champaign County has one pri-mary population center that makes upover half of the county population.This population center is comprisedprimarily of the City of Champaign,City of Urbana, and the University ofIllinois. Like many local governmentagencies, Champaign County hascompeting interests in the allocationof limited highway improvement andmaintenance funds.

Champaign County’s currentannual road maintenance and con-struction budget is approximately $3million. Of this total road funds, $2million are dedicated to improvingand maintaining the county’s highwaynetwork. The other $1 million areallocated to improving roads that arenot owned or maintained by ChampaignCounty. These diverted funds arededicated to funding “fringe road”projects that are generally owned oroperated by the City of Champaign,City of Urbana, or other local agency.

The issue of funding highwayimprovements on non-county roads isa significant issue between the Countyand local government agencies. It isgenerally recognized that transporta-tion improvements lead to economicdevelopment and growth, thereforethe County has a vested interest in

improving area transportation facilities,even if they are not specifically withinCounty jurisdiction. This creates a needfor an analytical means to determinethe required funding for the countyowned roads while still providingfunds to the local agencies to improvethe overall transportation networkand foster economic development.

Recently, the county implementeda pavement management system usingthe Rolling Wheel Deflectometer(RWD) as a means to improve budg-eting, planning, incorporate pavementpreservation, and have a scientificallydefensible means of showing the fundsrequired to maintain the highway net-work in acceptable condition.

Pavement Management SystemImplementation Approach

The PMS implementation fol-lowed through the following activitiesto provide the data, models, and eco-nomic analysis capabilities needed

for active pavement management.Network Definition & Condition

Assessment PMS requires knowingwhat you have and its condition.Using a digital video system, imagesof the pavement were recorded and apavement distress survey conducted.Figure 1 shows the pavement dis-tresses from a flexible pavement sec-tion. Pavement roughness data wascollected with a high-speed laser pro-filer, and pavement deflections weremeasured with the RWD. Figure 2shows the RWD deflection profile ofCR 32, identifying strong and weakpavement sections.

Determine Pavement PerformanceTrends The county has primarilyasphalt and composite pavements.Pavement performance models weredeveloped that show on average anHMA road requires rehabilitationafter 14 years.

Pavement Preservation, Rehabilit-ation, and Reconstruction Champaign

Figure 1. Fatigue cracking of the AC surface due toheavy, repeated wheel loads on CR 9.

Figure 2. Example of three distinct pavement deflection profiles on CR 32.


County used the PMS implementationas an opportunity to incorporate pave-ment preservation into the potentialfixes to roadway problems. Figure 3shows how routine maintenance, pre-ventive maintenance, rehabilitation,and reconstruction are all considered inthe management system. Since pave-ment deflections were incorporated inthe PMS, a treatment selection matrixthat includes pavement structure is usedto identify when preventive mainte-nance, thin overlay, or thick overlayare acceptable. Figure 4 shows anexample of the treatment matrix.

Development of Capital ProgramThe goal of the PMS implementationis to understand the ramifications ofchanges to funding on the roadwaynetwork. Figure 5 shows that with thecurrent funding levels the pavementcondition will decrease over the next5 years and that an additional$500,000 per year is needed to keepthe county road network at its currentlevel. In addition to improved under-standing of funding requirements, acapital projects list is generated withprojects that give the best “bang forthe buck.”

The Bottom LineChampaign County now plans

projects based on the results of thePMS, and these results are alreadyshowing benefit. A PMS improvesdecision-making, quantifies the valueof the highway network, improvescommunication between countystakeholders, and offers the ability tounderstand the ramification of chang-ing investments on the County’s roads.

As the County Engineer I estab-lished a simple goal for this project:“The overall goal is to provide anobjective tool for the inventory,assessment, and management ofChampaign County’s road network.”We have accomplished this goal!

Figure 3. Pavement treatments, their cost, and effect on condition

Figure 4. Champaign County treatment matrix.

Figure 5. Effect of spending on overall highway condition—5 year analysis.


any before they fall below the newretroreflective minimums.

A wide range of vehicles drive onpublic roads. Retroreflective signsmust accommodate them all. Forsafety, retroreflective performancemust produce signs that are as brightand visible for drivers in tractor-trailers as they are for those in thesmallest passenger car.

Why is higher visibilityimportant?

The driving environment is chang-ing in ways that increase safety concerns. • Roadway fatalities occur more often

at night than during the day based onmiles traveled which makes night-time visibility more significant.

• The overall population of drivers isgetting older as the Baby Boomersage. Aging in general produces nat-ural declines in eyesight, hearing,mobility and reaction times.

• Rural roads are more dangerous thanother roads, with fatalities 2.75 timeshigher per 100 vehicle miles traveled.

• Drivers of larger vehicles (such aslarge pick-ups and SUVs and partic-ularly commercial tractor-trailers)are disadvantaged by sign retrore-flective inefficiency.

