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232 Completion Date: December 31, 1979 Funds: $ 154,452 The objective of this project was further refinement and field evaluation of the two prototype moisture sensors developed under Projects 21-2 and 21-2~2~. This included fabrication of the sensors and readout instrumentation, their installation in the subgrade portions of pavements in Arizona and Pennsylvania, and evaluation of data col- lected at the field sites. Research has been completed, with accomplishment of the intended tasks. Although neither sensor meets all of the desired criteria, the research indicates that each has some potential for practical applicator to the soil moisture measurement problem. Operational problems encoun- tered during the field evaluation should be resolved during the development of production models. A production model of the dielectric sensor is available from Ecotec Corp., Needham Heights, Mass. The essential findings of the study have been published as NCHRP Research Results Digest 121. The agency report has been distributed to the Program sponsors and other interested persons. It will not be published in the regular NCHRP report series but is available on a loan basis (see final page of this section for ordering infor- mation). AREA 22: VEHICLE BARRIER SYSTEMS Project 22-1 FY '69 Concepts for Improved Traffic Barrier Sys- tems Research Agency: Principal Invest.: Elective Date: Completion Date: Founds: Walter W. White Walter W. White Marvin A. Shulman October 1, 1970 December 31, 1971 $25,000 The objective of the research was to produce one or more traffic barrier system designs, described with sketches and narrative to the degree necessary to convey understanding, that offer promise of: preventing penetra- tion by a standard-size U.S. automobile weighing 4,000 to 5,000 lb and impacting at 25 and 65 mph; smoothly redirecting errant vehicles relatively parallel to traffic flow; providing a range of controlled dynamic deflections by varying design parameters; retaining longitudinal con- tinuity following a collision; permitting adequate visibil- ity; being capable of quick and easy repair; performing satisfactorily in various foundation conditions; limiting decelerations at the center of gravity of the vehicle to 5g lateral, 10g longitudinal, and a total of 12g when averaged over any 200-millisec period; having reasonably low first cost and pleasing appearance; and minimizing vehicle damage. The design was analyzed and technical infor- mation was presented to demonstrate the degree of achievement of the foregoing. Working drawings suitable for fabrication and installation of a prototype were pre- pared for each barrier system. The final report was not published in the NCHRP report series; however, microfiche of the report may be purchased (see final page of this section for ordering in- formation). Project 22-1A FY '73 Testing and Evaluation of Bridge Rail Con- cepts Research Agency: Texas A & M University Research Foundation T. J. Hirsch March 1, 1974 May 30, 1975 $40,000 Principal Invest.: Elective Date: Completion Date: Funds: The objectives of NCHRP Project 22-1, "Concepts for Improved Traffic Barrier Systems," were accomplished by the development of a traffic barrier system that was analyzed using the Barrier IV computer program. The results of this analysis indicate that the proposed system meets the desired criteria. The objective of Project 22-1A was to evaluate the prototype of the proposed barrier by full-scale impact tests. The accomplishment of this objective included the fol- lowing tasks: 1. Fabrication and construction of the barrier system shown in Figure 6 of the final report on Project 22-1 (Pages 148 to 173, NCHRPSummary of Progress Through 1972~. 2. Testing and evaluation of the system under the fol- lowing impact conditions: (a) A passenger vehicle impacting the bridge rail at 60 mph and 25. (b) A passenger vehicle impacting the bridge rail at 60 mph and 7. (c) A passenger vehicle impacting the approach railing- bridge rail transition at 60 mph and 25. Research has been completed, and the essential findings have been summarized in NCHRP Research Results Di- gest 81, "Crash Testing and Evaluation of Attenuating Bridge Railing System." Microfiche of the agency's final report may be pur- chased (see final page of this section for ordering infor- mation).

