I have recently managed to dig up some old documents from the earliest days of car regulation. Here is a report from NHTSA on the state of affairs near the turn of the 20th century.

National Horse Trail Safety Administration (NHTSA)

Regulation of new Horse-Auto-mobile Vehicles (HAV), sometimes known as "Horseless carriages."

In recent years, we've seen much excitement about the idea of carriages and coaches with the addition of "motors" which can propel the carriage without relying entirely on the normal use of horses or other beasts of burden. These "Horseless carriages," sometimes also known as "auto mobile" are generating major excitement, and prototypes have been generated by men such as Karl Benz and Armand Peugeot, along with the Duryea brothers, Ransom Olds and others in the the USA. The potential for these carriages has resulted in many safety questions and many have asked if and how NHTSA will regulate safety of these carriages when they are common.

Previously, NHTSA released a set of 4, and later 5 levels to classify and lay out the future progression of this technology.

Levels of Motorized Carriages

Level 0

Level zero is just the existing rider on horseback.

Level 1

Level one is the traditional horse drawn carriage or coach, as has been used for many years.

Level 2

A level 2 carriage has a motor to assist the horses. The motor may do the work where the horses trot along side, but at any time the horses may need to take over on short notice.

Level 3

In a level 3 carriage, sometimes the horses will provide the power, but it is allowed to switch over entirely to the "motor," with the horses stepping onto a platform or otherwise being raised to avoid working them. If the carriage approaches an area it can't handle, or the motor has problems, the horses should be ready, with about 10-20 seconds notice, to step back on the ground and start pulling. In some systems the horse(s) can be in a hoist which can raise or lower them from the trail.

Level 4

A Level 4 carriage is one which can be pulled entirely by a motor in certain types of terrain or types of weather -- an operating domain -- but may need a horse at other times. There is no need for a sudden switch to the horses, which should be pulled in a trailer so they can be hitched up for travel outside the operating domain.

Level 5

The recently added fifth level is much further in the future, and involves a "horseless" carriage that can be auto mobile in all situations, with no need for any horse at all. (It should carry a horse for off-road use or to handle breakdowns, but this is voluntary.)

(Level 5 was just added based on input from the Society for Advanced Equestrianism (SAE) to make it clear that these horseless carriages will at first only be able to operate in limited areas.)

Communications

We believe that in order to build carriages above level 3, these horseless carriages must be able to communicate with one another. Horses have an innate herding sense and communicate to other horses. It will be a great challenge for the horseless carriages to mix with these vehicles. We have proposed that the coachman in an HAV regularly shout out messages in a variety of protocols under design:

• WHINNY (Well Horse IN New Yaw) -- announces upcoming steering decisions
• WHOA (Well Horse Opposite Acceleration) -- to signal braking
• NEIGH (Near Emergency Immediate Gallop by Horse) -- to signal alert or sudden speed changes
• YEE-HIA (Yell Equine Event -- Here I Am) -- reports position of carriage to other carriages, also known as the BSM (Bronco Status Message)

Coachmen with horseless carriages, placed on the roof of the coach as they usually are, will be able to shout these messages or use semaphores to alert other coachmen of changes in path or velocity.

States

While NHTSA has not made any regulations around the levels, in some states the Departments of Manure Viscosity (DMV) which previously have mostly dealt with horse emissions are examining regulation of horseless carriages. In particular, California decided to initially not permit level 4 and above (carriages with no horse). In addition, Vermont and the UK both have passed laws requiring that any horseless carriage be preceded by a footman waving a red flag or lantern to warn bystanders of the approach of the carriage. Pennsylvania passed a law that upon encountering cattle, operators of horseless carriages should immediately stop and dismantle the automobile to hide the components to avoid aggravating the livestock, but the governor has not yet signed it.

NHTSA is planning to require all developers of these horseless carriages to comply with its new 116 page regulations. It is unusual for us to regulate before a technology is developed but we feel it is necessary this time. The regulations include 16 items which each vendor is asked to certify compliance with, however at present they are technically voluntary. Vendors wishing to take on extra legal risk in lawsuits can state that they decline to comply.

Our new regulations include rules on how the motor should be harnessed safely to the carriage, rules about the connection and disconnection of horses from the system, and the use of the reins, along with the whip, to control motor speed and direction. We believe the traditional rein/whip based interface is the one most familiar to coachmen. Rein/whip has had extensive user interface studies and there is a large body of literature, while proposed wheel/pedal/lever interfaces are almost entirely unknown.

Response to critics

We at NHTSA are excited by this new technology, but some feel it is shortsighted to classify and regulate these new carriages from the primarily context of the role horses play in them. We point out that they are still carriages, and we at NHTSA and the state DMVs, as well as those at SAE have decades of experience with carriages of all sorts and how to pull them. The safety rules we have learned still apply, and our expertise in this area is considerably more than that of men like Karl Benz and others. For example, we have seen reports that Karl Benz recklessly allowed a woman (!) to operate his carriage with no horse over a 65 mile journey. While the woman had two young males to assist her, this is an example of the disregard for safety we have seen from these otherwise laudable pioneers.

We are happy to work with such men, but we know how to ensure safety with this technology and want to put regulations in place before too many of these carriages get on the road. These new carriages are unlike the steam powered prototypes seen previously, and they have the potential to massively change the world.