Fewer motorists are on the road since the safer-at-home order was issued in March, but the speed at which they are driving has not decreased, according to a staff report to the city’s Transportation Advisory Commission.
The commission was scheduled to hear an update on local travel patterns at 4 p.m. today. The meeting can be viewed at
To determine the actual impacts on traffic patterns, the department initiated a study to monitor traffic volumes, speeds and collisions.
According to that study, traffic dropped by about 55 percent at the beginning of the lockdown and has steadily increased every month since the order was lifted.
By June, the decrease was down to 25 percent and now remains at a 10 percent reduction.
Before the pandemic, traffic volumes were 10 percent higher, compared to the same time last year.
But while traffic decreased, speed increased. Once the order began, average traffic speed increased by 2 mph and motorists traveling 10 mph above the posted speed limit increased by approximately 60 percent, compared to the same period in 2019.
Drivers began to slow down after the city implemented traffic calming measures at the end of April. Now motorists traveling 10 mph above the posted speed limit is about the same as in 2019.
For the study, the Department of Transportation obtained traffic data from the Streetlight software platform and the city’s collision database. Streetlight is a “big data” platform that provides an array of traffic data, including origin-destination, traffic volume, travel time, vehicle speed, and top routes for the entire city’s roadway network.
The data provided through this platform is usually updated monthly, representing information collected one month earlier and represents the latest figures available on traffic volume and speed.
As part of the study, traffic volume and speed data were monitored at 12 street segments representing arterials and major collectors.
“The Transportation Department will continue to monitor trends in traffic volumes, speeds and collisions to make informed decisions on outreach, engineering and operations enhancements to the multimodal network,” states the report.
Traffic collisions, according to the report, have remained in line with the changes in traffic volume, decreasing by 65 percent, compared to the same period in 2019, and increasing as the order was relaxed. Collisions are still about 25 percent below 2019 numbers.
Once the safer-at-home order was implemented, pedestrian and bicycle collisions decreased by about 90 percent, compared to 2019, and still remain below 2019 numbers.
In raw numbers, DUI collisions have decreased by about 10 percent compared to 2019.
Due to the low number of fatal and severe injury collisions over the seven-month period, it is difficult to establish a statistically significant conclusion.
There were three fatal and 16 severe injury collisions in 2019, and two fatal and nine severe injury collisions in 2020 over the seven-month period.
The data from this ongoing study is updated every month to reflect the most current traffic information.