The objective of this project is to develop guidance for the collection, extraction, and documentation of In-Service Performance Evaluation (ISPE) data to compliment the analysis procedures developed under NCHRP 22-33. The results of this research were published as NCHRP web only document 407 in 2024, which is available here: Data Collection Practices for Use with In-Service Performance Evaluations
The objective of this project was to use finite element analysis (FEA) computer simulation to evaluate MassDOT's BR-MTL2 bridge rail under AASHTO Manual for Assessing Safety Hardware (MASH) for Test Level 2 (TL-2) impact conditions and performance criteria.
The objective of this project was to use finite element analysis (FEA) computer simulation to evaluate MassDOT's CP-MTL3 bridge rail under AASHTO Manual for Assessing Safety Hardware (MASH) for Test Level 3 (TL-3) impact conditions and performance criteria.
The objective of this project was to use finite element analysis (FEA) computer simulation to evaluate MassDOT's existing CT-MTL2 aesthetic concrete bridge rail under AASHTO Manual for Assessing Safety Hardware (MASH) for Test Level 2 (TL-2) impact conditions and performance criteria. Two design cases were evaluated: 1) a curb mounted and 2) a sidewalk mounted system.
The objectives of this project were to 1) perform a comprehensive review of AASHTO M 180-18 and its associated AASHTO and ASTM standards and 2) propose needed revisions to bring the specifications into conformance with current requirements and the state of practice for highway guardrail systems. AASHTO M 180 is the AASHTO "Standard Specification for Corrugated Sheet Steel Beams for Highway Guardrail". AASHTO M 180 defines the strength and geometrical properties of generic (i.e. non-proprietary) w- and thrie-beam guardrail as well as transitions and some associated connectors and parts. AASHTO M 180 has been the industry standard for those components since 1961. The results of this research were published as NCHRP Research Report 1020 in 2022, which is available here: Investigation of Material Requirements for Highway Guardrail Systems
This project developed a unified and nationally compatible ISPE methodology. The approach builds on recent research and capitalizes on the variety of individual state databases available. Six pilot Transportation Agencies tested the methodology by using it to perform assessments using their own already-collected data. The results of this research were published as NCHRP Research Report 1010 in 2022, which is available here: In-Service Performance Evaluation: Guidelines for the Assembly and Analysis of Data
The report, accompanying training slides, and Excel workbook present a systematic methodology for assessing when existing roadside hardware should be considered for replacement with hardware tested to the 2016 Manual for Assessing Safety Hardware (MASH). In particular, the report looks at one of the most common systems, 27-3/4" tall strong-post w-beam guardrail and evaluates conditions where replacing it with 31" tall strong-post w-beam guardrail is appropriate. The results of this research were published as NCHRP Web-Only Document 292 in 2021, which is available here: Roadside Hardware Replacement Analysis: User Guide
This project continued the theoretical development of the modelling methods used in RSAPv3. More robust and accurate methods for assessing and predicting crashes were developed taking advantage of some recent research. A quantifiable systematic methodology was developed for assessing and evaluating the effectiveness of roadside designs that can be used to update future editions of the Roadside Design Guide. The results of this research were published as NCHRP Research Report 972 in 2022, which is available here: Development of Safety Performance-Based Guidelines for the Roadside Design Guide
This project developed risk-based guidelines for determining when and what type of median barrier is necessary based on the traffic and highway characteristics at a particular site. This project was extended to include the development of guidelines for the use of roadside barrier to shield fixed objects. The results of this research were published as NCHRP Report 996 in 2022, which is available here: Selection and Placement Guidelines for Test Level 2 Through Test Level 5 Median Barriers
Development of Methods to Evaluate Side Impacts for Next Edition MASH NCHRP 22-32
The objective of this project is to develop recommended test and evaluation procedures for side impact crash testing that can be considered for inclusion in a future update of the Manual for Assessing Safety Hardware (MASH).
The objectives of this project are to: 1) review existing NETC bridge rail and AGT designs and assess performance aspects to determine preliminary MASH compliance/equivalency, 2) review current standard details and specifications for NETC style bridge rails and transitions used by MEDOT, NHDOT, RIDOT and VTrans to identify differences in material specifications and dimensional details and 3) evaluate the crash performance of the NETC bridge rail and approach guardrail transition (AGT) designs using finite element analysis (FEA) computer simulation for MASH TL4 compliance.
The objectives of this study were to define the critical minimum length of the system to achieve minimum barrier deflection when the system is impacted at its midpoint under MASH Test 3-11 conditions (i.e., 5,000-lb pickup impacting at 60 mph and 25 degrees); and to then evaluate the crash performance of this critical-length system at impact locations approaching both the leading and trailing ends of the system for MASH Test 3-11 conditions. This system has been successfully full-scale crash tested to MASH Test Level 3 at the Texas Transportation Institute.
The objective of this project was to evaluate the crash performance of the MassDOT S3-TL4 bridge rail design using FEA. The impact conditions and assessment procedures conformed to the specifications in MASH for TL-4, which included evaluations of structural capacity, risk of occupant injury and vehicle stability during impact and redirection. Two design options for the bridge rail were evaluated: 1) a curb-mounted option in which the bridge rail was mounted onto the top of an 8-inch reinforced curb that is integral to the bridge deck, and 2) a sidewalk-mounted option in which the bridge rail was mounted onto the top of a 5-ft wide sidewalk with an 8-inch curb face.
