The speed limit on Spanish motorways, which is 120 km/h, was reduced many years ago to 110 km/h. It was - they said - a governmental aid for drivers so we could save fuel during the crisis. Such a stupid interventionist claim! If I want to save fuel, I ease my right foot, but it's not up to any government to impose to do so.
Then they said it was for environmental reasons, to reduce CO2 emissions. But it happens that most of the modern cars have their gearboxes designed so they run at 120-130 km/h just below the maximum torque so at the best engine running point. Reducing the speed to 110 km/h made many cars to run too low on rpms and some even shift to a lower gear to maintain reasonably the 110 km/h. So fuel economy was not as nice as expected for many cars.
Result: no real CO2 emissions reduction. Absolutely useless from the environmental point of view.
BUT – and this is the funny part – the gas consumption yes was slightly reduced, and as more than 60% of the price we pay in Spain for gas is taxes, the government saw their income reduced. They quickly came back to 120 km/h.
By the way, 120 km/h seems too low for me, as modern cars can safely drive at 130 km/h in modern motorways.
