Pavement loops break down and require considerable maintenance. Sending workers to gather data on site is expensive. In addition, these techniques are locally focused and don't provide a full picture of current traffic flows. Aerial cameras, however, could monitor traffic in an area for an hour or more. The field of view could be anything from a single intersection to a regional view of a city.
Satellites now can differentiate between cars, small trucks and large trucks.
Applications include just about everything dealing with traffic, Hickman says. One of these could be timing traffic signals. Whether those cars will get to the intersection before they turn off and just how fast they get there is difficult to estimate. In the future it may be feasible to use a satellite in geosynchronous orbit or even a ballon to continuously monitor traffic platoons near a city's major intersections. Remote sensing also can be used to determine the wear on a roadway based on the numbers and types of vehicles that use it.