Roadway Engineering

This section contains research regarding roadways.  It is divided into two sections:

  1. Barriers
  2. Engineering and Infrastructure: Blackspot, Rumble strips, Intersections, Curves

Barriers Research Studies

2015 – “Road Safety Devices Assessment for Sliding Motorcyclists Protection”

Statistics show that the impact with a roadside safety barrier of a motorcyclist sliding on the pavement after an accident is potentially more dangerous than the accident itself. In recent years, in effort to avoid the most serious consequences, the approach to barriers design changed and specific devices have been introduced to improve motorcyclists’ safety.  At LAST Crash Labs, the effectiveness of one of these devices was experimentally and numerically investigated.

2014 – “Protecting Motorcyclists in Collisions with Roadside Barriers”

In this study, statistical analyses of motorcyclist collisions with fixed hazards indicate that posts and poles are significantly more hazardous to motorcyclists than roadside barriers regardless of barrier type or whether the barrier has been tested for motorcycle impact crashworthiness. This analysis supports the use of barriers in front of such fixed objects to improve the safety of the roadside for motorcyclists. However, this New Zealand crash study again indicates (and supports previous studies from this program, e.g. Stage 3, and European and US studies) that barriers are substantially  more  hazardous  to  motorcyclists  than  passenger  vehicle  occupants  in  the case  of barriers not designed for motorcycle crashworthiness, where 50% of motorcyclist-barrier casualty collisions  resulted  in  serious  or  fatal  injury,  while  only  13%  for  vehicle  occupants.

2014 – “Study of High-Tension Cable Barriers on Michigan Roadways”

Final report by Wayne State University.  Overall, it appears that the installation of cable barriers on Michigan freeways has not had a significant effect on motorcyclist safety, however the sample sizes of motorcycle-involved target crashes on control segments were quite low and strong conclusions regarding the effect median treatment type on motorcycle-involved crash severity outcomes cannot be made.

2013 – “Cable Median Barrier Program in Washington State

The purpose of this report is to summarize the evolution and accomplishments of the Washington State Department of Transportation’s (WSDOT’s) cable median barrier program. The objective of this program is to reduce fatal and serious injury collisions by targeting cross‐median crashes on high‐speed controlled access highways. This report compares crash rates before cable median barrier was installed with crash rates of the various barrier treatments that followed. The report provides a summary of ten collisions involving motorcycles and cable median barrier in Washington State.

2013 – “Motorcyclist Impacts into Roadside Barriers. Is the European Crash Test Standard Comprehensive Enough?”

This paper reports on a study that reviewed the European Standard EN 1317-8 for motorists crashing into barriers and the relevance to Australian motorcycle fatalities. The data collection and analysis of 78 Australian motorcyclist-into-barrier fatalities described here were used to justify the review.  Includes a review of the literature. A rub rail along the bottom of the barrier and a smooth surface along its top would reduce motorcycle-into-barrier injuries.

2010 – “Fatal Motorcycle into Road Safety Barrier Crashes”

This paper presents an overview of key findings of a research project investigating motorcycle crashes into roadside safety barriers carried out at the University of New South Wales.  Wire rope barriers were found to have around half the fatality rate of W beam and concrete barriers. No statistically significant association between barrier type, crash posture and barrier post impacts, and injury severity within the limitations of the small dataset of fatal only motorcyclists, could be established

2010 – “Motorcycle Crashes into Roadside and Median Road Safety Barriers”

PowerPoint presentation describing Transport and Road Safety (TARS) Research, University of New South Wales.

2010 – “The Effect of Barrier Type on Injury Severity in Motorcycle to Barrier Collisions in North Carolina, Texas, and New Jersey”

This study presents an analysis of the injury risk in 951 motorcycle-barrier collisions, involving 1,000 riders, in North Carolina, Texas, and New Jersey. The barriers examined included W-beam guardrail, cable barrier, and concrete barrier.

2009 – “Simulation of Motorcycle Crashes with W-beam Guardrail: Injury Patterns and Analysis”

Abstract. This study uses computer simulations to study the impact of a motorcycle with the conventional w-beam guardrail. In light of the results, the authors suggest that the design of guardrails should be reviewed with a focus on the safety of motorcyclists.

2009 – “Overview of Motorcycle Crash Fatalities Involving Road Safety Barriers”

Many myths still pervade concerning how injuries occur when a motorcycle strikes a roadside barrier. The main reason is that there have been relatively few recent real world studies of such crashes. This paper presents some preliminary findings from a major research project.

