Eliasson was a professor of transport system analysis at the KTH Royal Institute of Technology, Stockholm from 2007 until 2016.

He was actively involved in the discussions on traffic planning in several large cities in Sweden and abroad.

He has been working with road congestion pricing and cost benefit analysis.

[5] From November 2019, Eliasson is the goal director for accessibility at the Swedish Transport Administration.

[6] In 2023 he was awarded the Chauvenet Prize of the MAA (jointly with Kimmo Eriksson).