it is situated between vezirhan and bilecik bypassing the gülümbe pass with hairpin turns. the -long twin-tube tunnel carries two lanes of traffic in each direction. the -long ertuğrulgazi tunnel is located north of it. the highway mekece-bilecik-bozüyük on the north-south directed d.650 at a distance of is a heavy traffic route for transport of industrial and agricultural products connecting the regions marmara, aegiean, central anatoli and mediterranean.