Rachael Wilsey said it was lucky her horse Oscar did not leap out into the car’s path after her husband James caught the frightening incident on camera.
She was returning to the stables after a ride when she saw the driver hurtling towards her on the B1403 joining Misterton and Gringley-on-the-Hill.
She said: “I could tell the driver wasn’t slowing down from about 50 metres away.
“At the point of realising she wasn’t adjusting her driving at all I put my arm out and slowly waved it up and down signalling for her to slow down.
"She didn’t respond at all and was completely oblivious.
“Drivers should pass a horse and rider at 15mph and leave at least a car’s width between their vehicle and the horse.
"We think this driver went past us at about 55mph.
“I drew breath and was just praying she would slow down. It was really frightening because you have no idea what your horse is going to do.
“I knew I had to keep calm and stay absolutely relaxed because horses can feel your muscle tension.
“What non-horse people don’t know is that horses can jump sideways as well, either into the path of a vehicle or away from it.
“If a 660kg horse like Oscar jumps and lands on someone’s bonnet then it’s going to kill the driver.
“It was absolutely awful and I just wish drivers would slow down and be more responsible.
"It just takes 30 seconds to get past and I’d ask drivers not to accelerate until they have fully gone by a horse.
Rachael said it was the second bad experience she had with a speeding car on the same road that same day while riding her nine-year-old Irish sport horse Oscar.
She said: “I have to go onto the road to get to the bridleway. We had just left the yard when another driver was coming past too fast.
“James waved at him to slow down but he just shouted abuse out of his convertible.
“Oscar isn’t a spooky horse and he was very good on the road until last year when a truck sped up before letting us past.
"It went through a big puddle and the sound of that scared him.
“That time he leapt away from the vehicle. It took about two months with a semi-professional rider before he could go back onto a road and so he wouldn’t jump.
“Horses learn from experience. It only takes one time for a horse to get frightened and for it to get strongly embedded in their behaviour.
"It can ruin a horse and take them months to get back on track.”
Police Constable Tanya Hodgkiss, of Nottinghamshire Police, said: “It’s a potentially fatal disaster for all parties involved if a vehicle and a horse have a collision.
“It’s important that drivers are reminded that horses are allowed on the roads.
“The Safer Neighbourhood Team at East Bassetlaw has received several reports of vehicles passing horses far too closely and at speed that are legitimately using the rural country roads to access bridleways.
“I would ask motorists to please bear in mind that horses are extremely nervous animals and to please give enough room when passing a horse rider.
“Horses should be passed wide and slow, leaving at least the width of a car and travelling at 15mph or less.
“We all need to share the highways and have respect for each other.
"This means thinking about those who might be more vulnerable than you and altering your speed accordingly."