TEXAS TRANSPORTATION

A Publication of the Texas Transportation Institute • Member of The Texas A&M University System • Vol. 37 • No. 2 • 2001

TTI’s Intelligent Transportation Systems (ITS) research is directed toward easing congestion and improving emergency response

The alarm sounds . . . communities today stem from LINKING “Station 4. House Fire at 1910 the fact that the transportation TRANSPORTATION Elm St. Engine 6 and Ladder 2 system does not operate as if ELEMENTS respond.” it is one seamless system — as Intelligent transportation systems The firefighters at Station 4 if it is under single ownership (ITS) establish ways for agencies immediately head for the trucks. and management,” says Tom to share information and work In this business, a matter of min- Urbanik, associate agency direc- together to improve operational utes can mean the difference tor and head of the Transporta- efficiency and safety of the Charley V. Wootan between life and death. The truck tion Operations Group (TOG) at entire system. In working toward is almost there, only one block to Texas Transportation Institute this goal, TOG is developing 1926 – 2001 go. As the truck approaches the (TTI). “For example, if fire last intersection, a train arrives, dispatchers had a complete pic- —continued on page 2 —see tribute beginning on page 7 blocking the route. If the dis- ture of the transportation system patcher had known exactly when as the result of communication the train would cross the intersec- and information technology, we INSIDE THIS ISSUE tion, the dispatcher could have could save lives and property. If directed the trucks to take a dif- cities’ traffic signal systems and ferent route or may have been able the state’s freeway management Managed to dispatch other trucks . . . but centers supported emergency Lanes: Dynamic now, all anyone can do is hope for vehicle dispatch, lives, time and Archiving the best. money could be saved.” ITS Data the future Message “Many of the transporta- of freeway Signs tion problems that we face in our 512travel 13 Seamless transportation, cont. innovative approaches for linking Link facilities can also be used all elements of the transportation for professional development and network. training purposes following Researchers have been study- implementation. ing methods of monitoring train movements and predicting arrival NEW ITS DIRECTIONS and departure times at highway TTI is pursuing new initiatives grade crossings. This information such as the Center for Transporta- is being used to better operate tion Infrastructure Management the traffic signals and improve during Emergency (CTIME). The emergency response. focus of CTIME is to optimize the Other areas of research focus use of the transportation infra- on improving and enhancing road- structure during major emergen- way sensors, motorist information cies through the application of systems and incident manage- existing technology, development ment processes, and better coor- of new technologies and unified dination of ramp metering and inter-agency response. This effort traffic signal operation. will focus primarily on two major areas of need: TRANSLINK® • major military deployments LABORATORY • natural disasters TTI’s laboratory facilities, field test Military branches continue to beds and research tools serve as modernize, work toward improved settings for ITS research. One efficiency and assume new respon- facility, the TransLink® Research sibilities. These new responsibil- Laboratory located in Texas A&M ities include the Army’s recently University’s Research Park in Col- established 96-hour deployment lege Station, Texas, is a state-of- goal and the new Joint Task Force the-art lab designed to promote for Civil Support. Both of these and facilitate research and train- new initiatives call for U.S. mil- ing in transportation operations. itary personnel (in conjunction TTI researchers use TransLink to with numerous other agencies in design, develop and evaluate new the case of the latter example) to technologies and concepts for mea- “do more with less,” actively col- suring and improving operations. laborate and cooperate with other Through the use of simulation operating agencies and integrate equipment and real-time connec- and/or exchange real-time data tions to traffic management cen- across physical and jurisdictional ters, researchers develop and test boundaries. ITS provides a means new concepts and strategies for of accomplishing these goals in managing almost every aspect regard to transportation issues. of the surface transportation ITS research also responds system, including: to needs that arise as a part of • traffic signal systems hurricane evacuations. Roughly • highway-railroad grade one out of every five Americans crossings resides in an area at direct risk The TransLink® Research Laboratory • deployment of emergency for hurricanes. The latest sta- vehicles tistics indicate the number is • transit operations rising, with an estimated 3,500 located at Texas A&M University is • freeway management persons per day (fueled primarily Once ideas are developed and by retiring baby boomers) relo- a state-of-the-art lab designed to tested under controlled laboratory cating to at-risk coastal regions. conditions, they are taken to TTI’s Given these conditions, massive promote and facilitate research and test beds for real-world refine- evacuations such as the one ment. This systematic approach experienced during Hurricane provides products and methods Floyd in 1999 will become more training in transportation operations. ready for implementation. Trans- commonplace. The evacuation

2 Texas Transportation Researcher State officials honor ‘Father of Texas highway system’

On May 31, state transportation officials The Texas Transportation Hall of Honor paid tribute to the man considered to be recognizes individuals whose vision and the father of the Texas highway system leadership made possible the transporta-

TTI Assistant Research Scientist Bob Brydia gives a when they inducted Dewitt C. Greer into tion system Texas enjoys today. presentation to TransLink partners on state-of-the- the Texas Transportation Hall of Honor. “Dewitt Greer was a man of excep- practice review of alternative methods of data entry. “The impact he had on the state’s trans- tional honor, vision and integrity,” Texas portation system — not just the on roads Transportation Institute Deputy Director (Opposite page, top and center photos) TransLink but on the industries that help build the Dennis Christiansen said in announcing partners participate in a training session on railroad preemption. roads — and the method and structure Greer’s selection. “All of us who travel the he used to put together this system were highways of Texas today have him to thank (Opposite page, bottom photo) TransLink research- masterful,” Texas Transportation Commis- for the prosperity and quality of life those ers preparing hardware-in-the-loop simulation sioner Robert Nichols said during the highways have brought to our great experiment. induction ceremony. state.” Greer, a 1923 graduate of Greer was the chief admin- Texas A&M University, istrator of the Texas High- resulting from Hurricane Floyd was the joined the Texas Highway way Department during the largest evacuation in American history and Department in 1927 and construction of the inter- involved an estimated six million people. served as the engineer- state highway system. ITS technologies tested in the lab can ensure director of the depart- The Colson-Briscoe Act, smooth operations during these types of ment from 1940 until of which Greer was the emergencies. his retirement in 1968. chief architect, He then became a allocated funds for IMPROVING THE FUTURE OF member of the Texas statewide farm-to-mar- TRANSPORTATION Highway Commission ket roads. With the help “Through these efforts and others, TTI from 1969 until 1981, of federal funds, the legis- research is contributing to development of a serving under Governors lation enabled the depart- surface transportation system that operates Preston Smith and Dolph ment to nearly double the seamlessly while maximizing the effective- Briscoe. At the time of his number of paved rural roads ness and efficiency of the movement of people death in 1986, Greer had com- in the state within two years. and goods,” says Urbanik. “Using intelligent pleted more than half a century During Greer’s tenure, the number transportation systems, we can make sure of service to the state. of miles of paved roads in Texas grew from the correct people have the correct informa- “Mr. Greer spent the majority of his 22,000 to more than 72,000. tion to make the correct decision in a timely life developing, constructing, maintaining Ray Barnhart, former member of the manner.” and administering over 72,000-plus miles Texas Transportation Commission and of highway system in this state. He was former administrator of the Federal High- dedicated to developing the best trans- way Administration, noted, “It is fitting For more information, contact Kevin Balke at (979) 845-9899 or portation system possible for the state of that Dewitt Greer be inducted into this [email protected] Texas,” said Luther DeBerry, retired direc- hall of honor. For truly if ever a man’s life tor of the Texas Department of Trans- epitomized the meaning of that word, it portation. “He not only served Texas, by was his. In the instance of the man called developing a great highway system, he also Mr. Greer, words such as honor, principles, touched the lives of people all over the integrity and dedicated public servant are world as an advisor on transportation. not hyperbole. They were intrinsic to his Leaders sought his ideas and advice.” being and to his leadership.”

