Lt. Gov. David Dewhurst and House Speaker Joe Straus declared the session Monday evening.
Texas lawmakers approved a constitutional amendment that would boost transportation spending by about $1.2 billion per year.
The money would come from oil and gas revenues diverted away from the state's rainy day fund.
Lawmakers agreed to a deal that would put the amendment in front of voters in 2014 and require the Legislature to set a minimum balance for the Rainy Day Fund every two years.
Conservatives had hoped to set the minimum balance in the Texas Constitution.
The measure falls short of the $4 billion a year experts say the state needs for roads.
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