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PUBLISHED BY THE TEXAS TRANSPORTATION INSTITUTE. TEXAS A&M UNIVERSITY. COLLEGE STATION . TEXAS

VOLUME 6 . NO.2 APRIL 1970 URBAN TRANSPORTATION PROBLEMS ARE APPRAISED AT A&M CONFERENCE

Urban transportation problems and transportation in terms of establishing possible solutions were explored at the goals, objectives, and criteria; setting 12th annual Transportation Conference, standards for the allocation of re­ April 9-10, at Texas A&M University. sources; administering authority and Special attention was given to trans­ responsibility necessary for decision portation problems in the growing making; and regulating resource use. metropolitan areas of Texas. Carter, UMTA assistant administrator Carroll Carter of the U. S. Depart­ for public affairs, said public transpor­ ment of Transportation's Urban Mass tation has a new national priority, as Transportation Administration discussed evidenced by President Nixon's commit­ national plans and programs at the ment to a $10 billion, 12-year program opening-day luncheon. to build new transit systems with $3.1 The meeting, jointly sponsored by the billion available almost immediately. MacDonald Chair of Transportation and The federal official said the motoring public now understands that cities need the Texas Transportation Institute, at­ James Earl Rudder tracted industrial and governmental something more than highways and freeways-even if those improvements TEXAS AND THE NATION transportation representatives fro m MOURN THE LOSS OF throughout the nation. are buses and rapid transit systems that others would use. A&m PRESIDENT Program speakers included Texas Major General James Earl Rudder, A&M Engineering Dean Fred Benson, Speaking of "The City," Benson point­ President of the Texas A&M University discussing "The City;" TTI Director ed out that urban mass transportation System, died March 23 at the age of Charles J. Keese, "What Is Urban problems center around several facets. 59 after a long illness and surgery. Transportation?"; Eugene Maier, for­ Too many people live in too small an mer director of transportation and di­ area due to natural increasing popula­ He was acclaimed as a hero of the rector of public works at Houston, tion within the city and migration from D-Day invasion of France during World "Whose Responsibility?", and MacDon­ rural areas. Also, population segre­ War II when he led the Rangers up ald Chair Professor John P. Doyle, gates itself by affluence as suburban the cliffs of Normandy. "Regulation of Time and Space." and inner city. He felt the numerous political subdivisions of an urban area Rudder's colorful career included Texas State Highway Engineer J. C. need to cooperate and coordinate ac­ pre-war service as a football coach and Dingwall presided at the opening tivities in the direction of uniform deci­ teacher at Brady High School and luncheon. Dr. Horace R. Byers, Texas sions. He said also the attitudes and Tarleton State College in Stephenville. A&M academic vice president, wel­ desires of the people need to be influ­ After the war, he returned to Brady and comed participants and Dr. C. V. Woot­ enced by education and appropriate served as mayor from 1946 to 1952. an, TTI associate director, officially regulation and that the organized pres­ The following year he became vice opened the conference. sure groups and governmental agen­ president of Brady Aviation Company. A major portion of the conference cies must think in terms of the over-all Following graduation from Eden High was devoted to workshops which were impact of their interests on the city's School in 1927, Rudder enrolled at discussed by Robert 1. Hardin Jr. of U. character. Tarleton. In 1930 he transferred to S. Steel Corp., formerly vice president Keese commented that urban trans­ Texas A&M, where he studied industrial and executive director of Pittsburgh portation is so complex that it defies education and lettered in football. He Urban Transit Council, and Kenneth P. meaningful definition. To truly under­ was graduated in 1932. Tubbs, manager of the Dallas Cham­ stand it, he said it is necessary to un­ Rudder was appointed Texas land ber of Commerce's Transportation De­ derstand the purposes for which people, commissioner in 1955 and served three partment and president of the National goods and services move about and the years. Industrial Traffic League. other functions that the space allocated to transportation is expected to per­ In 1955, the Eden native also began Professor Doyle served as conference his eight-year command of "Texas' coordinator. form. Space for streets, for example, is used for parking, accessibility of serv­ Own" 90th Infantry Reserve Division. In opening the conference, Dr. Woot­ ices such as fire, police and garbage, After serving one and a half years an suggested taking a look at urban (Continued in column L page 12.) (Continued in column L page 2.) TEXAS TRANSPORTATION RESEARCHER Published q uarterly by the EFFECTIVE SURFACE COATINGS ARE FOUND Texas Transportation Institute Texas A&M University College Station, Texa s FOR FREEZE-THAW PROTECTION