Texas Transportation Researcher 3 Innovative use of ITS technology reduces pavement damage and improves safety

A big rig driving at full speed down a a personal computer, researchers devel- sumption and pavement wear and tear. rural highway approaches a traffic signal oped a system that detects when a truck Since implementation of the North at an isolated intersection. The light turns approaches an intersection and relays that American Free Trade Agreement, some yellow and the truck driver applies the detection to the computer. The computer highways in Texas, particularly in border brakes. Can the driver stop the truck in sends a message to the signal controller areas, have seen an increase in truck traf- time? Will the truck jackknife or roll to take appropriate action, such as delay- fic. The concept developed and tested in through the intersection instead of stop- ing a light change from green to red to this project provides a way to moderate ping safely? How much damage will the give the truck time to clear the intersec- some of the problems associated with this truck do to the highway pavement during tion safely. increase. the stop? A Texas Transportation Institute TTI Assistant Research Engineer Srini- “This project broke ground because it (TTI) project has provided a way to reduce vasa Sunkari and Hassan Charara, associ- was the first effort to look specifically at problems associated with signalized inter- ate research scientist, headed up a project truck traffic in regard to this problem,” sections having high truck traffic. team that modified traditional classifier notes Sunkari. “A subsequent project now “Pharr, Texas, District Engineer operation and installed a test unit at Sulli- underway is looking at signal operations Amadeo Saenz was looking for ways to van City, Texas, near the state’s border with at isolated signalized intersections from improve truck operations along the Texas- Mexico. The project has been selected for an overall perspective, which will give us Mexico border,” says Tom Urbanik, TTI presentation at the annual meeting of the comprehensive data for continuing devel- associate director. “We proposed the truck Institute of Transportation Engineers in opment and implementation.” priority concept as a means to address sev- Chicago this summer. eral concerns of Mr. Saenz.” “A classifier traditionally stores infor- For more information, contact In many cases, intelligent transporta- mation about vehicle classification for later Srinivasa Sunkari at (979) tion systems (ITS) are providing just such download,” explains Sunkari. “What we 845-7472 or [email protected] a means of applying innovative solutions did here was to get the classifier to report to chronic problems that have been dif- vehicle classifications immediately to a ficult to solve with traditional methodol- computer, which monitors and changes Hassan Charara at (979) ogy. The “simple solution” in this project the signal operation where appropriate.” 845-1908 or was a way to reduce the number of stops The project found inductive loops con- [email protected] trucks made at a rural traffic signal. nected to a classifier very accurate in Minimizing the number of truck stops detecting and classifying trucks and mea- reduces pavement damage, lowers traffic suring their speeds. The resulting system Related publication: Report 1439-8, Reducing delay for all vehicles and improves safety. cut the number of truck stops by at least Truck Stops at High-Speed Isolated Traffic Signals Using a vehicle classifier connected to four percent, resulting in reduced fuel con-

Reduced truck delay at Truck approaches traffic signal isolated intersections Signal controller places hold on green light

Computer triggers phase hold

Vehicle classifier recognizes truck and alerts computer

Loop detector detects vehicle

Using a vehicle classifier connected to a personal computer, researchers developed a system that detects when a truck approaches an intersection and relays that detection to the computer. The computer sends a message to the signal controller to tak e appropriate action, such as delaying a light change from green to red to give the truck time to clear the intersection safely.

