Roadway Engineering
This section contains research regarding roadways. It is divided into two sections:
- Barriers: Here is a review of a project Assessing The Risks of Wire Rope Barriers on Motorcyclists
- Engineering and Infrastructure: Blackspot, Rumble strips, Intersections, Curves, Roadway distractions.
National Academies Transportation and Infrastructure – Highways is an almost unbelievable source for research and information on this topic. The National Academies Press (NAP) publishes the publications of the National Academies of Sciences, Engineering, and Medicine. NAP publishes more than 200 publications per year on a wide range of topics in science, engineering, and medicine, providing authoritative, independently researched information on important matters in science and health policy. There are more than 1,000 books available for free download in this section on highway engineering. This is an outbound link so don’t forget to return to www.smarter-usa.org
Barriers Research Studies
2023 – “Characterization of Motorcycle Encroachments in the US”
In 2020, there were 5,579 motorcyclist fatalities in the US, which is the highest on record. Despite accounting for only 3% of registered vehicles, motorcycles are involved in 42% of fatal guardrail impacts. Roadside safety hardware testing guidelines are outlined in the Manual for Assessing Safety Hardware (MASH) for passenger vehicles and large trucks but these procedures do not include any motorcycle impacts. This study compared the encroachment and impact characteristics of motorcycles, passenger vehicles, single-unit trucks, and tractor-trailer trucks in the US. Large trucks and motorcycles were found to rollover at a higher frequency than passenger vehicles. This study indicated that a large percentage of riders lose contact with the motorcycle during the first crash event and are separated during any subsequent events. Based on these results, future motorcycle-barrier tests should consider an upright configuration and an impact angle of 24 degrees.
2022 – “Influence of Road Safety Barriers on the Severity of Motorcyclist Injuries in Horizontal Curves”
The main objective of this study is to investigate relations between the presence and type of road safety barriers and the consequences of motorcycle crashes on rural roads. The results show that run-off-road crashes and nighttime driving are significant risk factors. There was no significant positive impact of the presence of safety barriers on the crash consequences due to the unsuitability of the barriers for motorcyclists, which proves the fact that the functionality of existing safety barriers should be upgraded.
2021 – “Synthesis on Barrier Design for Motorcyclist Safety”
The purpose of roadside barrier systems is to reduce the severity of injuries and number of fatalities by controlling and mitigating crash forces. While barrier systems have been designed and proven to be beneficial for motor vehicles they do not currently address the problems associated with motorcyclist crashes. This synthesis of research presented in this report concluded that motorcyclists are more vulnerable than drivers of motor vehicles and that motorcyclists are more likely to be severely injured when they crash into a barrier system. This synthesis report summarized several new barriers and retrofit systems currently used or under development that are specifically intended to improve motorcyclist safety in addition to retaining the existing benefit for motor vehicles. The final portion of this report summarizes testing parameters to be considered for both upright and sliding impacts into roadside safety barriers that should be investigated during the planning, development, and research of testing standards in the United States. This publication addresses Motorcyclist Advisory Council recommendations.
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.
2012 – Motorcycle Crashes into Road Barriers: the Role of Stability and Different Types of Barriers for Injury
This research focused on motorcycle crashes into road barriers and addressed two research questions: the first to assess if injury risk for motorcyclists is affected by collisions with different types of barriers, and the second, to examine if injury outcome in these crashes can be affected by being in an upright position during the collision. Police‐reported motorcycle crashes into road barriers in Sweden between 2003 and 2010 were analyzed across different barrier types, using the Fatal‐Serious‐Injury Ratio (FSI). The analysis of police records showed no statistically significant difference between the FSI‐ratios for wire rope barriers, Kohlswa‐beam and W‐beam barriers, although these FSI‐ratios were generally very high. The small number of in‐depth case findings, however, showed that injury severity was lower in crashes in which the motorcyclists were in an upright position during the collision. The proportion of subjects with ISS 16+ was 24% lower in those crashes compared to those who slid into the barrier.
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.