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233 Project 22-2 FY ,69, FY '72 and FY '73 Traffic Barrier Performance and Design Research Agency: Principal Invest.: Elective Date: Completion Date: Funds: Southwest Research Institute M. E. Bronstad J. D. Michie Jan. 1, 1972 Oct. 1, 1973 Sept. 30, 1973 Mar. 31, 1975 $125,000 $80,000 Among the most important of current needs in the area of vehicle barrier systems is a safer terminal design. The work of Project 22-2 was structured to emphasize the systematic experimental development of terminal treat- ments to fulfill this need. Terminal treatments for a num- ber of selected guardrail systems were investigated. This study built on earlier preliminary NCHRP efforts that are described in NCHRP Reports 118 (1971) and 129 (1972~. The initial task in Phase I included a review of terminal concepts previously developed under Project 15-1~2), the development of several new concepts, and an examination of concepts developed outside the NCHRP. More than 20 of these concepts have come under consideration. This work was covered in an interim report. Although the report will not be published, it is available on a loan basis. Based on the interim report, the project panel selected designs and established priorities for full-scale testing of several terminal systems. The experimental program con- sisted of some 26 full-scale crash tests. Interest in this testing was concentrated on a breakaway cable terminal (BCT) in combination with the W-beam guardrail and median barrier systems most often used. Ten crash tests were carried out on the BCT with the flared W-beam guardrail. The second part of the experimental program, comprising some 16 tests, was concentrated on the de- velopment of a crash-cushioning terminal for use with median barriers. Microfiche of the agency's Phase I report may be purchased (see final page of this section for or- dering inflation. Phase II research has been completed. Task 1 led to the refinement of BCT designs to provide more safety to smaller cars and to improve economy relative to the first cost, maintenance, and repair. Findings from the Phase II research were reported in NCHRP Research Results Digest 84 (March 1976~. Microfiche of the agency's final report on Phase II may also be purchased (see final page of this section for ordering information). Subsequently, the Federal Highway Administration sponsored additional tests on the median barrier BCT. NCHRP Research Results Digest 102 summarized the findings of these and previous tests and clarified recom- mended details for both guardrail and median barrier terminals with either steel or timber posts. A separate task of Phase II, funded at $20,000, was intended to develop uniform barrier testing criteria and procedures. Research has been completed on this task, and the final report has been published as: NCHRP Re- port 153, "Recommended Procedures for Vehicle Crash Testing of Highway Appurtenances." Project 22-2~2) FY '73 Multiple Service Level Highway Bridge Rail- ings Performance and Design Criteria Research Agency: Southwest Research Institute Principal Invest.: M. E. Bronstad Elective Date: August 1, 1976 Completion Date: April 30, 1979 Funds: $195,000 The initial objective of this project was to identify and document realistic performance criteria and correlated design criteria for bridge railing systems on roadways providing various (at least three normal, higher, and lower) levels of service. The major objective was to de- velop at least one design based on criteria for the lower service level and to validate this system using analytical and full-scale testing methods. The research included the following tasks: 1. Identify traffic and other parameters for use in de- fining appropriate categories of roadway service levels. 2. Establish reasonable performance criteria for bridge railings to be employed in each category. 3. Propose bridge railing design criteria for each cat- egory. 4. Develop and validate, through analytical simulation and full-scale testing (in accordance with the relevant provisions in NCHRP Report 153), at least one lower service level bridge railing design with first cost and main- tenance advantages over normal service level systems. The railing will be designed according to the criteria proposed in Task 3, to give performance consistent with the criteria developed in Task 2. Bridge railing designs considered in this task may include some already in use. 5. Through analytical simulation, evaluate the per- formance of this railing when struck by a 25,000-lb (11,340 kg) school-type bus under various impact con- ditions. 6. Compare the developed bridge railing design with the present AASHTO static-elastic bridge railing design requirements. 7. Recommended appropriate modifications to current bridge railing design practice based on this study. Research has been completed, and loan copies of the final reports on Phase I (Tasks 1-3) and Phase II (Tasks 4-7) may be obtained from the NCHRP upon written request.