4 Texas Transportation Researcher STORING AND ORGANIZING Working cooperatively with traffic management centers, Texas A&M University departments, TxDOT districts and other groups, TTI researchers developed a prototype system that demonstrates tech- niques for archiving data. The prototype gives access to a test audi- ence using the world wide web. As a result, several TxDOT districts and traffic management centers are beginning to archive data in a way that will permit access to a wide audience of transportation agencies. The TransGuide® system in San Antonio archives ITS data, and TTI researchers worked with TransGuide to analyze data quality and determine how data could be archived more effectively. Houston TranStar® is in the process of developing a full-scale data warehouse accessible to other agencies, and several TxDOT districts are begin- ning projects to archive data and make it available through regional information clearinghouses. “We see data archiving as a way to maintain information for Planning, designing and operating the transportation system are data- planning purposes,” says Natalie Bettger with the North Central intensive sciences. Today’s intelligent transportation systems (ITS) Texas Council of Governments (NCTCOG). “It would give us access to collect vast amounts of data to help transportation officials create regional information to feed into our planning models and validate the best system possible. Vehicle detectors, for example, collect infor- our decisions.” NCTCOG plans to test an archiving system this year mation about vehicle volumes and speeds. Global positioning systems that would collect information from some regional agencies — includ- and radio/cellular phone triangulation determine vehicle location. ing TxDOT districts and the City of Fort Worth. Automatic vehicle identification systems collect travel times of vehicles. And the list goes on. MAKING DATA ACCESSIBLE Each year, the Texas Department of Transportation (TxDOT) and If archiving ITS data is such a good idea, why isn’t it being done every- other agencies collect data from hundreds of sensors about travel where? Data archiving has been limited due to a number of factors, times, vehicle volumes, speed, traffic mix and other aspects of travel. including: Typically, the data collected are used in “real-time” and then filed • Data quality. To be useful, archived data must meet certain stan- away or discarded and not used again. If the information could dards for quality, weeding out suspect or erroneous data, missing be reused for other transportation planning, design, operation and data and inaccurate data. research needs, it would provide a base for multiple design and imple- • Compatibility. Compatibility problems exist among methods and mentation needs. software used to store data in different agencies and workgroups. New data archiving methods under investigation by the Texas • Distribution. Until recent advances in the use of computers, the Transportation Institute (TTI) provide a way to store, organize and internet and world wide web, distribution of and access to data — access the wealth of transportation information collected by ITS even when archived — were difficult. equipment. The purpose of this research is to identify what types of • Proprietary concerns. Data ownership, maintenance or control data are already being collected that could be put to work in other claims may cloud the issue. areas of transportation system development. • Resource allocation. Archiving takes additional time that must be accounted for in planning efforts and budgets. IDENTIFYING MULTI-PURPOSE DATA • Awareness. Project managers may not recognize the utility of “Our experience shows a demand for archived ITS data in a number their data to other applications. of different types of analyses,” says Shawn Turner, researcher on sev- The TransLink project deals specifically with resolving problems eral TTI data archiving projects. “For example, TTI’s Annual Mobility associated with data quality, compatibility and distribution. Report is just one of several transportation projects that will soon be “The ultimate aim is to have a system that will let transporta- using archived data” (see related story on page 14). tion professionals use archived ITS data to make better decisions Researchers in TTI’s TransLink® lab are developing possible ways and communicate information to the public,” says Turner. “These to use stored travel data through a process called ITS Data Archiving. systems give us an effective way to provide more predictive, more The work done at TransLink® has focused on providing general guid- personalized traveler information and make better decisions about ance in terms of what type of data might be saved, what level of detail managing existing facilities or investing in a wide range of infra- to save and how to set up a database that is easily accessible. Once iden- structure improvements.” tified and organized, enormous amounts of information can be made available for utilization in the data-hungry science of transportation. For more information, contact Shawn Turner at (979) 845-8829, Archiving provides a cost-effective way to gather information that or [email protected] can be used for a number of purposes and make it accessible to those who need it. Transportation agencies can reuse data for numer- ous transportation planning, design, operations and research needs. Retrieving information from database archives can produce signifi- cant cost savings over having to re-collect even a small percentage of the data using manual methods or special studies.

Texas Transportation Researcher 5 It’s the stuff of the movies — the hero’s What’s being done to prevent Researchers car is stuck on the railroad tracks with preempt traps? the oncoming train looming large. In In November 1999, TTI TransLink® Hollywood, the hero always gets off the researchers began research into the causes recommend track and out of the train’s way in time, and possible solutions to the preempt even if his car doesn’t. Outside of Holly- trap. According to Roelof Engelbrecht, lead “quick fix” for wood, though, cars trapped on the tracks researcher, there are guidelines available with an oncoming train are in very real that address traffic signal preemption. danger. In 2000, in Texas alone, 52 people However, these guidelines usually do not safer rail died and 163 were injured in vehicle/train address the effect of variations in warning crashes. One potential cause of these times or train arrival times. crashes could be a phenomenon known “Engineers usually design for the crossings as the “preempt trap.” worst case scenario — what happens if Texas Transportation Institute (TTI) the train arrives at the earliest expected researchers, working through the Trans- time. But that approach doesn’t consider Link® Research Program, are investigating what happens if the train slows down and developing solutions to the problem and arrives later than expected, after the and have recommended a “quick fix” to track clearance phase is complete. That the Texas Department of Transportation kind of gap can create the preempt trap,” (TxDOT). said Engelbrecht.

What is the preempt trap? What’s the quick fix? When a train approaches a highway-rail- As a short-term solution, researchers have road grade crossing, the computer con- discovered a quick fix. “If you extend the trolling a nearby traffic signal receives a track clearance green phase, at least until “preempt” call. This “call” starts the traf- the gate arms start to descend and, ideally, fic signal sequence that is designed to until the gates block the path of approach- clear vehicles from the railroad tracks and ing vehicles, says Engelbrecht, “you reduce allow for the safe passage of the train. the probability of the preempt trap.” A The track clearance phase — the green good rule of thumb is that the track clear- light that clears vehicles from the railroad ance green duration should be equal to tracks — ends, ideally, after the warning the expected advance preemption time — lights have flashed plus 15 seconds. Of course, there are no for a few seconds guarantees with this strategy because of and the crossing train speed variations, but it is based on gate arms have federal grade-crossing requirements and just descended is a good interim prevention measure. TTI to a horizontal is proposing additional research to inves- position. tigate more long-term solutions to prevent A preempt the preempt trap and its resulting dangers trap occurs when from occurring. the green light to “We hope that future research in this clear the railroad area will result in a more guaranteed solu- track ends before tion,” says Engelbrecht. TxDOT is cur- the warning lights rently reviewing the research findings for start to flash and possible further research and future imple- the crossing gate mentation in the districts. Vehicles can become trapped on railroad arms start to close. Because the warning tracks if the green light ends before lights have not been activated and the For more information, contact warning lights flash and the crossing gates are still vertical, vehicles can con- Roelof Engelbrecht at (979) gate closes. tinue to cross and become trapped on the 862-3559 or [email protected] railroad tracks in the path of the approach- ing train.

6 Texas Transportation Researcher Charley V. Wootan A Lifetime in Transportation A life well lived

1926 – 2001 “He was among the few people I have known who never said a superior word to me. He thought more of me than I deserved, and that made me behave better than I naturally wanted to.” – paraphrased from The Virginian by Owen Wister

Texas Transportation Researcher 7 A tribute to Charley Wootan PERSONAL THOUGHTS ...

