Between 2002 and 2006 when we had a Republican in the White House and Republican majorities in Congress, total public construction spending on roads went from $62,553,000,000 to $78,215,000,000, an increase of 25%. At the same time, we were fighting two wars, creating new national education and Medicare programs, and cutting taxes. Lest anyone think Republicans are anarchistic social Darwinists.
Between 2007 and 2010 the Republican was succeeded by a Democrat in the White House and Democrats took over both houses of Congress. Public spending on roads went from the previous $78,215,000,000 to $80,100,000,000, an increase of...wait for it...2%. Certainly it hasn't risen anymore since Republicans took back the House at the end of 2010, but if you're only going to increase it by 5% over 4 straight years of Democratic control, any argument about what the other guys do is hilariously hypocritical.
The really insidious thing about this data is what occurred right in the middle of that second time period: Stimulus! The American Recovery and Reinvestment Act passed in February 2009 by the Democrat-led Congress and signed by President Obama was sold as an "emergency" measure designed to jump start our economy primarily by funding "shovel-ready" (HA HA HA HA HA) infrastructure projects and green energy investment. It did neither. The month the stimulus was passed, public spending on roads was $81,762,000,000. One year later it was 5% lower at $77,779,000,000 and didn't peak until May 2010 at $86,203,000,000.
The main thing the stimulus did (apart from cutting taxes, which I could have sworn was a bad thing...) is create a massive slush fund for public sector unions. At a time when tax revenues were down during and immediately after the recession, states took a hit to their bottom line and faced cutting employees. Given the overwhelmingly Democratic leanings of public employees, that just wasn't an option. So the stimulus basically propped up state budgets to keep their employees working (and contributing to their unions). That's why Department of Education appropriations from the stimulus were twice as high as Department of Transportation. Instead of repairing old bridges, we kept school administrators comfortable. Instead of repaving roads, the NEA stayed happy.
There is certainly an argument to be made (though not one I'd agree with) for maintaining state employment during tough economic times with massive infusions of federal tax dollars. But that's not the argument that was presented to the American people. Instead we were told that all our infrastructure problems would be solved and the economy would bounce back. Neither happened.