Second· class postage paid a t College Station, OF CONCRETE BRIDGE DECKS Texa s 77843, The protection against freeze-thaw tures, one applied after the other had TEXAS TRANSPORTATION INSTITUTE scaling afforded by penetrants, tars, thoroughly dried, covering a b out 40 Charles J. Keese, Director Charley V. Woota n, Associate Director and asphalts has been determined by square feet of surface per gallon gave Louis J. Horn, Research Editor Dr. Howard L. Furr, Leonard Ingram, the best results. and Gary Winegar in a phase of a COLLEGE OF ENGINEERING Old concrete that had already begun comprehensive study of bridge deck Fred J. Benson, Dea n to scale can be made somewhat more deterioration sponsored by the Texas durable with the linseed oil-kerosene Vo!. 6, Number 2 April, 1970 Highway Department in cooperation treatment, too. The treatment is not as with the Bureau of Public Roads. effective, however, on the lightly de­ Best coatings were (I) a mixture of teriorated concrete as it is on new con­ Eighth Right of Way Seminar equal parts of boiled linseed oil and crete. kerosene, (2) a mixture of equal parts The Eighth Annual Right of Way The linseed oil treatment had a more of tung oil and kerosene, and (3) hot Educational Refresher Seminar will be noticeable benefit when applied to con­ boiled linseed oil. One patented prod­ held at Texas A&M University on crete that had dried out thoroughly. uct sold under the name Thompson's August 5, 6, and 7, 1970. It is spon­ Water Seal performed well in some Of all treatments tested, properly en­ sored by Region 2 of the American tests but it was not as consistently a trained air was the most beneficial. Right of Way Association and the Texas good performer as the linseed and Concrete specimens with 5% entrained Transportation Institute. About 225 rep­ tung oils. Tar and asphalt coatings a ir had not scaled to any serious con­ resentatives of telephone, pipeline, were penetrated by the salt water; and dition at 300 freeze-thaw cycles when powerline, railroad, highway, and other the concrete surface, hidden by the tests ended, even when specimens had agencies involved in acquisition of coatings, was deteriorated in freeze­ no surface treatment. Surface treat­ rights of way are expected for the ses­ thaw action. ment added only slightly to the dura­ sions. Dr. C. V. Wootan, the associate bility of the air entrained concrete. director of TTl and head of its trans­ Reinforced concrete bridge decks are portation economics division, and Ory sometimes damaged by mechanical No surface treatment used in the test G . Poret, chief assistant, Register of and chemical action of water when it successfully sealed cracks to prevent State Land, Louisiana State Land Office, penetrates the concrete. The damage scaling in the crack area. will be in charge. occurs when the water freezes and Skid resistance was reduced by all when it carries corrosive compounds surface treatments of the penetrating TEXAS AND THE NATION MOURN- to the reinforcing steel. The damage type, but the linseed oil-kerosene treat­ (Continued from column 3, page 1.) is in the form of surface scaling due to ed surface was the least affected of all. as vice president, Rudder was named freeze-thaw action, and spalling due, president of Texas A&M in July, 1959, at least in some measure, to corrosion ANGLE IMPACT IS STUDIED IN and president of the Texas A&M Uni­ of the top mat of reinforcing steel. Re­ FURTHER ATTENUATION versity System in September, 1965. peated cycles of freeze-thaw tempera­ EXPERIMENT:A TION tures gradually erode the surface leav­ His decade of leadership at Texas Studies of field adaptation of impact ing rough surfaces, and corrosion of the A&M was a period of growth, change, attenuation systems are continuing un­ steel causes large areas of concrete to and diversification. der supervision of Dr. T. J. Hirsch. The burst out leaving the steel exposed for work is under sponsorship of the Texas further and more serious deterioration. Rudder was a member of more than Highway Department and the Bureau of 30 professional, honorary, and military Asphaltic surface sealing and surfac­ Public Roads and will determine reac­ organizations. His military decorations ing has not always provided the neces­ tion of the impact attenuation systems included the Distinguished Service sary protection of the concrete against designed for specific field locations to Cross, Legion of Merit, Silver Star, these actions. Salt water ponded on angle impact. Bronze Star with Oak Leaf Cluster, top of concrete sealed with an MC-O The most suitable design configura­ Purple Heart with Oak Leaf Cluster, primer and Ampet AC-5 cover pene­ tion for the attenuation system field French Legion of Honor with Croix de trated the coating and scaling pro­ locations selected will be determined Guerre and Palm, and the Belgian Or­ gressed unseen under the asphalt in fhrough tests and through the research der of Leopold wifh Croix de Guerre freeze-thaw tests in the laboratory. and Palm. He was retired from the staff reviewing with THD personnel the Coatings of a mixture of boiled lin­ Army Reserve in 1967 with the rank plans for the installation and selection of major general after 35 years of seed oil and kerosene on a 50 '}'0-50 ,},0 of additional sites. basis by volume delayed laboratory service. freeze-thaw scaling of non-air entrained An annotated bibliography of refer­ Baylor University awarded him an concrete until it had undergone some ences on skidding and a supplement honorary Doctor of Laws degree and 30 to 35 freeze-thaw cycles. Tung oil to an earlier bibliography on the sub­ Sports Illustrated magazine named him mixed in the same proportion with ject of noise abatement have been com­ a member of its Silver Anniversary kerosene had essentially the same ef­ piled by F. S. White in the TTl library All-American Football team. fect. Two coats of either of these mix- program.

