The British Horse Society (BHS) is urging drivers to slow down to 15mph when they meet a horse and rider on the road.
Its Dead Slow campaign follows the revelation that in the last five years 36 riders and 181 horses have died as a result of incidents on the road.
Seventy-five per cent of the 2,000 incidents reported to its horse accidents website have been attributed to vehicles getting too close to the animal while passing. A quarter of respondents also said they had been subjected to road rage while riding.
Lee Hackett, director of policy at the BHS, said: “We are asking drivers to slow down to 15mph when they see a horse on the road.
“A lot of people aren’t sure how to safely pass a horse when driving, and so we have produced a video showing exactly how it should be done.
“It’s worth remembering that these statistics are just the accidents reported to us, there will be countless others. Almost everyone who rides horses can recount a story about a time they had a near miss on the roads.
“We are campaigning for legislative change, but that can take a long time. That is why we are asking for this instant change in behaviour from drivers.”
The launch of the campaign follows the injury of horse carriage master Mark Evans and the death of his horse Wil, who was hit by a car in Wales last month as he pulled a funeral cortege.
The BHS figures reveal that the majority of incidents occurred on minor rural roads. Of the 2,070 respondents, 1,799 were involved in an accident in England, 146 in Wales, 115 in Scotland, and 10 in Northern Ireland.
Lancashire saw the third-highest number of road incidents, with 81 reported to the BHS site. It came just behind Essex, with 155 reported road accidents and Kent, with 89 road accidents.
Kevin Clinton, head of road safety at the Royal Society for the Prevention of Accidents, said: “Horses are large, powerful animals and they can easily panic and bolt if startled. This is dangerous for the horse, the rider and other road users.
“All drivers should be aware that they may come across horse riders at any time, especially in rural areas.
“If you see one, slow right down as you approach and pass it slowly and smoothly, without revving your engine or sounding your horn. If there’s not room to pass it safely, wait until there is.”
Horse accidents can be reported to the BHS at www.horseaccidents.org.uk