- Roadside safety researcher.edit
The report contains the results of a side impact crash test involving a 1982 Dodge Colt and a slipbase luminaire support. The test was performed at the Federal Outdoor Impact Laboratory (FOIL) located in McLean, Virginia. The automobile... more
The report contains the results of a side impact crash test involving a 1982 Dodge Colt and a slipbase luminaire support. The test was performed at the Federal Outdoor Impact Laboratory (FOIL) located in McLean, Virginia. The automobile impacted the pole at 20.8 mph (33.5 km/h) on the driver's side door. The impact location was aligned with the side impact dummy's shoulder with the seat in the midtrack position. This test is a repeat of Test 4 except that the bolt clamping force was reduced from 14 to 6 kips. Unlike the Test 4 case, lockup did not occur. Damage to the side structure of the vehicle was less severe. The maximum crush was 10 in. (254 mm) in this test, compared with 18.8 in. (477.5 mm) of crush in the lockup test (Test 4). The comparable Enquist-Svensen-Vanke (ESV) pole test (Test 2) resulted in a vehicular crush of 9.0 in. (229 cm). The Head Injury Criteria (HIC) and the Thoracic Trauma Index (TTI) values were not obtainable in this test due to failure of the d...
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This report contains the results of a frontal impact crash test involving a Volkswagen (VW) Rabbit and an energy dissipating Enquist-Svensen-Vanke (ESV) luminaire support. The test was performed at the Federal Outdoor Impact Laboratory... more
This report contains the results of a frontal impact crash test involving a Volkswagen (VW) Rabbit and an energy dissipating Enquist-Svensen-Vanke (ESV) luminaire support. The test was performed at the Federal Outdoor Impact Laboratory (FOIL) located in McLean, Virginia. The automobile impacted the ESV pole at 20 mph (32 km/h) on the front bumper. The impact location was aligned at the middle of the front bumper. The test data indicate that the hypothetical driver of this vehicle would be subjected to acceptably low values of impact velocity with the vehicle interior and ridedown accelerations. This test suggests the ESV pole meets both the AASHTO and NCHRP criteria for 20 mph (32.2 km/h) impacts with luminaire supports.
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A great deal has occurred in the highway safety field in the last 15 years: there have been societal changes which have altered the character of the vehicle fleet; there have been technological changes which have resulted in new safety... more
A great deal has occurred in the highway safety field in the last 15 years: there have been societal changes which have altered the character of the vehicle fleet; there have been technological changes which have resulted in new safety hardware, new types of vehicle structures, and better accident data; and lastly, there have been philosophical changes which have resulted in new concepts for designing and warranting roadside safety hardware. The following paper examines these issues and suggests areas which should be addressed by researchers, practitioners and policy makers as the next century approaches.
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The report contains the results of a side impact crash test involving a 1984 Honda Civic and an energy dissipating Enquist-Svensen-Vanke (ESV) luminaire support. The test was performed at the Federal Outdoor Impact Laboratory (FOIL)... more
The report contains the results of a side impact crash test involving a 1984 Honda Civic and an energy dissipating Enquist-Svensen-Vanke (ESV) luminaire support. The test was performed at the Federal Outdoor Impact Laboratory (FOIL) located in McLean, Virginia. The automobile impacted the ESV pole at 29.9 mph (48.1 km/h) on the driver's side door. The impact location was aligned with the side impact dummy's shoulder with the seat in the midtrack position. The purpose of this test was to investigate the effect of this door structure on the impact response of the dummy, vehicle, and pole for a 30 mph (48.3 km/h) impact. Unfortunately, the ESV pole in this test was defective, and fracture occurred at its base. Because of the fracture failure, it is inappropraite to directly compare the results of this test to those of Tests 1 and 2. It is of interest to note, however, that the head of the dummy was only subjected to a glancing blow from the pole and both the Head Injury Criteri...