2 TEXAS TRANSPORTATION RESEARCHER presented in 2 above is appropriate. VERTICAL AUG NMENT EFFECTS ON One gross difference, however, exists. SAFE VEHICLE OPERATION The driver cannot associate the pedes­ trian in the traveled way with an emer­ By DONALD L. WOODS* gency situation unless he can discern the edges of the roadway. Not expect­ ing a pedestrian in the roadway, this Introduction deficiency can rob the driver of the • • lead time SO vital in meeting fhe emer­ In recent years technologists have pavement surface which, in most cir­ gency situation. been placing a great deal of emphasis cumstances, will provide reasonably on improving the roadway cross sec­ safe operation. For sports cars, con­ 4. Vehicles on the Left Half of the tion. Large amounts of money have vertibles, motorcycles, small compact Roadway-A vehicle which either drifts been devoted to widening bridges, im­ vehicles, etc. this criterion is insuffi­ onto the left half of the roadway or is proving and paving shoulders, rework­ cient. engaged in a passing maneuver results ing the side slopes, and widening traf­ in a substantially increased hazard for 2. Intersecting Minor Roadways - fic lanes. The vertical alignment in the driver. The inability to discern the The current design philosophy dictates most cases was changed very little re­ edges of the pavement often makes it that intersecting roadways with any sulting in a roadway with a 70-mph difficult for the driver to establish the appreciable traffic volume be located horizontal alignment and a 50-mph relative location of the veh icle on the where the sight distance is sufficient vertical alignment. roadway. At night, the opposing head­ to provide reasonably safe operation. lights give advance warning of the ap­ Similarly, the vertical alignment de­ Land service roads and local driveways proach of the vehicle, however it is im­ sign criteria used on modern roadways are often not controlled to the same possible to determine whether or not have simply evolved from the standards degree. Even more critical, we nor­ the vehicle is on the wrong side of the of the past. Truly, they are logical ex­ mally drive assuming that the roadway roadway. Therefore, it is logical to as­ tensions of these standards, but they a head w ill be clear even though we sume that the opposing vehicle is in are not necessarily compatib le with cannot see far enough a head to be the proper lane thus increasing the per­ needs of modern high speed operation. certain. To put it in a brief statement, ception-reaction time when th is expect­ Modern operating speeds combined we overdrive the available sight dis­ ed situation turns out to be incorrect. with higher safety standards require tance in a lmost every situation w here consideration of a bold new approach the sigh t distance is restricted. All of these examples illustrate the to the establishment of vertical design need for a design concep t which pro­ criteria. Stopping sight distance is always vides the driver visual contact w ith the provided so there is really no problem roadway surface greater than is cur­ Prevailing Conditions -or is there? The perception-reaction rently being provided. Visual contact with the roadway sur­ time assumed is 2.5 seconds and it is face has been established as a primary well established that the perception­ Some Design Considerations source of information to the driver." 2 reaction time under complex situations The examples cited above graphical­ Its importance can be illustrated by a often is 4 or 5 seconds' When the ly illustrate one point: the importance series of examples: operating speeds were 45 to 50 mph, of driver expectancy in safe motor ve­ doubling the perception-reaction time h icle operation. I. The Passing Maneuver-The initi­ was not so critical. At 70 mph this ation of a passing maneuver on two­ Driver Expectancy-The concept of difference becomes a great deal more lane roadways requires that the driver driver expectancy has been included important. have a sight distance sufficient to in­ to some degree in traffic engineering sure that the passing maneuver can be 3. Pedestrians or Animals-Pedes­ philosophy for many years. For exam­ completed safely. The system of mark­ trians or animals on the roadway are ple, consistency of interchange design ings currently being used has been normally not expected by the driver in and consistent location of control de­ desi'gned to advise the motorist when rural areas thus grossly affecting the vices have long been advocated to adequate passing sight distance can­ response time of the driver to this un­ reduce the degree of driver noncompli­ not be provided. This distance is meas­ usual situation. Stopping sight distance ance. Driver expectancy, simply de­ ured to a point 3.75 feet above the criteria apply and the same discussion scribed, is the situation w hich the driver expects as a result of the infor­ mation available to him. The expected TABLE I situation is constantly changing as the Minimum Response Distances for Unexpected Situations driver receives more information. When P-R Time Assumed = 5 Seconds the ph ysical situation confirms the ex­ pected situation, there is only a slight Distance AASHO possibility of uncertainty. When the Design Traveled Stopping Total physical situation differs from the ex­ Speed During P-R Time Sight Distance Distance (mph) (feet) (wet condition) (feet) pected situation, a very complex deci­ sion-making process is involved. It 30 220 70 290 probably follows a three-step sequence: 40 300 130 430 1. The information available to driver 50 370 210 580 60 440 300 740 must be sufficient to convince him that 70 520 390 910 • Associate Research Engineer, Driving En­ 80 590 510 1I00 vironment Program, Texas Transportation Institute. APRIL, 1970 3 his expected situation is indeed incor­ TABLE rrr rect. This information is a great deal Desirable more extensive than would be neces­ Design Criteria sary to confirrri his expectation. Design Sight 2. The incorrect set of expectations Speed Height of Height of Distance must be replaced with a new set. (mph) Eye (feet) Object (feet) (feet) 3. The usual perception-reaction proc­ 50 3.75 0* 600 ess is carried out in order to arrive a t 60 3.75 O' 750 an appropriate course of action. 70 3.75 0* 900 80 3.75 0* lIDO This sequence must be defined as complex regardless of the environ­ 'Visual contact with the roadway surface p rovided. mental situation. Startle Effects--In the situations de­ A design sight distance of this magni­ DATA ENCOURAGE IMPROVEMENT scribed above, the driver is very likely tude would probably be unrealistic. Of' CONSOLIDATION PRACTICES to be startled by the situation and thus IN CONCRETE PAVEMENT overrespond. There is a tendency to Suggested Design Criteria CONSTRUCTION brake suddenly and steer sharply to A new conceptual format for vertical Dr. W. B. Ledbetter and Harvey Trey­ the right or left. This combination is alignment which will more nearly meet big have made research findings for one of the more critical ones from a the needs of the driver can be devel­ improvement of consolidation practices vehicle stability point-of-view and loss oped based on the results presented in in concrete pavement construction. The of control of the vehicle is a common Table I. This is given in Table Ill. result. With adequate sight distance, work was sponsored by the Texas the driver can anticipate a problem Other Considerations - When these Highway Department in cooperation then plan and execute the evasive ac­ sight distances to the pavement surface with the Bureau of Public Roads. can not be provided for anyone of a tion which is least dangerous. When The investigation involved an exami­ number of reasons, care should be roadside hazards are present, the driver nation of current technology on con­ exercised to insure that there is a mini­ can more nearly select an emergency crete consolidation, current continu­ mum probability of objects, pedestrians, path to avoid these hazards. ously reinforced concrete pavement animals, or slow-moving vehicles in Response Time-It has been noted that area. (CRCP) consolidation practices in Tex­ previously that when the actual situa­ as, and selected current concrete pave­ tion disagrees with the expected situa­ Communication Is Necessary ment problems through field examina­ tion the perception-reaction time may This concept is not intended to re­ tion and laboratory investigation. be as long as four or five seconds. Thus place the passing sight distance and While the vast majority of concrete for various operating speeds and an stopping distance design criteria but pavements were in excellent condition, assumed perception-reaction time of rather to supplement them. The view­ inadequate concrete consolidation was five seconds the distance at which the of-the-roadway surface concept would found in many areas of Texas, the most roadway s urface would desirably be be used where possible but when the prevalent locations occurring adjacent visible to the driver can be computed. conditions dictate that something more to transverse construction joints in Normal Focal Point of the Driver's restrictive be used, it must be recog­ CRCP. The researchers concluded that Eye-Matson, et a I' indicate that the n ized that the driver is not being kept proper construction control, rigorously natural focal point of the driver's visual fu lly informed using the existing design enforced, could reduce these isolated attention increases with speed as indi­ criteria and thus there is an increased consolidation problems. They conclud­ cated in Table II. hazard associated with travel on that ed also that by introducing selected section of the roadway. changes in current practices, consolida­ TABLE [[ tion problems can be minimized. References Normal Focal Distance of Drivers Based on these conclusions, recom­ I. Rowan, Neilon I., Donald L. Woods in Free Flow Conditions mendations were made which involved and Iocille H. Iohnson, "A Summary the introduction of selected changes in Report of the Significant Points From Operating Focal Point current practices. Speed (mph ) (feet) the Diagnostic Field Studies," Re­ search Report 606-4, Texas Transpor­ OCEAN ENGINEERING PAPERS 30 800 tation Institute (in publication). 40 1140 ARE PRESENTED 2. ----, "Development of Infor- 50 1470 Dr. J. B. Herbich, Dr. L. L. Lowery, Ir. , 60 1800 mation Requirements and Transmis­ and Dr. R. M. Sorensen presented tech­ 70' 2120 sion Techniques for Highway Users," 80' 2460 nical papers at the recent Ocean Engi­ Vol. I, a Draft Research Report by neering Conference sponsored by the the Airborne Instruments Corpora­ 'Extrapolated from curve presented. A.SC.E. and the University of Miami. tion on NCHRP Project 3-12 (in pub­ Their paper titles were, respectively, lication). Although these figures would indicate "Methods for Deep-Ocean Mineral Re­ that a sight distance of 2000 feet or more 3. Matson, Theodore M., Wilbur S. covery," "Analysis of Pile Driver Re­ might be desirable, there is considera­ Smith and Frederick W. Hurd, "Traf­ quirements for Off-Shore Piles by the ble doubt that the driver would be able fic Engineering," McGraw-Hill Book Wave Equation," and "Effect of Pile to distinguish lane markings or pave­ Company, Inc., New York, N. Y., Surface Roughness on Wave Forces on ment edges at such a great distance. 1955, p. 17. Piles."

