Asian Highway 16 (Thai highway 12) in Phetchabun province. It is being widened to accommodate the expected increase of traffic as part of the "East-West Corridor", connecting the South China Sea with the Indian Ocean. It runs from near Hue in Vietnam, across Laos and Thailand, where it connects with AH1 which leads to near Moulmein and it's harbour in Burma.
<a href="//commons.wikimedia.org/wiki/User:Takeaway" title="User:Takeaway">Takeaway</a>
CC BY-SA 3.0
<span class="int-own-work" lang="en">Own work</span>