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The report contains the results of a side impact crash test involving a 1984 Plymouth Champ and a slipbase luminaire support. The test was performed at the Federal Outdoor Impact Laboratory (FOIL) located in McLean, Virginia. The... more
The report contains the results of a side impact crash test involving a 1984 Plymouth Champ and a slipbase luminaire support. The test was performed at the Federal Outdoor Impact Laboratory (FOIL) located in McLean, Virginia. The automobile impacted the pole at 18.9 mph (30.4 km/h) on the driver's side door. The impact location was aligned with the side impact dummy's shoulder with the seat in the midtrack position. Earlier FOIL side impact tests were conducted at a nominal impact speed of 30 mph (48.3 km/h). In Test 4, the same slipbase used in these tests was retested with the same 14 kip (62.3 kN) bolt clamping load but at a lower impact speed. This combination of high clamping force and low impact speed resulted in system lockup. The slipbase mechanism did not release and the resulting damage to the side structure of the automobile was quite extensive. The Thoracic Trauma Index (TTI) for this test was an acceptable 82 g's, but the calculated Head Injury Criteria (HIC...
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Reducing the severity of side impact collisions has been an emerging area of research during the past decade by a variety of organizations and research communities. The motor vehicle manufacturing and regulatory communities in both the... more
Reducing the severity of side impact collisions has been an emerging area of research during the past decade by a variety of organizations and research communities. The motor vehicle manufacturing and regulatory communities in both the United States, Europe and many other countries have developed dynamic side impact test and evaluation criteria to reduce the severity of vehicle-to-vehicle side impact collisions. Similarly, the international research community has developed test procedures for performing impacts into poles, one of the most severe types of side impact collisions. This paper presents preliminary side impact test and evaluation procedures for roadside safety hardware like guardrails, guardrail terminals, luminaire supports, utility poles and signs. The purpose of this paper is to summarize recommendations for performing roadside hardware side impact crash tests, describe the results of several side impact roadside hardware crash tests, compare the proposed test and eval...
Efforts to improve roadside safety have had a dramatic effect on the number of fatalities resulting from automobile accidents during the past 30 years. The 1966 annual traffic fatality rate of 5.5 fatalities per 100 million vehicle miles... more
Efforts to improve roadside safety have had a dramatic effect on the number of fatalities resulting from automobile accidents during the past 30 years. The 1966 annual traffic fatality rate of 5.5 fatalities per 100 million vehicle miles traveled dropped to 1.7 fatalities per 100 million vehicle miles traveled in 1993. This was achieved through a dedicated effort by every segment of the highway transportation industry, including the roadside design community. The Federal Highway Administration, American Association of State Highway and Transportation Officials, Transportation Research Board, the states, and others have undertaken a variety of research activities to improve roadside safety. These activities include analyzing accident trends, formulating improved analysis procedures, developing new hardware, and promoting a sounder base of accident information. To further improve roadside safety all these efforts should be continued, but attention should also be devoted to a number of...
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This synthesis will be of interest to state department of transportation (DOT) roadway design, traffic, structural, maintenance, and research engineers and others concerned with highway safety issues. This synthesis describes the current... more
This synthesis will be of interest to state department of transportation (DOT) roadway design, traffic, structural, maintenance, and research engineers and others concerned with highway safety issues. This synthesis describes the current state of the practice for the use of guardrails and median barriers and their crashworthiness. It includes information about the crashworthiness and typical applications of the most common, permanently installed, nonproprietary guardrail and median barrier systems used in the United States today. A significant amount of detail is included in the text to aid the design, selection, and locating processes for safe and effective guardrails and median barriers. The report presents data obtained from a review of the literature and a survey of state DOTs. The synthesis presents a description of the typical longitudinal barriers in use today, including drawings, the extent of their use, and the most recent testing on each guardrail and barrier system, with particular emphasis on NCHRP Report 230 and 350 requirements. In addition, it discusses the maintenance issues, cost constraints, and common problems with each type of barrier. The synthesis only discusses the crashworthiness of guardrails and median barriers; their transitions and terminals are not discussed.
