The estimated cost of connecting Russia and Crimea with a bridge across the Kerch Strait has been raised three times in the last few months.
State road builder Avtodor, which is overseeing the project's design, selected a combined 11.7 kilometer rail and auto option with a 283 billion ruble ($8.1 billion) price tag, dismissing 73 other proposals, Itar-Tass reported Thursday.
The bridge itself costs 150 billion rubles ($4.3 billion), but the price is driven up by the need to lay 25 kilometers of road and 83 kilometers of track to connect the bridge to existing transport links.
At this price, it would be Russia's most costly bridge.
In March transportation officials said it would cost an overall 50 billion rubles ($1.3 billion) to build the bridge. The price doubled in April before doing the same in May, and now it has shot up again.
The possibility of building a tunnel instead of a bridge was discussed earlier, but Avtodor officials dismissed it as being "too expensive."
Those crossing the bridge will be charged a toll, and Avtodor estimates that between 142 billion rubles and 228 billion rubles ($4 billion and $6.5 billion) could be raked in over the next 20 years.
Russian Railways earlier said it was ready to build the rail infrastructure for the bridge, while news reports have said that China and South Korea investors are interested in shouldering the burden of construction.