The recent run of extra-challenging slow morning commutes – especially southbound out of Everett – has made travel times a big point of discussion. With several commutes topping the 100-minute mark – topped by a 140-minute time in late September – our travel times page has been getting a workout.
|Travel times posted on our website let people know what their|
commute looks like before they leave their home.
They update every five minutes.
Instead, I thought it might be interesting to take a look at just how we compute those travel times. We know people rely on them to plan their trips, and we use technology and data to make them as accurate as we can. It’s important for us to provide useful data to the public. So how does it work? Glad you asked.
|Travel times listed on highway message boards give commuters|
an idea of how good (or bad) their commute ahead is.
But we don’t just rely on our loops. From time to time, we also have people drive the various routes at different times of the day to calculate travel times. We’ve found that the results are usually close to what our posted travel times are, which gives people a good idea of about how long it will take them.
Each month, we look at data from the previous three months to come up with the average travel time. If you watch our travel time page closely, you’ll notice that the average travel time changes throughout the day. That’s because we come up with averages based on time and day of the week, so the average time for the drive from Everett to Seattle at 8:15 a.m. on a Tuesday may be different than the average time for the same route at 7:35 a.m. on a Thursday.
|Loop sensors embedded in the pavement of highways measure|
the speed of each vehicle going over them, which are then
converted to travel times.