Saturday, March 6, 2021

City Council, March 8th - Speed Zones and our Autoism

Also on Council's agenda for Monday are a couple of transportation items that deserve some notice.

Two Speed Studies

Though the details are pretty wonky, the two speed studies and adjustments to posted speeds are very interesting.

And we should read them in light of the fact, as Salem Reporter noted, in West Salem on Doaks Ferry Road, a person was apparently driving lawfully at 40mph, or close enough, that after they struck and killed Selma Pierce, the "the Polk County District Attorney’s review...found there was no evidence to justify criminal charges." 

Speed kills even when there is no obvious carelessness or unlawful driving. (Previous notes here.)

At Nebraska on 17th,
70% of drivers exceed "limit."
The limit is 30mph, the average is 32,
and 85th percentile speed is 36.

I think this is the first time that we have seen a speed zone evaluated by the 50th percentile rather than 85th percentile speed. Last year ODOT changed the rules around evaluations like these, and here is what might be the first fruit of that in Salem. This is actually a remarkable moment!

When numbers of people drive on a road, they vary their speed. And because we have normalized an acceptance for casual speeding, there is quite a range. An 85th percentile speed will be significantly faster than a 50th percentile speed. So by saying that we should center our analysis on a 50th percentile, we are also saying we are going to normalize an expectation for slower speed. This resets a little the traditional approach to raise the posted limit to conform to actual practice. This is an incremental improvement in formal engineering doctrine.

With this new paradigm, however, ODOT still looks at a safety problem and says, "we should raise the speed limit." Even with this new method, the system is still screwed up.

In an urban environment 50% still should not necessarily be the target. It still formalizes that half of people will casually speed.  A 50th percentile analysis also doesn't change the road design and doesn't curb the top end of most dangerous speeding.

By itself this new analysis is not a solution, but at least it centers our thinking on a better sense for what actual behavior we want on the roadway. Still, if the roadway is wrongly designed, even the average speed may not be what we want to see and may not align with the posted speed.

The official engineering doctrine also still rewards bad behavior.

On FB a person writes:

People will ignore limits if they seem too low. Tailgating will increase. People in a hurry will become more easily frustrated and that makes them more dangerous.

That's almost the language of an abuser: Don't make me frustrated, because I might hurt you. This is a clear instance of the way "might makes right" in our autoism.

City Public Works may still feel this vestigially. The Staff Report on the cases is a little confusing, and seems to disparage the 50th percentile approach, focusing on driver compliance and convenience rather than on safety, even if they admit urban situations are a little different. The dominant interpretive mode is highway driving.

Effective May 1, 2020, the process ODOT uses for conducting speed zone investigations and determining recommendations was revised. There are a number of factors considered when conducting a speed zone study including traffic volumes, crash history, roadway geometry, roadside development and density, and vehicle speeds. The biggest change in the process is the consideration of the 50% speed verses using the 85% speed as was in the earlier process. Studies suggested posting speeds near the 85% speed (the speed at or below which 85 percent of the vehicles are traveling) minimizes crash occurrences and provides better driver compliance. Recent studies suggest that posting speeds near the 50% speed is more applicable for urban higher density areas. [Italics added]

So that's an introduction to two speed studies and a mixed Staff Recommendation to

Concur with the speed limit review by the Oregon Department of Transportation (ODOT) that recommends retaining the 30 mph speed limit on 17th Street NE from State Street NE to Silverton Road NE, and recommends reducing the speed limit on 45th Street NE from 35 mph to 30 mph.

[And] Reject ODOT’s recommendation to increase the speed limit on 17th Street SE/NE between Mission Street SE to State Street NE from 25 mph to 30 mph.

The second part is particularly messed up. ODOT says, "Nah, let's raise the speed limit."

Staff further summarize the ODOT analyses:

17th Street SE/NE

According to the ODOT speed study, 17th Street has an average daily traffic volume of 10,000. From January 2016 through December 2018 there were 149 reported crashes with no fatal crashes and three Injury A (severe) crashes. In the 25 mph section (between Mission Street SE and State Street NE), 99% of the vehicles exceed the speed limit with the 50% speed at 32 mph. In the 30 mph section (between State Street NE and Sunnyview Road NE), between 49% and 93% exceeded the speed limit with the 50% speed at 30 mph to 32 mph. (Note: there were multiple speed measurement locations on this segment of 17th Street NE.)

ODOT recommended the existing 30 mph speed limit be retained on the section of 17th Street between State Street and Silverton Road NE. This recommendation is based on the percent of vehicles exceeding the existing posted speed limits and the low number of Injury A crashes verses total crashes. Public Works staff agree with this recommendation.

ODOT further recommended the section of 17th Street between State Street and Mission Street that is currently posted at 25 mph be posted at a higher speed of 30 mph. ODOT’s recommendation is based on the 50% speed. Public Works staff does not believe it prudent to increase the speed limit at this segment of 17th Street.

45th Street NE

According to the ODOT speed study (Attachment 2), 45th Street NE has an average daily traffic volume of 5,700. From January 2016 through December 2018 there were 12 reported crashes with no fatal or serious injuries. Additionally, 48% of the vehicles exceed the 35 mph speed limit. The 50% speed is 35 mph.

ODOT recommended the speed limit be lowered to 30 mph based on the speed limit being no more than 5 mph below the 50% speed. Public Works staff agree with ODOT.