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234 Project 22-2(3) Fy '78 Multiple Service Level Highway Bridge Rail- ings Selection Procedures Research Agency: Principal Invest.: Elective Date: Completion Date: Funds: Southwest Research Institute Maurice E. Bronstad January 1, 1979 May 31, 1981 $200,000 The concept of multiple service level bridge railings was developed in NCHRP Project 22-2~2~. The objective of Project 22-2~3) was to further refine these procedures to make them more usable and accurate with respect to the needs of the highway community. Certain improve- ments had already been indicated from comments re- ceived on the initial studies. Several aspects of the Multiple Service Level Approach (MSLA) were controversial and more comprehensive in- vestigations were needed. The following steps were carried out in this program: 1. Perform a sensitivity analysis and refine MSLA pro- cedures accordingly. 2. Develop bridge railing systems for a number of ser- vice levels. 3. Determine total costs of bridge railing systems for a number of service levels. 4. Based on cost, determine number of service levels needed. 5. Develop an upgrading strategy using MSLA. 6. Prepare a users' manual for practicing engineers. 7. Assess the legal implication of MSLA and make modifications as indicated. Research has been completed, and the final report pub- lished as: NCHRP Report 239, "Multiple-Service-Level Highway Bridge Railings Selection Procedures." The findings of a small side study on the breakaway cable terminal have been published as Research Results Digest 124. Project 22-2(4) FY ,79 Procedures for Testing Highway Appurte- nances Research Agency: Principal Invest.: Elective Date: Completion Date: Funds: Southwest Research Institute Jarvis D. Michie May 1, 1979 February 28, 1981 $30,000 In 1962, the first procedures for full-scale vehicle crash testing of guardrails were published in Highway Research Correlation Services Circular 482. The one-page document delineated vehicle mass, impact speed, and approach an- gle. Although Circular 482 did bring some some order to traffic barrier research being performed at several re search agencies, a number of questions arose that were not addressed. Under NCHRP Project 22-2, SwRI addressed these questions and developed NCHRP Report 153, "Recom- mended Procedures for Vehicle Crash Testing of Highway Appurtenances" (1974), which provided testing and re- search agencies with recommended procedures to vehicle crash test highway appurtenances. The procedure rep- resented technical input from more than 70 individuals and agencies and the results of extensive deliberation of a special ad hoc panel. It was recognized then that several parts of the procedures were based on inadequate expe- rience or research. It was decided, however, to retain coverage of these areas in order to provide a more com- plete testing procedure. These procedures have gained wide acceptance since their publication in 1974. It was recognized at that time that periodic updating would be needed, and, in January 1976,TRB Committee A2A04 accepted the responsibility of maintaining the efficacy of the procedures. Question- naires were submitted to committee members in late 1976 to ascertain areas of the document that needed revision. The responses generally fell into two categories: (1) minor changes that would require expanded discussions of cer- tain provisions and problem areas and the addition of more detailed guidelines; and (2) major changes that would require broadening the scope to include testing with trucks and buses, reevaluating the criteria for impact severity, and treating special highway appurtenances such as construction barriers. The committee agreed to address the minor changes through special committee action; this was done, and Transportation Research Circular No. 191 is the product of TRB Committee A2A04. For the major changes, the committee felt that the task was beyond its resource and requested TRB/NCHRP to investigate the possibility of having the work performed under a funded research contract. Project 22-2~4) was intended to address these major changes. Its objective was to review, revise, and expand the scope of Transportation Research Circular loo. 191 to reflect current technology. This study per- mitted research on points needing more in-depth analysis than could be provided by the TRB Committee. Research has been completed, and the final report has been published as: NCHRP Report 230, "Recommended Procedures for Safety Performance Evaluation of High- way Appurtenances." Project 22-3 FY,73 Field Evaluation of Vehicle Barrier Systems Research Agency: Principal Invest.: Effective Date: Completion Date: Funds: Calspan Corporation J. W. Garrett N. J. DeLeys January 1, 1974 February 15, 1975 $25,000

