Who is at fault?

Three quarters of motorbike accidents are crashes with another vehicle, usually a car. The remaining one quarter are single vehicle accidents. A study showed that the most typical motorbike accidents are “right of way” accidents, a loss of control on bends and filtering between/passing traffic.

Rider error

In the UK, overall, bikers are found to be fully or partly to blame in around 50% of their accidents. A European study reduced this figure and stated that in 37% of cases the primary contributing factor was human error on the part of the motorcyclist with 50% of the errors being made by drivers of other vehicles. Traffic control violations (such as breaking a stop sign or a traffic light) by motorcyclists in that European study caused 8% of the accidents whereas the same breaches by car drivers caused 18% of the crashes.

In the accidents caused by bikers, lack of attention to the driving task is a common cause. In rear end shunt accidents the rider is more likely to be at fault than other accidents. The rider is likely to be young and male here and 40% of those crashes concern scooters or mopeds. In addition, single vehicle accidents are more often caused by rider error. This is usually caused by slide out and fall due to over-braking or running wide on a curve due to excess speed or under-cornering.


Unlicensed riders are significantly more likely to crash and this has been shown by many studies. 50% plus of the accident riders in a USA study had less than 5 months experience and many had learned from family or friends with no formal training.

Vehicle failure

Vehicle failure is a small factor in motorbike crashes. The Hurt Report (a USA study) found that vehicle failure is likely to be a factor in less than 3% of accidents. MAIDS (a European report) found tyre failures most relevant but found vehicle failure to contribute to less than 1% of cases. A London study stated that 95% of road accidents in general involve human and not vehicle error. Given that tyre failures are the biggest factor here it would be wise to check your tyres every time you take your bike out.

What you do need to be careful of however is problems with your vehicle after a crash. Fuel leaks and spills are present in 62% of accidents after the crash and this is a big risk for fire.

Problems with the road surface

Problems with the road surface are a crash factor in 2 – 3% of cases. Despite this low figure it is worth remembering that minor hazards for a car (such as potholes, puddles, oil and debris) can be very serious for a bike. Indeed one of our cases involved an accident caused by a pothole (our biker sued the County Council). In rural bend accidents there has been some evidence of a problem with oil, gravel and mud on the road.

Car driver error

In an accident involving a car and motorbike, the car driver is shown to be responsible in over 50% of cases.

“No continuity of observation” was the biggest cause of accidents in one study. Of these accidents, the riders were at fault in 10.9% whereas other road users accounted for 77.1%.

A huge problem is “right of way” accidents, where one vehicle infringes another’s right of way and causes an accident. 38% of all motorbike accidents in one study involved a right of way violation. Motorcyclists were to blame in less than 20% of these cases; it was primarily the car driver at fault. An American study showed that the most frequent of these crashes occurs where the bike is going straight and the car makes a turn into its path.

The reason behind the high incidence of this type of crash is simple: the car driver does not see the motorcyclist. It is argued that they are looking for and expecting a car and this is why they miss the bike. Over 65% of accidents include a situation where the driver failed to see a motorbike that should have been in clear view and was in clear view to witnesses. There may also a phenomenon called “inattentional blindness” at play. This is where people are less likely to see a bike if they are looking at it directly than if it falls outside the visual field. Indeed, many drivers overlook the foreground while concentrating on the distant view. In addition, when they are rapidly scanning the view they expect and look for larger vehicles. Interestingly, drivers of other vehicles who are also licensed to ride a motorbike are less likely to overlook a motorbike indicating that it is indeed a problem of awareness of motorbikes on the road.

It is interesting that bikers are more at risk of not being seen by skilled, older, car drivers. The average age of the driver at fault in a right of way accident is 41. In other accidents it is only 36. The reason put forward for this phenomenon is that skilled drivers have developed expectations of what happens on the road and this allows for their fast and accurate prediction and behaviour. Their expectation that it is more likely that they will see a car leads them to ignore the motorbike accidentally.

In summary, intersections are the most likely place for an accident and you need to be careful there.

Accidents where the bike was filtering through traffic are also more likely to be caused by car drivers.


In a USA study, weather was found to be a factor in only 2% of accidents. In a European study it was found to be a factor in 7.5%. There are no such statistics based on Ireland but with our climate, it would be reasonable to believe that the percentage is higher.

Viewing difficulties

Sometimes a car’s view of the bike is limited by glare or another car.

Type of road

While the type of road may not necessarily cause the accident in and of itself, it may contribute. The majority of accidents occur at T-junctions (3 times as common as roundabouts or crossroads). Uncontrolled T-junctions (no traffic lights or signs) in urban environments are the most dangerous.



For any kind of motorbike query don’t hesitate to call us on 045 431542 for an opinion of your case. You can also email us at info@motorbikelaw.ie or use our “Evaluation of your Case” link at the top of this page and we’ll get back to you.*


* In contentious business a solicitor may not calculate fees or other charges as a percentage or proportion of any award or settlement.