‘Mac News’ wondered how the ODOT/Oregon
Department of Transportation calculates travel times on its electronic reader
boards in Newberg and Dundee for the Newberg-Dundee Bypass.
Mac News asked ODOT and ODOT replied on the same day, 9/21/2020.
An ODOT
representative told ‘Mac News’ the Newberg-Dundee
Travel Time system’s travel times are calculated by the “same method we are
using for all of our Travel Time corridors.”
“The
ODOT travel time system uses sensors along both routes to measure the time in
which it takes a Bluetooth (BT) device to reach the next sensor. Because the
sensors use a hashed Media Access Control (MAC) address from a Bluetooth
connected device (such as a paired phone), we only get a portion of the
vehicles that are actually using the route to report back to the Bluetooth
sensor.
“Although
there is no simple way to connect a MAC address with a person, the MAC
addresses are truncated, hashed and only retained for enough time to perform
the travel time calculation as additional privacy protection. When the hashed
MAC address can be matched between two points, filters remove travel times that
are outliers (e.g. a car that has stopped along the route then continued or a
Bluetooth device used by a pedestrian or cyclist) and the remaining travel
times within that time period are averaged.
“The
computed travel times are displayed on signs at each end of the two routes.
These signs are updated every 2 minutes if Travel times change.”
('Mac News' photo)
