Category: Vision Zero

Hmm. 16th St traffic calming

Dan Allison2 Comments

A new traffic calming feature has showed up on 16th Street approaching R Street in midtown Sacramento. Paint and flex posts have been placed between the travel lanes. Advance yield lines (‘sharks teeth’) were also painted, showing where drivers should stop when yielding to pedestrians.

16th St lane channelization

I’m not sure what to think of this. Certainly this is a problematic intersection. Cars stopped for the light rail gates between R Street and Q Street often stop throughout the intersection, blocking both the north and south crosswalks over 16th Street, as well as the intersection itself, preventing vehicles along R Street from proceeding while the traffic is stopped. As with all multilane streets, but particularly high speed, one-way arterials, drivers in one lane may stop for a walker while the others will not. I see this every day, and this intersection is worse than most. For reasons I don’t understand, traffic speeds on 16th Street northbound are noticeably higher than 15th Street southbound, even though the design of both streets in the same.

So, how’s it working. Well, I’ve so far only had the chance to observe it for 15 minutes. I’m not sure it is making much difference. About 10% of drivers stopped at or close to the advance yield lines. About 70% of drivers stopped at the forward edge of the flex posts, about 10% stopped over the crosswalk, and about 10% did not stop for people using the crosswalk. I saw three people nearly hit by drivers. This is not unusual, and it not worse than before, but it is not good.

Below is an example. The driver to the left stopped over the top of the crosswalk, even though it was clear that traffic ahead was stopped for the light rail gate, and there was no space to proceed into. The driver to the right stopped before the crosswalk, but not at the advance yield line. Not visible it the driver in the closest lane who did not stop at all because there was a space in that lane across the intersection.

walker using the crosswalk over 16th St at R St

While I appreciate the effort, I’m not sure if the results will be what is desired, which is the ability of walkers to safely cross the street.

In the long run, the reallocation of roadway on 16th Street to reduce the general purpose lanes from three to two will help this location a great deal, but I don’t know when that will happen. It could be years away.

With the new businesses on R Street to the east, and the street dining area on R Street to the west of 15th Street, this intersection has become quite busy with walkers, bicyclists, scooters, and motor vehicles. It does deserve attention.

AB 550 allows speed cameras

Dan AllisonLeave a comment

AB 550, by Assemblyman David Chui, would allow the use of Automated Speed Enforcement (ASE, or speed cameras) in certain circumstances. I can’t point you to the language for specifics, since the legislative website has not been updated yet. You might call this a gut and amend bill, but since the original subject was ‘pedestrian safety’ it is really more of an amend.

The bill would establish a pilot program, which local transportation agencies could participate in. It would not start until July 2022, more than a year from now, in order for CalSTA (California State Transportation Agency) to develop an implementation plan. The program would rest with Caltrans and local transportation agencies, not with law enforcement agencies, which is a critical distinction to reduce the use of discriminatory pretext stops by law enforcement.

This legislation for ASE is a key component of the Vision Zero movement: “Managing speed to safe levels.”

It has long been my theory that most fatal crashes, whether the victim is a driver, passenger, walker or bicyclist, are caused by egregious speeders, drivers who travel more than 10 mph over the speed limit, the sort of people that CHP occasionally catches going 120 mph on the freeway, and is the same person driving 50 mph on a residential street. If that person is getting repeated automated speeding tickets, then they (he) can be targeted for more serious consequences like loss of freedom and loss of vehicle. Of course loss of vehicle probably requires other law changes, but this bill is at least a start.

When the bill language is available and hearing scheduled, I’ll post again. Keep an eye out here, or Streetsblog, or Twitter.

Streetsblog SF: Lawmaker Tries Again on Automated Speed Enforcement

from Streetsblog SF, original source unknown

the VZ solution we won’t talk about

Dan AllisonLeave a comment

The one thing that no one in the transportation advocacy community wants to talk about is speed-limiting vehicles. Speed-limiting means that vehicles cannot operate over the speed limit selected for a section of roadway. The technology for doing this is largely already in place on modern motor vehicles, as they already monitor their speed and already have available information about the speed limit on the street they are on. Older vehicles of course don’t, and would need to be retrofitted.

Why speed limiting? Because it is a simple solution that cuts through all the other discussion and contortions and expense of other solutions. Some people think education is the solution, as though all the education to date has done any good. Some people don’t want any traffic laws enforced, because ‘freedom’, meaning of course the freedom to operate a vehicle recklessly and kill people. Some people think that the solution is to redesign roads so as to prevent speeding. I’m not against that solution, but our mis-designed transportation system has a value of trillions of dollars, and fixing it will require trillions of dollars. We could spend our money that way, but why when we have so many other good causes to spend on. Vision Zero efforts are admirable, at least when they don’t have the involvement of law enforcement, but there has been very slow progress or regression in the United States because the engineering profession and law enforcement really don’t believe in the idea, giving it lip service while trying to subvert it.