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Side impact accidents account for approximately 8,000 fatalities in passenger cars each year in the United States. This represents more than one third of the approximately 25,000 passenger car fatalities that occur each year. Side impact... more
Side impact accidents account for approximately 8,000 fatalities in passenger cars each year in the United States. This represents more than one third of the approximately 25,000 passenger car fatalities that occur each year. Side impact is, therefore, a significant problem in transportation safety. This presentation will examine some of the characteristics of side impact accidents derived from the Nattional Accident Sampling System and Fatal Accident Reporting System data.
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This Circular contains the proceedings of a workshop sponsored by the Transportation Research Board (TRB) Committee A1A04 on Roadside Safety Features and the Federal Highway Administration. The workshop was held January 13-14, 1991, in... more
This Circular contains the proceedings of a workshop sponsored by the Transportation Research Board (TRB) Committee A1A04 on Roadside Safety Features and the Federal Highway Administration. The workshop was held January 13-14, 1991, in Washington, D.C., U.S.A. Breakout Group 4 included representatives from Spain, the United States, the Netherlands, England, Canada, and Australia. The following discussion topics were addressed by all of the Breakout Groups: (1) Critical differences in test and evaluation philosophies; (2) Specific national conditions that may affect test and evaluation philosophies and procedures; (3) Impediments to a common measurement framework or methods to translate the results for comparison; and (4) Steps needed to increase harmonization.
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This research was conducted to identify and investigate aspects of NCHRP Report 230 which require additional technical research. This report deals with five broad areas of concern: (1) the importance and effect of soil conditions on the... more
This research was conducted to identify and investigate aspects of NCHRP Report 230 which require additional technical research. This report deals with five broad areas of concern: (1) the importance and effect of soil conditions on the dynamic performance of barriers, (2) methods for re-evaluating pre-Report 230 test results in light of the current Report 230 criteria, (3) linking the occupant risk factor to "real-world" accident cases, (4) assessing the potential hazards of the redirected vehicle, and (5) replacement of the 4500-lb test car.
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This report contains a summary of 12 side impact crash tests performed at the Federal Outdoor Impact Laboratory (FOIL) to evaluate the performance of several types of roadside structures. The tests are described and results presented. The... more
This report contains a summary of 12 side impact crash tests performed at the Federal Outdoor Impact Laboratory (FOIL) to evaluate the performance of several types of roadside structures. The tests are described and results presented. The results of these tests are then combined with earlier test series and statistical models that predict dummy responses from test results are developed. These preliminary models could be used to evaluate the risk to occupants based on the response of hypothetical anthropometric dummies.
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This research was conducted to identify and investigate aspects of NCHRP Report 230 which require additional technical research. This report deals with five broad areas of concern: (1) the importance and effect of soil conditions on the... more
This research was conducted to identify and investigate aspects of NCHRP Report 230 which require additional technical research. This report deals with five broad areas of concern: (1) the importance and effect of soil conditions on the dynamic performance of barriers, (2) methods for re-evaluating pre-Report 230 test results in light of the current Report 230 criteria, (3) linking the occupant risk factor to "real-world" accident cases, (4) assessing the potential hazards of the redirected vehicle, and (5) replacement of the 4500-lb test car.
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This paper summarizes the findings of the 1995 Transportation Research Board (TRB) Committee A2A04 Workshop, which brought together transportation professionals to discuss the current status of roadside safety research and explore new... more
This paper summarizes the findings of the 1995 Transportation Research Board (TRB) Committee A2A04 Workshop, which brought together transportation professionals to discuss the current status of roadside safety research and explore new approaches and methods that could produce safety benefits in the coming decade. Following introductory comments on the need for and purpose of the meeting, each of the five discussion and work groups (which were formed following invited presentations) is summarized. The work groups were as follows: (A) Development of a Strategic Plan for Roadside Safety; (B) Severity Indices Development; (C) Vehicle Fleet Characteristics, ITS Research Needs, Driver Behavior, Accident Data Collection and Analysis Research Needs; (D) Crash Testing and Simulation Research Needs; and (E) In-Service Evaluation and Barrier Performance Research Needs. The fifteen research needs statements identified by the discussion groups and their rankings by attendees are presented in a t...
