Surface traffic jam safer than Viaduct traffic jam? SPD explains decisionmaking behind 5-hour, 4-mile Highway 99 closureJune 23, 2014 at 11:02 am | In Transportation, West Seattle news | 34 Comments
There is an incident blocking all lanes of East Marginal Way SB just south of Spokane St. Use Alt routes pic.twitter.com/ivmFKEWfY9
— seattledot (@seattledot) June 10, 2014
(Above, SDOT tweet with traffic-cam screen grab shortly after crash happened)
Two weeks ago, an almost-citywide traffic jam resulted when four miles of southbound Highway 99 were closed for five hours while Seattle Police investigated a head-on crash at East Marginal/Idaho/Nevada (map). As we have noted, investigative closures of that duration are not unusual when SPD’s Traffic Collision Investigation Squad is assigned to gather evidence at a scene. But questions persisted about why traffic wasn’t allowed to continue at least as far as the West Seattle Bridge, and what kind of consultation was made between city departments and officials as traffic continued to back up on alternate north-south routes as a result.
As noted in our first major followup, the decision on when and what to close rested solely with SPD. Councilmember Tom Rasmussen sent the acting leaders of that agency and SDOT a list of questions, published here. This morning, Councilmember Rasmussen shared the reply from SPD, and said that SDOT has told him theirs is in progress. One key point from the SPD reply signed by SPD Traffic Section Acting Captain Ken Hicks – the department feared that allowing anyone onto 99 between the Battery Street Tunnel and the crash scene would have led to drivers getting stuck “in an area without services,” surmising that traffic jams on surface streets were safer for drivers. Read the entire reply for yourself, ahead:
I am the SPD Traffic Section Captain at this time. I am going to provide as many answers to your questions about the collision on SR 99 on June 10th as I can.
The collision in the southbound lanes of 99 was a serious-injury head-on collision. The involved vehicles and debris field completely blocked all southbound lanes.
Although this collision was serious, requiring the callout of the Traffic Collision Investigation Squad, it was not an unusual occurrence. TCIS is called out multiple times weekly for serious collisions. The time and place of the collision compounded the serious impacts to the City.
The first report of the collision was broadcast at about 1:44 pm. This is just before the beginning time frame for the outbound rush hour traffic.
Patrol units and a Patrol Sergeant were dispatched to the collision. Those units quickly began arriving and taking control of the scene and the roadway, along with Seattle Fire Units.
It was reported all southbound lanes north of the collision were completely stopped with traffic backed up on the entire Viaduct. The request was made for more units to assist in the clearing of the Viaduct and 99.
Patrol units started the process of moving vehicles off at the Atlantic/Edgar Martinez exit and to the West Seattle exits. This was only partially successful as more traffic kept entering the Viaduct from the north. The Patrol Sergeant contacted his chain of command and screened the collision and closure.
At 2:00 pm the request was made by Patrol to SPD Radio for the Battery St tunnel southbound to be closed and the closure light activated. The closure and the previous requests start a notifications process from SPD Radio.
Because this collision was serious with possible impairment issues, TCIS was called out to investigate. When TCIS is called out their investigations are always done with the knowledge that there may be a death involved due to the injuries.
Because of this factor the investigation is done under strict parameters. The investigation must be able to stand up under scrutiny in both criminal and civil actions. If it is less than that, it affects the justice for the victim (s), the accountability of the offender (s) and the exposure of the City to liabilities.
If the Detectives are not provided with a safe environment, their attention is divided from the investigation to their concerns with the traffic around them. Because this is a collision on a roadway, there is only one opportunity to investigate the collision and maintain the possible crime scene, unlike a static location where the crime scene can be revisited.
Because of the expected length of the investigation, Traffic units began self-assigning to relieve the patrol units on the scene for traffic control duties. A Traffic Sergeant responded to assist and eventually relieve the Patrol Sergeant. Once there the Traffic Sergeant assigned all available Traffic Officer Units to the collision to relieve as many Patrol Officers back to 911 services as possible.
Once on scene the Traffic Sergeant was faced with several factors and options. The Sergeant went through a deliberate process weighing these factors and their consequences before making a decision on his options.
Factors he was faced with;
· Serious collision, with TCIS callout, at the beginning of rush hour. This also encompasses the heavy rush hour traffic on all north/south routes (1st Ave, 4th Ave, 23rd Ave, Rainier corridor, etc.) as well as I 5, I 90, West Seattle Freeway and SR99.
· The beginning inbound traffic congestion caused by a Mariners game at Safeco Stadium. The Atlantic/Edgar Martinez exit from SR 99 directly impacts this already-congested intersection of corridors. Adding the traffic from the Viaduct would have brought all directions to a standstill.
· If the tunnel was left open and the traffic was moved off on the Atlantic St exit, it would have backed the traffic up on the raised Viaduct, effectively trapping motorists in an area without services. If an emergency of any nature would occur, such as medical, a traffic collision or disturbance, there would be no way of approaching the problem except on foot. This would put all the stranded motorists at a needless risk.
· Allowing the tunnel to remain open and then forcing motorists off at the West Seattle exits would have resulted in a similar stranding of motorists on the Viaduct. The West Seattle Freeway corridor is just as congested during the rush hour as other corridors.
· The need to keep the collision scene intact for the investigation and the safety of the investigators on the scene, and the preservation of evidence in a felony investigation, prevented the option of letting traffic flow through the scene. The scene actually consisted of all southbound and two northbound lanes.
· Communications also made notifications. I do not want to speak for them but I believe the on duty Captain and South Precinct Captain may have been notified.
The Traffic Sergeant contacted another Traffic Sergeant to discuss the options. The options were then relayed to the on-duty Traffic Lieutenant. After screening the incident with the Lieutenant, the decision was made to continue the tunnel closure until the investigation could move off the SR 99 corridor.
Moving the traffic off the 99 corridor onto surface streets does create enormous traffic impacts. But it prevents the risks of trapping motorists on the Viaduct. The motorists are then able to use the traffic control on the surface streets to at least make some progress.
At 3:45 pm an estimate of 3 hours was given for the completion of the investigation and reopening of SR 99. The processing of the vehicles and evidence by SPD and the eventual cleanup of the scene by SDOT are all part of the time delay.
The actual time the highway was reopened was 7:24 pm. The closure allowed the investigators to complete the investigation in an hour less than expected. And there were no more emergencies attributed to the incident as consequence of the decisions.
Acting Captain Ken Hicks
We’ll of course have another followup when SDOT’s response is in. We’re also asking Councilmember Rasmussen for his reaction, and whether this might be the subject of a meeting/hearing.
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