million vehicles, generating a total revenue of $391 million (both bridges and motorways combined). Standards Mainly because the country already has a wide network of double carriageways, the standards for motorways in comparison are very high. Most sections of otoyols have 3 lanes in each direction, aside from the O-4 around Izmit, a small stretch of the O-3 between Silivri and Esenyurt, and the section of O-32 between Alaçatı and Çeşme, which only have two lanes in each direction. Also the O-2, the O-7 and the O-20 all have four lanes in each direction along the entire route. The lanes are each 3.75 meters wide. Most exits have a connection road, which helps avoiding wrong-way driving and illegal access to the road (bikes, tractors and horses are not allowed on otoyols). The minimum speed is and the maximum allowed speed is , although speeding is not punished under . However, on sections of the O-1 through central Istanbul the speed limit is . In most tunnels the speed limit is . Alongside otoyols, there are resting areas, which are standardized as A, B, C and D type service areas. The D type is mainly a parking area. The C type has a fuel station added. The B type has a fuel station and a vehicle service station added. The A type additionally has a motel (in urban ones, this motel is traded for a large shopping mall). Dangerous stretches such as tunnels or bridges where there is often fog, exits, interchanges and service areas are illuminated. Since gradients are expected to be very low and turning radii are expected to be very high, otoyols have many bridges and tunnels which makes them very expensive to construct. Otoyol signs in Turkey are green and uses the Highway Gothic typeface. Statistics Length Longest otoyol: , O-21 between Ankara and Tarsus. Shortest otoyol: , O-1 in Istanbul Longest bridge: 1915 Çanakkale Bridge, carries the O-6 over the Dardanelles. Longest tunnel: Tunnel 4 between Gebze and İzmit, on the O-7. Highest pass: Cankurtaran Pass with 1.580 metres on the O-4 at Ankara-Bolu border. Provinces Provinces with an otoyol route(s): 28 provinces (Adana, Aksaray, Ankara, Aydın, Balıkesir, Bolu, Bursa, Çanakkale, Düzce, Edirne, Gaziantep, Hatay, Istanbul, Izmir, Kahramanmaraş, Kırklareli, Kırşehir, Kocaeli, Konya, Manisa, Mersin, Nevşehir, Niğde, Osmaniye, Sakarya, Şanlıurfa, Tekirdağ, Yalova) Provinces without an operational otoyol, but with an otoyol construction undergoing: 1 province (Denizli) Most