High-speed rail while providing potential benefits at the nodes, guarantees costs along the lines. Evidence from hedonic price studies (the same kind of studies that were used to assess the accessibility benefits of public transit in a previous section) show that each additional decibel of noise reduces home value by 0.62 percent (Levinson et al. 1997). Using the methodology in (Levinson et al. 1997) , the noise per train, and the number of trains per hour determine a noise exposure forecast. Applying the noise exposure forecast to the number of houses effected by each level of noise, and summing over all of the houses, and multiplying by the value of each house, gives the economic noise damages associated with the trains. So for instance, for a project running 20 trains per hour at 241 km/h through an area with 1000 housing units per square kilometer, each with a value of $250,000 would produce a total noise damage cost per kilometer of track of $1.975 million, a not insignificant cost. For a line of 500 km, this would be a system noise cost of nearly $1 billion. These relationships are non-linear, even one train per hour would produce a total cost of $269 million. Running 20 trains at an average speed of 350 km/h would produce a cost of $1.5 billion.
The noise damages can be avoided if preventive measures are adopted. These include acquiring a much wider right-of-way so there is no housing near the tracks, or noise walls. Whether those costs are less expensive than accepting damages depends on the circumstances.