Texas and the nation lost one of its greatest citizens March 24,2001. A giant in the field Too many times, great men who make great accom- of transportation, a devoted family man, an influential mentor and educator, a beloved plishments in this life become prideful and unapproach- friend to so many—Dr. Charley Wootan, director emeritus of the Texas Transportation able. Charley was never guilty of these faults. He was Institute (TTI), passed away at his home after a long battle with cancer. Dr. Wootan’s as humble and approachable as anybody I have ever accomplishments in the transportation and education communities, and his outstand- known. . . . He was one of the finest men I have ever known. My prayers go out to Doxie and the ing human character, are best illustrated by the heartfelt words of his friends and col- family for that comfort which only God can provide. leagues as they have shared their thoughts and memories through a remembrance page —Joe Button, division head, Texas Transportation on the TTI web site (http://tti.tamu.edu). His lifetime contributions to the state of Texas Institute and the nation are so massive in number and significance—they could easily span a book. A standard profile article in this newsletter really Most of us thought of Charley as a member of the cannot do him justice. So using the words of those who department . . . His participation on a national scale knew and loved him, and historical photos collected brought to us a broader and more up-to-date knowl- edge of transportation research. here at TTI through the years, this feature presents an –Mark Goode, former engineer-director, Texas overview of his career in transportation and education, Department of Transportation what he did for TTI, and who he was as a person. Our hope is that it will stand as a tribute to Dr. Wootan, his family and his memory. It was Charley’s constant pleasant and positive approach to daily events that I most readily recall. Most memorable are the mentoring efforts he provided to me. . . His words and wisdom often helped guide my professional development decisions. His willingness to assist so many, so readily, so freely, demonstrates In honor of his memory the impact his life has had on those he touched. Father of 2. Grandfather of 5. Beloved husband of 50 —John Mason years to Doxie. Golfer. Fisherman. Hunter. Gardener and expert steak connoisseur. Hundreds attended Dr. Wootan’s funeral services on March 27, as well as an April 24 memorial celebration of his life. There, Dr. Herb Richardson pre- He encouraged without commanding, he made one find sented the Wootan family with a resolution from the Senate of the State of Texas, 77th Leg- their best without imposing, and he expanded horizons islature extending its sincere condolences to the bereaved family and stating that when without imposing his own. He was the gentlest person and manager I have ever known. It was difficult to it “adjourns this day it will discern where Charley the boss stopped and Charley do so in memory of Char- the friend began. To him there was no difference, he ley V. Wootan.” Speakers was the same in every circumstance. I do not think he included former engineer- ever recognized any difference between management director of TxDOT Mark and friendship. That attribute, I think, was why he had the respect of everyone that ever encountered him. I will Goode, current Executive miss him, as all do . . . Director Wes Heald, Direc- —Sadler Bridges, tor of the Transportation special assistant to Research Board’s (TRB) the agency director, Cooperative Research Pro- Texas Transporta- tion Institute grams, Bob Reilly, and five longtime TTI employees, many of whom worked with Wootan for over 25 years. In his closing remarks, Dr. Dennis Christiansen, TTI deputy director announced the creation of the Charles J. “Jack” Keese – Charley V. Wootan Memorial Fellowship Fund (see related item on p. 11). He also shared the contents of a letter from John W. Johnson, chairman of the Texas Transportation Commission: “Texas owes a great debt of gratitude to Charley. We are proud of our transportation system and we know that it is a system without peer. We should be — and are equally proud — of the selfless role that people like Charley Wootan played in making it so . . . We will miss Charley, and on behalf of the Texas Transportation Commission and the Texas Department of Transportation, thank you for sharing him with us.”

88 TexasTexas TransportationTransportation ResearcherResearcher Charley Wootan Tribute A Friend and Mentor Education was at the heart of almost everything Dr. Wootan did. He was a firm believer in the value and importance of a good education. In fact, by 1991, throughout his service to TTI, over two thousand Texas A&M students had worked on TTI research projects. Since 1983, he served on the boards and in leadership positions for the Greater Texas Higher Edu- cation Authority, Greater East Texas Higher Education Ser- vicing Corporation, and the Texas Guaranteed Student Loan Corporation. He was a friend to so many—probably too many to count. What is amazing is the number of people who worked Knowing Charley Wootan has with and for him who consid- been one of the great plea- ered him, not only a boss, a col- sures of my now very long league, and an advisor, but also career in transportation. We worked together on many a very good friend. Their words occasions and he would always speak volumes about his character, move things along with a smile why he was able to take TTI where rather than a fist! He was central he did, and how, throughout his 45 to the CUTC (Council of University Transportation Cen- years in the business, he was able to have such a profound ters) founding and growth. He was a pivotal figure for me as we worked to start PTI (The Penna. Transporta- impact on Texas, on transportation research and educa- tion Institute.) When I wanted career guidance, tion, and on the entire transportation community. I could, and did, call — knowing I would get honest, no-varnish advice (and even over the phone I could see the twinkle in his eyes!). Perhaps A Visionary what I want to say most is that his was a TTI was not the only organization to benefit from Dr. Wootan’s involvement. He took the life well lived. We should all take lessons, and concept of a cooperative research program between universities and state departments of hope to approach the living of just such a life. transportation and, working with the Texas Department of Transportation, saw that —Tom Larson, former administrator, Federal Highway Administration become a national model of how DOTs and universities can work together to solve transportation problems. Charley Wootan tirelessly contributed invaluable service to many

I have many good memories of Charley Wootan, both national transportation associations and organizations throughout his career. He served personally and professionally. He was one of those rare as chairman of TRB executive committee in 1980 and personalities that perhaps come along once in a lifetime. continued accepting chairs and task force memberships Professionally his contributions to transportation were over the twenty years following. extremely important to TxDOT and to the citizens of Charley was an idea guy. In 1963 he had the idea Texas. Equally important, and perhaps more significant, was how his personality influenced so many people. for holding a refresher seminar for members of the Charley had a warm friendly disposition, wit, humor, International Right of Way Association (IRWA). He got integrity, was respectful to others and always had such the right people together, made it happen and directed a positive attitude. Time seems to fade many memories, an annual gathering of land acquisition agents, public but I will always remember Charley Wootan as Mr. TTI. utilities and railroad companies from all over the –Charles W. Heald, executive director, Texas Department of Transportation world. “Dr. Wootan was an integral part of the IRWA for so long that, when he retired, we could not imagine the A&M Seminar without him. He was always there Since becoming active in the early 1960s, Charley held to greet us with a friendly smile and we looked for- virtually every volunteer leadership position Transpor- tation Research Board (TRB) has, and he earned our ward to his welcome at the opening ceremony each top awards. Charley was talented and hardworking, year,” said Rita Cavaness, IRWA Region 2 Chair. Dr. Wootan was also partially respon- but he was so much more. An unassuming member sible for the idea of a Council of University Transportation Centers (CUTC). He, along with of the Greatest Generation, Charley was remarkable former Federal Highway Administrator Tom Larson and others, was involved in creating, for his generous spirit, quiet confidence, and good nurturing and growing CUTC, and twice over the past 25 years served as its president. humor. When Charley took on an assignment for TRB, we knew we were fortunate; now we are fortunate At the 2001 TRB Meeting, CUTC honored Charley Wootan with its prestigious Career to have so many unforgettable memories of him. Achievement Award presented to those who have made a distinguished contribution to —Bob Skinner, Executive Director, university transportation education and research. Tom Larson remarked that “Charley Transportation Research Board Wootan is the model of leadership. His career and life define it. He believes in and demon- strates hard work, he has vision, and he knows how to make that vision reality.”

