A new analysis and data suggests there are significant traffic impacts from a major event at KeyArena at Seattle Center.
Kirkland-based Inrix examined five different dates in 2016, using real-time GPS data, to see how traffic is impacted in the South Lake Union and Lower Queen Anne neighborhoods by a sporting event or concert at the Key.
Related: Full Inrix data on KeyArena traffic
The City of Seattle is currently soliciting bids for a major renovation of the building that will allow for an NBA or NHL franchise to play there.
"We've generally seen higher levels of traffic around that area," said Bob Pishue, a transportation analyst for Inrix.
Pishue looked at the data and said two weekday major concerts in particular caused massive disruptions in the area.
He examined Queen Anne Avenue, Denny Way, First Avenue, Mercer, Fifth Avenue, and Roy Street on the five select dates, including two Pac-12 women's tournament games, a Justin Bieber concert, and two Adele shows last year. The concerts were sold out, and filled KeyArena to capacity.
The study only covered Queen Anne to the west and Highway 99 to the east, and did not include the rest of the roads connecting to Interstate 5 through South Lake Union.
While the Pac-12 games only caused minor disruptions, Bieber and Adele prompted significant backups, said Pishue.
"Heading east on Denny Way, for example, we saw traffic congestion increase from anywhere between 20 percent to about 70-75 percent during the prime p.m. travel commute," Pishue said.
In fact, his data shows Bieber prompted an additional 35 minutes of delays on those roads between 4 p.m. and 7 p.m. for his KeyArena concert on March 9, 2016. That data did not include Roy Street.
Adele's show on July 25 increased travel time delays by 42 minutes on the roads around the Center during the same time frame, and 36 minutes on the show the next night, a Tuesday. Those two data points included Roy Street.
The traffic is an issue that the city says will need to be addressed in the coming months as it reviews plans for a KeyArena renovation.
Two groups, AEG and OVG, are expected to submit bids. The city has asked for bids by April 12. The Seattle City Council announced Monday that they will begin a series of meeting on the submittals in a select committee beginning on March 27.
City leaders in favor of exploring the renovation have suggested traffic impact will be reduced by the opening of the new tunnel. Once completed, the city will connect currently dead end streets, including Harrison and Thomasc which some transportation leaders believe will reduce the load on Mercer and Denny.
However, traffic flows out of the tunnel are another story. Pishue said the impact of those changes are a great unknown at this point.
"It's a good question, and remains to be seen," Pishue said.
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