4 TEXAS TRANSPORTATION RESEARCHER face, "the tire-pavement interface," Ihat EFFICIENCY PRODUCES SAFETY FOR may result in loss of control of the ve­ hicle. There are any number of ways THE NATION'S HIGHWAYS by which the efficiency of the roadway system can be described. With so many By CHARLES J. KEESE and LOUIS J. HORN interactions a safety researcher sees confusion, The quest for highway safety is an jurisdictional, and multiagency respon­ The complexity of problems today e ndless purs uit and involves the road­ s ibility. The social and economic makes it difficul t for an individual or way, the vehicle, and the human being. dependence on motor vehicle transpor­ even a small group to do meaningful The needs for it are immediate and tation for mobility prevents the use of research. It has become necessary to must be met promptly and con tinually the negative approach to improve sys­ get input from a number of disciplines and in accordance with changing con­ tem efficiency. It is difficult, but not formerly not associated with the trans­ ditions. impossible, to eliminate certain groups portation field. A study of traffic oper­ 01 the driver population, to eliminate ational efficiency may well involve the What is highway safety? Few people certain vehicles, or to eliminate ineffi­ traffic engineer, design engineer, math­ really know. Even highway technolo­ cient roadways. However, if we are ematician, statistician, computer spe­ gists have different definitions for it. going to improve the efficiency of this cialist, and others. The interdiscipli­ system in time to reduce the toll of nary team approach has been found to The highway traHic system is com­ deaths and injuries on our roadways, posed of the driver operating a vehicle be necessary to solve complex problems it is going to be necessary that we take in a roadway and traff ic environment. requiring input from a variety of disci­ the positive approach which is gen­ Making this system safe for use b y pli nes or speceializations. erally more effective anyway. millions of people is a complex prob­ lem, and there is no simple answer. The philosophy that it is important Efficiency Requires Measurability in the field of safety to lind adequate Before we can provide safety, we One of the major problems of the and timely results will direct resea rch need to know what it is . Safety is not road-driver system is describing system toward those parts of the system most something you can buy or that can be efficiency and learning how to measure easily changed. Some of the elements scared into people. It cannot be legis­ it. What is a truly efficient system of of the system shown in Figure I can be lated into existence. In our work at the traffic operation? All too frequently a ltered rather rapidly w hile others may Texas Transportation Institute we define those close to only one part of the require long periods of time and some safety as the by-product of efficiency. problem tend to describe that part as may never be subject to meaningful This has given us something to analyze the total problem, In the highway field change. to determine what is required to pro­ there is a tendency to describe the vide safety. efficiency of our roadway system in To make the masses of drivers more terms of the volume of traffic, "the out­ skillful must be a long range goal. It Figure I illustrates the complexity of put of the system." Others describe it may be easier, however, to change the the road-driver s ystem with the inter­ in terms of level of traffic service (which system to lit a ll drivers than it is to faces between its major elements and has now been quantitized) , however change the drivers to fit the system. some of the external influences. It must this is measured in terms of traffic flow be realized that this complexity is and therefore does not reflect the The drunk driver, for example, is un­ increased b y multigovernmental, multi- inefficiency in the road-vehicle inter- questionably an inefficient element in the system. This problem must be solved. Drivers are of many tempera­ ments, different ages, and varying VERTICAL AND HORIZONTAL FORCES FRICTION, GRAVITY, ENERGY physical ability and well-being. Their FIRST COLLISION VEHICLE CHARACTERISTICS practice of conduct varies and is sub­ ject to change by conditions of the moment or a physical or mental state. Also, their interests and destinations and the urgency of the journey make r a difference in traffic. TRAFFIC STREAM PLANNING CHARACTERISTICS DESIGN AND To bring about necessary changes in SPE ED, VOLUME, GAP OPERATIONS ACCEPTANCE the automobile is a difficult problem CON FLICTS AND because of the fact that it is possible CO LLISIONS to operate almost any vehicle with safety. It is unquestionably true, how­ ever, that many of today's vehicles can easily be operated in an unsafe man­ ner without the driver even suspecting MISCELLANEOUS ENVIRONMENTAL that such operation is unsafe. Horse­ OTHER VEHICLES FACTORS-WEATHER, TIME, OTHER ROADWAYS power, speed, and response time have PEDESTRIANS A 8 C been increased much more rapidly than 4 ENVIRONMENTAL FACTORS highways and streets could be modern­ ized to accommodate these changes. Figure I. Traffic system components and critical interfaces to be considered in highway .afety re.earch. There is certainly a mismatch between APRIL, 1910 5 that the motorist will slow down when the pavement is weI. How much should he slow down? At wha t speed is the interface between his tires and the pavement unstable? Different vehicles have widely different charaeleristics (Figure 2). As a matter of fael, the characteristics of any individual v e­ hicle change with time. Tire tread, tire pressure, vehicle load, reaction of the suspension system, and other charac­ teristics are subjeel to critical change as far as safe vehicle operation is con­ cerned.

A personal observation is that the varia bles between vehicles such as tire condition, load, etc., indicate that in a hig h-speed, high-density traffic situa­ tion some of the motorists are operating on the knife-edge of disaster.

