Thread by @shayshinecastle

Now a report on traffic/street safety in #Boulder. documents.bouldercolorado.gov/WebLink/DocVie…

So much to report here.... basically, aside from 2020 (an anomaly), the number of crashes overall has declined in recent years but the number of crashes resulting in severe injury and/or death has stayed fairly consistent.

Boulder does a Safe Streets Report every 3 years that looks at crashes and trends

65% of severe crashes happen on arterial streets (larger ones) despite the fact that they make up a minority of all Boulder's streets

52% of bicycle-involved crashes on arterials
94% of left turn crashes on arterials
77% of ped-involved crashes on arterials

11% of crashes happen on local streets (tho they make up 54% of city network)

We may get into this later, as we talk about Boulder's new CAN focus (Core Arterial Network)

40% of crashes happen at signalized intersections
At least three per year at
- Foothills & Arapahoe
- 28th & Colorado
- Broadway & College & 14th
- S Broadway & Table Mesa

2018-2020
5,743 total crashes (1,914 per year on average)
151 severe crashes (3%, 50 per year on average)
14,500+ ppl involved in car accidents
9 ppl killed (2 walking, 1 bike, 6 in a car)
150 ppl seriously injured (25 walking, 55 on a bike, 70 in a car)
$275M+ societal cost

Most severe crashes involve
Bicyclists
Left turns
Speeding

Let's look at each of those (plus some other trends)

Walking
2% of all crashes
18% of severe crashes
77% in crosswalk (all crashes)
70% in crosswalk (severe crashes)
77% on arterials

Since 2009, 46% of ped crashes and 68% of severe ped crashes involve
- left-turning vehicles (26%, 11% of severe)
- ped dashing into traffic (12%, 30% severe) or
- car failing to yield in intersection (8%, 19% of severe)

The worst intersections for peds
- Baseline & Mohawk (4, 2 severe)
- Arap & 55th (3, 1 severe)
- Canyon & Boulder Main LIbrary (3, 1 severe)

Biking
6% of all crashes
36% of severe crashes

63% in crosswalk (all)
47% in crosswalk (severe)
20% intersection (all)
16% intersection (severe)
6% bike lane or paved shoulder (all)
14% bike lane or paved shoulder (severe)
52% were on arterials

Worst intersections for crashes involving bikes
- 28th & Colorado (9, one severe)
- Baseline & Canyon Creek Rd (7, two severe)

Speeding
9% of total crashes
32% of severe crashes
33% of drivers were ages 20-25
78% of drivers were males (in severe speeding crashes)

Worst intersections
- Broadway & Regent (7)
- Broadway & Baseline (6)

Worst corridors
- Broadway
- 28th
- Arapahoe

Left turns
16% of all crashes
34% of severe crashes

Worst intersections
- Baseline & Mohawk (2 severe)
- S Broadway & Table Mesa (2 severe)

The city has made a lot of improvement here. Phasing changes at 25 intersections reduced crashes 87%. Those were made along:
28th
Pearl Parkway
Foothills
Arap
Broadway
Canyon
30th

A couple other trends in crashes:

Impairment
5% of all crashes
11% of severe crashes
71% of drivers were male (all)
84% of drivers were male (severe)
57% under the age of 30
24% between 30 and 49

Worst intersections
- Foothills & Arap (6, two severe)
- Valmont & Foothills (4)

And, interestingly enough given how young people are involved in a lot of crashes, staff ID'd the 65+ age group as a rising trend in crashes

65+ were involved in
17% of all crashes (but only 12% of population)
25% of severe crashes

In 54% of crashes with this age group, the 65+ person was at fault

We've already moved on to council questions, but I have more notes!

Benjamin asked about red light cameras.
Devin Joslin, principal traffic engineer, says they are "extremely effective" at deterring folks from running red lights. Or at least reducing crashes from folks running red lights.

I realized I didn't really define what Arterial roadways are other than to say they're the bigger, main streets.

That's true, but also: They typically have much higher speeds and many more lanes. So more opportunity for crashes and severe ones.

Speer asked about the age of victims in crashes that happen in local neighborhoods. The city didn't look at that, Joslin said, but they can.

That was in response to concerns about kids and speeding cars as the city turns its focus from speed management in neighborhoods to those arterials where the majority of severe crashes happen. Per council's direction.

More info on that coming in a story this week. (And later in this presentation, probably)

This all pertains to Vision Zero, Boulder's goal to eliminate all serious injury and death from car crashes (by reducing the number of crashes and eliminating the serious ones altogether).

Boulder adopted Vision Zero in 2009, so 13 years ago. Severe traffic crashes decreased until about 2016, and have really stayed steady since then. So not a lot of progress.

2009-2020: 675 serious injuries or deaths from car crashes in Boulder

Context is always helpful, so....

Nationwide, between 2015 and 2019 (2020 excluded due to COVID-19)
- 7% increase in total crashes
- 6% increase in vehicle miles traveled
- 3% increase in population

In Boulder, during that same time
- 13% decrease in total crashes
- 10% increase in vehicle miles traveled
- 2.4% increase in population

Why are we not really looking at 2020? Bc it was so freaking weird on car travel.

During 2020,
- VMT dropped 29%
- Total crashes dropped by nearly half
- Severe crashes fell by a third
- Ped, bicyclists and impaired driver crashes all decreased

So it's not really useful to look at when measuring long-term progress.

Council is betting that a focus on the arterial networks will further Vision Zero goals, bc so many of the severe crashes happen there.

You can learn more about CAN here. boulderbeat.news/wp-content/upl…

I haven't touched on Twenty is Plenty yet, but I've got NOTES.

Reminder: That's when the city lowered speed limits in neighborhoods from 25 to 20 mph

It did not decrease speeds in a statistically significant way
“Speeds remain largely unchanged," staff wrote, and in some places, increased (very, very slightly)

“Average speed increased slightly” from 21.57 mph to 21.9 mph (1.54%)
“There was a slight increase in the number and percent of vehicles traveling over 30 mph and 35 mph”
5.88% *fewer* cars traveling under 20 mph
1.99% cars driving over 30 mph and .46% above 35

That's not unusual. In 4 peer cities, the findings were all the same.

Portland and Eugene, Oregon
Seattle
Cambridge, Mass
All 4 reduced residential speeds to 20mph
Portland, Cambridge and Seattle reduced arterials speeds by 5mph

None found significant reductions in speed
Much more important than speed limits is street design

As staff noted:
“Local streets that are wider and have a painted yellow centerline saw faster vehicle speeds than streets that were narrower and without a centerline.”

In those 4 peer cities, all now design streets to the target speed (20 mph) rather than what most drivers will actually drive.

V few comments from council on this one. They're already done! And I have more notes!

Rare is the day when I'm ready and wanting a council meeting to last longer. That one left me unsatisfied.

But I do plan to follow up with a story. If ya'll have any questions you'd like me to ask about this general topic, let me know. I've got an interview tomorrow a.m., with a story coming later this week.

@threadreaderapp please unroll. Thanks!