The value of the transportation contracts --- at least for the top firms --- more than tripled during the past three years.

Twelve of the top 20 state contractors --- excluding those for the university system --- were road construction companies, receiving a combined $1.48 billion in taxpayer money, according to an AJC analysis of State Accounting Office payments for the fiscal year that ended June 30.

Other companies on the top 20 contractor list include a private prison operator, computer companies and Bank of America.

Some on the list were major donors to political campaigns of state leaders, while others gave little or nothing. Several had teams of lobbyists registered at the Capitol, while others had none.