2026 – “Safeguarding Vulnerable Road Users – Summary Report of PRIME Road Trials – 2023 to 2025”
In this phase 2 of the research, innovative road markings for motorcyclists, designed as Perceptual Rider Information for Maximising Expertise and Enjoyment (PRIMEs) were installed on the approach to demanding bends at a total of 18 trial sites (13 new trial sites plus 5 sites used in previous years’ research) and two comparison sites across the West Highlands of Scotland. Unique PRIME Road markings for motorcyclists produced statistically significant positive behavioural changes in speed, lateral lane position and braking at sites around the Scottish Highlands. Data analysis suggests long-term sustained behaviour change following the installation of PRIME road markings. This in-depth study identifies important behavioural factors that support Transport Scotland’s ‘Road Safety Framework to 2030’ and the ‘Safe System’ approach to motorcycle casualty reduction.
2025 – “Evaluating a New Road Sign and Traffic Markings for Motorcycle Safety on Untreated Roads”
This research, conducted by Transport Scotland, investigated effects for ne traffic markings on the user behavior of motorcycle riders. A road sign and traffic markings were installed at six trial sites. At fie sites speed was reduced by a significant margin. At four sites there were significant improvements in road position at the final traffic marking. At five of the trial sites on the apex of the bend, there were significant improvements in road position. This research has generated international interest for installing the road sign and traffic markings in other regions and contributes to the Scottish Government’s Road Safety Framework by reducing motorcyclist causalities
2024 – “Safety in Rural Curves”
This is a summary and link to a presentation regarding innovative road markings for motorcyclists’ research conducted by the Austrian Road Safety Board (KFV). The presentation was at the International Motorcycle Safety Conference, November 25, 2024. The KFV research team developed a new type of optically conductive road marking, which was used in 2019 in 19 critical curves where other mitigation measures had already failed. White elliptical-shaped films which – strung together like a string of pearls along the center line – are intended to ensure more space from the oncoming lane. The before and after analysis delivered an impressive success result. The innovative optical support brought about an 80% reduction in the number of motorcycle accidents in the test curves. Presentation video here: #IMRSC24 | Martin Winkelbauer: "Safety in rural curves"
2023 – “Safer Roads for Motorcyclists – Moving Towards a Systematic Approach for Motorcycle Safety”
This report is a follow-up to The Institute of Highway Engineers (IHE) Motorcycling Guidelines Road Design & Traffic Engineering published in 2005. This report should be essential reading along with the “Guidelines,” which it references, to a broad range of stakeholders. The Guidelines were the first such publication to set out practical guidance for policy makers, transportation professionals and users on providing a safer environment for motorcycles, mopeds and scooters. Its individual chapters cover Policy; Road-Design; Road Safety; Travel Plans; Parking; Maintenance and Road Safety Audit. The IHE Guidelines have been cited as “best practice” both domestically and internationally. To access the “2005 Guidelines" visit the website at www.motorcycleguidelines.org.uk/
2023 – “Safeguarding Vulnerable Road Users: Summary Report of PRIME Road Trials 2020-2022″
Innovative road markings for motorcyclists, designed as Perceptual Rider Information for Maximising Expertise and Enjoyment (PRIMEs) were installed on the approach to demanding bends at 22 trial sites and two comparison sites across the West Highlands of Scotland. These road markings were presented as a series of ‘gateways’ to encourage safer riding. Significant reductions in speed, changes in lateral position, better positions on approach to the bend, changes in lateral position at the apex of the bend, and significant reductions in braking were observed.
2023 – “Motorcycle Rider Perceptual Countermeasures”
This is an abstract of a research report conducted by Austroads, the association of the Australian and New Zealand transport agencies. The report details a trial conducted to evaluate whether a suitable road-based perceptual countermeasure (PCM) could influence the travelling speed as well as lane position of motorcyclists to induce a safe curve negotiation. The trial results show a larger proportion of motorcyclists tended to position further away from the centerline compared to before the treatment. Motorcycle travel speed at the apex of both treated curves tended to decrease. Moderate reduction in travel speed at the apex of the treated curves was also observed for light and heavy vehicles. The trialed PCM design has high potential to enhance motorcyclist safety at critical curves along regional and rural routes.