Speed kills. It increase the severity of crashes, making severe injury and fatality more likely. It also increase the frequency of crashes, because drivers have less time to react and avoid, or slow before impact. You have all seen a version of the graph below, and it is important to remember that at every speed, speed is a contributing factor.

Speed limited does not mean changing posting speed limits, though it turns out that reducing speed limits does indeed reduce traffic speeds and reduce crashes and injury severity. However, speed limits are not set to the design speed of the road, but lower than than. As a result, drivers are encouraged by road design to speed, while fingers are wagged and tickets are written. But the problem is not solved. Crashes and severe injuries and death continue apace, or increase in the case of this last year.

With speed-limiting, no vehicle goes faster than the speed limit. If there are no crashes, maybe it gets increased a bit. If there are crashes with severe injury or fatality, then it gets reduced. We don’t need to change speed limit signs, we just change the permissible speed which vehicles respond to and follow.

Of course we should redesign streets to make them friendlier and safer for walkers, bicyclists, transit users, and drivers for that matter. But in the meanwhile, I want no one to die or be seriously injured on the streets and roads we have. Speed-limiting is the solution.

It is worth pointing out that designers and manufacturers of autonomous vehicles don’t want this to happen. They are assuming they will be allowed to violate speed limits, because they know that their primary target driver audience, young aggressive males, won’t buy vehicles that go the speed limit. They are just hoping no one notices that they are going to bypass this, and probably will get away with it.

Sac Vision Zero new intersections map

Dan Allison1 Comment

Thinking about the intersections maps and what they show (Sac Vision Zero top intersections all modes, Sac Vision Zero top ped intersections, Sac Vision Zero Top 5 Corridors and top intersections), I thought it might be interesting to present the data in a different way. The two maps below show all of the top intersections identified in the all-modes, pedestrian, and bicycle data. They are divided into a north section and a south section so that the intersections and their labels are visible. The maps are available as pdfs (north, south).

legend for intersections on maps below
Sacramento top collision intersections, north section
Sacramento top collision intersections, south section

The intersection data is in the table below.

What’s next? I’ll take a closer look at some of these intersections. For people who follow traffic engineering, it will probably be immediately obvious why these intersections are dangerous. A detailed analysis requires looking at each collision record individually, which I don’t have time to do. The city did make use of incident reports, which contain more information than the data in SWITRS, in developing the Vision Zero Plan.

Sac Vision Zero top intersections all modes

Dan Allison3 Comments

And now for the third analysis of high injury network intersections and the relationship to the Sacramento Vision Zero Top 5 Corridors. The dataset this time is all killed or severe injury collisions in Sacramento, for all modes of travel, for the period 2009-2017. Of the 1641 collisions in the city, 322 (20%) were at intersections defined by the intersection of arterial and/or collector streets. There is also a pdf map available.

Sacramento high injury network intersections and Vision Zero Top 5 Corridors

Of the eleven intersections with four or five collisions, three are on the Top 5 Corridors:

  • Stockton Blvd & Broadway, 4 (on Stockton-Broadway corridor)
  • Stockton Blvd & Lemon Hill Ave, 4 (on the Stockton South corridor)
  • Stockton Blvd & 47th Ave & Elder Creek Rd, 4 (on the Stockton South corridor)

and eight are not:

  • Watt Ave & Auburn Blvd, 5
  • Del Paso Blvd & Evergreen St & Lampasas Ave, 5
  • Julliard Dr & Kiefer Blvd & Folsom Blvd, 5
  • Power Inn Rd & Fruitridge Rd, 4
  • Freeport Blvd & Florin Rd, 4
  • Center Pkwy & Cosumnes River Blvd, 4 (not on map)
  • Bruceville Rd & Cosumnes River Blvd, 4 (not on map)
  • Franklin Blvd & Mack Rd, 4 (not on map)

The three last intersections are not on the map because I wanted to maintain the same scale as used for the previous maps, but they would be off the south edge of the map. Note that the number of collisions at these intersections is not directly comparable to the bicycle collisions map I created because I used a different dataset, degree of injury and span of years. I may go back and update the bicycle map to be consistent, but it is probably more worthwhile to look at some of these intersections in more detail.