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This paper present · detail of proposed improvemcnl~ to the way that fullcale crash test data are analyzed. In particular, the basic form_ulation of the Dail space method presented in NCHRP Report 230 is shown to contain several... more
This paper present · detail of proposed improvemcnl~ to the way that fullcale crash test data are analyzed. In particular, the basic form_ulation of the Dail space method presented in NCHRP Report 230 is shown to contain several simplifications that have never before been examined in detail. The NCHRP Report 230 formul~tion a.nd its .history are briefly reviewed, followed by an extensive discussion of improvements that would make the Dail space method more physically correct and more general. The potential ourcc. and magni.tude of error in the current model are explored, and new techmques a1·e de ·cribcd . Examples μsing actual crash te t data are provided to illustrate typical magnitudes of error associated with each simplilication. A computer program is briefly described that implements these improvements.
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The history of public domain finite element models of the side impact anthropometric test dummy are summarized and recent improvements are briefly discussed. The performance of the two most recent finite element models are discussed with... more
The history of public domain finite element models of the side impact anthropometric test dummy are summarized and recent improvements are briefly discussed. The performance of the two most recent finite element models are discussed with respect to the predictions of acceleration time histories as compared to standard bench calibration tests as well as an in-vehicle full-scale vehicle crash test. The thoracic trauma indices and the maximum pelvis accelerations are calculated based on the finite element models and are compared to the results obtained in physical calibration tests. The responses and fidelity of the finite element models are discussed and recommendations for further improvements are provided. NOTATION LURY maximum lateral acceleration observed at the left upper rib LLRY maximum lateral acceleration observed at the left lower rib TTI thoracic trauma index T12 maximum lateral acceleration observed at the 12 th spine segment Py maximum lateral pelvis acceleration
This synthesis will be of interest to state department of transportation (DOT) roadway design, traffic, structural, maintenance, and research engineers and others concerned with highway safety issues. This synthesis describes the current... more
This synthesis will be of interest to state department of transportation (DOT) roadway design, traffic, structural, maintenance, and research engineers and others concerned with highway safety issues. This synthesis describes the current state of the practice for the use of guardrails and median barriers and their crashworthiness. It includes information about the crashworthiness and typical applications of the most common, permanently installed, nonproprietary guardrail and median barrier systems used in the United States today. A significant amount of detail is included in the text to aid the design, selection, and locating processes for safe and effective guardrails and median barriers. The report presents data obtained from a review of the literature and a survey of state DOTs. The synthesis presents a description of the typical longitudinal barriers in use today, including drawings, the extent of their use, and the most recent testing on each guardrail and barrier system, with ...
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The metrication of roadside hardware is detailed in the revised edition of the "Guide to Standardized Highway Barrier Rail Hardware." This article highlights the most important recommendations regarding specifications,... more
The metrication of roadside hardware is detailed in the revised edition of the "Guide to Standardized Highway Barrier Rail Hardware." This article highlights the most important recommendations regarding specifications, guardrails, bridge railings, and concrete median barriers. The most useful feature of the new guide is the exclusive use of the International System of Units (SI)--a modernized metric system, which will be an invaluable resource to states in the process of converting their roadside hardware standards to SI prior to the September 30, 1996, deadline.
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The report contains recommendations for performing and evaluating side impact crash tests of roadside structures like luminaire supports, guardrail terminals, and utility poles. A 50 km/h full broadside test using a small car is... more
The report contains recommendations for performing and evaluating side impact crash tests of roadside structures like luminaire supports, guardrail terminals, and utility poles. A 50 km/h full broadside test using a small car is recommended. Evaluation criteria include recommendations for structural adequacy, occupant risk, and post collision trajectory. The occupant risk criteria use indices obtained using anthropometric dummy test devices.