Another observation is that drivers c= and frequently do make m=euvers that are much more critical than those associated with the designed path of Figure 2. Geometries, pavement, and vehicle are of concern for safety, the roadway. For example, when one vehicle passes another on a straight tangent two-l=e, two-way roadway, the capabilities of the 1970 automobile can be done, within the constraints of the vehicle doing the passing negoti­ and th e roadway designed twenty time and money, to make our streets ates a path involving four curves. Each years ago. The match ing is left entirely and h ighways safer. This program is curve is counter to the slope of the up to the driver. Whose fault is it that based on the assumption that two ele­ roadway. If his curves are sharp =d this mismatch exists? It is certainly ments of the. system, the driver and the his speed and acceleration great and impossible to remodel the entire street vehicle, must be accepted as they are, the pavement wet, the driver may well and highway network every five years and that changes in the roadway ele­ spin out of control even on the best or so to accommodate changes in auto­ ment and its interfaces with the other roadway. He has no way to anticipate mobiles. On the other side of the coin, elements will be brought about through tha t he is about to spin oul. He prob­ the automobil e m=ufaelurers are a l­ planning, design, construction, opera­ a bly does not even realize that he may ways going to build what the public tion, and mainten=ce of new facilities have a smooth tire or a tire with inade­ wants. If it wants power and speed, and through remodeling and more effi­ quate pressure. Whether there is = that is what it will get. cient operation of older facilities. answer to this problem remains to be seen. Research has already been ex­ New roadways are under construc­ Although this is an incomplete ap­ tremely valuable in helping to explain tion every day. Because of the com­ proach to total system efficiency or many accidents such as why people plexities and time involved in planning, safety, it has resulted in the creation designing, and construeling these fa­ of facilities that have experienced lower cilities, the accommodation of new tech­ and lower accident rates. Increases in nology comes slowly and m=y road­ traffic have overshadowed these im­ ways are somewhat obsolete soon after provements in rates, resulting in = in­ they are opened to traffic. crease in the total number of people Geometries Must Modernize who are killed and injured each year in automobile deaths. Consider how When an office bUilding is construel­ many more deaths and injuries there ed, however, it is frequently remodeled would be if efforts were not constantly before its first tenants move in, and it being made to make facilities safer. is usua lly renovated periodically dur­ ing its useful life. The public has not The relatively low rate of accidents yet recognized the need to remodel on freeways and other high-type facili­ existing streets and hig hways even ties indicates that drivers can and will though the requirements of the users operate with reasonable safety in an change quite rapidly through the years. efficient environment. Drivers are not If the highway engineer misses in his able, however, to adjust to certain estimate of traffic requirements several changes. For example, the inability of years in the fu ture, he is severely criti­ the driver to adjust to wet rocld condi­ cized. tions is refleeled in the greater number There is at present a concentrated of accidents in wet weather as com­ f igure 3. Bus tires are evaluated in skid effort in the h ighway field to do what pared to dry. The assumption is made tes ts in public interest. 6 TEXAS TRANSPORTATION RESEARCHER - The driver of a vehicle fo llowing an­ other on a ramp has the same series of decisions and must also guess what the driver ahead is going to do. If the trailing driver is search ing for h is gap at the time the first driver stops, a rear­ end collision is likely. This false-start accident is common on freeways. The frequency of collisions between ve­ hicles in the merging area and on free­ way ramps indicates that this is an area of inefficiency.

Merging Control Aids Freeways Several years ago the Texas Trans­ portation Institute undertook a program of freeway research in cooperation with the Texas Highway Department and Bureau of Public Roads. The broad objective of this work was to improve the efficiency, and thus the safety, of existing freeways. Analyses indicated that the efficiency of the merging oper­ Figure 4. Driver studies map before following s!rax;tge roul.e de~ignaled for him 10. Irav.el ~ilh observer in research to e valuate and unprove s lgnlng ~ delineahon, markIng, and lllumlnation. ation could be improved by developing a merging control system that would select an acceptable gap in the traffic run off the inside of curves when the in signing, delineation, marking and in the outside freeway traffic stream force analysis would indicate that they illumination and make recommenda­ and release a vehicle from the ramp 5hould go off the outside of the curve. tions for improving communication be­ in order to reach the merge area at the tween the road and the driver (Figure proper time. Safety Involvement Is Comprehensive 4) . This merging control system has elim­ The Texas Transportation Institute One thing few: drivers can do effi­ inated the rear-end ramp accidents has been and is now involved in a ciently is anticipate action of other during the periods of control and has rather comprehensive research program drivers with any degree of certainty. improved the over-all freeway efficien­ with the Texas Highway Department, When a driver is entering a freeway, cy to the extent that all accidents on Bureau of Public Roads, the American he has a series of quickly spaced deci­ the main lanes decreased 31 '1'0 during Association of State Highway Officials sions to make while operating at high the periods of control compared to the through the National Cooperative High­ speed. He must select a gap in the same periods before control (Figure 5). way Research Program administered by freeway traffic, and judge the choice of The freeway flow (vehicle miles of the Highway Research Board, and with stopping if he feels he has misjudged. travel) increased 16'1'0, average speed the Bureau of Standards to understand the vehicle-road stability problem and find ways to improve roadway and traffic operational characteristics.

In the early phase of this research program, characteristics of bus and automobile tires were evaluated in stopping and in negotiating curves (Figure 3). As a result of these studies, the research program has been expand­ ed to include further evaluation of road­ way design, pavement friction charac­ teristics, pavement drainage, hydro­ planing, truck jack-knifing, a study of actual paths fo llowed by vehicles, and other factors relating to the road-vehicle interface. At the same time in another project supported by several state highway de­ partments the road-driver interface is being studied. This diagnostic study of the highway visual communication sys­ tem involving lay persons and tech­ nologists driving inspectional routes, is designed to e valua te current practices Figure 5. Merging controlled by computer is enhancing freeway operation. APRIL, 19·70 7

• vehicle. Early in the program a quick­ fix solution was developed and imple­ mented on highways in Texas. With the aid of multistate support the re­ search continued through the devel­ opment and use of a mathematical computer simulation technique with validating crash tests conducted at the TTl Highway Safety Research Center. Several acceptable designs were de­ veloped and breakaway sign supports are now in general use. Many lives have a lready been saved through the use of th is concept. The same approach was used in de­ veloping a breakaway design for the strong poles supporting luminaires used to light highways. This research was sponsored by a ll state highway depart­ ments through the National Coopera­ tive Highway Research Program ad­ ministered by the Highway Research Board. The results have been widely implemented and have reduced the toll from collisions with these hazardous Figure S. Television monitors and cons ole serve in freeway surveillance and control in Houston. objects. The development of a breakaway design for the supports for large free­ increased 12 miles per hour and total has been a program to make the road­ way sign bridges is being sponsored travel time decreased 25 /,0 as a result ways more forgiving of human error by twenty-one state highway depart­ of the freeway ramp control system. and mechanical failure, particularly in ments and the Bureau of Public Roads. loss of control. Recently conducted crash tests indicate The continuing freeway research ef­ that the concept is practical. fort on the Gulf Freeway in Houston The first phase of the program was and on the North Central Freeway Cor­ the development of a support for mas­ To protect b ridge piers, bridge gores, ridor street system in Dallas is being sive freeway signs that would break and other rigid obstacles, a vehicle directed toward the further develop­ away when s truck by an out-of-control crash cushion has been developed, ment of control and communication systems based on real-time decisions. Television systems (Figure 6) are being used to evaluate instantaneous deci­ sions through the use of real-time com­ puters.