2008 – “Barriers to Change: Designing Safe Roads for Motorcyclists”

Position paper (not research) on motorcycles and crash barriers by the European Road Assessment Programme.  When an obstacle-free roadside is not achievable and crash barriers are needed, the Panel believes that motorcyclists have the right to expect and demand safe vehicle restraint systems.

2007 – “Ameliorating Motorcyclist Injury Risk from Flexible Barrier Collisions in Victoria”

Flexible barriers used over long lengths of roadway have shown great potential, especially in high-speed settings. However, there have been concerns that these barriers pose considerable injury risk to motorcyclists who strike them. In order to address these concerns, while still obtaining the safety benefits for the vast majority of road users, a number of barrier devices with the potential to ameliorate rider injury risk have become available. This paper reviews the main options available and identifies those that may be suitable for trial on Australasian roads.  

2007 – “Roadside Barrier and Passive Safety of Motorcyclists Along Exclusive Motorcycle Lanes”

In order to investigate the passive safety of motorcyclists while in collision with w-beam guardrail, this study carried out computer simulation of typical crash scenario and conducted a physical crash test to validate the simulation model.

2006 – “Motorcyclists and Wire Rope Barriers”

Despite their good overall safety record for general road users, motorcyclists have raised concerns that the cable used in WRSBs may act as a ‘cheese cutter’ in the event of a collision by a motorcyclist, whilst exposed posts supporting the cable barrier may also increase the severity of any injury if struck by a motorcyclist sliding along the ground.  Potential may exist to try and further protect fallen riders from exposed support posts, particularly in places where motorcyclists may be most at risk.  The literature review identified two alternative forms of protection specifically designed for WRSBs

2005 – “The Influence of Wire Rope Barriers on Motorcyclists”

A Master’s Thesis, the main part of the study concerns an assessment of the influence of wire rope barriers on motorcyclists speed, performance and choice of travel routes.

2005 – “Motorcycle Impacts into Roadside Barriers: Real-World Accident Studies, Crash Tests and Simulations Carried Out in Germany and Australia”

A paper that describes relevant, real-world accident scenarios, the different roadside protection systems used for the tests, the crash tests, the modeling simulations and the results, and proposed improvements to barrier systems to reduce injury severity

2003 – “Flexible Barrier Systems Along High-Speed Roads – A Lifesaving Opportunity”

This report addresses the issue of run-off-road crashes in Victoria, through the large-scale use of flexible barriers along high-speed roads. The report identifies four possibilities for improving barriers for motorcyclists.

2000 – “Motorcycle and Safety Barrier Crash-Testing – Feasibility Study”

While conventional barrier systems have performed well for the occupants of passenger cars, their effects on the safety of other road user groups, especially motorcyclists, is not well understood. The main purpose of this feasibility study was to recommend a research method for investigating the interactions between motorcycles and road safety barriers. A review of the relevant national and international literature was conducted, revealing a relative lack of published material regarding the nature of motorcycle collisions both with roadside barriers as well as motorcycle crashes in general.

Engineering and Infrastructure: Blackspot, Rumble strips, Intersections, Curves.

2018 – “Study on Motorcycle Safety in Negotiation with Horizontal Curves in Florida and Development of Crash Modification Factors”

Motorcycle crashes are overrepresented on horizontal curves, especially along rural two-lane roads. Most roadway design and traffic control strategies on horizontal curves include limited considerations for motorcycles. It is necessary to conduct a study to investigate the factors contributing to motorcycle crash risk on horizontal curves and identify effective countermeasures to improve motorcycle safety. This project aimed to fill the gap by completing a comprehensive literature review, a crash, a field experiment and a before-after crash analysis. Recommendations to address the identified curve-related safety issues for motorcycles in Florida and prevent motorcycle injury on horizontal curves are provided.

2018 – “Identifying Infrastructure-Based Motorcycle-Crash Countermeasures: Phase I Final Workshop Finding Report.”

In 2017, the Federal Highway Administration sponsored a project to identify three to five infrastructure-based motorcycle-crash countermeasures to consider for future research. To develop a list of prioritized infrastructure based motorcycle-crash countermeasures, a workshop was conducted.  The workshop opened with an introduction (Power Point presentation)  that provided participants with results from the prior tasks of the project, including an analysis of the data from the Motorcycle Crash Causation Study and a literature review. Participants discussed countermeasures from the prior tasks as well as the addition of other countermeasures. At the end of the workshop, a number of participants voted for their preferred countermeasures to develop a list of prioritized countermeasures. This report presents the workshop overview and results.  