Sac Vision Zero top ped intersections

Dan Allison3 Comments

As promised, a follow-on to my post on the top bicycle collision intersections in Sacramento (Sac Vision Zero Top 5 Corridors and top intersections), here is the same sort of analysis for pedestrian collisions. I used a somewhat different data set, this time only killed and severe injury crashes (KSI), for the years 2009-2017. This mirrors the data the city used in the Vision Zero Top 5 Corridors document, and so is not directly comparable to the different criteria I used on the bicycle post.

Pedestrian (walker) collisions are more dispersed that bicycle collisions, fewer occurring at intersections and more in between. Of the 408 collisions, 70 were at intersections, 17%, compared to 69% for bicycle collisions. Of these 408 collisions, twelve intersections stood out: Amherst St & Florin Rd, Marysville Blvd & Grand Ave, and Watt Ave & Auburn Blvd, each with three; and 15th St & Capitol Mall, 29th St & Florin Rd, 5th St & N St, 7th St & J St, Stockton Blvd & Broadway, Stockton Blvd & Lemon Hill Ave, Riverside Dr & X St, and Julliard Dr & Kiefer Blvd & Folsom Blvd, each with two. Of these 12 intersections, 4 are on Top Five corridors: Marysville Blvd & Grand Ave on the Marysville corridor, Stockton Blvd & Broadway on the Stockton-Broadway corridor, Stockton Blvd & Lemon Hill Ave on the South Stockton corridor, and 29th St & Florin Rd on the Florin corridor.

The map belows shows the city corridors and the twelve intersections, with the number of collisions and intersection name labeled. There is also a pdf available.

map Vision Zero top pedestrian intersections
Sacramento pedestrian collision top intersections, with Vision Zero corridors

There is a better alignment between the five designated corridors and pedestrian collision intersections than was true for bicycle collisions.

I will point out that the Julliard Dr & Kiefer Blvd & Folsom Blvd intersection is the site of three pedestrian collisions and four bicycle collisions, which is higher than any other intersection in the city. It should really be a focus for the city.

Addition 2021-03-02: Someone asked how the pedestrian collision locations relate to disadvantaged communities. Below, a map with CalEnviroScreen 3 2018-06 (CES) layer, with red end being higher pollution, green being lower, and weighted with income. CES is not the only measure of disadvantage, but it is one commonly used.

Sac Vision Zero Top 5 Corridors and top intersections

Dan Allison3 Comments

As promised in my previous post, Sac Vision Zero flaws, here is a limited analysis of high injury network intersections in Sacramento. I used bicycle crashes for 2014 through 2018 from the SWITRS crash database, and matched these to intersections of arterials and collectors in the city. It is known that most crashes occur at or near intersections, not in between. Of the 1112 crashes in this time period, 763 occurred at intersections, or 69% (for all crash types, the city said it is 78%). I selected eight intersections to highlight, which had 4, 5, or 7 crashes at the intersection or within 120 feet of the intersection, meaning on the approach or departure from the intersection. The other 590 intersections had 3, 2, 1, or no crashes. I did not analyze the crashes for fatality or serious injury, but that would be a useful.

The map below shows the Sacramento Vision Zero Top 5 Corridors, in red, and the top eight crash intersections with a bicycle symbol. The number to the right is crashes, and the location is labeled with cross streets. This is also available as a pdf.

Of the eight intersections, one is part of the Florin corridor, at 24th Street and Florin Road. The other seven are not.

I ask that the city revise its Vision Zero program to include high injury intersections. The number might be as many as 10, and selection should include the same equity criteria used to select the corridors. That means that the three central city locations might not be selected, or might be lower on the priority list, and that is good. The challenge of the Stockton Blvd & Fruitridge Road intersection is that it is on the city/county boundary, so complete treatment of the intersection would require some cooperation with the county. But with seven bicycle crashes in the time period, it is a very important intersection.

A strong advantage to giving high injury intersections recognition and attention is that they could receive near-term safety improvements that require only reallocation of roadway width and new paint. Full safety improvements probably would require redesign of the intersection.

Again, I fully support the city’s Vision Zero efforts, and want to see them be the best they can be. That means including high injury intersections.

Addition 2021-03-02: Someone asked how the bicycle collision locations relate to disadvantaged communities. Below, a map with CalEnviroScreen 3 2018-06 (CES) layer, with red end being higher pollution, green being lower, and weighted with income. CES is not the only measure of disadvantage, but it is one commonly used.

Sac Vision Zero flaws

Dan Allison2 Comments

Edit: Added graphics for El Camino – Grove intersection and Broadway – Stockton intersection, excerpted from the Sacramento Vision Zero Top 5 Corridors document.

