Horses and highways are a volatile and dangerous mix.

Recent evidence was a tragic accident near Milton, a tiny town just north of the Massachusetts-New Hampshire border. Lincoln Geist, an elderly man driving on a rural road, hit a horse and rider. The teenage girl was thrown to the ground and suffered a fractured pelvis; the horse, named Blue, suffered severe internal injuries and was euthanized by a veterinarian at the scene. Geist briefly slowed his automobile after the collision, and then drove away without offering any assistance to the stricken horse and rider.

Geist later called police from his Sanbornville home and reported that "he believed he had struck a horse," according to Lt. Richard Krauss of the Milton Police Department. Although the accident occurred in mid-afternoon, Geist reportedly told police that he didn’t see the horse and rider.

Geist was charged with a Class B felony for leaving the scene of an accident, a serious offense not limited to automobile-horse collisions. But what about the more mundane, equine-specific traffic laws? My highly unscientific—and by no means comprehensive—survey showed that many states have specific rules of the road governing the conduct of horses, drivers of horse-drawn buggies, and automobiles.

Everyone should know these laws, whether you’re riding a horse, driving a horse-drawn buggy, or sitting behind the wheel of an automobile or truck.

Rules for Automobiles

At least a dozen or so states require automobile and truck drivers to take care when approaching a horse. The law in New Hampshire, where Blue and his rider were struck, is typical:

"Every person having control or charge of a vehicle shall, whenever upon any way and approaching any horse, drive, manage, and control such vehicle in such a manner as to exercise every reasonable precaution to prevent the frightening of such horse, and to insure the safety and protection of any person riding or driving the same."

The language is tortured, not a surprise for state statutes, but the legislative intent is crystal clear: Drivers should slow down and move over when sharing the road with a horse. This should be common sense, not requiring a law.

Rules for Riders

Traffic laws in a few states, including Colorado, Michigan, and New Mexico, specifically state that horses have all the rights and obligations of other vehicles when they are being ridden or driven on a public highway. Everywhere else, except in states like Louisiana where it appears to be illegal to ride a horse on a paved road, riders and drivers probably enjoy similar rights and obligations by implication.

Some states prohibit specific conduct when riding on a highway: It is illegal to ride a horse at night in New Mexico; to cross bridges at a gait faster than a walk in Idaho, Mississippi, and Pennsylvania; to ride or drive a horse "recklessly" in Nevada; to race or run horses on a highway in Kentucky, New Jersey, Pennsylvania, New York, or New Jersey; to ride on a levee in Kentucky; and to ride on interstate highways in several states. Horses should be ridden on the right-hand side of the road, going with the flow of traffic, almost everywhere except Colorado, where riders must ride on the left.

Rules for Horse-Drawn Buggies

Horse-drawn buggies are considered "slow-moving vehicles" in several states (Colorado, Kentucky, Iowa, Missouri, and Ohio among them), a classification requiring some sort of warning emblem on the buggies. There is little debate about whether these brightly colored, reflective warning emblems make horse-drawn buggies more visible—they do—but objections to the emblem requirement from a conservative Amish sect in Kentucky have drawn national attention.

Several members of the strict Swartzentruber sect faced fines or jail time for refusal to equip their buggies with the state-mandated emblems, claiming that the emblem requirement violated their constitutional right to freedom of religion. The Kentucky Court of Appeals upheld the constitutionality of the statute last year, and the case now is heading for the state supreme court. The Kentucky legislature is considering bills that would amend the warning emblem requirement to allow reflective tape in lieu of the warning emblems.

Finally, horse-drawn sleighs cannot be driven on highways in New Jersey unless they are equipped with a "sufficient number of bells attached to the horse’s harness to give warning of its approach." Just how many bells are necessary is left to the sleigh driver’s judgment.

Do the traffic laws in your state provide enough protection for horses being ridden or driven on the highway?