• The vast majority of late modelvehicles come factory-equippedwith VOA (visually/opticallyaimed) headlamps that are designedto “cut off” illumination at theedges to reduce glare but can alsocompromise sign performance bycutting visibility in half.

Taken together—older drivers,nighttime fatalities, dangerous ruralroads and compromises in sign retroreflective efficiency—these changesstimulated the FHWA to develop newnighttime visibility standards for theMUTCD. In before and after studies(D.A. Ripley, 2005 Mid-ContinentTransportation Research SymposiumProceedings), researchers stated that

“implementation of highly reflectivesigns and pavement markings…showed statistically significant reduc-tions in injury collisions followinginstallation of highly reflective signs.”

How are we meeting these new standards?

Sign sheeting comes in differentgrades to indicate the brightness of anew sign. Illinois Department ofTransportation designations includetypes and performance levels fromType B (the lowest level, which willnot meet the new MUTCD minimums)up to higher performance levels suchA, AP, AZ, and ZZ.

Over time, higher brightnesssheeting also maintains its reflectivecompliance longer. Tests backed bywarranties indicate that the extendedlife of brighter sheeting such as TypeA and Type AP deliver greater value.A longer lifecycle lowers total costs.

Continued from page 1

TYPE B AND TYPE AP REFLECTIVE SHEETINGSigns made with Type B and Type AP sheeting may look similar during daylight conditions, but nighttime inspection

reveals reflectivity differences. The higher level of brightness provides the nighttime visibility preferred by older drivers and is especially helpful in a visually cluttered environment.

Continued on page 9


Factor Type B Type APSign cost (example only) $35.94 $40.63Optical efficiency 7% 32%Expected life 7 years 10 yearsCost per year $5.13 $4.06

What does this mean foragencies across Illinois?

From the date of the final ruling(now scheduled for November, 2007),

state and local agencies have twoyears to assess signs and prepare areplacement plan and seven to tenyears to change out any non-compli-ant signs.

The new minimum reflectivitystandards are intended to improvenighttime visibility for greater safetyin all road conditions and for all driv-ers and pedestrians. IDOT is support-ing that effort by upgrading to a min-imum of Type AP and using Type ZZ

for signing situations where optimalperformance is needed.

For more information about theFHWA ruling, how to meet the newMUTCD standards and ways toaccomplish this, visithttp://safety.fhwa.dot.gov/roadway_dept/retro/sign/sa03027.htm.

To learn more about assessmentand management methods visithttp://safety.fhwa.dot.gov/roadway_dept/retro/sign/back_method.htm

Continued from page 8


Over the last two years, IllinoisDepartment of Transportation’s(IDOT) Bureau of SafetyEngineering, Bureau of Local Roads& Streets, Bureau of InformationProcessing, and Division of TrafficSafety have partnered to addressfatalities and Class A injuries on thelocal highway system. The Safe,Accountable, Flexible, EfficientTransportation Equity Act: A Legacyfor Users (SAFETEA-LU) federallegislation signed into law on August10, 2005 established the HighwaySafety Improvement Program (HSIP).

As a new Federal-aid funding

core program, the HSIP was author-ized to achieve a significant reductionin traffic fatalities and serious injurieson all public roads. HSIP includes theHigh Risk Rural Roads Program(HRRRP). In Illinois, these federalprograms increased local safety dol-lars from around $700,000 per yearto over $7,000,000 per year withincreasing amounts each year of theauthorization bill.

As part of SAFETEA-LU, IDOTdeveloped a Comprehensive HighwaySafety Plan (CHSP) - www.dot.il.gov/illinoisCHSP/default.html - withthe goal of reducing fatalities on

Illinois highways to 1,000 by 2008.Since 50% of the statewide fatalitiesoccur on the local system, local high-way agencies are vital to this goal.Therefore, besides only funding spe-cific local projects through a compet-itive grant process, IDOT identifiedinitiatives to improve highway safetyat the local level.

ILLINOIS CRASH DATAIn Illinois, IDOT is responsible

for storing all crash data. Prior to2005, IDOT did not locate crashes onthe local system in geographical for-mat (GIS, longitude/latitude).

IDOT HIGHWAY SAFETY INITIATIVES FOR LOCAL AGENCIESBy James P. Allen, P.E., Safety Implementation Engineer, IDOT and

Kevin Burke III, P.E., Local Policy and Technology Engineer, IDOT

Screen shots from IDOT’s local agencydata location web interface.


Therefore, local highway agenciesneeded to use wall maps with pins,paper maps with markers, or locatetheir own crashes in GIS. Since HSIPrequires projects to focus on fatal andClass A injury crashes, historicalcrash data with location is needed.Recognizing this fact, IDOT workedclosely with the Illinois Associationof County Engineers (IACE) andMunicipal Planning Organizations(MPOs) to provide $1,060,000 tocounties and MPOs to begin locatingall fatal and Class A injury crasheson the local system from 2001-2004.