9 Texas Transportation Researcher Texas Transportation Researcher Charley Wootan Tribute 9 The early years at TTI SHARED MEMORIES ... A marine during World War II and a 1950 and 1951 graduate of Texas A&M University, after working in Dr. Wootan’s style of leadership encouraged and moti- New York for a few years, Charley Wootan returned to vated those around him. He was a man of character and his alma mater in 1956, joining the newly established he led by example. Whether he was on the mountain peak of success or near the valley of defeat, he always kept his Texas Transportation Institute as an associate research positive attitude and his sense of humor. Those who had economist and project leader. He was a key player in the privilege to work closely with him knew by the sparkle the Institute’s early commodity studies and conducted in his eye that he loved life. His chuckle and his laugh valuable economic research on the effects of the inter- told us he loved being with people. When he spoke, we state highway system in Texas. It didn’t take Charley knew to listen carefully or we would miss some good advice or an interesting story. His presence will be sorely missed, long to rise to the top, as he became division head of but he left us a legacy for how to spend a worthwhile life. transportation economics and planning at TTI in —Marie Schoeneman, fiscal officer, Texas Transportation 1961, and then associate director of the institute and Institute professor of economics at Texas A&M in 1965. He also played a key role in strengthening TTI’s cooper- ative relationship with the Texas Department of Transportation While searching for a good doctoral program in 1978, I visited (TxDOT) as he took on the job of program coordina- five very good universities. During my TAMU visit, I was talking tor of the Annual Transporta- to faculty members and graduate students when Charley tion Short Course put on Wootan stopped me in the hallway. In a three minute conver- by TTI and TxDOT. sation he quickly put me at ease, found out what I needed, “Most of us thought and made me an Aggie forever. These three actions describe him completely. He cared about people, and he loved TTI of Charley as a member and TAMU. Those of us whom he helped loved him in return. of the department ... His —Dan Turner, director, University Transportation Center for participation on a national Alabama scale brought to us a broader more up-to-date knowledge of transportation research,” said Mark Goode, former engi- I came to Texas A&M University on neer-director, Texas Department of Transportation. August 15, 1978. At that time the pack- age deal for young professors was a dictionary and a calculator, and only a A Leader meadow existed where the CE/TTI building Filling the shoes of former TTI Directors Fred Benson and Jack Keese would seem an stands today! I met Charley Wootan shortly impossible task for many, but Charley Wootan had no problem with it when he took the after my arrival and have worked with him and TTI reigns in 1976. Bringing a non-specialist’s eye to the ever since. He has always struck me as someone who had engineering-dominated organization, his training this rare gift of generating a balanced atmosphere of serious business attitude and caring relaxed attention among the people as an economist helped him appreciate both surrounding him. At the same time, he always had this happy the actual and hidden costs of research and its smile on his face which made you wonder what he had up implementation. He firmly believed that all facets his sleeve. It has always been a pleasure for me to work with of transportation needed investigation, and he him and the organization that he managed so well. On the brought credibility to this belief through his road of life, some things are worth the stop, some are worth the detour, and some are worth the trip. For me, working with remarkable understanding of complex engineer- Charley and TTI has definitely been worth the trip from France. ing concepts—despite his lack of formal training —Jean-Louis Briaud, research engineer, Texas Transportation in that area—and his insight into the scientific Institute and technical challenges of research. This, along with his perpetual positive attitude and caring, He was largely responsible for attracting literally hundreds of “hands-off” managerial style, earned him the researchers with national and international reputations to come employee respect and motivation that was a large to work for the Texas Transportation Institute. A great many of part of why TTI became the fastest-growing uni- these people could have worked anywhere they desired, often at versity-based transportation research organiza- higher compensation levels, but they chose TTI, and a big part of the reason for that choice was our director, Charley Wootan. tion in history. When Dr. Wootan retired in 1992, For some of us, we ended up spending our lives and careers in TTI was ranked the largest and one of the finest College Station, something that never would have happened had transportation research centers in the country. He it not been for Charley. . . . He will be missed as a leader in the served as director of TTI throughout a turbulent era in field of transportation and as a very close friend and advisor. transportation research, a time of increased competition and legislative battles for research —Dennis Christiansen, deputy director, Texas Transportation Institute funding. Despite that, during his tenure as director, TTI’s research budget grew from 3.9 to 18 million a year—a rate in excess of 10 percent a year for 17 years. TTI also received patents on eleven innovations.

1010 TexasTexas TransportationTransportation ResearcherResearcher Charley Wootan Tribute CHARLES J. “JACK” KEESE- CHARLEY V. WOOTAN MEMORIAL FELLOWSHIP FUND

Over the past year both Jack Keese and Charley Wootan have passed away. This is a great loss to the Texas Transportation Institute (TTI) and the entire transportation community. These individuals served as Director of TTI for over three decades, and both remained active in Institute and transportation activities until the time of their death. They both held the title of Director Emeritus. Jack and Charley were Texas A&M alumni, and they both joined TTI in the early 1950s. Jack served as Direc- tor of TTI from 1962 to 1976, and Charley led the Institute from 1976 to 1993. During this period, the size and stature of the Institute’s pro- grams grew massively. These indi- viduals, working closely with TxDOT,

