Bad rural road design causes bike crashes

Austroads crashes

Some bike crashes are caused by poor rural road design, according to an Austroads report.

The Austroads Road Design Task Force report analyses a wide range of rural road design theories, with a special section just for motorcycles.

This is a welcome departure for Austroads, the leading transport and traffic authority in Australia and New Zealand, which has previously shown scant regard for motorcycles in other reports.

Some of the identified problems with rural roads that cause crashes include a lack of sealed shoulders, steep downhill grades combined with curves, roadsides with close hazards such as trees and high-volume intersections.

The report proposes a number of possible changes to Austroads road design guides aimed at reducing the casualty crash risk on rural roads.

It also identifies elements specific to motorcyclists and sources a 2010 study of more than 30,000 curves.keep calm road safety crashes

The study identified four road design elements that had a significant impact on bike crashes: length of the curve, curve radius, distance from the end of the curve and shoulder width.

It says that as the curve length increases, motorcyclists have an increasing risk. A 1% change in curve length increased the crash frequency by 0.39%.

Of course, longer curve lengths are usually on roads with higher designated speeds.

“This may indicate that the motorcycle riders may not be able to handle their motorcycle over these higher speeds,” the report says. “It may be, that when the motorcyclist travels around the curve, they tend to accelerate to a ‘high-speed instability’ compared to the straight sections.”

They also identified that rider crash frequency increased significantly the tighter the curve radius.

For every 30m beyond the curve, the motorcyclist crash rates decrease by 43%, up to a distance of 100m.

The report also identifies that the shoulder width has an influence on bike crashes. Shoulder widths less than 1.80m were found to have an increase in motorcyclist crash rates of 52% over wider shoulders.

motorcycle safety
Markings make lane appear narrow

In their summary of recommendations, they suggest widening shoulders, increasing the inside width of a road to decrease the curve and visible road markings at an approaching corner.

The latter solution is basically a visual trick with road markings that makes the road look narrower.  The result is that the motorists will slow their speed before entering the corner.

It’s called “perceptual countermeasure” and was developed by Melbourne’s Monash University in 1999. It has been rolled out on only a few rural roads.


  1. For starters don’t believe anything that comes out of Monash, not without a kilogram of salt least ways.
    I had my only ever at speed off due to bad road design and markings.
    I was in a group riding to a camp site on a reasonable quality road just after the Big fires around Canberra. It was a 100kmph road and it had some nice bends
    The advisory sign on the bend I entered said 75 so I and everyone else basically ignored it
    I was setup to go round so I was admiring the burnt out scenery when at about half way round there was another advisory sign showing 65 kph right where I spotted this there was a dip in the road that got me airborne just as I need to lean over more, so instead of making the bend I had to straighten up and break now if there had been a paved shoulder or the gravel and dirt had not been rutted by fire trucks I wouldn’t have dropped it.
    But if the advisory sign had said 65 I would have slowed down and paid more attention to the road.
    So it’s not the riders over cooking it or their skills not matching their bike and egos it’s most likely the signage and road being deceptive and the scenery distracting the rider

  2. Sorry but I don’t believe this for an instant, Driver’s and Rider’s attitude is the key for getting out of the ” it won’t happen to me syndrome ” along with poor maintenance of some roads rather than poor design.

    Ride to the conditions prevailing while remaining within the Law AND your own ability and that of your chosen Bike.

    I ride and I often have heard it said on radio etc slow down in the Wet or what ever , sod off I will NEVER slow down in the Wet or Snow or any other road condition !!!
    What I WILL do however is ride as the conditions decree. That people is why many die !! They are very often NOT operating their vehicle as per the prevailing conditions and within those of the bike and them selves and NOT the road design.

  3. BergDonk is correct, roads don’t cause crashes; though road design, construction and/or maintenance maybe a contributing factor to a crash, alongside possible/potential consequences.
    How about road markings? What of the type of material used in those markings and how such may contribute both directly and indirectly to motorcyclists and other road user behaviour(s)?

    How about the cohesive co-efficient or lack thereof inherent in the chosen and applied road marking materials used predominately in AUS & NZ?

    In Asia where motorcycles represent or make up a higher percentage of vehicle types, many (though admittedly not all) road markings are offer much higher degrees of adhesion than the more typical ‘paint’ used in many first world countries. How often do motorcyclists have to manoeuvre, avoid or take evasive actions round road markings because of the inherent dangers riding on said surface. Both the manoeuvre itself alongside the consequences of having to be in a less than ideal position may/can have less than ideal potential outcomes. Add a little water from any source and the potential consequences may catastrophic.

    Much more politicking and lobbying IMO needs to be put into having the archaic use/misuse of regular paint that provides little to no adhesive/grip properties for two wheeled vehicles, replaced with much more favourable product as used on roads in many parts of Asia.

  4. Seeing as there never seems enough to even fix the potholes
    i really can’t see the point of the study.
    money spent on ausroads might be better spent on a
    a couple of blokes with shovels.
    As for coming off on corners, some riders might do
    better spending their money on training and confining
    racing to track days

  5. Roads mostly don’t cause crashes. Their poor maintenance may contribute however.

    But some roads increase the consequences to riders if they make a mistake. Ride smart and learn to read the road and ride to the conditions, don’t blame the road for your mistakes.

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