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235 The objective of this project was to determine the degree to which accident data currently being accumulate by various agencies meet the needs of those concerned with the effectiveness of vehicle barrier systems and, to the extent warranted, to recommend new approaches that may better serve those needs. Research has been completed, and the essential findings from the final report have been summarized in NCHRP Research Results Digest 76, "Field Evaluation of Vehicle Barrier Systems." Microfiche of the agency's final report may be purchased (see final page of this section for or- dering information). Project 22-3A FY '73 Field Evaluation of Vehicle Barrier Systems Research Agency: Principal Invest.: Elective Date: Completion Date: Funds: Arthur L. Elliott Arthur L. Elliott July 1, 1974 December 31, 1974 $10,000 The relative in-service performance of most guardrail systems is unknown. Although over-all performance of guardrail installations, in general, might be determined from state and national efforts in accident investigations, limitations in the data preclude the analysis of specific guardrail systems in terms of safety and cost. Accordingly, the relative merits of two or more systems must be eval- uated on the basis of idealized laboratory experiments (including full-scale crash tests) and gross accounting pro- cedures. The use of accident data to evaluate the field performance of barrier systems would be very desirable. The use of formal accident reports had been investigated under NCHRP Project 22-3. At the same time, Project 22-3A was concerned with an investigation of a less formal approach to barrier eval- uation. This approach consisted of personal interviews with highway agency maintenance, safety, and traffic op- erations personnel to obtain any data they may have had and to solicit their subjective opinions on the performance of various barriers. Five representative states were visited for this purpose. Research has been completed, and the essential findings from the final report have been summarized in NCHRP Research Results Digest 76, "Field Evaluation of Vehicle Barrier Systems." Microfiche of the agency's final report may be purchased (see final page of this section for or- dering information). Project 22-4 FY '83 Performance of Longitudinal Traffic Barriers Research Agency: Principal Invest.: Elective Date: Southwest Research Institute J. D. Michie, M. E. Bronstad July 1, 1983 Completion Date: July 15, 1987 Funds: $503,954 Existing crash test performance of longitudinal barrier systems was reviewed for compliance with NCHRP Re- port 230. Based on this review a matrix of five guardrail, two median barrier, and four bridge systems was evalu- ated with full-scale crash tests for occupant risk with 1,800-lb sedans. The results were evaluated using the recommended values of NCHRP Report 230 to which all systems were essentially in compliance. In addition, evaluation of five guardrail and one median barrier systems was performed with an 1,800-lb sedan impacting at 60 mph and a 20-de" angle (test S13 of NCHRP Report 230~. The purpose of these tests was to provide further insight into the performance of the barrier systems. Six insight tests using vans to determine barrier performance thresholds for this type of vehicle were per- formed. Seven transition tests were performed as follows: three guardrail/bridge rail transitions, two guardrail/ guardrail transitions; and two median barrier/median barrier transitions. Finally, two additional insight tests were performed. The first was a van impacting a G1 cable guardrail system mounted at a 24-in. height. The second test evaluated a blocked-out W-beam system with round wood posts. The final report, published as NCHRP Report 289, includes the crash test results, design drawings for the systems tested in this research as well as for systems tested in other studies, and recommended changes to the test criteria. Project 22-5 FY '84 Develop Performance Stanclards and Hardware for Low Service Level Guardrail Systems Research Agency: Principal Invest.: Elective Date: Completion Date: Funds: Southwest Research Institute L. R. Calcote and K. Hancock May 1, 1985 January 31, 1989 $200,000 Currently operational guardrail systems have been de- veloped for 60-mph, 25-degree impacts with 4,500-lb ve- hicles. The use of design criteria based on this severe test condition has resulted in relatively expensive installations (e.g., high-cost terminal anchorage systems). For low ser- vice level roads, there is a need to determine the conditions under which less stringent guardrail requirements are warranted in order to reduce costs while providing safety performance based on demonstrated need. The objectives of this project are: (1) to examine the need for guardrails on low service level roads and develop performance standards for guardrails, transitions, and ter- minals and (2) to design, test, and develop low-cost guard- rail systems based on these performance standards.