Roadways Are Made More Forgiving As operating speeds have increased, so have the instances of loss of control by drivers with great endangerment to themselves and passengers. Ob­ stacles along the roadway become seri­ ous hazards when vehicles leave the traveled way at high speed under such circumstances. In order to create a safe recovery area along our roadways, the Texas Highway Department along with a number of other state highway de­ partments in cooperation with the Bu­ reau of Public Roads initiated a re­ search program to eliminate roadside hazards. The philosophy used in improving roadside safety has been: If it isn't necessary, remove it. If it cannot be removed, make it break-away. If it can't be made break-away, then pro­ Figure 7. Accident scene at branching of tT . S. 59 and IH 10 shows thai emply drums cushioned tect it with a soft crash cushion. This impact. 8 TEXAS TRANSPORTATION RESEARCHER crash tested, and implemented by the complex interchang e areas fro m hig h DISTINGUISHED GRADUATE Texas Highway Department and others. towers. Lighting over the entire road­ BECOMES PRESIDENT Here again, a quick-fix answer was way environment provides a much bet­ OF TEXAS A&M necessary. The Bureau of Public Roads ter perspective view for the driver, and UNIVERSITY sponsored a research program to de­ his driving task is therefore more effi­ Maj. Gen. A. R. Luedecke, who re­ velop vehicle attenuation systems. In cient. turned tClTexas A&M in 1968 after an searching for a quick-fix answer, a set illustrious career in the Air Force and Needs Must Be Met While Belter of functional specifications was devel­ other government service, March 30 Ways Develop oped based on what were considered was named acting president of the to be tolerable deceleration rates. The Certainly there is a need to attack first attempt involved "discarded metal the safety problem on several fronts beverage containers" which are plenti­ simultaneously. But the urgency of the ful along our highways. Packaging problem will not permit us to sit back these into a functional device presented and wait for the dedication of sufficient a problem. They were tested first in resources to make this possible. We burlap bags, then in wire cages and must do what we can now, with the finally in used oil drums. The crash technology at hand, keeping in mind test results indicated that the empty oil the important needs. Most urgently we drums alone would make a good sys­ need to coordinate the efforts of those tem. These were tested, proven satis­ agencies experienced in safety research factory, and implemented on highways and implementation and to make maxi­ in Texas. These experimental installa­ mum use of existing research facilities tions have been struck numerous times and resources, without injury or fatality so far (Figure 7). Collisions at these same sites prior Improved efficiency will result in im­ to installation of the devices had re­ proved safety. Assuredly, efficiency can be defined and measured. There­ sulted in a number of fatalities. fore, with systematic evaluation the Guardrail systems are also being safety of the highways can be progres­ improved to give safety for human sively perfected. error. The search for the long range solu­ Alvin R. Luedecke Interdisciplinary Diagnosis and Solution tion should certainly be our goal. But in the meantime, quick-fix answers Unive rsity and the Texas A&M Uni­ In searching for a way to study com­ should be sought and applied to meet versity System. plex problems such as roadway com­ immediate needs while we are working munication systems, rail-highway grade toward those far-reaching objectives. He retired in 1958 from the Air Force crossings, and highway illumination, to become general manager of the U. S. the diagnostic approach employed by Atomic Energy Commission. medical doctors and veterinarians has PANELS, BEAMS, AND DECKS Board President Clyde H. Wells an­ been used with reasonably good suc­ OF CONCRETE BRIDGES nounced the interim appointment for cess in our highway safety research. ARE UNDER STUDY the position held by the late General In complex highway traffic situations, A study of prestressed panels and Earl Rudder, who died March 23. The inefficiencies can be caused by any composite action in concrete bridges board unanimously favored Luedecke. made of prestressed beams, prestressed number of factors or complex interre­ General Luedecke, a 1932 chemical subdeck panels, and a cast-in-place lationships. We organize teams of spe­ engineering graduate of Texas A&M, deck is being made in team research cialists from research and practice and returned to his a lma mater in 1968 as in the structural research program. The let them diagnose and treat the prob­ an associate dean of engineering and Texas Highway Department and the lems. Experience in the application of engineering research coordinator. Last Bureau of Public Roads are sponsors the "diagnostic team approach" to cer­ year he assumed additional responsi­ of this Texas A&M and University of tain complex highway problems indi­ bilities as associate director of the Uni­ Texas endeavor. cates that this technique may be quite versity's Texas Engineering Experiment effective. Treatments based on known Objectives are to conduct a field Station. technology can eliminate many "ill­ study of existing bridges of the subject Prior to joining the Texas A&M staff, nesses and malfunctions" in the high­ type to determine the condition of bond General Luedecke served three years way traffic system and give improved between precast panels and a cast-in­ as deputy director of the Tet Propulsion efficiency and safety. place deck and to determine the extent Laboratory at California Institute of of composite action between beams, The diagnostic team approach ap­ Technology. He is credited with play­ panels, and s lab and the pattern and plied to the study of roadway lighting ing a major role in the renowned space extent of cracking of the deck. revealed that the "puddles" of light research of that facility. spilled on the roadway at regular in­ The investigation seeks also to exam­ Luedecke previously served almost tervals did not provide the quality of ine the effect of fatigue loading on the six years as AEC general manager. visibility needed by the driver particu­ transfer length of prestressing strands larly in complex areas such as inter­ in the subdeck panels and to discover The 59-year-old native of Eldorado, changes. Work toward a solution has the response to static fatigue and de­ Texas, entered the Army as a field ar­ resulted in the application and rather structive loading of a full-scale labora­ tillery officer in 1932 and transferred to wide acceptance of floodlighting of tory model of a bridge. the Air Force a year later. He was