2022 – “Safeguarding Motorcyclists: Trialing New PRIME Road Markings for Casualty Reduction” ABSTRACT
Where only a motorcyclist was involved, the typical causes of incidents are attributed to a poor turn or manoeuvre, exceeding the speed limit, loss of control, travelling too fast for the conditions or sudden braking. Innovative road markings for motorcyclists, designed as Perceptual Rider Information for Maximising Expertise and Enjoyment (PRIMEs) were installed on the approach to demanding left-hand bends at six trial sites and a comparison site across the West Highlands of Scotland. These road markings were presented as a series of ‘gateways’ to encourage safer riding. The results of this research provide statistically significant evidence for sustained effects of PRIMEs on rider behaviour.
2021 – “Addressing the Motorcyclist Advisory Council Recommendations: Synthesis on Roadway Geometry, Pavement Design, and Pavement Construction and Maintenance Practices”
Roadway geometry, pavement design, and pavement construction and maintenance practices are designed to construct and maintain roadway facilities that provide for motor vehicle travel. Typical practices focus on passenger car or truck needs and may not specifically recognize the special needs of motorcycles. This synthesis highlighted the general recent history of motorcycle specific safety research while also addressing specific road design, pavement design, and construction and maintenance issues related to motorcycles. Significant gaps in design, friction needs, and motorcycle-specific concerns related to roadway and pavement construction and maintenance are identified. The final portion of this report summarized potential research topics that could be investigated to help improve the safety of both motorcycle travel and all other types of motor vehicle travel in the United States.
2020 – Motorcyclist Advisory Council Recommendations
The Motorcyclist Advisory Council was reestablished by the FAST Act on 2015. Under that section, the MAC is responsible for providing advice and recommendations concerning infrastructure issues related to motorcyclist safety including: barrier design; road design, construction, and maintenance practices, and the architecture and implementation of intelligent transportation system technologies. Additional recommendations regarding architecture and implementation of intelligent transportation system technologies and recommendations that address other issues relevant to the Motorcyclist Advisory Council’s charter are also included. Not strictly research however the recommendations are well documented.
2020 – “Recording and Evaluating Motorcyclists’ Gaze Behaviour in Rural Roads”
The present study deals with motorcycle riders’ gaze behaviour due to out of the vehicle sources of distraction. The most generic conclusion of the analysis is that both at urban and suburban environment exist too many elements that attract the attention of the driver. Average distraction times differ among drivers but every one of them is being distracted for unsafe periods – more than 1 sec at suburban environments and more than 1.2 seconds for urban environments. These distractions last enough to create the circumstances for an accident to take place.
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 – “Evaluation of Perceptual Countermeasures for Motorcyclists Stages 1 and 2 Final Report”
This project, by Monash University, Accident Research Centre, Melbourne, Australia evaluated the effects of two types of perceptual countermeasure treatments on motorcycle speed and lane position. A controlled before after design was used to compare speed and lane position before treatment installation with two periods after treatment installation. Overall, the treatments produced significant net speed reductions in the short-term but were not effective in maintaining the reductions in the long-term. Changes to lane position adopted by motorcyclists when negotiating the curves were evident in the short-term for the peripheral transverse lines treatment and the enhanced guideposts treatment installed on approach to a single curve. In the long-term, these changes were maintained for the enhanced guideposts treatment only. As this study is the first of its kind to be conducted with motorcyclists, a follow-up trial and evaluation were recommended
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 – “ Intelligent Transportation Systems and Motorcycle Safety”
The current review aimed to investigate the extent to which ITS have been applied to motorcycles (including both existing and emerging technologies) and discuss these ITS according to their likely safety benefits to motorcycle safety. A literature review and expert consultations confirmed that very few motorcycle-specific ITS currently exist, with advanced braking systems a notable exception. The potential to adapt emerging and existing ITS for other vehicles to motorcycles is also highlighted. Future motorcycle ITS developments must be safety-driven, but also consider issues such as acceptability.
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.