# Truck Axle Weights and Interaxle Spacings from Traffic Surveys in Mexican Highways
## 3 Logistics, Equipment, and Survey Procedure  
### Survey in 2016  
The first survey was conducted on 13 September 2016, from 11 a.m. to 7 p.m. (local time) on the Irapuato-Zapotlanejo (designated as MEX 90, type A4) highway approximately at km 7 + 000 (i.e., at km number 7 with zero extra m; this format applies to other cases  
Figure 1: Surveying sites. (**Top**) Irapuato-Zapotlanejo highway, (**a**) plan view and (**b**) profile. (**Bottom**) Guanajuato-Los Infantes highway, (**c**) plan view and (**d**) profile. Through Google Maps. below). This is a two-way, four-lane highway that allows heavy traffic [22]. The location was chosen based on a previous inspection by IMT; the decision was also based on space, visibility, pavement conditions, and for security reasons, among others. The equipment was a portable PAT scale, model DAW 300 PC, NS 291 [22], with a calibration certificate IC-IP-039/14 issued in October 2014. The equipment weighs loads, statically or dynamically (for low speeds), by means of two platforms, axle by axle. According to the manufacturer the precision is around 3%; nevertheless, the IMT reports that from their laboratory calibration and adjustments [22], they obtain deviation no larger than \(\pm\) 50 kg by axle with a resolution of 10 kg. Traffic devices for signaling were used as aids in the surveys. Figure 2 shows images of the equipment (e.g., platforms, software, and other devices). To carry out the survey, equipment was installed beside the highway in one of the traffic directions (Irapuato-Abasolo direction). Originally, it was planned to carry out the survey in both directions with the aid of the Federal Police; however, the attempt was unsuccessful because aid was not obtained in time. Therefore, it was decided to ask heavy truck drivers at a nearby gas station to help us by allowing the IMT crew to weigh their vehicles. This resulted in only 19 vehicle axle weights being recorded. The total weights along with the axle weights are listed in Table 1 in the DOI associated with this data [17]; they are also reproduced, described, and discussed later. Unfortunately, for the 2016 surveys, the axle spacings were not measured; nonetheless, IMT provided typical axle spacing for each truck designation in Table 1 based on different sources [22], as shown in Table 2 given later (see also the associated DOI [17]), and spacings were designed by axle number to axle number (from the front part to the rear part of the trucks). Figure 3 illustrates the execution of the survey. Figure 2: Surveying equipment. (**a**) Portable PAT, (**b**) Recording hardware, (**c**) PAT in site, (**d**) Signaling devices. Pictures are either by the authors and/or by the IMT reports hired by UG, e.g., [22]. The second survey was conducted on 5 October 2016, on the Guanajuato-Los Infantes (designated as MEX-110-GTO, type C) highway at km. 6 + 000. This is a two-way, two-lane highway where heavy traffic is not allowed (K \begin{table}
\begin{tabular}{l c c c c c c} \hline \hline
**Truck** & & & & & & \\
**Designation** & **Axle 1** & **Axle 2** & **Axle 3** & **Axle 4** & **Axle 5** & **GVW** \\ \hline PICKUP 3 1/2 & 13.93 & 18.53 & - & - & - & 32.46 \\ PICKUP 3 1/2 & 21.57 & 32.26 & - & - & - & 53.84 \\ PICKUP 3 1/2 & 16.38 & 48.25 & - & - & - & 64.63 \\ PICKUP 3 1/2 & & & & & & \\ with two-axle & 12.36 & 30.89 & 32.36 & 5.30 & - & 80.90 \\ towing & & & & & & \\ C2 & 15.98 & 17.06 & - & - & - & 33.05 \\ C2 & 21.48 & 21.77 & - & - & - & 43.25 \\ C2 & 22.46 & 22.16 & - & - & - & 44.62 \\ C2 & 19.71 & 25.01 & - & - & - & 44.72 \\ C2 & 27.07 & 24.81 & - & - & - & 51.88 \\ C2 & 28.15 & 33.73 & - & - & - & 61.88 \\ C2 & 26.28 & 41.48 & - & - & - & 67.76 \\ C2 & 30.69 & 39.13 & - & - & - & 69.82 \\ C2 & 28.83 & 42.76 & - & - & - & 71.59 \\ C2 & 22.75 & 50.80 & - & - & - & 73.55 \\ C2 & 44.82 & 31.77 & - & - & - & 76.59 \\ C2 & 33.34 & 45.11 & - & - & - & 78.45 \\ C2 & 43.44 & 59.62 & - & - & - & 103.07 \\ C2 & 43.64 & 65.61 & - & - & - & 109.25 \\ C2 & 33.24 & 79.24 & - & - & - & 112.48 \\ \hline \hline \end{tabular}
\end{table}