The circuit has been modified at least twice in its history. It had been modified before the final Formula One Grand Prix run on the circuit (1978 Swedish Grand Prix), with the modifications to the penultimate Norra corner, which resulted in the length increase from 4.018 km to 4.031 km, and it remained in that configuration until at least 1986. And then it was later modified again and slightly shortened to its present-day length of 4.025 km.