Distinct from the situation of loose horses straying on to the road is the case where a horse with a rider comes into contact with traffic. This will sometimes lead to the rider either suing the driver or the driver suing the rider and with a subsequent counter claim.
Road safety is of paramount importance to horse riders due to the high risk of being injured on the roads or endangering others.
Although some horses are described as being “bombproof in traffic” all horses are unpredictable creatures and will usually retain an element of nervousness when close to large vehicles or agricultural machinery. There is also the risk of a horse ridden along a road spooking at something in a hedge or on the pavement and shying into the path of passing traffic. Therefore it is useful to see how the Courts have approached the question of who is to blame when there is a ridden horse/vehicle collision.
Claims against horse riders will usually be brought under the Animals Act 1971 and in negligence, whereas claims by horse riders against drivers will be in negligence.
An example of an unsuccessful negligence claim against a horse rider is Haimes v Watson  CA. The horse was being ridden by the Claimant along a country lane when it shied into the path of the Defendant’s car. The Claimant’s claim was settled and it came to trial on the Defendant’s counterclaim for his damaged car. The Court of Appeal overturned the trial judge’s decision that the horse rider was liable in negligence for failing to control his horse. In a decision firmly on the side of the horse rider, the Court of Appeal held that the trial judge’s decision was tantamount to imposing an absolute duty on a rider of a horse on a road to prevent it from going out of control. The rider’s explanation that he did his best, but could not stop the horse from moving out into the path of the car, was thought by the Court of Appeal to be sufficient to avoid liability. The horse behaved in a sudden and unpredictable way and the Defendant had not called any evidence to show that the Claimant could have done anything about it.
On similar facts, the Court of Appeal again sided with the horse rider in Clark v Bowlt  EWCA Civ 978. It overturned the first instance decision that the rider was liable under s.2 of the Animals Act 1971, negligence against both the driver and the horse rider not being made out. The Court of Appeal said that the trial judge had got into a muddle and had overlooked the need to link the characteristic in s.2(2)(b) with the risk of injury in s.2(2)(a). Lord Justice Sedley said that the accident was an unfortunate mischance and there was no liability under the Animals Act 1971 because “Section 2(2) is not intended to render the keepers of domesticated animals routinely liable for damage which results from characteristics common to the species. It requires something particular, and there was nothing of the specified kind to render the keeper liable here.”
Recently the Court of Appeal considered the respective liability of a teenage horse rider and a car driver when there was a collision between the two, but not as a result of an unexpected movement by the horse. In Stoddart v Perucca  EWCA Civ 290 liability was apportioned 50:50 between the Defendant driver and the 14 year old Claimant horse rider. The Claimant was riding with a friend down a bridleway which met a road. The Claimant’s friend had already crossed the road on her horse but there was a short gap before the Claimant emerged as she had taken a jump in an adjoining field. The Claimant rode straight out into the path of a camper van and there was a collision between the camper van and her horse which fell on her.
The Court of Appeal upheld the trial judge’s apportionment of liability commenting that starting from a realistic appraisal of blameworthiness as being greater in the Claimant than the Defendant, he was required by law to adjust that apportionment for the relative potency of the vehicles (I include both the horse and the car in that phrase) involved in the accident. The accepted concept in pedestrian cases that a car driver has a high burden to reflect the fact that a car is potentially a dangerous weapon (Lunt v Khelifa  EWCA Civ 801) clearly had a part to play in adjusting liability to equal parts although the Claimant was more blameworthy.
In can be seen from these cases that car drivers are likely to have difficulty in making out a case of negligence when a horse unexpectedly moves into their path and the driver cannot point to any obvious lack of skill or fault of the rider in failing to control the horse. Further, even where there is obvious, and perhaps greater, fault on the part of the rider, drivers should expect the Court to include in the assessment of liability that greater causative effect is likely to be attributed to the car driver.