In trail days, "reading trail" or "reading [Indian] sign" was vital to the welfare of emigrants. This science made use of any evidence that something or someone had been over the ground. An experienced scout could tell from a broken blade of grass, disturbed soil, tracks, a bead, a feather, or dung, such things as what game was near; how many Indians of what tribe had proceeded, when and in what direction; the number of horses, how fast they had been moving, and whether they had been mounted or stolen; whether it had been a hunting party or a whole camp moving; whether an individual had been walking, running, or attempting to leave a false trail.
Today reading trail can be a rewarding pastime as well as essential for serious trail students. And, since authentic trail ruts are the most valuable and interesting resources connected with historic trails, something should be said here about reading and interpreting them.
Because so many current ranch and mineral development/production trails and roads look more like the old trails than the old trails do, it is not always easy to identify authentic trail ruts. There are, however, some guidelines. The romantic notion that trail ruts are always two lines stretching into the sunset is just that, romantic. Where possible, westering Americans usually traveled several abreast to avoid breathing dust. All kinds of parallel trail ruts also developed because of water, land features, or browse. Swales (saucer-shaped depressions) in the landscape 50 to 100 feet wide, developed where wagons traveled abreast and close to each other. At other times, what would property be called "trail corridors" (up to 1 mile wide) developed.
Trail followers should do their homework and have good maps so that they know in advance approximately where trail ruts should be. Most modern trails, or disturbed land (a buried pipeline for instance) run straighter than the old trails. That modern tire tracks can be seen only means someone recently drove down the old trail.
One should study the overall terrain well, especially the vegetation. Sometimes the vegetation is fuller in old ruts, sometimes it is sparse. In some areas where the hard topsoil was broken up (and continually fertilized by the draft animals) rain water penetrated deeper and, as a result, the growth is more lush, even today. It is also true that ruts tend to collect water, which aids growth. In some instances, however, the broken topsoil was simply blown away, leaving a poorer subsoil which, even today, supports only sparse growth. The best way to learn to read trail is by experience.
In the matter of protecting trail ruts, someone once said in reference to following the old trails, "Take nothing but photographs; leave nothing but footprints." Good advice. Ruts are not as fragile as many think. They were created, after all, by plodding animals pulling wagons weighing tons and rolling on iron tires! They can be damaged, however, by careless use of motorcycles and ORVS, and totally destroyed by road crews, agriculture, urban sprawl, utility corridors, pipelines, mining and other extractive industries, and a host of other modern activities. Walking in ruts seldom causes damage to them, it may even help preserve them. Even careful driving in ruts might do no harm. Proper management, legislation, and parameters for use should be sought.Source: Historic Resource Study - Mormon Pioneer National By Stanley B. Kimball, Ph.D., May 1991. (The study focuses on the history of the trail from its official beginning in Nauvoo, Illinois, to its terminus in Salt Lake City, Utah, during the period 1846-1869. During that time, thousands of Mormon emigrants used many trails and trail variants to reach Utah. This study emphasizes the 'Pioneer Route' or 'Brigham Young Route' of 1846-1847. The sections on Mormon beliefs and motivations for going west have been omitted. Interested persons can find ample sources for that information. The footnotes, bibliography, maps, pictures, pioneer companies by name and dates for the 22-year period, and historic sites - about 2/3 of the book - have also been left out for space considerations. Thanks to Dr. Kimball and the National Park Service for the availability of this information.)