Research Interests: Crash and Crash Test
The objective of this task is to review, analyze, and report on two computer simulations of a small vehicle impacting frontally into a small, base bending sign support. The theory behind the two simulations is presented in the report... more
The objective of this task is to review, analyze, and report on two computer simulations of a small vehicle impacting frontally into a small, base bending sign support. The theory behind the two simulations is presented in the report titled "Automobile Impacts with Small Signs". The review performed and documented here is a combined effort by Advanced Technology and Research Corporation, Vanderbilt University, and Texas Transportation Institute. Three independent reviews are presented followed by a summary of the overall opinions and combined recommendations. The three independent reviews all agree that additional work is necessary to develop a reliable computer model to be used for designing an advanced bogie test vehicle.
This research was conducted to identify and investigate aspects of NCHRP Report 230 which require additional technical research. This report deals with five broad areas of concern: (1) the importance and effect of soil conditions on the... more
This research was conducted to identify and investigate aspects of NCHRP Report 230 which require additional technical research. This report deals with five broad areas of concern: (1) the importance and effect of soil conditions on the dynamic performance of barriers, (2) methods for re-evaluating pre-Report 230 test results in light of the current Report 230 criteria, (3) linking the occupant risk factor to "real-world" accident cases, (4) assessing the potential hazards of the redirected vehicle, and (5) replacement of the 4500-lb test car.
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In recent years nonlinear finite element analysis has been used as a tool for exploring the effectiveness and performance of roadside safety hardware. A finite element assessment of barrier performance involves detailed models of both the... more
In recent years nonlinear finite element analysis has been used as a tool for exploring the effectiveness and performance of roadside safety hardware. A finite element assessment of barrier performance involves detailed models of both the roadside safety hardware and the impacting vehicle. The ability of the combined model to accurately explain or predict the behavior of the barrier in a physical event is a function of the fidelity of both the vehicle and barrier model. Most recent analyses of roadside hardware collisions have used general purpose public-domain vehicle models as a way to develop models quickly without necessarily verifying the fidelity of the vehicle models. This paper assesses the fidelity of several of the most common publicdomain vehicle models with respect to their ability to correctly replicate accelerations at the center of gravity in centerline frontal impacts into rigid poles. A variety of quantitative assessment parameters are used to make these comparisons...
In-service performance evaluation of traffic barriers is the process of observing the results of collisions with such devices in real-world collisions. Unlike accident data analyses where performance is deduced only from police reports,... more
In-service performance evaluation of traffic barriers is the process of observing the results of collisions with such devices in real-world collisions. Unlike accident data analyses where performance is deduced only from police reports, in-service evaluations involve police reported data, maintenance information and most importantly a visit to the site relatively soon after the impact has occurred. An in-service evaluation can provide a great deal of detailed information about specific barrier damage and impact performance that is not available in typical accident data analyses. A project is currently underway in the U.S. to examine the performance of several common guardrails and guardrail terminals in several data collection areas located in the States of Iowa, North Carolina and Connecticut. Data was collected during a two-year period on strong post W-beam guardrails, weak-post W-beam guardrails, cable guardrails, the breakaway cable terminal and the modified breakaway cable term...
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The workshop featured invited presentations by prominent researchers that established a common background on the major issues, recent and on-going research efforts, and expected opportunities for the future in the area of roadside safety... more
The workshop featured invited presentations by prominent researchers that established a common background on the major issues, recent and on-going research efforts, and expected opportunities for the future in the area of roadside safety issues. After the presentations, the workshop participants were divided into four breakout groups to pursue additional discussions of research needs and opportunities for improving roadside safety. The four groups addressed: data and analysis needs; selection and design of roadside safety treatments; efficacy of simulation methods; and assessing and developing roadside hardware. Several common themes emerged from the four discussion groups. First, roadside safety involves much more than developing new roadside safety hardware. It involves the whole range of possible harmful events that could take place on the roadside. Second, the importance of properly selecting and locating roadside safety hardware was discussed by several breakout groups. The thi...
