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Liability considerations in unreasonable obstruction cases


In the High Court decision of McDonald v M S Amlin Corporate Member Limited, HHJ Salmon provided an interesting analysis of accident reconstruction evidence and arguments over liability and contributory negligence in a case where unreasonable obstruction was alleged.

The facts

  1. The claim arose out of a road traffic accident that occurred on the east bound bore of the Lime House Link tunnel, East London. The claimant was riding his Piagio scooter when it collided into the rear of a stationary Scania lorry.
  2. The claimant sustained a spinal and severe traumatic brain injury but had no recollection of the collision. Sadly, the driver of the defendant vehicle had died by the time of the split trial on liability. The tragic accident was captured by a CCTV camera in the tunnel.
  3. The lorry driver stopped some distance after a left hand bend because he heard a noise from his vehicle and stopped to investigate. The claimant argued that it was negligent for him to take this action as it caused an unreasonable obstruction in the tunnel. It was said that he should have stopped further ahead where the road widened into two lanes.
  4. The defendant denied negligence contending that:

a.     The lorry driver did not create a dangerous obstruction because three other vehicles were able to pass.

b.     The lorry driver alerted his position by a flashing beacon.

c.     His actions were justified as it was reasonable to stop and investigate the cause of the noise so as to avoid danger to other road users.

d.     Even if the lorry driver was negligent, the claimant was also negligent.

e.     The claimant’s negligence was so great in colliding with the stationary lorry which had flashing lights and was visible for a significant distance it should be regarded as gross negligence.

f.       Even if there had been an unreasonable obstruction caused by the defendant, the gross negligence on the part of the claimant should be regarded as the sole cause of the accident.

g.     If they were wrong about this then there should be an apportionment of liability with significant responsibility being attributed to the claimant.

Expert accident reconstruction evidence

There was important expert evidence from Ms Eyres for the claimant and Mr Mason for the defendant.

They disagreed about the appropriate reaction times with the judge preferring the evidence of Ms Eyres because her evidence was “careful and considered”.

On the issue of perception/reaction time, Ms Eyres suggested 2.2-2.7 seconds based upon research from Muttart, while Mr Mason said a more appropriate time was 1-2 seconds. The judge was critical of his approach, firstly because Mr Mason made the assertion without explaining how he came to his figures. Also, after seeing Ms Eyres’ report, he criticised the use of the Muttart figures whilst still failing to provide any explanation as to why his time should be prefered. At trial under cross examination, Mr Mason for the first time said his opinion came from research in a well-known book written by Kraus which he contended was widely accepted by experts. However, Kraus’ book was not produced and Ms Eyres was never directly cross examined about this research. The Judge said “…it is axiomatic for any expert to explain their reasoning for the opinion they come to and Mr Mason’s failure to provide this in his report seriously undermined his evidence.”

There was an argument about whether the use of the research by Muttart was acceptable because the defendant asserted it was applicable only to high speed roads and not of relevance in this case. The judge acknowledged that Muttart’s work was “difficult to follow” but was satisfied having read the explanation of Ms Eyres that it was not only limited to high speed roads. The footnotes that set out “Limitations for Use” of the Muttart data did not suggest it was only suitable for situations where approaching speeds were over 35mph.

The judge acknowledged that it was common ground that the table in Muttart did not include a “detection and recognition phase”. This was a period where the hazard was not recognisable, something which needed to be added to the Muttart table figures. Therefore the judge concluded that the Muttart table was an appropriate guide to use, however some additional time needed to be added to his figures.

The experts agreed that flashing lights would have potentially increased visibility but the judge concluded the presence of lights do not automatically mean a vehicle is stationary as opposed to slow moving.


The judge found for the claimant on the following basis:

  1. It was common ground the lorry created an obstruction.
  2. The obstruction was dangerous because the lorry blocked both lanes and created a risk of collision with the potential for very serious injury. Whilst the illumination of the lorry created an element of visibility, rotating flashing lights off the tunnel walls did not provide any significant assistance and could be easily confused with movement.
  3. The Judge did not accept that creating a dangerous obstruction was justified in all the circumstances. Dangerous obstruction may be justified in an unavoidable situation e.g. a well maintained car that breaks down without warning. However, in this case the lorry driver heard a noise. He could and should have continued slowly with flashing lights to stop further up the road where the lane divided into two and there would have been less of an obstruction.

In summary the lorry driver parking up the lorry in the position he did was negligent as his actions created a dangerous and unjustified obstruction.

Contributory Negligence

The judge accepted that the claimant was guilty of contributory negligence but not gross negligence as alleged by the defendant. In the circumstances he rejected the argument that there was a break in the chain of causation. It followed that there should be an apportionment of liability between the negligence of the claimant and defendant.

The judge concluded that the claimant should not have moved from one lane into the other until he was capable of seeing and assessing what was in front of him. He should have seen the flashing lights in lane one which would have alerted him to a potential hazard ahead.  Therefore the claimant in “nipping between lanes” and entering the slip lane without ensuring it was safe to do so failed to take reasonable care.

The claimant contended that the degree of apportionment should be 85/15 split in favour of the claimant and the defendant contended for 30/70 in favour of the defendant.

The judge provided detailed reasons in arriving at his conclusion but the lorry driver who created the obstruction should bear the greater blame for the accident and the appropriate apportionment was 60/40 in favour of the claimant.

Practice Points

  1. The judgment provides useful guidance in relation to the likely approach of the Court in considering whether a driver has been negligent in causing a dangerous obstruction on a carriageway.
  2. The normal test to be applied is whether the person stopping their vehicle has acted reasonably in accordance with what a reasonably prudent driver would do when faced with such circumstances.
  3. The first question is whether the obstruction was dangerous i.e. did it cause a foreseeable risk of injury to other road users? If the obstruction was dangerous was it reasonable to cause such a risk in all of the circumstances?  There will be occasions where a dangerous obstruction is not negligent, for example where a well maintained car unexpectedly breaks down and it is not possible in the circumstances to move it to a safer place.
  4. If causing the obstruction is negligent as identified above, are the actions of the driver who collides with the obstruction grossly negligent, breaking the chain of causation so that damages would not flow from the initial dangerous obstruction?  In this regard the actions of the driver running into the dangerous obstruction would have to be highly culpable to achieve such a result.
  5. Has the driver running into the dangerous obstruction been negligent in failing to stop or break and swerve to avoid the collision? This question will be fact specific depending on matters such as visibility, speed, lighting, traffic conditions and perception reaction time.
  6. If the person causing the dangerous obstruction and the person driving into such obstruction are both negligent how should respective culpability be apportioned?  Again this exercise is fact specific depending on the degree to which the dangerous obstruction is culpable, and the degree of the person’s culpability who ran into it.

The case also highlights the crucial importance of carefully preparing and presenting accident reconstruction evidence. The judge preferred the evidence of Ms Eyres on perception reaction time because the expert had properly explained her figures by reference to the research of Muttart, compared to Mr Mason who failed to reference the research of Krauss until cross examination at trial. Ultimately this led to the court accepting a relatively long perception reaction time for the claimant.

Jamie McCabe

Jamie McCabe


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