LOCAL SAFETY SERVICES“Crash Data Analysis & EngineeringSolutions for Local Agencies” (R27-18) is a research project sponsored byIDOT with the Illinois Center forTransportation (ICT) - www.ict.uiuc.edu/default.asp. This project willevaluate other states' safety serviceprograms for local agencies anddevelop a plan to establish a success-ful Illinois program. The researchwill help create a system to analyze

crash data and develop reports usefulto local agencies; and provide crashanalysis to local agencies, including a list of potential improvements toreduce the incidence of crashes, when requested.

ROAD SAFETYASSESSMENTS (RSA)A RSA is a formal safety perform-ance examination of an existing orfuture road or intersection by anindependent assessment team. TheRSA team considers the safety of allroad users, qualitatively estimatesand reports on road safety issues andopportunities for safety improvement.RSA training teams will introducethe concept to local agencies over thenext several months. IDOT will thenhelp establish regional RSA teamsthat will provide this service toneighboring local agencies. RSAswill serve as a useful tool for identi-fying good projects to apply for localHSIP funding.

RURAL LOCAL AGENCYTRAFFIC SIGN UPGRADE In FY2007, IDOT identified fourcounties (Bond, Cumberland,Henderson, and Piatt) to participate inthe pilot program. For FY2008, thepilot program was modified andextended to another 9 counties(Franklin, Iroquois, Marion, McDonough,Montgomery, Vermilion, Wayne,Whiteside, and Will). These countieswere selected from each IDOT Districtbased upon the number of fatal andClass A injury crashes over the past 5years on the local system and finan-cial need relative to rural mileage.The program is intended to upgradeexisting regulatory and warning signsin rural areas for highways under thejurisdiction of road districts, counties,or municipalities (with populationless than 5,000) to comply with mini-mum in service retroreflectivity levelsproposed for the Manual on UniformTraffic Control Devices (MUTCD).Each local agency participating willneed a sign inventory, summary ofquantities, and location map.

Mock webpage for LocalSafety Services crash analysis.

The Technology Transfer (T2) Program is a nationwide effort financed jointly bythe Federal Highway Administration and individual state departments of trans-portation. Its purpose is to transfer the latest state-of-the-art technology in theareas of roads and bridges by translating the technology into terms understood

by local and state highway or transportation personnel.

The Illinois Interchange is published quarterly by the Illinois Technology Transfer Center at the Illinois Department of Transportation. Any opinions, findings, conclusions, or

recommendations presented in this newsletter are those of the authors and do not necessarilyreflect views of the Illinois Department of Transportation, or the Federal Highway

Administration. Any product mentioned in the Illinois Interchange is for informational purposes only and should not be considered a product endorsement.

Illinois Technology Transfer CenterIllinois Department of Transportation

2300 South Dirksen Parkway - Room 205, Springfield, IL 62764Fax (217) 785-7296

E-mail us at [email protected]

Local Policy & Technology EngineerKEVIN BURKE

[email protected] • (217) 785-5048

Training and Graphics SpecialistAMY NEALE


Training Development TechnicianROY WILLIAMSON


Visit our website at www.dot.il.gov/blr/t2center.html

State of IllinoisRod R. Blagojevich, Governor

Illinois Department of TransportationBureau of Local Roads and Streets

T2 ADVISORY COMMITTEEThomas E. Klasner (Chairman)

County Engineer, Jersey County201 West Pearl, P.O. Box 427, Jerseyville, IL 62025

(618) 498-5571

Douglas BishopCounty Engineer, Perry County

3698 State Route 13/127, Pinckneyville, IL 62274(618) 357-6556

Eldon StahlHighway Commissioner

Medina Township (Peoria County)R.R.#1, Dunlap, IL 61525

(309) 579-3101

Olen KiblerHighway Commissioner

Newman Township (Douglas County)608 North Howard, Newman, IL 61942

(217) 837-2723

Ed ReederDirector of Public Works

City of CarbondaleP.O. Box 2047, Carbondale, IL 62901

(618) 549-5302

Lynn KraussDirector of Public Works

Village of Oak Lawn9446 S. Raymond Ave., Oak Lawn, IL 60453

(708) 499-7816

Heidi LiskeResearch & Technology Transfer Engineer

Federal Highway Administration 3250 Executive Park Drive, Springfield, IL 62703

(217) 492-4637

Presort StandardMAIL

U.S. PostagePaid

Springfield, ILPermit No. 880

2300 South Dirksen ParkwaySpringfield, Illinois 62764

ADDRESS SERVICE REQUESTED

Printed by authority of the State of Illinois, 10/07, 4,325

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