fuel consumption
A speed limit on the Autobahn saves that much fuel
In view of the energy imports from Russia, the speed limit debate is picking up speed again. Photo: Patrick Pleul/dpa-Zentralbild/dpa
© dpa-infocom GmbH
Drive slower, save fuel – and thus support Russia less: How much saving does a speed limit on the highway bring? A fact check.
The introduction of a speed limit on autobahns has long been the subject of controversy in Germany. With the Russian war of aggression in Ukraine, the topic is picking up speed again.
Due to a lower speed, vehicles should consume less fuel and thus less oil imported from Russia. What is the point of a speed limit on German autobahns?
Claim: A speed limit on the autobahn makes Germany less dependent on Russian oil imports.
Assessment: That’s true, but the overall fuel consumption of cars only decreases by about 1.5 to 4 percent.
Facts: Germany imported about 81 million tons of crude oil in 2021. Of this, 35 percent came from Russia, i.e. a good 28 million tons. According to experts, about 0.2 to 0.35 liters of fuel are produced from one liter of crude oil in German refineries, depending on whether it is petrol or diesel. By the end of 2022, Germany wants to be almost independent of Russia in this area.
According to preliminary data from the Federal Ministry of Transport, cars alone consumed 23.82 billion liters of petrol and 18.3 billion liters of diesel in Germany in 2020. The transport sector therefore offers great savings potential in terms of oil consumption.
There is often talk of a speed limit on Germany’s autobahns, which are around 13,000 kilometers long. According to the Federal Highway Research Institute (BASt), the proportion of stretches without speed limits in the entire motorway network is 70 percent. That means: There is no speed limit on a good 9,000 kilometers of motorway.
In general, the faster a vehicle is traveling, the more fuel flows through the engine. One reason is the air and rolling resistance, which increases with increasing speed. Conversely, this means that the more restrictive a speed limit is implemented, the lower the fuel consumption and environmental impact.
Anyone who consumes fuel always damages the environment with carbon dioxide (CO2) from the exhaust – and both quantities help to calculate the savings. The Helmholtz Association of German Research Centers explains: “If a vehicle consumes one liter of petrol, it emits around 2.37 kilograms of CO2. If diesel was fueled, it is 2.65 kilograms of CO2. »
The Federal Environment Agency (UBA) does not consider petrol and diesel cars separately on motorways, “because the CO2 emissions of average and therefore typical vehicles are very similar depending on the speed”. The following calculations are therefore based on the assumption that the consumption of one liter of petrol produces 2.5 kilograms of CO2.
Car is the most used means of transportation in the country
To put this in context: the car is the most commonly used means of transport in Germany. 57 percent of all journeys are made by car, in rural areas it is 70 percent. This emerges from the result report “Mobility in Germany”. According to the UBA, passenger cars and light commercial vehicles caused greenhouse gas emissions of around 30.5 million tonnes of CO2 equivalents on German motorways in 2020. The term serves as a unit of measure to standardize the climate impact of different greenhouse gases.
In detail: The calculations have shown that Tempo 130 on the freeway would save 1.5 million tons of CO2 and thus 600 million liters of fuel. While CO2 emissions account for around five percent of the total amount, this measure only reduces the total fuel consumption of cars by just under 1.5 percent.
Greater potential for savings can only be achieved with more drastic speed limits: According to UBA, a maximum of 120 km/h on the motorway would reduce emissions by 2.0 million tons of CO2 equivalents annually – that’s the equivalent of 800 million liters of fuel. With a speed limit of 100 km/h, it is 4.3 million tons of CO2 – after all, a good 1.7 billion liters of fuel, i.e. about 4 percent of the total consumption of cars.
The environmental authority points out that the mileage in 2020 was lower than in previous years due to the corona virus. For comparison: With the values from 2018, the UBA assumed a saving of 1.9 million tons of CO2 at 130 km/h, 2.6 million tons at 120 km and 5.4 million tons at 100 km/h. If the fuels used abroad and used in Germany were also included, the effect would be “14 percent higher” according to the UBA.