System Overview Turkish State Highway System

the d.100 in kadıköy, istanbul.

unlike motorways in turkey, state highways not have minimum design standard. despite majority of system consisting of four-lane, dual highways, other routes can two-lane highways or dirt roads, in mountainous areas. routes, within major cities, have been upgraded controlled access highway standards; while other routes, such d.650, between arifiye , bozüyük, , d.200, between eskişehir , ankara, consist of minimal at-grade intersections. bridges , tunnels common among system, yet not plentiful on motorways.

numbering

all state highways have three-digit designation preceded d. system numbered based on direction , location. route numbers range 010 977, while 010 490 east-west routes , 505 977 north-south routes. even-numbered routes run north-south, while odd-numbered routes run east-west. exception rule 4 north-south routes, d.550, d.650, d.750, d.850 , d.950, have even-number designations. second criteria based on geographical location of route. north-south roads, routes in west have lower numbers, while routes in east have higher numbers. east-west roads, routes in north have lower numbers higher towards south.

main roads designated multiples of 100 , 50, exception being d.010. multiples of 100 main east-west roads, while multiples of 50 main north-south roads. d.010 exception rule.