Average speed camera warning in Spain. Credit: DGT
Spain’s traffic authority has packed motorways and A-roads with average speed cameras in recent years, yet one design quirk still lets some drivers drop out of the calculation altogether.
Cameras at each end of a measured stretch time number plates from point A to point B. Take an earlier slip road and the second photo never happens, so no average speed, and no automatic ticket, can be produced for that control. This appears to be an error on behalf of the designers of these speed traps.
In the UK, average speed cameras are generally laid out so there are are no exits to wipe the reading. Spain’s DGT system only completes the sum when the same plate is timed at both published ends. Cameras are not routinely fitted on every slip road in between. That looks like a layout mistake on longer motorway stretches, not a trick the DGT has endorsed.
How average speed cameras actually work
Infrared cameras sit at the start and the finish of a signed section. First gantry logs the plate and a GPS-synced time. Last gantry does the same. A central computer matches both readings and works out the mean speed. Pass both cameras in less time than the minimum time calculated for that distance and a fine is generated automatically.
Those cameras are not usually mounted on every intermediate exit. Without a matching exit stamp for the same plate, the system has nothing to compare it with. That is why a last-second dive off the motorway can wipe that particular average speed camera from the equation. Official DGT explainers already describe the two-point method; motoring reports this week have spelled out the consequence when drivers never reach the second gate.
This is not a green light to race. Fixed boxes, mobile units and Guardia Civil patrols still operate on the same roads. Reckless weaving at a junction can earn a separate fine. Treat the gap as a technical limit of one device, not a strategy.
How many of these sections are now on Spanish roads
DGT-run average speed cameras jumped from 92 in spring 2024 to 153. Add regional kits in Catalonia, the Basque Country and Navarra, plus big-city council devices, and the national total is 299. About 140 section cameras were installed between 2021 and 2026. Policy under Pere Navarro has favoured longer corridors so drivers have less room to sprint then brake.
Spain’s longest average speed test is on the CL-615 in Palencia, kilometre points 34.61 to 67.51 towards Guardo: 32.9 km limited to 90 km/h. Second is the A-68 between Cortes and Tudela, 30.5 km at 120 km/h. Another Palencia stretch on the CL-615 covers 23.1 km. Those distances make mid-section exits more common, and more relevant to how the maths works.
EWN has already mapped Spain’s longest average speed camera and the legal ways to check published DGT lists. Locations of fixed and section cameras are public; radar detectors and jammers are not.
What this means if you clock a gantry too late
Anyone who spots the first camera late and knows an exit sits before the finish may drop off the measured pair. That appears to be an oversight in how many of these kits were laid out: long motorway sections often have service roads and junctions between the two check points.
Do not bank on it. Extra cameras can be added at busy slip roads. Other offences still apply. Speed limits apply whether a computer is watching that exact stretch or not.
Fines for being over the average still run from €100 with no points for modest excesses up to €600 and six points for the worst cases. Section systems typically allow a 10 per cent tolerance when the speed is calculated.
Steady driving still beats a last-gasp slip-road scramble. Average speed cameras were built to stop that yo-yo habit. On some layouts, leaving before the last camera simply means that one system never finishes its sum.