This report summarizes the crash test results as well as the construction, maintenance, and accident experience observed for three types of guardrails: the modified South Dakota 3-cable guardrail, the modified Minnesota 3-cable guardrail... more
This report summarizes the crash test results as well as the construction, maintenance, and accident experience observed for three types of guardrails: the modified South Dakota 3-cable guardrail, the modified Minnesota 3-cable guardrail and the modified thrie beam guardrail. The modified South Dakota 3-cable guardrail is similar to the standard G1 cable guardrail except that a lighter, less expensive 4-lbs per foot flange-channel post is used instead of the standard S3x5.7 post. The modified Minnesota 3-cable guardrail uses a closer post spacing and wooden posts with a weakening hole. This hole helps minimize the chance of causing a small car to roll over. The modified thrie beam guardrail is a variation of the standard G9 thrie beam guardrail. It uses a unique guardrail blockout that helps improve the barrier performance in large vehicle collisions. The development of these systems is summarized and the basic design principals are explained. Where available, construction, cost, an...
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The current crash testing and evaluation procedures which must be followed to evaluate the effectiveness of new safety hardware have been in place since 1981. This paper critically analyzes these procedures, improves on the flail space... more
The current crash testing and evaluation procedures which must be followed to evaluate the effectiveness of new safety hardware have been in place since 1981. This paper critically analyzes these procedures, improves on the flail space model for determining occupant risk data, and recommends specific changes in existing procedures with respect to test vehicles, measures of impact severity, unaddressed roadside hardware, crash-testing conditions, energy dissipation/trapping/redirection critera, and alternatives to full-scale crash testing
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Importance de la structure et de la geometrie d'un vehicule dans l'efficacite des elements de protection situes sur les bas-cotes d'une route
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Characterizing Roadside Hardware Materials for LS-DYNA 3 D Simulations. AE Wright, MH Ray 1997. Finite element models have three parts: geometry, connections and material properties. Being the visible parts of a model ...
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The Finite Element Method (FEM) is now regularly used by engineers to analyse the crashworthiness performance of roadside safety barriers. In particular, the improvements in nonlinear Finite Element (FE) codes and the available access to... more
The Finite Element Method (FEM) is now regularly used by engineers to analyse the crashworthiness performance of roadside safety barriers. In particular, the improvements in nonlinear Finite Element (FE) codes and the available access to supercomputing facilities have now allowed engineers to simulate in detail crash tests between vehicles and roadside safety barriers. Computer FEM simulations allow investigating the performance of new designs or retrofitted modifications to existing systems. However, it is essential that the numerical model is accurately verified and validated to provide reliable results. In particular, quantitative methods should be used to pursue an objective assessment of the level of Verification and Validation (VVs reliability.
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The development of the Roadside Safety Verification and Validation Program (RSVVP) is described. The program is used to assess the similarities and differences between two curves and was developed to assist engineers and analysts in... more
The development of the Roadside Safety Verification and Validation Program (RSVVP) is described. The program is used to assess the similarities and differences between two curves and was developed to assist engineers and analysts in performing verification and validation activities. The program pre-processes the data by filtering, removing signal bias, re-sampling to the same data collection frequency and synchronizing the singles. Once the signals are pre-processed, the values of 15 different shape-comparison metrics are calculated and presented to the user. A simple example using an analytical shape is presented to illustrate the characteristics of the metrics. Finally, the Sprague-Geers MPC and ANOVA metrics are proposed for use in roadside safety computational mechanics. Malcolm H. Ray, Marco Anghileri and Mario Mongiardini 3 Development of the Roadside Safety Verification and Validation Program Malcolm H. Ray, P.E., Ph.D., Mario Mongiardini and Marco Anghileri, Ph.D INTRODUCTIO...
Qualitatively comparing the shapes of time histories to validate experiments with computational simulations is a common technique in both general computational mechanics as well as computational roadside safety. Qualitative comparisons,... more
Qualitatively comparing the shapes of time histories to validate experiments with computational simulations is a common technique in both general computational mechanics as well as computational roadside safety. Qualitative comparisons, however, are subjective and open to interpretation. A variety of quantitative metrics are available for comparing time history data as well but developing acceptance criteria for these methods often relies on equally imprecise engineering judgment. This paper presents the results of time-history comparisons of 10 essentially identical full-scale vehicle re-directional crash tests with a vertical concrete wall. Five of the crash tests used exactly the same type of vehicle whereas the other five used a similar vehicle that was within the EN1317 test vehicle specifications for that class of vehicle. A variety of quantitative shape comparison metrics were calculated for each set of repeated crash test cases and the results are presented. The results are ...
