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Incident Response - Blocking & extraordinary incidents

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Incident Response measures showing Blocking & extraordinary incidents

Incident Response - Blocking & extraordinary incidents

Incidents blocking highways cause negative impact on economy, safety and commute time. Keeping track of Blocking or Non-blocking incidents is important to increase highway performance.

Blocking incidents are incidents that obstruct at least one lane of travel. WSDOT tracks these incidents as they have a greater impact on incident-induced delay.

Non-blocking incidents occur on the shoulder or off the roadway altogether. They have less effect on traffic, but frequently result in traffic delays due to drivers being distracted and slowing down while passing the incident.

Extraordinary incidents take six hours or more to clear. They have huge impact on commute, safety and economy.


Source: Washington Incident Tracking System.

Note: WSDOT’s Incident Response managment program indicates incidents took six hours or more to clear as extraordinary incidents. For more detail on WSDOT Incident Response Phase 3 research method (pdf 5.9 mb).

Multi-year trends

Between 2015 and 2019, the percentage of incidents that blocked the roadway ranged from 24.0% to 26.3% of all the incidents to which IR teams responded. During this five-year period the number of extraordinary incidents was between 33 to 42 annually out of which, approximately one-third involved commercial vehicles such as semi-trucks.

Annual highlights

In 2019, 25.3% of the incidents WSDOT’s IR teams responded to blocked at least one lane of traffic. Blocking incidents caused 61.5% of the incident-related congestion costs for 2019. Among all blocking incidents for the year, 41 took more than six hours to clear with 15 of these involving commercial vehicles.

In 2018, 26.3% of the incidents WSDOT’s IR teams responded to blocked at least one lane of traffic. Blocking incidents caused 64.1% of the incident-related congestion costs for 2018. Among all blocking incidents for the year, 42 took more than six hours to clear with 15 of these involving commercial vehicles.

In 2017, 24.8% of the incidents WSDOT’s IR teams responded to blocked at least one lane of traffic. Blocking incidents caused 61.6% of the incident-related congestion costs for 2017. Among all blocking incidents for the year, 36 took more than six hours to clear with 20 of these involving commercial vehicles.

In 2016, 24% of the incidents WSDOT’s IR teams responded to blocked at least one lane of traffic. Blocking incidents caused 60.4% of the incident-related congestion costs for 2016. Among all blocking incidents for the year, 33 took more than six hours to clear with 19 of these involving commercial vehicles.

In 2015, 26.2% of the incidents WSDOT’s IR teams responded to blocked at least one lane of traffic. Blocking incidents caused 62.2% of the incident-related congestion costs for 2015. Among all blocking incidents for the year, 41 took more than six hours to clear with 15 of these involving commercial vehicles.

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