The maximum tax-free subsidy that employers, including the federal government, can pay for their workers to use public transit in their commuting would nearly double to $240 a month under a provision in the transportation bill the Senate passed Wednesday.

The maximum had been $230 a month in 2009-2011 under a series of temporary laws, but when a further extension wasn’t passed by the end of last year, the amount reverted to its previous level of $125 a month. Meanwhile, a subsidy for parking at commuter lots to take public transportation rose from $230 to $240 a month due to an inflation adjustment.

The Senate language, which moves to the House, would set the maximum transit subsidy at $240 a month for calendar year 2012, retroactive to the start of the year.

“Improving transit benefits will prove incredibly important to all working people that use or would like to use public transportation and are seeking critical relief for commuting costs,” National Treasury Employees Union President Colleen M. Kelley said in a statement.