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236 This project consists of two phases: Phase I Task 1 Review, evaluate, and document available data in order to establish performance standards for low service level guardrail systems including transitions and terminals. Establish and, if necessary, develop general warranting criteria for use of such systems. Task 2 Using the performance standards from Task 1, develop conceptual and preliminary designs with working drawings of the guardrails, terminals, and tran- sitions using structural analysis, computer simulation, or other techniques. Existing hardware and systems in wide- spread use with demonstrated effective field performance will be fully considered. Make estimates of initial and maintenance (life cycle) costs for these guardrail systems. Task 3 Prepare a letter report on the findings of Tasks 1 and 2 for review by the NCHRP. This report will also contain a detailed work plan for Phase II in- cluding recommendations for further development of the guardrail systems. Phase II Task 4 Test and develop the guardrail systems se- lected by NCHRP using the approved performance stan- dards. Task 5- Prepare a final report including the follow ~ng: a. Low service guardrail performance standards. b. Documentation of the design and development of low service level guardrail systems. c. Recommended low service level guardrail drawings and specifications. d. Estimated life cycle costs of the guardrail systems. e. General warrants for use of low service level guard- rail. Research has been completed, and the draft final report Is being reviewed. Project 22-6 FY '85 Roadside Safety Design for Small Vehicles Research Agency: Principal Invest.: Elective Date: Completion Date: Funds: Texas A & M Research Foundation Dr. Hayes E. Ross, Jr. June 1, 1985 June 30, 1988 $350,000 Most current roadside safety appurtenances were de- signed and tested with passenger vehicles ranging from 4,500 down to 2,250 lb. Research is currently in progress to investigate the performance of hardware and roadside features with vehicles in the 1,800-lb range. Under some conditions, barrier impacts become increasingly hazard ous for smaller vehicles; however, little is known about the performance of current hardware and roadside safety features with vehicles smaller than 1,800 lb. The objectives of this project are (1) to assess the per- formance of selected existing highway safety appurte- nances and roadside features with passenger vehicles below 1,800 lb and (2) to project the limits of vehicle characteristics that can be safely accommodated through improvements in current hardware and roadside features. This research includes the following tasks: Phase I: Task 1 Review, evaluate, and document foreign and domestic information on the performance of safety appurtenances and roadside features with passenger ve- hicles weighing 1,800 lb and less. Task 2 Identify all types of 4-wheel sedans below 1,800 lb that may constitute a significant portion of the vehicle fleet in the United States within the next 10 years. For the vehicle types identified, acquire, measure, or, where necessary, estimate the dynamic properties and other characteristics required for the computerized sim- ulation of their reactions with safety hardware and road- side features. Task 3 Select specific appurtenances for study in this project. The following items will be included: a rigid longitudinal barrier; a flexible longitudinal barrier; a breakaway support; a base-bending support; an impact attenuator; and a guardrail terminal. Task 4 Select specific roadside features for study to identify performance limits when traversed by small cars. As a minimum, these features will include slopes, ditches, and curbs. Task 5 Using available data from crash tests with the lightest vehicles tested, calibrate selected existing com- puter programs for simulation of impact performance, and use the calibrated programs to simulate occupant- risk tests for the selected hardware and roadside features with a 1,500-lb sedan. Task 6 Prepare an interim report on the findings of Tasks 1 through 5. This report will contain a detailed working plan for the remainder of the study. Phase II Task 7 Conduct full-scale crash tests using vehicles in the 1,200 to 1,500-lb range to recalibrate the model and to demonstrate the validity of the computerized sim- ulation to be carried out concurrently in Task 8. Task 8 Using existing simulation models for a va- riety of appurtenances and roadside features (including potential improvements), vehicle types (including projec- tions down to the lowest conceivable weight range), and crash test conditions, delineate the limiting values of par- ticular vehicle characteristics for which feasible designs

