Right. We look at the rail traffic and the road traffic, and they call that the cross-product. It has to do with the interference, how long trains might be taking to clear the lines. This relates to impeding traffic, safety, the number of accidents that happen between vehicle traffic and train traffic. There can also be problems with pedestrian mobility, bicycles, those kinds of things.
In some cases, particularly in the urban areas, if they aren't grade-separated and it's a level crossing, the train's also going to have to do a lot of whistling, so that makes other kinds of noise. We take all those factors into account in deciding whether to grade separate or not. A lot of the times, it's the amount of time that a vehicle has to sit and wait for the train to cross. Windsor is a good example. We were having trucks coming out of Chrysler plant having to wait 15 to 25 minutes for the train to cross, because it's a busy corridor.