Traffic reporting is the near real-time distribution of information about road conditions such as traffic congestion, detours, and traffic accidents. The reports help drivers anticipate and avoid traffic problems. In addition to periodic broadcast reports, traffic information can be transmitted to GPS units, smartphones, and personal computers.
==Methods of gathering information==
There are several methods in use today to gather traffic speed and incident info, ranging from professional reporters, to GPS crowdcrowding to combinations of both methods.
* INRIX uses its network of over 175 million vehicles and devices to gather speed data and licenses an incident platform to many of its partners as well as its own editorial staff.
* Google Traffic works by crowdsourcing the GPS information from phone users. By calculating the speed of users along a stretch of road, Google is able to generate a live traffic map.
* Monitoring police radio frequencies. Some radio stations have agreements with states' highway patrol that permit a direct connection with a law enforcement computer. This methodology enables real-time information gathering of the latest accident reports to states' highway patrol divisions. However, more and more, state departments of transportation have agreements with various technology providers to deliver automated traffic tracking data which is resold and redistributed.
* Many areas have helicopters to overfly accident scenes and other areas of high traffic volume. For example by the company Global Traffic Network.
* traffic cameras
* Reporting by drivers via telephones or app like Waze.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』