D.100, popularly referred to as E-5, is a west-to-east state highway in Turkey. The route starts at Kapñkule, the Bulgarian border check point, and ends in Gürbulak, the Iranian border check point. Running all the way from west to east, it crosses most of the north-to-south state roads, including the D.650, D.750, D.850 and D.950.
The highway is joint into the European Route E-80 in some parts.
The highway's name was changed in 1992 to D.100, but the public refers to it as E-5 to this day. The actual E-5 highway is between Scotland and Spain spanning 3,100 kilometers.
On March 10, 2017, a Sikorsky S-76 helicopter owned by Swan Aviation hit the antenna of the Endem TV Tower in heavy fog and crashed onto the State Road D100. All seven people on board were killed.