I live on a large farm with a lot of land, but even so, I like to trail ride out on the road. Some people have never had this cool experience before, and many find it strange, but it is actually a lot of fun! Where I live, there are many, many, miles of country back roads, and the amount of cars coming by are not bountiful, we are lucky to get six in one hour. These are the best kind of roads to ride on, you definitely do not want to be on a public road with cars whizzing by every few seconds… safety FIRST!!!
If you take your horse to shows, he is probably used to noise, vehicles, and a variety of sights, but he may not necessarily be used to the idea of a car passing in close proximity to him on a road, or zooming by; most people slow down when they see a horse and rider out on the road, but not all do, and these are the ignorant people that you have to watch out for. Some people think it is cute or funny to honk their horn as they pass you and your horse on the road; as riders, we know that there is no humor in this situation; it is extremely dangerous. A startled horse has a tendency to run or act up, and you must be prepared to cope with the situation.
As I train my young horses, I ride them on the road to desensitize them, but only after I know that they are far enough along that they will listen to me if something happens to scare them. I train them to ride out on the road, as I know that they will be ridden on the road in the future. But, if you have an older already trained horse, and you want to make him comfortable on the road, lead him out there for a couple hours a day and let him graze along the road. As cars pass, see how he reacts. Even if he is eating, how he reacts to cars while on the roadside grazing will give you almost a perfect example of how he will react when being ridden. I also advise that he not startle and spook easily, as some people who do not know better WILL honk their car horns as they go by and alarm your horse. Do some spook training with him on noises BEFORE riding or leading him on the road.
Gear for road-riding will be slightly different than for regular riding. For you, it would be wise to wear a body protector, a reflective vest, and a helmet, along with your regular riding gear (jeans or breeches, boots, maybe chaps or half-chaps, a riding friendly shirt, and gloves). A spill while riding on the asphalt is definitely going to cause more damage than an accident in the field or arena, and you don’t want any injuries that CAN be prevented. For your horse, you may wrap his legs or put tendon/brushing boots on him, outfit him in bell boots, or use knee protection, all to keep him safe should he slip or fall.
After he is used to cars, take him out for a short hack and see how he does. Always watch AND listen for oncoming cars. Coming around a turn, a car will most likely not see you. I advise staying on the outside shoulder of the road when encompassing a long turn that you cannot see around, going against the flow of traffic. If you horse does well riding on the road quietly, does, you can go for a longer ride each time, until you are riding to a friend’s house if you want to!
As you go though, please remember to keep an eye and ear open for cars so that YOU are aware of approaching traffic even if your horse is not. In most cases, the horse will hear the traffic even before you do, and flick his ears and listen as it comes. If he happens to spook because of a loud engine or horn, sit calmly, and relax yourself as much as possible to let him know that it was just a noise; most times, the horse may jump forward a few steps, but once he realizes that you are unafraid, he will settle to just flicking his ears around, and then becoming placid as his usual self once again.