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Encroachment probability models such as the Roadside Safety Analysis Program (RSAP) have traditionally assumed that heavy vehicles and passenger vehicles share the same encroachment characteristics. This assumption was reviewed in... more
Encroachment probability models such as the Roadside Safety Analysis Program (RSAP) have traditionally assumed that heavy vehicles and passenger vehicles share the same encroachment characteristics. This assumption was reviewed in developing bridge railing selection guidelines in NCHRP 22-12(03), where an examination of a specific highway and a national sample of data indicated that trucks encroached at a different rate than passenger vehicles. This paper describes the development of a new vehicle-type encroachment adjustment factor (EAF). The results confirmed previous findings, but this analysis controlled for traffic volumes, highway type, percentage of heavy vehicles [i.e., percentage of trucks (PT)], and segment length. The result was a more robust model that was valid over a wider range of average annual daily traffic and PTs. The large data set included 635,464 segments of data from the states of Ohio and Washington. The proposed EAF was recommended for inclusion in RSAPv3. I...
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Roadside safety engineers lack a quantitative method to balance the philosophies presented in AASHTO's Roadside Design Guide (RDG) with situations encountered on existing roads, especially where it is not possible to follow the... more
Roadside safety engineers lack a quantitative method to balance the philosophies presented in AASHTO's Roadside Design Guide (RDG) with situations encountered on existing roads, especially where it is not possible to follow the guidelines in the RDG. In general, the goal of roadside design is to minimize, insofar as is practical, the chances of severe or fatal injury crashes on the roadway. Engineers are often left to use good engineering judgment to make these choices. This paper presents a risk assessment methodology and demonstrates through example problems how this methodology may be used as a more quantitative approach for measuring the inherent risk of roadside design alternatives so that engineers can identify where the greatest safety benefit can be realized. Benefit–cost methods have been used in roadside safety for more than 35 years to balance improvements in safety with implementation costs. Although the methods have been widely used, the approach has presented sever...
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The probability of a vehicle encroaching onto the roadside is influenced by several geometric characteristics of the roadway. The horizontal curvature and vertical grade encroachment adjustment factors (EAFs) used in the third version of... more
The probability of a vehicle encroaching onto the roadside is influenced by several geometric characteristics of the roadway. The horizontal curvature and vertical grade encroachment adjustment factors (EAFs) used in the third version of the Roadside Safety Analysis Program (RSAPv3) were adopted from adjustment factors introduced in 2003 in NCHRP Report 492 during the original development of RSAP. These adjustments were developed by interpreting earlier work on curves and grades. Given the weaknesses and limitations of the earlier study, it was suggested that a larger-scale study with larger sample size and more representative crash severities would be appropriate. This paper describes the development of new horizontal curve and vertical grade EAFs for rural areas. EAFs were developed from a cross-sectional model of crash data that controlled for geometric influences, traffic volumes, segment length, and highway type. The proposed EAFs are not identical to the current factors, which...
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Full-scale crash tests are traditionally used to assess the danger posed by roadside object. Crash test evaluation criteria should relate the observable response of the vehicle and the struck object to the likely risk of injury to vehicle... more
Full-scale crash tests are traditionally used to assess the danger posed by roadside object. Crash test evaluation criteria should relate the observable response of the vehicle and the struck object to the likely risk of injury to vehicle occupants in similar real-world collisions. Side impact collisions are particularly serious impacts, but no evaluation guidelines exist. A simple method is presented for determining human risk in a side impact collision with a roadside object from the velocity profile of the impacted face of the struck object. This method not only eliminates the use of anthropometric test devices in crash tests, but also gives conservative values to account for the variable occupant position at the time of impact.