TTI Remembers Charley I learned a great deal from my association with Charley. On were instrumental in developing and On April 24, TTI colleagues and others from many occasions over the years I sought his advice and expanding the cooperative research the local community held a special memorial guidance. I thought of him as a mentor or someone I program that has become the model service celebrating Charley’s life and career. could approach on any issue within our profession. He followed by many other states. earned the respect and admiration of all who knew him. In recognition of the tireless and It is clear that Charley’s legacy will con- He was an outstanding ambassador for TTI and Texas A&M tinue to improve our world through the ideas University and a great Texan who I will long remember. effective work performed by these two and characteristics that he shared with family, —C. Michael Walton, Ernest H. Cockrell close friends, TTI, with support from friends and colleagues. Centennial Chair in Engineering the A&M Foundation, has established the Charles J. “Jack” Keese-Charley V. Wootan Memorial Fellowship Fund. This permanent fund will be man- While no words can express my true feelings at this difficult time for all of us, I want you to know that Dr. Wootan had a tre- aged by the Texas Transportation mendous influence on my life. He was a sort of administrative Institute and will be used annually mentor for me when I was developing the Transportation Stud- to provide a fellowship to a graduate ies Program at Texas Southern University. I learned so much student employed by TTI. from him through his informal counseling about transportation Donations to the fund can be sub- education and research. He was a respected and influential leader in the transportation community ... One of the best! mitted through TTI’s web site. Both I will miss him ... the Keese and Wootan families will —Naomi Ledé be notified of each gift, and you will receive a receipt for your tax records.

http://tti.tamu.edu/keese_wootan.stm Dr. Wootan was an integral part of the International Right of Way Association for so long, that when he retired, we Keese-Wootan Memorial Fellowship Fund could not imagine the A&M Seminar without him. He was Texas A&M Foundation always there to greet us with a friendly smile and we looked 401 George Bush Dr. forward to his welcome at the opening ceremony each year. College Station, TX 77840 —Rita Cavaness, International Right-of-Way Association (IRWA) Region 2 Chair 11 Texas Transportation Researcher Texas Transportation Researcher Charley Wootan Tribute 11 The Katy Freeway — Houston. LBJ technologies could enhance the there needs to be a way to Managed and Central Expressway — Dallas. operation of the lanes, as well smoothly implement the change. IH35 — San Antonio. Loop 1 and as the overall traffic flow of the “We plan to provide a multi- IH35 —Austin. They are a few entire freeway system? dimensional decision matrix that Lanes among the many major freeway These are some of the ques- will show how to incorporate flex- systems in Texas that are experi- tions being addressed by a ibility into a facility to allow that encing tremendous growth. Over cross-disciplinary team of Texas to happen. “ The future of the last ten years, in an attempt Transportation Institute (TTI) In the first year, the research to combat the enormous increase researchers working on a multi- team is producing a thorough freeway travel in traffic demands, transportation year effort to assist the Texas review of current practice and professionals have been struggling Department of Transportation state-of-the-practice literature. In to find new and innovative ways (TxDOT) in optimizing the perfor- addition, a symposium held in to make them operate more effi- mance of freeway managed lane February in Austin was very ciently and handle this growth. facilities. The project entitled successful with over 90 profession- While adding lanes seems Operating Freeways with Man- als from across the state attend- like a logical solution, making aged Lanes is a joint effort with ing the one-day event featuring Texas Southern University (TSU) experts from Texas and around and involves 24 tasks designed to the country. “We wanted to begin investigate all of the issues sur- generating a dialogue between all rounding the use of managed lanes the potential partners, as well in an urban area. The key product as provide insight into managed to emerge will be a comprehen- lanes operations,” says Ginger sive Managed Lanes Manual for Daniels, the TTI co-research TxDOT engineers. The manual supervisor for the project. will cover how to plan, design and Other tasks that are under- operate a managed lanes facility, way include the use of simulation as well as adapt that facility to technology to analyze operational meet the changing mobility needs scenarios based on user groups, of a region over time. development of a concept mar- “We’re addressing very com- keting strategy and recommen- plex issues,” says Beverly Kuhn, a dations for geometric design of TTI research supervisor heading managed lanes. The project team the project. “Making a managed is also hosting a web site (http:/ something bigger isn’t always lane facility really work effectively /managed-lanes.tamu.edu) and A comprehensive better. Today, construction costs, involves multiple areas — plan- publishing a quarterly newsletter land consumption, neighborhood ning, design, operations, Intel- to document lessons learned as Managed Lanes impacts and other environmen- ligent Transportation Systems the research progresses. tal issues are major concerns (ITS), enforcement and safety. Carlos Lopez, director of traf- Manual for in developed urban areas and Everything is interrelated, and fic operations for TxDOT and often necessitate practical limits everything has an effect.” The project director for the managed on freeway expansion projects. user group of a lane may drive lanes project, believes that “the TxDOT engineers Adding high-occupancy vehicle the geometric design, which will results from this project will (HOV) lanes or other special-use influence the signs and mark- be of great benefit to TxDOT will cover how to lanes is generally a viable option ings and involve numerous safety in handling the ever-increasing and does improve traffic flow at issues. Multiple user groups may challenge of providing efficient plan, design and certain times of the day. But drive operations decisions and transportation systems and serv- how can we maximize the effec- ITS needs. ing the mobility needs of Texans tiveness of those lanes through- According to Gary Trietsch, in the future.” operate a managed out the entire day? How can Houston district engineer for we encourage travelers to use TxDOT, “flexibility is an impor- For more information, lanes facility. the lanes when it would best ben- tant factor in optimizing mobility contact efit them? Who should use the for targeted users of the managed Beverly Kuhn at (979) 862-3558 or lanes and when? How can differ- lanes.” For instance, if an inci- [email protected] ent vehicle groups be permitted dent occurs on the freeway main access to the lanes on a real-time lanes, and opening the managed Ginger Daniels at basis without creating conges- lane to another user group during (512) 467-0946 or tion? How do we communicate that time would improve traffic [email protected] the rules on usage and make flow, then traffic engineers need sure travelers follow them? What to be able make the switch, and

12 Texas Transportation Researcher Researchers study changeable message format NEXT RAMP CLOSED 290 RAMP CLOSED AUG 25-26 US 290 EXIT CLOSED MON-WED

