Seattle Drivers Hit Road Before Storm – Stayed Off Roads After

The "Bomb Cyclone" that hit Seattle disrupted cellular communications, resulted in nearly 500,000 people without power, and disrupted the road network. As communications and power come online, Departments of Transportation, local utilities, and households have a huge job ahead of them clearing brush, getting assistance, and attending to family needs.

Analyzing traffic patterns across the region, our incidents team logged nearly 50% more road incidents (closures, blockages, etc.) than the typical Tuesday/Wednesday.

In terms of impacts to travel times, some routes were hit harder than others, as people headed home to avoid the worst of the storm. Here is a quick first look at travel times on key commuting routes heading up to, and after, the storm.

I-5

Travel times between Seattle and Everett surged Tuesday evening to 76 minutes, up from the average Tuesday travel time of 65 minutes, a 17% increase. Wednesday traffic was significantly less than prior Wednesdays, except around noon. Travel times at 11:30 AM increased to 45 minutes on Wednesday, up 49% over previous Wednesdays at that time.

Travel times heading southbound, interestingly, were significantly lower than past weeks on both days.

I-405

Northbound I-405 saw significant travel time increases on Tuesday over the Tuesdays before it, taking 38 minutes to travel the corridor during the PM commute period, a 12% increase. Wednesday saw lower volumes and faster travel times, taking about 25 minutes at 5:00PM versus 44 minutes on the typical Wednesday, a 43% decrease.

Southbound travel between Bellevue and Renton looked fairly similar on Tuesday compared to the average Tuesday, though the congested peak period ended about 45-60 minutes earlier than normal. Wednesday saw the largest drop in travel times on I-405 SB. Normally taking 34 minutes to travel, travel times on Wednesday were just 23 minutes during the normal 'rush hour,' a 32% decrease, though travel times peaked at about 3:45 PM. Also notable was the increase in travel times throughout the morning and afternoon.

SR 520/I-90

Eastbound travel across the bridges was significantly less on both days, perhaps due to the significant amount of East/West telecommuting and the location of power outages and downed trees. Travel times at night increased on these on SR 520, and only little change on Eastbound I-90.

Conclusion

It will take time to restore power to thousands and clear the road network of debris and hazards. We will continue to monitor this situation and provide updates to keep the public informed of storm cleanup progress on the transportation network. In the meantime, drivers in the Seattle metro should monitor traffic apps and DOT updates on the latest road and travel conditions.

Stay tuned for another blog tomorrow that focuses on where traffic has been most effected.