Temporary winter roads of ice for trucks are a key part of Arctic transportation infrastructure. The Alaska North Slope Borough's Transportation Plan explains how they are built and maintained, and what they cost to build. You start with the paperwork:
Permits must be secured from BLM and the NSB for all ice roads. Once permitted, water or ice chips are placed on the surface. Water trucks apply water over the route until the surface is built up to at least six inches thick. Ice roads are staked to facilitate driving and help with snow removal. Over the course of the ice road’s operation, litter or contamination is removed by ice road monitoring personnel. When an ice road is ready to be shut down for the season, it is inspected for any remaining contamination, cleaned, stakes are removed, and snow is piled at the entrances to prevent further use of the route. At break-up, the ice road melts. The routes are inspected by helicopter during the summer for any remaining litter or debris. In Nuiqsut, some residents have concerns that post-season clean ups are insufficient while others think they are adequate.
Ice roads are expensive:
In Alaska’s Prudhoe Bay NPR-A region of the North Slope, the cost to construct an ice road is approximately $100,000 per mile. It takes about a day to complete one mile of ice road in the short season of only 100 to 120 days when temperatures are cold enough to sustain it....
In addition to these costs, construction of ice roads requires substantial water resources. One mile of an onshore ice road six inches thick and 40 feet wide requires 1 to 1.5 million gallons of water, construction of an ice bridge needs 10 million gallons, a single ice pad requires 2 to 3.6 million gallons, and an ice airstrip needs 8 million gallons of water, according to BP's and Phillips' NPR-A plans.
The report was written in 2005, so the prices are already somewhat out of date. And the warming climate is reducing the working lifetime for each winter's new roads:
In 1970, temperatures were cold enough to allow safe tundra travel on ice roads for more than 200 days of the year, according to the Alaska Department of Natural Resources (DNR). DNR statistics now show that period has shrunk to about one hundred days.
Warming trends on the North Slope make reliance on ice roads complicated, as they are being built later in the season and melting sooner. Ice roads are best constructed when weather is about -20º to -30º F.21 Alaska has been through warming trend cycles over the last several decades as reported by the Center for Global Change and Arctic System Research. Their models indicate that Alaskan temperatures may increase 3º F to 4.5º F by 2030, with the greatest increases in the arctic region. By 2100, models predict increases of 7º F to 18º F and an increase in precipitation up to 25 inches. A result of the warming trend is a reduction in the ice road season.
The paper is not clear, but I assume that this is the cost of an ice road built over the tundra and small water bodies, and that the costs of a road across a large frozen lake, or across an arm of the sea, might be somewhat different.