2018 – “Traffic Safety Messages on Dynamic Message Signs (DMS)”

This technical assistance report investigated the existing state of practice across the nation for placing safety campaign messages on dynamic message signs (DMS) and reviewed relevant studies that documented any evidence of effectiveness in influencing driver behavior and providing a public safety benefit.

2018 – “Emerging Practices for Addressing Motorcycle Crashes at Intersections”

This a US DOT Federal Highway Administration report that includes a review of existing literature on motorcycle-related infrastructure improvements at intersections, analysis of available data to quantify the crash, injury, and fatality risk for motorcyclists at intersections, identifying multiple State or local projects in which infrastructure treatments were implemented to specifically improve motorcycle safety, overall safety (including motorcycles), or which were found to have improved motorcycle safety even though they were not a specific focus of the project.

2017 – “Improving Motorcycle Safety by Enhancing Roadway Design”

Certain design elements, such as predictable road geometry, good visibility, obstacle-free zones and a high-quality road surface with high levels of skid resistance may be especially important to enhance the safety of motorcycles. While safety awareness campaigns and modified guardrails have proved to be effective countermeasures, ways to further enhance roadway design to improve motorcycle safety need investigation. This report is an examination of research and related resources that address roadway design to enhance motorcycle safety.  

2017 – “Safety Effects of Horizontal Curve Design on Motorcycle Crash Frequency on Rural, Two-Lane, Undivided Highways in Florida”

The association between horizontal curve design (e.g., radius and type) on rural, two-lane, undivided highways and motorcycle crash frequency is not well documented in existing reports and publications. This study aimed to investigate the effects of design parameters and associated factors on the occurrence of motorcycle crashes with consideration of the issue of unobserved heterogeneity.

2017 – “Modeling Safety Effects of Horizontal Curve Design on Injury Severity of Single-Motorcycle Crashes with Mixed-Effects Logistic Model”

The impacts of horizontal curve design on motorcycle crash injuries are not well documented in previous studies. The current study aimed to investigate and to quantify the effects of horizontal curve design and associated factors on the injury severity of single-motorcycle crashes with consideration of the issue of unobserved heterogeneity.

2016 – “Motorcycle Road Safety Audit Case Studies”

Road Safety Audits (RSAs) are a formal safety performance examination of an existing or future roadway or off-road facility and are conducted by an independent, experienced, multidisciplinary team. This case study document provides a review of the RSA process and three case study examples of RSAs that had a demonstrated high-frequency of crashes involving motorcyclists. The case studies include photographs, a project background, and key RSA findings and suggestions.

2014 – “Motorcycle Crashes into Roadside Barriers: Stage 4, Protecting Motorcyclists in Collisions with Roadside Barriers”

Previous studies (Stages 1 to 3) have established an understanding of the nature of motorcyclist-barrier collisions. The focus of this present Stage 4 study is twofold. Firstly, to provide an understanding of how motorcyclists can be better protected in collisions with W-beam barriers and what the limitations are when concrete barriers are used. Secondly, to provide background information why the revision of the Australian/ New Zealand Road Safety Barrier Systems and Devices Standard now includes a motorcycle into barrier crash test requirement.

2012 – “Infrastructure Countermeasures to Mitigate Motorcyclist Crashes in Europe”

The Federal Highway Administration, American Association of State Highway and Transportation Officials, and National Cooperative Highway Research Program sponsored a scanning study of five European countries to evaluate infrastructure improvements to aid motorcyclists.

2008 – “Effects of Center-Line Rumble Strips on Non-Conventional Vehicles”

No Minnesota crash reports investigated in this study implicated the rumble strips as a factor in the accident. There were also no visible indications of rider correction or overcorrection in 40 hours of roadside observations.

2006 – “IHIE Guidelines for Motorcycling – Improving Safety Through Engineering and Integration”

Paper presented at the 2006 International Motorcycle Safety Conference by Anthony Sharp, IEng, FIHIE, MIHT, Vice President, Institute of Highway Incorporated Engineers. The  Guidelines (not research), which were a first in the UK, aim to assist highway and traffic engineers in developing a safer and more motorcycle friendly road environment.

2006 – “Effect of Prior Blackspot Programs on Motorcycle Safety”

The Victoria, Australia blackspot program was effective in reducing casualty motorcycle crashes at treated sites by a statistically significant 31%, which was also the estimated reduction for casualty crashes involving all types of vehicles.