If you are a trekking enthusiast or if you have been dragged “forcibly” by your friends into the mountains, you will surely have asked yourself at least once: but how are the average times of the paths calculated? It often seems like they don’t get it right: for some, reading that number is a psychological obstacle even before leaving, for others it becomes a personal challenge to overcome. Yet, those numbers are not random. The site of CAI (Club Alpino Italiano) explains that there is a precise method, based on a complex mathematical formula but which can be represented in a very intuitive way through a graphic. The distance averages calculated in this way taking into account distance and altitude difference do not serve to establish new records, but to guarantee the safety of people: slightly overestimating the time, in fact, allows even those who are less trained to plan their return in time (before, for example, the sun goes down) and to tackle the route without risks, walking at the right pace and taking the right breaks.
The reference system used was created by the Swiss institute Schweizer Wanderwege and is represented as a Cartesian graph with the distance travelled on theX axis (horizontal) and the height difference (positive if you go up, negative if you go down) onY axis (vertical).
To obtain a precise calculation, the route of the path surveyed col GPS it is not analyzed en masse, but it comes divided into many small parts. Within this graph, there are some red curved lines: each of them represents a minute. To calculate how long it takes to travel a distance, you look at the intersection point between the distance (black vertical line) and the difference in height (black horizontal line). The exact point where these intersect will fall on a specification red line of time. By adding the results of all the small segments, you get the total time of the excursion.
To better understand the differences, let’s take a long stretch of path 1000 meters and let’s see how the time changes based on the slope:
- Flat: if we travel those 1000 meters without any difference in altitude, it will take us approx 14-15 minutes.
- Uphill: if the same 1000 meters have a positive difference in altitude of 100 m, the time expands, reaching approximately 20 minutes; if the positive difference in height is 300 m we will make use of it 49.
- Downhill: the time is reduced compared to the climb when the difference in altitude is small (– 100 m in 14 minutes). When the difference in altitude is large, however, the descent requires caution and the time does not decrease as one might think (– 300 m in fact they are traveled on average in 27-28 minutes).
This model is designed to calculate timescales up to one maximum slope of 40% (for every 100 meters traveled horizontally, you go up (or down) 40 meters vertically (or vice versa). Beyond this threshold we are no longer talking about simple hikingbut you enter the territory ofmountaineering.
Often the times indicated on CAI signs are perceived as overestimated by those who are more trained. This is because it is one general averagewhich takes into account not only expert hikers, but also families or older and older people. The goal of these estimates is not to establish performance, but to ensure performance safety. Calculating slightly longer times, in fact, will allow everyone, even the less trained, to plan their return and avoid unnecessary risks – such as walking in the dark or facing sudden drops in temperature for which they may not be equipped.