APRIL, 1970 9 named assistant chief of air staff for the China-Burma-India Theater in 1943. DEVELOPMENT AND EVALUATION At the age of 34, he was promoted to brigadier general. OF BREAK-AWAY COLUMNS General Luedecke advanced to air FOR SI GN BRIDGES planner with the Joint Chiefs of Staff in 1946 and was named executive direc­ By ROBERT M. OlSON* tor of the Atomic Energy Commission Military Li aison Committee in 1949. Development and crash testing of a photographs. The car in this test was Two years later he was promoted to break-away support for overhead sign a 1963 Ford sedan weighing 4090 deputy chief of the Armed Forces Spe­ bridges continues at the Texas Trans­ pounds. Speed at impact was 47 miles cial Weapons project and became chief portation Institute's Highway Safety Re­ per hour. Damage to the front of the in 1954. He also was named Joint Task search Center. The concept originally vehicle was slight; however, the bump­ Force Seven commander in charge of proposed by D. L. Hawkins, now engi­ er, grill and hood required replacement. nuclear test series "Hardtack" on Eni­ neer of maintenance in the Texas High­ wetok and Johnston Islands. An unexpected situation occurred in way Department, employs break-away a test in which a 1959, Simca sedan The general has received numerous features at the base of each support decorations and awards for his varied column. The upper end of the column public service career. His own govern­ is bolted to the top chords of the sign ment has awarded him the Distin­ bridge truss, and the column is attached guished Service Medal, Legion of Merit to the bottom chords of the truss by a with cluster, and Bronze Star with two pin connection. Thus when the support clusters. Two years ago, the National· column is struck by an errant vehicle Aeronautics and Space Administration the base connection disengages, the awarded him its Exceptional Service vehicle load near the base produces a Medal. shearing force at the upper connection He also has been honored with Co­ causing the bolts to shear, and the col­ lombia's Cruz de Boyaca, the Cloud umn pivots about the pin connection. and Banner of China, and has been The support swings upward, clearing named Commander of The British Em­ the vehicle. This pendulum behavior pire. of the column produces a substantial Texas A&M awarded General Lue­ impact force on the lower chords of the decke an honorary Doctor of Laws De­ truss. An energy absorbing device gree in 1946 and Distinguished Alumni was designed to distribute this load Award in 1967. to the truss members.

SAFETY ANALYSIS PROGRAM FOR Crash Tests Favor Desig n ROADSIDE ENVIRONMENT A series of eight tests was proposed IS BEING ADAPTED by members of the Multi-State Project A three-year study to apply mathe­ Policy Committee, consisting of engi­ matical simulation techniques in deter­ neers from Alabama, Arkansas, Con­ mining the dynamic response of ve­ necticut, Florida, Georgia, Hawaii, Ken­ hicles and their passengers when in col­ tucky, Louisiana, Maryland, Michigan, lision with various roadside objects or Mississippi, Montana, Nebraska, New when traversing curves in the road, Hampshire, New Mexico, Rhode Island, shoulders, or other situations is in prog­ South Dakota, Tennessee, Texas, West ress a t the Texas Transportation Insti­ Virginia, Wyoming, and the District of tute. Sponsors are the Texas Highway Columbia. Six tests in the series have Department and the Bureau of Public been completed with satisfactory re­ Roads. Researchers include Ronald D. sults. The support columns, overhead Young, Richard J. Bridwell, and Hayes truss, and the entire structure have E. Ross, Jr. sustained the impact forces produced As part of the first year's work, the by vehicles colliding at 25 to 55 miles single vehicle accident computer pro­ per hour, head-on and at an angle of gram developed by Cornell Aeronauti­ 15 degrees. Vehicle weights range from cal Laboratory has been adapted to 2000 pounds to 5000 pounds. the IBM 360 computer facilities at Texas Typical behavior of the support col­ A&M University. In this task the re­ searchers have familiarized themselves umn is shown in Figure 1. The load distribution devices, developed during with the logic and coding of the pro­ the study consist of 12-inch-diarneter gram and written a document which describes its input data requirements. oil field pipe, 17 inches in length. In adapting the program, they have These can be seen in the sequential made additions and modifications to • Associate Research Engineer, Structural Re­ Figure 1. Sequ entia l views show 4090-pound search Division, Texas Transportation lnsti· car colliding with sup port a t 47 miles per increase its flexibility and usefulness. tute. hour. 10 TEXAS TRANSPORTATION RESEARCHER predicts impact behavior. Output from as well as two static tests on the total this mathematical model has been veri­ structure. The author is principal in­ fied by the six full-scale crash tests. vestigator on the project. A draft final Dr. D. L. lvey, an associate research report will be forwarded to the spon­ engineer, has conducted the crash tests sors on or about June 12, 1970. DISCARDED BATTERY CASES AS SYNTHETIC AGGREGATE IN ASPHALTIC CONCRETE

