SDOT’s Traffic Counting Guru

Meet Vincent Prince, SDOT’s supervisor in charge of collecting data on traffic volumes around the city. It’s a big job with about 2,000 to 3,000 traffic counts administered per year. What goes into a single “traffic count”? A rubber tube is laid across the travel lanes coming into a particular intersection in one direction. You may notice these tubes if you keep a close eye out. The tube is connected to a metal data box that receives and records the pulse of air generated when a vehicle crosses the tube—even bikes. This info is recorded every 15 minutes for one week providing a snapshot of traffic volume for that location.  This process is repeated, 2,000 to 3,000 times a year, all around the city. Vince works with three other folks, Julius Hubbard, Joyce Robinson and Brian Rogers, to accomplish the task.

Why so many counts? It’s all part of careful study when SDOT makes changes and improvements to city streets. The requests are mostly generated by staff from SDOT’s Traffic Management division who use the data to determine where and when to install improvements like new traffic signals, speed bumps, crosswalks, and other safety improvements. The counts are one piece among a number for factors considered when making decisions. As needed, Vince and his staff also study and record pedestrian/bicycle volumes, vehicle turning movements, speeds, and types of vehicles. Counts are also taken to update the city’s traffic flow map, which gives a general picture of how much traffic moves through different corridors around the city. Finally, this data is used as an input for SDOT traffic modeling which helps plan for the future.

When asked about how he got into this field Vince was happy to say he started at an entry level job more than 25 years ago. He was a traffic recorder out on the streets literally counting cars. He even remembers when the current, small, seven pound traffic count box was a 35 pound hulk that recorded data on paper punch cards. He worked his way up, building skills for the field at night school. Vince grew up in Sequim and currently lives in Duvall, and he loves the excitement of working in Seattle. Vince’s family was also recently honored in the transportation world. The new 64-car ferry plying the waters of his home region was named MV Chetzemoka after his great-great-great grandfather Chief Chetzemoka (1808-1888) an influential Native American leader in the Sequim area who helped ease tensions with settlers.

Good data is critical for making the best choices for Seattle’s transportation system. Vince is just one of the many people who work behind the scenes to make it all happen.