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237 are capable of providing satisfactory performance ac- cording to the guidelines in NCHRP Report 230. When these evaluation criteria are not satisfied, determine the changes in impact conditions that would be required to achieve compliance. Task 9 Identify design modifications to hardware and roadside features to improve performance for vehicles at the low end of the weight spectrum. Such modifications will be supported by computerized simulation. Task 10. Prepare a final report. Research has been completed and the final report is being revised, in preparation of its publication in early 1989. Project 22-7 FY '89 Update of "Recommended Procedures for Safety Performance Evaluation of High- way Appurtenances" Research Agency: In developmental stage Principal Invest.: Elective Date: Completion Date: Funds: (30 months) $200,000 The objective of this study is to update the recom- mended procedures for the safety performance evaluation of both temporary and permanent highway appurtenances in such a manner as to reflect advances in technology and to accommodate current and anticipated roadway and vehicle characteristics. This project will consist of two phases to be performed consecutively, with a review required at the completion of Phase I on which authorization to proceed with Phase II will be based. Phase I Task 1. Develop a comprehensive list of topics to be examined in updating the recommended procedures. This list shall be based on a critical review of past and on-going research, and input from knowledgeable indi- viduals involved with and interested in the subject area. Task 2. Evaluate the relative importance of each of the topics cited in Task 1 and identify important issues within each topic. Task 3. Prepare an interim report documenting the efforts completed in Tasks 1 and 2. The interim report shall also include an annotated outline of the final report and a detailed work plan describing the activities required in Phase II. Submit the interim report to the NCHRP Project Panel for review and approval. A meeting between the research team and the NCHRP Project Panel will be planned at the completion of Task 3 to discuss the results of Phase I and the work planned for Phase II. The in vestigators shall prepare a revised interim report to reflect the outcome of the meeting and distribute it to the project panel members. Phase II Task 4. Using the information generated in Phase I, prepare a first draft of the final report and document, under separate cover, how each of the issues identified was resolved. The investigators shall also prepare a pro- posed list of reviewers from the highway community-at- large for approval by the panel. A second meeting between the research team and the project panel will be planned at the completion of Task 4 to discuss the first draft of the final report, the list of issues identified and how they were resolved, and the proposed list of reviewers. The investigators shall prepare a second draft of the final report to reflect the outcome of the second meeting and distribute the revised document to the project panel mem- bers and to the reviewers approved by the project panel in this task. Task 5. Evaluate the reviewers' comments and prepare a brief discussion of the comments and their disposition. Based on the results of this effort, prepare a third draft of the final report. A third meeting between the research- ers and the NCHRP Project Panel will be scheduled at the completion of Task 5 to discuss the comments received from the community-at-large, the disposition of those comments, and the third draft of the final report. Task 6. A final report shall be prepared based on the outcome of the third meeting between the researchers and the NCHRP Project Panel. Project 22-8 FY '89 Evaluation of Performance Level Selection Criteria for Bridge Railings Research Agency: In developmental stage Principal Invest.: Elective Date: (21 months) Completion Date: Funds: $200,000 The objectives of this research are (1) to determine the adequacy and validity of the performance levels and the performance-level selection procedures contained in the "Guide Specifications," (2) to estimate the impact of im- plementing the "Guide Specifications" on state and local agencies, (3) to recommend appropriate improvements to the "Guide Specifications," and (4) to evaluate the fea- sibility of extending the multiple performance-level ap- proach to all longitudinal barrier systems. This research shall include four phases. Phase I cor- responds to the first objective; Phase II, to the second and third objectives; and Phase III, to the fourth objective. Phase IV encompasses the preparation of the final report.