We explore the decisions in Parliament about the Swedish tax deduction for commuting since the 1980s. The aim is to explain the continuity of the tax regulation despite several attempts from motions in Parliament and public investigations to reform it towards environmental goals, e.g., reduced emissions of CO2. When reforms have been proposed, the political majority in Parliament has regardless of political colour voted against and retreated to the original motives for the tax deduction; economic growth and the enlargement of regional labour markets. The interests of Swedish mass motorisation succeeded in finding the arguments to slow down reforms and at the same time reinforce the path dependency by adding new legitimacy to the regulation. If the attempts to reform the tax deduction had been part of a broader reform of the transport sector and the tax system, they might have succeeded in breaking with the old path.