Many drivers see horses as a hazard on the road.
But horses actually have the right of way and should be given a wide berth by drivers.
They are, however, even less predictable than most car drivers - twitchy, nervous and likely to react badly if frightened.
Road safety charity the Institute of Advanced Motorists gives the following advice.
Don’t risk startling them by rushing up or making sudden noises when passing.
Give them enough space: riders are reluctant to take a horse on to the verge, as long grass can hide a multitude of hazards.
Horses don’t like standing still for long periods - if you are stopped in a queue, give them plenty of fidgeting room.
If you catch a horse up from behind, give it and its rider time to see you, this is even more important in a hybrid or electric car, which are quieter – they won’t like a surprise.
In traffic, most riders won’t use the right hand lane to turn right, as this puts the horse between lanes of moving traffic. Respect the rider’s decision.
Horses will often ride side by side on the road. This isn’t so their owners can have a chat – it is to protect less experienced, or nervous, riders and horses in traffic.
In urban areas they will do this to claim road space for improved safety.
IAM chief examiner Peter Rodger said: “Summer sees more vulnerable road users on the road. They have as much right as car drivers to be there, but a lack of understanding puts them at risk.”