Which one of these messages is easiest Dynamic message signs (DMS) are a key to understand? Even simple ideas time was measured should be included component of intelligent transportation sys- can be difficult to communicate to (TRAVEL TIME TO DWNTN – 20 MIN AT 7:20 AM). tems (ITS). Often called changeable message drivers moving at highway speeds signs or variable message signs, DMSs display • The word “EXIT” should be used rather computerized messages customized to local- when messages are restricted in char- than the word “RAMP” when referring to an ized roadway conditions. Their effective use acter length. Finding out driver per- exit ramp on a freeway. • Route or interstate designations (I-, US, depends on proper sign design, placement, ceptions of phrases like the ones above message design and display conditions. SH, FM) should be used along with numbers DMSs convey vital information to motor- helps transportation system managers when referring to roadways. ists. At construction sites or during incident effectively communicate travel infor- • The term “HEAVY CONGESTION” can be used to indicate conditions that involve management, driver understanding is essen- mation to the driving public. tial to safe and efficient travel. more than 35 minutes of delay or down- stream operating speeds less than 25 mph. RESEARCH OVERVIEW FINDINGS The term “CONGESTION” conveys less severe “We looked at specific message design and In some cases, project findings were surpris- conditions. operation issues in order to determine the ing. While it might seem logical that calendar • DMS operators should use one-frame best approaches for TxDOT districts to take dates would provide the clearest communica- messages whenever possible and limit the with respect to designing and using mes- tion, findings show that drivers understand use of two-frame messages. sages,” says Jerry Ullman, principal investiga- messages better when they refer to weekday Of the messages shown at the beginning tor on one of Texas Transportation Institute’s descriptions. Tests showed that fewer than of this article, most drivers would find “US projects studying DMSs. “Then we developed one-fourth of Texas motorists understood 290 EXIT CLOSED MON-WED” easiest to standards and guidelines for DMS use at traf- when future roadwork was to occur if cal- understand based on project findings. fic management centers.” endar dates were used. On the other hand, Research yielded specific recommenda- As one road to discovering the best more than three-fourths understood days of tions about more than 40 abbreviations, com- approaches, researchers conducted human the week. binations, appropriate terms and operating factors studies in Austin, Dallas, El Paso, Fort In another discovery, the project found practices like the ones listed above. Research- Worth, Houston and San Antonio. They also that flashing all or parts of the message ers combined recommendations from this convened a TxDOT project advisory panel did not make drivers pay more attention or project with those of past studies into a set to select specific questions about DMS oper- give more importance to the sign – but did of DMS operating guidelines for use in traffic ation and used interviews and simulations lengthen reading time. In tests, flashing a management centers throughout Texas. with motorists from across the state to gauge DMS message resulted in significantly longer “TxDOT is considering adopting the recall and comprehension of information con- reading times than when the same message guidelines we developed in this project,” tained in test messages. was not flashed, revealing to researchers that explains Ullman. “TTI will continue to work DMS operators need ways to shorten more information can be displayed on a to find ways to help transportation profes- messages so that relevant driver information steadily lit sign. sionals operate dynamic message signs so fits within the limits of DMS space. Some Other findings showed: that they speak the same language as the portable DMSs limit messages to as few as • Actual days of the week (SUN-SAT) motorists who read them.” eight characters per line. With spaces that should be used for work activity that will tight, meaningful abbreviations can spell occur within the upcoming week and instead For more information, contact the difference between understanding and of the term “FOR 1 WEEK.” Gerald L. Ullman at (979) 845-1728, confusion. • The term “WEEKEND” should be used or [email protected]. “It’s important that sign messages be only if the work will start on Saturday morn- designed so that they will be interpreted Related publication: Report 1882-S: ing and end by Sunday at midnight. Improving Dynamic Message Sign accurately and quickly by motorists,” empha- • When displaying current travel times Operations sizes Ullman. on DMSs, the time of day that the travel

Texas Transportation Researcher 13 we need to address the problem,” Lomax says. He and Schrank stress that other means — including demand manage- RUSH HOUR? ment, operational efficiency improve- ments and better management of construction and maintenance projects Annual traffic The last time that “rush hour” actually — must also be employed as part of an lasted that long, Richard Nixon was Pres- overall mix of solutions. ident, lava lamps were popular (the first The report illustrates trends from study shows time around) and Rowan & Martin’s 1982 through 1999, and this year’s sta- “Laugh-In” was the hottest show on TV. tistics include a wide variety of findings it’s neither Things — including traffic — have from the 68 urban areas studied: truly changed since 1970. In fact, the • Average rush hour delay is 36 hours timeframe we refer to as “rush hour” in per person per year. the nation’s major cities has doubled in • The average rush hour trip takes less than 20 years, increasing from nearly 32 percent more time than the same trip three hours (morning and evening com- taken during non-rush hour conditions. bined) in 1982 to almost six hours in 1999. • The cost of traffic congestion nation- Congested travel periods today consume wide totaled $78 billion, representing the nearly half of the daylight hours in any cost of 4.5 billion hours of extra travel given workday. time and 6.8 billion gallons of fuel wasted That’s one of several findings while sitting in traffic. from the 2001 Urban Mobility Study, This year’s report is the product published in May by the Texas of a cooperative effort involving TTI Transportation Institute (TTI). In and eleven state departments of trans- the annual study, TTI researchers portation. Researchers are already look- David Schrank and Tim Lomax ing toward development of next year’s use a variety of measures to illus- mobility study analysis. The 2002 Urban trate the nation’s growing traffic Mobility Study will be the first one to problem. The findings provide use archived data (see related article on elected officials, policy makers page 5). and everyday commuters a collec- Because archived data provide con- tion of easily understood measures tinuously collected statistics, researchers to support local decision making expect to be able to identify congestion related to freeway and street sys- more precisely. For example, next year’s tems, as well as a variety of other report may be able to measure conges- land-use issues. tion by roadway or day of the week. Researchers say there’s no single solu- “Mobility studies so far have used tion to the worsening problem of traffic averaged data for comparisons. Contin- jams. uous data will give us more location- “Widening roads is part of the solu- specific and time-specific information tion, but it’s only one of many elements to work with,” says Shawn Turner, TTI researcher. “Improvement decisions are typically made at the corridor level — so having TTI researchers David detailed data at that level is very valu- Schrank (left) and Tim able,” adds Lomax. Lomax produce the Urban Mobility Study each year that provides elected For more information, contact Tim Lomax at officials, policy makers (979) 845-9960, or [email protected] and everyday commuters a collection of easily David Schrank at (979) 845-7323, or understood measures to [email protected] support local decision making related to free- Related publication: 2001 Urban Mobility way and street systems, Report as well as a variety of other land-use issues.

