Forty-five people died on Portland streets in 2017, according to the Portland Bureau of Transportation (PBOT).

It's the highest number of traffic deaths Portland's seen since 2003, when the city recorded 47, and well higher than Portland's homicide tally from last year. It's also just one higher than 2016's death toll.

At the same time, the number of people who died in traffic crashes while walking in 2017—19—was higher than any year dating back to 1996, which is as far back as I could readily find. Nearly 70 percent of last year's traffic fatalities occurred in the "high-crash network"—the list of busy streets that the city says is routinely responsible for half of fatal crashes.

I bring all this up partly because it shows this fast-growing city is drifting farther from Vision Zero, officials' stated goal to eliminate serious injuries and deaths from crashes. But it's also pertinent to point out in light of a decision by the Portland City Council today.

Starting in April, all of the city's residential streets will have a speed limit of 20 mph, down from 25.

In a 5-0 vote, the council took advantage of a right Portland won in last year's legislative session to set its own speeds on non-arterial roads around town. PBOT will now spend $300,000 putting up 2,000 new speed limit signs (and removing the old ones). By April, the bureau says, 70 percent of the city's street grid will have the new limit.

"We are poised to make a really significant step today in the City of Portland," PBOT Director Leah Treat said at this morning's meeting. "Five miles per hour may not seem like much, but it actually is a big deal. We all know that speed kills."

Treat's correct, and today's decision is certainly a potent symbolic move for a city council with at least three members who've lost loved ones to car crashes. What's less clear is that the speed limit change will do anything to change the ugly numbers above.

After putting up signs and rolling out an education campaign, the city has no plans to increase speed enforcement on the roads where the new limit is in effect, officials said today. They're partly hoping that people who speed will index that speeding to the new limit.

"There are some people that are gonna always speed—that’s just what they do," Captain Mike Crebs, head of the police bureau's traffic division, told council. "If we reduce it by 5 miles per hour, it's like they'll be driving 25 or 27 mph."

More basically, it's hard to tell how many serious crashes actually take place on these residential streets. When we asked PBOT if it had that data yesterday, the bureau sent back something else: a tally of all serious crashes, from 2006 to 2015, that took place within 25 feet of one of these streets. According to PBOT's figures, there were 2,362 crashes that resulted in death or serious injury in that time frame. The bureau says 803 of them of them occurred within 25 feet of residential streets.

"Bottom line, approximately a third of fatal and serious injury crashes are on or very near to residential streets," PBOT spokesperson John Brady said.

That's not at all the same as saying they occurred on those streets. After all, the number PBOT sent along ropes in crashes that occurred on busy streets, but also happened to be near the intersection of a residential street. Brady also sent along a map plotting out all these serious crashes, and while I haven't gone through it minutely, it suggests that the vast, vast majority of the crashes occur on busier streets. (I'm trying to get a shareable version.)

That's one reason safe-street advocates have been relatively muted in their enthusiasm for the change. Groups like the Street Trust and BikeLoudPDX are absolutely supportive of the new 20 mph limit, but insistent that more substantive steps need to take place on streets that are actually causing Portland's traffic carnage.

"The street design is what ultimately determines drivers' speed," says Emily Guise, a chair at BikeLoudPDX. "BikeLoudPDX wants to see the city lower the speed limit as soon as possible on arterials as well, and most importantly follow it up with changes to the street design that further decrease speeding."