Thursday, March 26, 2015

Weekend roadwork on SR 99 and I-90, and Seattle area events

By Mike Allende

One of the great things about living in the Seattle area is the number of big events we have. Whether it’s a large sports game, festival or convention, there always seems to be something going on in our area.

That also makes it tough to get roadwork done. Between major road and bridge projects and ongoing maintenance needs, there is a huge amount to do, and limited time to do it. When possible, we do work during off-peak driving hours such as nighttime weekday closures. But some work can only be done with extended closures, and those typically need to be done on weekends to avoid disrupting people’s work-week commutes.

When we have weekend-long work, we try to plan around events as much as possible to minimize traffic disruptions, but it’s impossible to close lanes for any extended period without it affecting people’s plans. It’s also pretty much impossible to do a full weekend closure without it coinciding with several events in the area.

In those cases, we look at a number of factors: expected attendance, anticipated traffic levels, where a particular project is in its schedule and what other work is happening in the vicinity. We know major sports events like the Seahawks (68,400 average attendance), Sounders (43,700) and Mariners (25,500) are going to have a large group of people going to the same place at the same time and while we do still have closures on game days, we try to avoid major work affecting traffic near the stadiums.

Traffic patterns are a bit different for most weekend-long events. In those cases, while we see a spike in traffic in the hour or so before the start of the event and near the close, we see traffic more spread out than we do with single-day events.

Let’s take a look at this weekend. Westbound I-90 will be detoured to the express lanes and the SR 99 Viaduct will be closed, along with other parts of SR 99, for a variety of work. Meanwhile, Emerald City Comicon is happening at the Washington State Convention Center, a Pro Bull Riders event is at KeyArena and Taste Washington! is at CenturyLink Field’s Event Center.

We know that we’ll see heavy traffic near the I-5 exits to the Convention Center leading up to the 10 a.m. opening of Comicon followed by more dispersed traffic throughout the rest of the day. But, a look at last year’s traffic volume chart for the Saturday of Comicon shows that traffic is basically the same as it is on any other Saturday. The only time we see any kind of real spike over normal Saturday traffic is on northbound I-5 in the 11 a.m. hour and around 5:30 p.m. as people arrive and leave. Traffic on southbound I-5 is basically the same as it is on any other Saturday.

A look at southbound (above) and northbound I-5 traffic on a
 normal Saturday compared to on last year’s Comicon Saturday.

Closing lanes at any time – especially when there are events going on – is never ideal, but it’s necessary to get work done to improve our infrastructure. The best way to maximize your fun and avoid being stuck in traffic is to adjust your travel plans, try to get to your event early or avoid the heavy traffic at the beginning of the event and get there a little later. Some planning ahead could be the difference between a long wait in traffic and a long wait in the autograph line.