14 Texas Transportation Researcher INSTITUTE NEWS

NATIONAL ACADEMY OF ENGINEERING HOLDS REGIONAL MEETING TOM URBANIK Some 47 members of the prestigious largest and most successful in NAE his- RETIRES National Academy of Engineering (NAE) tory,” Wulf added. attended a regional meeting at the George Prior to their meeting, NAE members After nearly 25 Bush Presidential Conference Center on toured the Bush Library and Museum, years with TTI, March 19. The gathering was hosted by Texas Transportation Institute’s Trans- Tom Urbanik Texas A&M University’s Engineering Pro- Link® Research Center and Driver Sim- has announced gram and the University of Texas (UT) at ulator, and the Offshore Technology that he will be Austin and included a mini-symposium Research Center. retiring from entitled “Creating the New Economy — In the afternoon, symposium speak- the Texas Trans- Enhancing Our Lives.” ers covered a range of technical topics. portation Insti- In his presentation on the Academy’s Dr. Yale Pratt, professor of electrical tute (TTI) at the role in our society, Dr. William Wulf, NAE and computer engineering at UT-Austin, end of June. Tom and his wife Cindy will be president, said that only about one in every and Dr. Sanjay Banerjee from the UT moving to the University of Tennessee, where 1,000 engineers is elected to membership. Microelectronics Center spoke on future Tom will become a chaired professor. It is an Wulf also noted that the Academy’s pur- trends in computers and communica- exciting career opportunity, and Tom will pose is “telling the truth to power” by pro- tions. Mr. Walter van de Vivier, presi- have the opportunity to contribute mean- viding unbiased and authoritative reports dent of Shell Exploration and Production ingfully to a number of programs at the Uni- to the federal government on critical sci- Company, and Mr. Erle Nye, chairman versity of Tennessee. ence, technology and engineering issues. and CEO of TXU Corporation, presented “Tom Urbanik has done an exceptional “This regional meeting was one of the energy issues. Mr. Tom Larson, former job of providing leadership and vision to the Federal Highway Administration TTI research program for nearly 25 years,” (FHWA) administrator, and Dr. said TTI Deputy Director Dennis Chris- William Powers, formerly vice- tiansen. “He has the ability to understand president for research for the Ford both the technical detail and to see the Motor Company, covered transpor- ‘big picture.’ His contributions to both the tation mobility, safety and sustain- Transportation Operations Group and the ability. Panel discussions followed leadership of TTI have been greatly appreci- each session. ated and will be missed.” Some 47 members of the prestigious NAE attended a regional meeting at the George Bush Presidential Confer- ence Center in March.

SUBSCRIPTION UPDATE To change your subscription or to be added to the mailing ORDERING INFORMATION list, please fill out this form and mail or fax to the address or number in the shaded box. A full catalog of TTI publications can be found online at http://tti.tamu.edu/product/catalog. name Include name and address of recipient. Prices include shipping title and handling when mailed in the U.S. Texas residents are required to add 8.25% sales tax or enclose a tax-exempt form with the order. Send a check or money order (in U.S. funds and company through a U.S. bank) payable to Texas Transportation Institute to the address below. address For international orders, write or fax (979) 862-3703 to deter- mine the air-mail shipping charge. city/state/zip Information & Technology Exchange Center Texas Transportation Institute The Texas A&M University System phone/fax 3135 TAMU College Station, TX 77843-3135 e-mail For information about purchasing TTI research reports, contact: Dolores Hott comments e-mail: [email protected] (979) 845-4853 fax: (979) 862-3703

Texas Transportation Researcher 15 THE BACK ROAD TEXAS TRANSPORTATION

Saying that transportation, and Texas Transportation Institute (TTI)/Information & Technology in particular traffic congestion, Exchange Center (ITEC) • The Texas A&M University System is “big news” is really an under- statement. We’re all well aware of Dr. Herbert H. Richardson Publisher/Director, TTI the problems created by a grow- ing demand for better and faster Susan M. Lancaster Editor/Director, ITEC transportation, and the difficulty Kelly West Managing Editor/Writer of building new infrastructure to ease the congestion on our roads. Rhonda Brinkmann Contributing Writers Elected officials at all levels of Leslie Pourteau government struggle with ways Penny Beaumont to speed the movement of people and goods in a time when our Kim Miller Designer/Production Artist infrastructure is overwhelmed and when transportation issues can affect a city or region’s ability to develop economically. James Lyle Photographer This issue of the Researcher focuses on the leading edge research being conducted at the Texas Transportation Institute Rhonda Brinkmann Copy Editor/Proofreader (TTI) in traffic operations and management, particularly in inte- grating various monitoring, emergency response, freeway man- agement and signal control operations. We call it Intelligent Texas Transportation Researcher is published by the Texas Transportation Institute to inform readers about its research, Transportation Systems or ITS, but for most travelers, its benefits professional and service activities. Opinions expressed in this are often unseen — except when the traffic moves more evenly publication by the editors/writers or the mention of brand names and traffic accidents or incidents are cleared more rapidly. TTI do not necessarily imply endorsement by the Texas Transportation researchers are working on the latest devices and processes to Institute or The Texas A&M University System Board of Regents. integrate all traffic management systems, creating an overall Texas Transportation Researcher (ISSN 00404748) is a quarterly system that ensures that travelers get the right information at the publication of the Information & Technology Exchange Center, right time to make better travel decisions. It’s exciting work, and Texas Transportation Institute, The Texas A&M University this issue highlights several TTI programs that are at the forefront System, 3135 TAMU, College Station, Texas 77843-3135. For more information or to be added to the mailing list, contact this address, of the ITS program, including the annual national mobility analy- call (979) 845-1734, or e-mail Debra Svec at [email protected]. sis conducted by Dr. Tim Lomax and his research team. Periodicals postage paid at College Station. We also bid farewell to our colleague Charley Wootan with a look at his distinguished career in transportation. Charley died on Postmaster/Bulk Mail Clerk Send address changes to: March 24 and his loss is felt keenly by all of us here at the Insti- Texas Transportation Researcher tute, as well as by his family and many friends across the country. Information & Technology Exchange Center Charley’s influence in transportation research and education was Texas Transportation Institute tremendous, and he leaves a legacy of accomplishment that will The Texas A&M University System long endure. A student fellowship honoring Charley and former 3135 TAMU College Station, TX 77843-3135 director Jack Keese has been established, and there is information on page 11 on how to contribute. Thank you for taking time to learn more about TTI research. I hope you continue to find this publication useful and interesting, and that you’ll check our website or contact us if you’d like more information. Visit TTI on the Internet at http://tti.tamu.edu

TEXAS TRANSPORTATION Periodicals Postage PAID Texas Transportation Institute/Information & Technology Exchange Center College Station The Texas A&M University System 3135 TAMU Texas 77843 College Station, TX 77843-3135

16 Texas Transportation Researcher