How did WSDOT start calculating travel times?
The desire for automated travel time information most likely started about ten seconds after the first congestion map was published. However, providing accurate travel times has been a problem not easily solved, and has been the topic of many research publications. Improvements in implementation of detection equipment led WSDOT to reconsider the use of travel times as a commuter tool. Although not sufficient for many academic uses, WSDOT believes that the available data is sufficiently accurate to be useful to drivers.