By BOB M. GALLAWAY*

Figure 2. Final position of small car that held to support in test. Many types of synthetic aggregate In combination with other aggregates, are being used in asphaltic concrete. according to the Marshall method of This is because various parts o f the mix design, the crushed battery case United States lack good natural aggre­ aggregate is suitable for asphaltic con­ gate sources and are forced to trans­ crete. Specifically, mixed with fine port aggregate over long distances to sand, it met all Marshall design cri­ job sites. The synthetic materials in­ teria. The crushed battery case aggre­ clude slag and expanded shale or clay, gate used with other aggregates is sometimes called lightweight aggre­ suitable for asphaltic concrete also, ac­ gate. Even fine sea shell is serving cording to the Texas Highway Depart­ as aggregate. ment modified Hveem method of mix The apparent success of these ma­ design. However, specifications which terials in use has encouraged searches are much higher in stability require­ for other replacements and supplemen­ ments may be difficult to meet using tations of natural aggregate. One of battery case material. Based on the the potential sources under experi­ Marshall study, the battery case crush­ mental scrutiny is waste materials of ings alone are not a suitable material various kinds. for asphaltic concrete. At the Texas Transportation Institute Hot mix-cold laid mixtures utilizing the author, with Phillip G. Manke and battery case crushings in part can Benjamin R. Schlapak, conducted a lab­ probably be adjusted to meet Texas oratory study to determine the suita­ Highway Department specifications. bility of using crushed storage battery Again, meeting requirements of some cases in asphaltic concrete for surface other agencies may be difficult. course mixtures. The investigation was High Marshall Ilow values and cor­ made for Lead Products Company, Inc., responding low Texas Highway Depart­ of Houston, Texas. ment stability values revealed by the Suitable for Small Paving Tobs study probably were caused by the Figure 3. Action of the energy absorbers near top of s upport is shown. Presently, more than 50,000,000 used semi-elastic nature of the battery case storage battery cases of various types particle. It is possible that the addi­ and sizes are thrown away each year. tion of a rubber additive,' would aid weighing 2100 pounds was made to A rough calculation indicates that when in lowering the high flow characteris­ collide with the break-away support. crushed these cases will yield about tics of the asphaltic concrete made up The front of the vehicle was deformed 115,000 cubic yards of material. which in part of battery box crushings. This significantly by the impact force. The is a fairly sizeable potential aggregate may be necessary to reduce the flow car snagged the lower end of the col­ source. If this material could be suc­ values to 16 in order to conform to umn, was lifted by the support, and cessfully incorporated as aggregate in Lefebvre's driveway and parking lot was dragged to a stop in the position hot-mix asphaltic concrete, it would be criteria.' shown in Figure 2. Speed at impact ideally suited for use on small paving The battery case crushings as aggre­ was 44 miles per hour. Although the jobs such as driveways, parking lots gate in asphaltic concrete have the de­ vehicle-post interaction was unexpect. and city streets. The problem of col­ sirable characteristics of being strong, ed, vehicle damage was about what lecting the cases is minimized by the lightweight, angular, and resistant to had been anticipated, and the vehicle fact that old batteries are usually abrasion. Their undesirable character­ was brought to a stop in a reasonably brought to a few central points to re­ istics include flammability, large per­ tolerable manner. cover the extractable lead. centage of smooth-sided particles, and The laboratory experiments with the a tendency to produce mixes with high Mathematical Model Is Developed storage battery cases, which in general, flow values. The final two tests are to be con­ are made of rubber, plastics, and as­ Further Research Can Extend Utility ducted in April 1970. Dr. J. E. Martinez, phalt with various types of fillers and assistant research engineer, and Dr. T. fibers, provided a number of findings. Further experimentation should be J. Hirsch, have developed a mathemati. conducted to more completely appraise 'Head, Construction Program, Texas Trans­ cal simulation of the support post which portation Institute. the adequacy of crushed battery case APRIL, 1970 11 FREEWAY CAPACITY IN RAIN IS ANALYZED FOR HOUSTON The effect of rain on freeway capaci­ ty has been determined for Houston by E. Roy Jones and Merrell E. Goolsby in level of service research sponsored by the Texas Highway Department and the Bureau of Public Roads.

The work involving Gulf Freeway traffic data and weather records showed that rain significantly reduces freeway capacity. During rain the ca­ pacity can be expected to be 81 to 86 percent of the dry weather capacity with 95 percent confidence. Additional­ ly, the frequency of rain during the peak periods in Houston is on the order of fifty times per year.

Dry weather capacity is very stable. Ninety-five percent of the dry weather capacity values can be expected to fall within 7 percent of the mean observed capacity 99 percent of the time. Bituminous pa ving mixtures ma de in part from w aste b attery ca ses being e valuated by Jo e M. Pig Iord, a civil eng ineering student, HERBICIDES ELIMINATE COMPETING PLANTS OF ROADSIDE BERMUDAGRASS material as an aggregate for asphaltic ing a functional priority to the various concrete and to subsequently adapt it uses of each street in the network, Bermudagrass usually does not be­ for effective practical application. Keese emphasized, can logical deci­ come established when it is seeded sions be made concerning the trade­ concurrently with annual ryegrass. The The work should include studies of offs between 'competing uses and the primary reason for the dominance ex­ (l) gap graded aggregate and crushed time sharing necessary to provide for pressed by the ryegrass is not a con­ battery case combinations to obtain a these uses. Time, space, and economy tained inhibitory substance, but the mixture that will meet both Marshall are three basic factors involved in all competitive effect particularly from and Hveem specifications; (2) the be­ transportation alternatives, he pointed shading, according to William J. Bow­ havior of the crushed battery box ag­ out. mer and Dr. Wayne G . McCully who gregate in a rotary kiln under actual are conducting research on establish­ hot-mix plant operational conditions; Maier, a consultant, said transporta­ ment and management of roadside tion must be developed as an integral (3) the effects of rubber additives on vegetation. The work is sponsored by part of the total urban environment. the flow characteristics of the battery the Texas Highway Department in co­ He called for a balanced transportation box asphaltic concrete, and (4) the operation with the Bureau of Public system of both freeways and transit. elasticity effects of the particles on Roads. compaction and stability. To make this possible he said realistic and achievable concepts of urban liv­ Herbicidal materials such as para­ ing and the urban environment must quat or the organic arsonates applied References first be identified as community values to the ryegrass preemergence to the bermudagrass will favor establishment 1. Bulletin T-lOO, U. S. Rubber Reclaim­ and adopted as community goals. He of bermudagrass, the two range scien­ ing Co., Buffalo, New York, 1964, a lso said that the key to solution of urban problems is held by the civic tists reveal. Other materials which p. 3. leadership of the business community. have a longer residual such as dalapon 2. Lefebvre, J., "Recent Investigations are not suitable for pre emergence use of Design of Asphalt Paving Mix­ Doyle in his speech on "Regulation on seeded bermudagrass. tures," Proceedings, Association of of Time and Space" suggested con­ sideration of downtown businesses pro­ Paraquat and the organic arsonates Asphalt Paving Technologists, Vol. are suggested for pre emergence appli­ 26, 1957, pp. 321-394. viding parking for employees and cus­ tomers. He brought attention also to cation to encourage grass establish­ advantages of peripheral order-taking ment from seeding when competitive URBAN TRANSPORTATION- and consolidated delivery in store re­ p lants are present. The same materials (Continued Irom column 2, pa ge 1.) supply, use of for-hire drayage, super­ also may have utility where it is de­ for loading and unloading passengers vision of h eavy hauling for downtown sirable to regulate the plant composi­ and goods, for access by services such construction, regulation of gasoline and tion on an area. as mail and repairmen, collection and oil products distrib ution, and reorgani­ drainage of storm water, and move­ zation of center-city rail sidings and Safety makes personal and business ment of pedestrians. Only by assign- terminal facilities. transport p leasant and effective.

12 TEXAS TRANSPORTATION RESEARCHER