Four miles of closure for five hours, six months ago. The June 10th crash/investigation closure of Highway 99 finally got its airing before the City Council Transportation Committee on Tuesday, and the presenters from SDOT and SPD declared that major changes had resulted.

If you want to just watch for yourself but didn’t see it in real time, full video of the discussion is in this Seattle Channel clip, starting 1 hour and 48 minutes in.

If not – toplines follow:

First, the June 10th situation was recapped: Three people seriously injured after a truck and car collided at East Marginal/Nevada (map) in the afternoon of June 10th. The car driver was suspected to have been under the influence, police said. That meant they had to investigate it as a vehicular assault, and potentially – in case someone died weeks or months later – as a vehicular homicide.

One of the biggest questions from the public that day was, why did SPD close Highway 99 all the way back to the Battery Street Tunnel, rather than allow traffic to the stadiums or even the West Seattle Bridge? Traffic Division Capt. Mike Nolan reiterated what had been said before – a Mariners game was scheduled and they were worried about “dumping” cars into the stadium zone.

Another question, why five hours? This answer was new: The Traffic Collision Investigation Squad‘s work was explained in more detail than we’d heard publicly before (along with its baseline staffing – eight detectives, one sergeant). For one, on most major roads/highways in the city, they use photos/video they have already shot of the road/highway in question – but in this case, their pre-existing footage ended just short of the crash scene, so they had to do extra work which added time.

Another factor was a “large debris field.”

The surveying equipment you might have noticed in photos of crash scenes we’ve covered (or any you have seen firsthand) is used to “shoot lines of sight” at crash scenes, the councilmembers were told: “You’re actually measuring every piece of debris, every section of every corner of vehicle(s) involved – the entire roadway curb to curb … so you can do a three-D reconstruction of the entire roadway and entire accident scene …”

If the area near the June 10th scene had been “pre-shot,” TCIS might have needed about three hours, rather than five, police told councilmembers.

Another line of questioning involved assigning officers to direct traffic during major reroute situations like the five-hour Highway 99 closure that day, and what their enforcement duties are while they are handling that responsibility. SPD reps pointed out that unless an officer in that role has backup, if s/he leaves their post to pursue a violator, suddenly the spot where they’re directing traffic is uncovered for 15 minutes or so, and that’s why you might not see an officer peel away in that kind of situation.

Separately, the biggest news to emerge from the discussion was that the SDOT Traffic Management Center is expanding its hours of operation. Though it is “24/7 ready now,” it’s not staffed 24/7, and they’re working to change that, SDOT reps said. They already have 24/7 information available from street-maintenance dispatch.

Right now, they’re up to 16 hours a day of Traffic Management Center on weekdays, 8 hours a day on weekends. (This is most noticeable if you follow @seattledot on Twitter, or if you have noticed information on the illuminated signs along major routes, especially leading to the West Seattle Bridge.) The rest of the time, on-call SDOT employees can “plug in” to the system remotely. Starting in January, someone will be in the Traffic Management Center 16 hours a day, 7 days a week, with the “remote” capability continuing the rest of the time. (Earlier this year, it only operated 13 hours a day, 6 am to 7 pm.) The phasing-in of longer operating hours is part of what’s detailed in this memo that was included with Tuesday’s agenda; it also includes more information on how agencies are improving their interaction in incidents like the one that sparked this review.

EARLIER COVERAGE: Councilmember Tom Rasmussen, who chairs the Transportation Committee, had previously questioned/reviewed the incident response in e-mail exchanges with the two city departments included in yesterday’s meeting – here’s our July coverage of the SDOT response, and our June coverage of the SPD response.