The purpose of this project was to evaluate the crash performance of an existing approach guardrail transition design for the Massachusetts Department of Transportation using finite element analysis.
MASH TL4 Evaluation of the Proposed Median Barrier Extension at the Bronx-Whitestone Bridge
The purpose of this project was to evaluate the crash performance of the proposed median barrier extension for the existing median barrier at the Bronx-Whitestone Bridge using evaluation procedures set forth in MASH for test level 4. This system has been successfully full-scale crash tested to MASH Test Level 4 at the Texas Transportation Institute.
NYSTA required a MASH Test Level 5 (TL5) bridge rail. Since no existing TL5 bridge rail designs were available that met the requirements for the given application, an existing TL4 design was adopted and then modified to increase its strength capacity to achieve Test Level 5 performance. This system has been successfully full-scale crash tested to MASH Test Level 5 at the Texas Transportation Institute.
The objectives of this project were to evaluate a proposed design modification for strengthening the Oregon 3-tube bridge rail and verify that the design change meets the FHWA criteria for "inconsequential / positive" change based on NCHRP Report 350 Test Level 4 performance conditions.
The objective of this research project is the development of a cost-effective TL-3 post-and-beam type bridge rail system designed for mounting to the steel fascia beam of Ohio rural bridges.
This project developed risk-based guidelines that quantify when bridge piers should be investigated for vehicular collision forces or be shielded with a longitudinal barrier. The results of this research were published as NCHRP Research Report 892 in 2018, which is available here: Guidelines for Shielding Bridge Piers
The objective of this project was to develop quantitative assessment measures that can be incorporated into the AASHTO Highway Safety Manual to evaluate the effects of roadside designs and features on the frequency and severity of lane departure crashes. Using the largest databases of State crash data available allowed for the development of two-lane undivided and four-lane divided highway models. Statistical adjustments for road features like curvature, grade, number of lanes, speed limit and many other conditions were modelled. The result was a model that predicts the frequency of fatal and serious injury crashes based on traffic conditions and highway characteristics. The results of this research were published in 2022 as NCHRP Web-Only Document 325 which is available here: Consideration of Roadside Features in the Highway Safety Manual
The objective of this project was to develop a field guide to assist highway agencies in deciding when guardrails need to be repaired based on the observed damage. The results of this research were published in 2021 as NCHRP Web-Only Document 304 in 2021 which is available here: Criteria for Restoration of Longitudinal Barriers, Phase II
The objective of this project was to develop a modified design of the NETC 4-Bar bridge rail to accommodate installation on steel through-truss bridges. This bridge rail was previously tested to Report 350 TL4 conditions, and the goal of the project was to achieve Report 350 TL-4 eligibility for the modified design in accordance with the (then current) FHWA eligibility requirements. The evaluations were performed using FEA. The final design modifications were determined to meet all structural capacity, occupant risk measures and vehicle stability criteria set forth in NCHRP Report 350.
Development Of A Strategic Plan For TCRS - NCHRP 20-7(360)
The objective of this research is to develop a strategic plan for TCRS that guides the technical committee activities in its role as the focal point for roadside safety policies and guidance.
The purpose of this project was to update and re-code the RSAP program used for roadside safety benefit-cost analysis. The methods and coding for the program were completely redone to take advantage of advances in statistical analysis methods and improved understanding of roadside crashes. RSAPv3 is used to evaluate roadside design based on either a benefit-cost approach or a risk of serious or fatal crash approach. RSAPv3 has been used and extended in many of Roadsafe LLC’s subsequent projects. The results of this research were published in 2022 as NCHRP Web-Only Document 319 which is available here: Roadside Safety Analysis Program (RSAP) Update
Update to A Guide to Standardized Highway Lighting Pole Hardware
The purpose of this project was to update the content of the AASHTO-ARTBA-AGC Task Force 13 Luminaire Guide and to put the guide on-line as a searchable database of crash tested luminaire designs.
A computer program was developed that compares the data collected in a crash test to the results of a finite element analysis. Quantitative measures were developed to rank the result allowing engineers to determine how much confidence they can have in their computer simulations. The results of this research were published in 2011 as NCHRP Web Document 179, which is available here: Procedures for Verification and Validation of Computer Simulations Used for Roadside Safety Applications
The objective of this project is to examine the likely performance of the guardrail installed on the TRC test track in the 1970’s and determine if it is adequate for future anticipated use.
This project developed risk-based guidelines for the selection of Test Levels 2 through 5 bridge rails considering in-service performance, benefit-cost analysis, and risk assessment. The results of this research were published as NCHRP Web-Only Document 307 which is available here: Recommended Guidelines for the Selection of Test Levels 2 Through 5 Bridge Railings
NCHRP Report 490
Twenty years ago, some of the current Roadsafe LLC staff developed NCHRP Report 490, “In-Service Performance of Traffic Barriers.” This document was the first comprehensive guide for performing in-service performance evaluations (ISPE). The guide includes a description of an ISPE methodology, a field guide, and the results of five ISPEs performed to demonstrate the techniques outlined in the guide.