One thing that is missing from these analyses is how those not in cars feel about safety and the road. Sometimes there are fewer crashes with injuries to people on foot or on bike because people not in cars avoid the road. Even with bike lanes 17th Street is not fully "family-friendly," and cars edging up to 40mph make is considerably less inviting.

Given the current, flawed way we handle safety and speeds, City Staff might have a reasonable take on the ODOT recommendations. It is good to see them resisting the recommendation to raise the speed limit on the southmost segment of 17th from 25 to 30. ODOT sees the enormous non-compliance there and says, "let's reward the bad behavior." But that is rather evidence the road design needs further adjustment.

And truly, we should want the northern section of 17th to be 25mph also. (Over on FB a neighborhood advocate has noted that they wanted 25mph on 45th also, but will take the reduction from 35 to 30.)

via Placemakers

But even limits for 30mph in an urban environment are often still too fast. If 50% of people are going faster than the signed 30mph on a road segment, then it's still too fast for most urban settings. We need slower speeds all the way around.

Back in the early 1980s Environmental Impact Statement for the Mission Street Overpass, we knew 17th was a problem and that many schools were on either side of it.

Circa 1980 we knew walking was hard here!

Lots of schools here (pre-Bush)

Look again at that speed profile at Nebraska on 17th. That's a school crossing. Even with the enhanced crosswalk and the signed 30mph limit, much more than half of drivers exceed that limit. It hardly functions as a limit! Again, the traditional approach has been to raise the speed limit to conform to actual practice, to reward the non-compliance; instead, we need to re-engineer the road to bring practice down to our expectation. Even if it is not an extreme case, 17th Street could use more calming, especially if we want to encourage more walking and rolling to school.

A Bikeway Proposal in South Salem

SCAN has been pushing for better bikeway connectivity and one fruit of this is an incremental set of adjustments to a connection between Willson and Clark Creek Parks. This could become a southern extension of the Winter-Maple Neighborhood Greenway.

The South Central Association of Neighbors (SCAN) sent a letter to the Public Works Director requesting that the City implement a bikeway connecting the Capitol Mall at Willson Park south to Clark Creek Park. The neighborhood association requested minor adjustments to the route from what is currently shown in the Council-adopted Salem TSP. Staff will install bicycle wayfinding signage along the route, including the proposed adjustments, and will amend the alignment contained in the Salem TSP during a future round of amendments.

Between State Street and Bush Park, Winter Street has a bike lane, so this would just be some improved signage. That won't really change anything.

South of Bush Park SCAN proposes a couple of minor route changes.

Two small changes in green

Since Howard Street actually connects with South High, SCAN proposes to make a better connection with it on the opposite side of a square. (By taxicab geometry this is equivalent!)

For the connection to Clark Creek Park, they avoid an uphill segment and use the lower entry to the park. A house was demolished at the adjacent lot in 2014 and the park entry hides behind a large berm for floodwater detention. The lower entry is a little hidden and the connection is not so great in the dark and in bad weather.

A parent, also, is not probably going to be very comfortable with a child taking the lane on Fairview or Vista.

So this route does not yet meet a full family-friendly standard, and merely to improve signage is not going to make a very large difference. Some key intersections and route segments likely need further modification and improvement for non-auto travel and safety.

(See previous notes here on the proposal.)

The bikeway passes this proposed hub
vision map

As a peripherally related matter, it is interesting that the route passes by a contested candidate site for a Neighborhood Hub. The City should create a new map that shows the bike system and posted speeds with the proposed hub locations. Hubs should have the kinds of businesses and destinations natural for reaching by bike rather than car, and it would be helpful to see how the hubs concept fits with our existing hopes for a bikeway system. If they are misaligned, then additional adjustments will need to be made. (Previous notes on Our Salem here.)

Bullets for the rest:

Addendum, Sunday

Here's a little more on why free parking at the Library does not in fact address equity very well and is more about convenience for people who just simply expect free parking everywhere.

Pedestrian Injury and Social Equity in Oregon
(ODOT, January 2021)

Poverty and carfree heatmaps
(2017 Cherriots Needs Assessment)

Addendum 2, Monday

Council is apparently going to support a second son of SRC.

Here we go again

If we are serious about reducing VMT for climate, we have to get serious about induced demand. Probably, with the prospect of a big Federal infrastructure bill, local governments desire to jockey for funding. This would be a move in the wrong direction.


Salem Breakfast on Bikes said...

Edits: Reordered sentences in a paragraph on the 50th percentile for better clarity. Added two charts on carfree households and free parking at the Library.

Ken said...

Bicycle Lane on 17th Street should be referred to as Painted Bicycle Gutter where debris accumulates to help bicycle riders get flat tires.

Salem Breakfast on Bikes said...

Yeah, sweeping the bike lanes has been a perennial problem for the City.

Added a note on City support for Rep. Evans' son-of-SRC bill.

Don said...

I would be interested to hear your thoughts on a light rail connection to portland from salem

Salem Breakfast on Bikes said...

The focus here isn't on regional transportation issues, and so probably I don't have very much for you.

Generally, I would like improved Amtrak service on the I-5 corridor.

Generally, I think new light rail is expensive, sometimes too expensive, both between cities and within a city.

Within Salem (as distinct from your question about Salem-to-Portland) we should instead think of Bus Rapid Transit on key arterial routes.