Which permit each excess of weight or dimensions calls for in Mexico, which authority issues it and how long it actually takes. And the detail that kills more installation dates than any other: the federal permit alone never gets you to the plant gate.
In Mexico the reference is NOM-012-SCT-2-2017, which sets the maximum weight and dimensions a commercial vehicle may run with on federal-jurisdiction highways. As long as the load fits inside it, it is a normal shipment. The moment it exceeds any of those values, it stops being one and may not run without prior authorization.
General values from NOM-012-SCT-2-2017, published in the DOF on December 26, 2017. The standard sets the exact value per vehicle configuration and per road class (ET, A, B, C and D). The maximums of an ET-class highway are not those of a C-class one, so the same shipment can be legal on one segment and over the limit on the next. Verify against the current text.
The order matters: first you know where it will run, then you know which permit it needs. It does not work backwards, because the permit that applies depends on the road class, and the road class comes out of the route survey.
Here is the mistake that costs the most, and it is not made by the one who knows nothing: it is made by the one who already pulled the federal permit and assumes that covers the trip. In Mexico the authority changes with the road, and a normal industrial move in the Monterrey metro area touches all three.
The SICT authorizes circulation on federal-jurisdiction highways. It is the permit everyone talks about and the one that covers the long leg of the trip, the highway.
State highways have their own authority and their own filing. A bypass or the road that connects to the industrial park is almost never federal, even if it looks just as wide on the map.
The last leg, the one that enters the city and reaches the gate. In Monterrey it is granted by the Traffic and Roads Directorate under the municipal traffic regulations.
The municipal one is the most overlooked, and it stops the move less than a kilometer from the destination, with the load on the trailer and the crane already rented and waiting on the other side. In Monterrey the procedure is published as P-SEG-VIT-06, permit to circulate with excess dimensions, and it covers load that sticks out from the trailer to the sides, above or behind. Each municipality in the metro area has its own, so a trip crossing three municipalities can require three separate authorizations.
The core permit of specialized transport. It authorizes one specific move, with its origin, destination and route, for load exceeding the standard's weight or dimensions. It is filed with the SICT and it is per trip: it is not a general license pulled once that covers the whole year.
It connects two segments: it allows running on B-class highways with the gross vehicle weight authorized for ET and A classes, as long as the distance traveled in each direction does not exceed 50 kilometers. It is the figure that solves the classic "the federal highway takes it, but the segment that reaches my plant is a lower class". The published resolution period is 60 calendar days, and that single number reshapes the planning of an entire project.
For loads over the standard clearance, the authority approves specific routes with a height above the general limit, on the order of 4.50 meters. It is not an open permit: it is tied to a route reviewed segment by segment, and it is the reason a detour cannot be improvised on these moves even with traffic stopped.
The last-mile one. It authorizes running inside the municipality with load that sticks out from the trailer. In Monterrey it is granted by the Traffic and Roads Directorate of the public safety secretariat, and it carries its own time-of-day restrictions, which in practice are what set the hour the move starts.
Almost none of these permits travels alone. It usually brings escort conditions, flags and signage, a travel window in low-traffic hours, restrictions against running at night or in rain, and in some cases coordination with the road authority or the power utility when lines have to be cleared. Those conditions are part of the permit, not suggestions.
Published lead times assume the file is complete on the first pass. In practice what blows up the timeline is almost never the authority: it is a missing data point that resets the filing. What has to be ready before submitting:
Running over weight or dimensions without the corresponding permit is a violation and gets sanctioned. The real cost, though, is rarely the fine: it is the unit detained with the load on it, the crane waiting at the site, and the installation window that closed.
The permit is tied to the carrier and its unit. We do not take it on faith: we verify it before assigning the unit, along with the currency of its insurance. It is one of the things that separate a coordinator from a middleman, and it costs nothing to ask your current provider whether he verifies it or just assumes it.
When the load exceeds what NOM-012-SCT-2-2017 sets: 2.60 m (8 ft 6 in) wide or 4.25 m (13 ft 11 in) tall as general maximums, the length that corresponds to the configuration, or the weight allowed for that configuration and road class. Exceeding any of them means filing before the move runs.
It depends on the road. The SICT on federal highways, the state government on its own highways, and the municipality inside the city. In Monterrey the municipal one is granted by the Traffic and Roads Directorate under the municipal traffic regulations.
It varies by type and authority. As a published reference, the special connectivity authorization has a resolution period of 60 calendar days. Per-trip permits are considerably faster, but they depend on the file being complete. That is why permit lead time gets calculated in the route survey, not at the end.
Not by itself. It covers federal-jurisdiction highways. The moment the move exits onto a state highway or enters city streets, the authority of that segment governs. The one that usually goes missing is the last one, from the highway to the gate.
The permit is tied to the carrier and the unit. Whoever coordinates the project builds the file and verifies the permit exists and is current before assigning. We verify it before assigning, instead of assuming the carrier has it.
Dimensions, weight, origin and destination are enough to know which authorities come in and how long they take. It comes inside the route survey, free.
