Motorcycle safety is a concern to all road users. Motorcyclists often are forced to use more of the travel lane or even swerve unpredictably in order to avoid hazards, increasing their chance of crashing.
A step in decreasing the ever increasing motorcycle crash rates and resulting injuries and fatalities is to design, construct and maintain roads to reduce hazards and increase safety for these vulnerable road users. Below are some tips to improve roadway safety for motorcycles.
Road Geometry, Signs and Markings
• Design with motorcycle maneuvering in mind. Curves are the leading location for motorcycle crashes. Half of motorcycle fatalities are related to road curves. When possible, design roads with fewer curves.
• Use additional signs and markings. If other vehicles are involved in the crash, drivers report not seeing the motorcyclist in time to take corrective action. The use of signs and pavement markings can provide a clearer, more consistent message to warn motorcyclists of curves and other unexpected road geometry.
• Consider installing motorcyclist hazard warning signs. Signage targeted toward motorcyclists can warn of conditions that are especially hazardous for riders. Examples include uneven pavement surfaces and rumble strips.
• Install Safety Edges. Untapered vertical shoulder drop-offs are even more dangerous for motorcycles than for other vehicles. Adopting a standard contract specification requiring a 30-35° angle asphalt wedge along each side of the roadway in all construction and resurfacing projects is a simple and cost-effective way to improve pavement edge safety. For more on the Safety Edge, visit safety.fhwa.dot.gov/roadway_dept/pavement/safedge/fhwasa09023/
Guardrails and Cable Barriers
• Place guardrail and cable barriers as far from travel way as practical. Guardrails and cable barriers prevent vehicles from crossing medians and going into oncoming traffic. However, they are unsafe for motorcycles. Nearly half of all motorcycle guardrail collisions result in fatalities.
Visibility and Sight Distance
• Increase sight distance and stopping sight distance (SSD), whenever possible, to improve safety. Motorcycles are less visible to most motorists due to their size. Sight distance is the length of roadway that a driver can see ahead. SSD is the minimum sight distance required to stop a vehicle on wet pavement after seeing an object without hitting it. Distances are set by American Association of State Highway and Transportation Officials (AASHTO ). Engineers use SSD to determine the minimum length of vertical curves and minimum radii of horizontal curves. SSD is meant for cars but not for other vehicles, including motorcycles.
Visit baystateroads.eot.state.ma.us/technotes/35_stopping_sight_distance.pdf for more information on SSD as well as refer to AASHTO ’s publication, A Policy on Geometric Design of Highways and Streets
• Ensure visibility of signs and roadway markings. Keep in mind that many motorcycles only have one head lamp for illumination. Apply retroreflective material to guardrails, cable barrier posts and other potential obstructions to increase visibility at night.
Skid-Resistant Surfaces
• Examine pavement for skid resistance during road maintenance. Older pavements often lose skid resistance quality. Grind, overlay, or apply a surface treatment to increase skid resistance and specify pavement surfaces with adequate pavement friction.
• Examine the friction characteristics of asphalt sealants, roadway markings, intersection markings, and metal road surface apparatus. Thermoplastics, especially used for broad, horizontal intersection lines, can create slippery surfaces for motorcycles trying to stop at intersections. Metal road surface components—either temporary or permanent— offer limited traction in many cases, and, when wet, are difficult to see.
Work Zones
Work zones are especially dangerous for motorcyclists.
• Post specific warnings for motorcycles. Place warning signs for grooved pavement, uneven pavement such as from milling operations, bumps, potholes, edge drop-offs, and other hazards. Edge traps prevent a motorcycle’s front wheel from moving side-to-side. Even a small edge trap may result in a crash.
• Use steel construction plates of an adequate size and with a skid resistant surface. Plates can be slippery when wet. Recess plates to avoid creating an edge trap.
• Use weighted work zone devices to prevent them from being blown into the travel lane. Many signs, cones, and barrels have a heavy rubber ring on the bottom. Use a second weighted ring in dangerous locations.
• Check work zones regularly to ensure correct placement of safety devices and that the zone is free of debris in the travel way.
August 2010 Florida T t2ctt.ce.ufl.edu Technology Transfer Quarterly 13
Pavement Maintenance
• Remove debris and fluid spills quickly and thoroughly. Tires, vehicle parts, accumulated vegetation, other debris and fluid spills become hazards. Sand along coastal roads poses greater hazards to motorcycles than to larger vehicles. Debris can deflect a motorcycle’s wheel or hit the motorcyclist. Fluid spills and loose materials can easily cause loss of traction. Loose materials are also common with certain types of treatments such as seal coating where liquid asphalt is applied over pavement and gravel is spread over liquid asphalt.
• Reduce uneven road surfaces. Parallel paving lane joints, parallel grids on bridges, steel plates, milled surfaces and other uneven roadway surfaces can be especially hazardous for motorcycles.
• Milling machines produce a coarse surface with longitudinal grooves. The course material may cause a motorcycle to lose traction. Grooves can create an edge trap. Edge traps often occur during paving operations. Current highway standards permit pavement edges of up to 1.5 inches without tapering.
• Patch potholes promptly. Potholes are more dangerous to motorcycles than to larger vehicles.
• Always post warning signs and repair potholes as soon as possible.
Installing an effective drainage system and crack seal can help prevent potholes.
• Require tidy crack repairs. A motorcycle’s traction can be seriously compromised by “tar snakes”, excess asphalt or other sealants used for crack repair. Crack sealing is an effective pavement treatment however, it becomes slick during warm weather.
Assess Motorcycle Safety
• Use Road Safety Audits to assess safety. Visit t2ctt.ce.ufl.edu for a list of Road Safety Audit courses or call David Page at 352.273.1685.
• Obtain motorcycle crash data. Use crash reports to decide which areas need improvements. Make a list of improvement needs, prioritize the list, and take action.
Article adapted with permission from KUTC Newsletter Winter 2009,
“Are your roads “easy riding” for motorcycles?”, UNH T˛ Center, Road
Business, Spring 2007, Vol. 22, No. 1 “Design Guidelines for Motorcycle Safety”, and 2007 FHWA Brochure, Roadway Safety for Motorcycles.