The Sacramento city council will be considering the new Sacramento Vision Zero Top 5 Corridors document at the council meeting on Tuesday, February 15. It is item 11 on the consent agenda, so will not be discussed unless a council member pulls it from the consent agenda.

I have taken a look at the document, though the one included with the with the agenda is a flat file, not searchable, and with low resolution graphics, making it hard to use. When a high resolution and searchable version becomes available, I’ll link to it.

The document continues the pattern established in the 2018 Vision Zero Action Plan of focusing on corridors and not on intersections. The five segments presented as the top five are segments of El Camino Avenue, Marysville Road, Broadway/Stockton Blvd, Stockton Blvd south, and Florin Road. I believe that this exclusive focus on corridors is a mistake. Nearly all other vision zero communities have a dual focus on corridors and intersections, but Sacramento does not.

The Vision Zero Action Plan acknowledges on page 11 that 78% of collisions occur at intersections, but then seems to ignore this fact in pursuit of corridor projects. Of course if a corridor is done correctly, the intersections will be fixed as part of the project. The issue is that these corridor projects will cost millions of dollars and will require seeking state and federal grants to accomplish. The costs are El Camino $16,450,000, Marysville $12,850,000, Broadway/Stockton $8,750,000, Stockton South $9,500,000, and Florin $11,900,000. And these are only for the most important fixes; less important or more expensive fixes are somewhere off in the distant future. But a focus on the high injury intersections within the corridor could yield significant safety benefit at much lower cost, perhaps within the range of general fund expenditures.

This focus on corridors leads to some flaws in the corridor plans. On El Camino, the plan misses that there is a dropped bike lane at eastbound at Grove Avenue and therefore does not recommend the countermeasure Extend Bike Lane to Intersection. At the Broadway/Stockton intersection, the plan does not recommend the countermeasure Bike Conflict Zone Markings for Broadway eastbound and westbound approaching Stockton, and seems to completely drop the bike lane on Stockton northbound approaching, even though a bike lane is already present there.

El Camino Ave & Grove Ave intersection
Broadway & Stockton Blvd intersection

Re-striping of lanes at intersections and green paint could make many intersections a great deal safer without requiring expensive intersection reconstruction and new signals. I recently wrote about Dropped bike lanes, using Broadway/Stockton as an example. Paint could fix a lot of the problems here.

The concerns expressed here are with bicycle facilities. I actually think pedestrian (walker) facilities are more important, but it will take a lot more time to look closely at those.

The bicycle-related countermeasures recommended in the Vision Zero Top 5 Corridors are:

  • Bike Conflict Zone Markings: Green pavement within a bike lane to increase visibility of bicyclists and to reinforce bike priority. The green pavement is used as a spot treatment in conflict areas such as driveways.
  • Class II Bike Lanes: Five to seven foot wide designated lanes for ‘bicyclists adjacent to vehicle travel lanes, delineated with pavement markings.
  • Close Bike Lane Gap: Closing gaps between bike lanes increases the amount of dedicated facilities bicyclists can use, reducing mixing of bicyclists and drivers and Increasing network connectivity and visibility of bicyclists m the roadway.
  • Extend Bike Lane to Intersection: In locations where a bike lane is dropped due to the addition of a right tum pocket the intersection approach may be re-striped to allow for bicyclists to move to the left side of right-turning vehicles ahead of reaching the intersection.
  • Provide Green Time For Bikes: Provide or prolong the green phase when bicyclists are present to provide additional time for bicyclist to clear the intersection. Can occur automatically in the signal phasing or when prompted with bike detection. Topography should be considered in clearance time.
  • Remove Right Turn Slip Lane: Closing a free-flow right-turn slip lane can help slow right turning drivers, eliminates an uncontrolled crossing for pedestrians, and shortens pedestrian crossing distances. The space reclaimed in closing the slip lane can be reused as pedestrian widen sidewalks, enhance curb ramps, more space for street furniture.
  • Separated/Buffered Bikeway: Designated bike lanes, separated from vehicle traffic by a physical barrier usually bollards, landscaping, or parked cars. These facilities can increase safety by decreasing opportunities for crashing with overtaking vehicles, and reducing the risk of dooring.
  • Slow Green Wave: A series of traffic signals, coordinated to allow for slower vehicle travel speeds through several intersections along a corridor. Coordinating signals for slower travel speeds gives bicyclists and pedestrians mare time to cross safely and encourages drivers to travel at slower speeds.

I support the Vision Zero concept and city actions to support this, but I want to make sure that both are the best they can be. I hope to look in the near future at the pedestrian elements of the Vision Zero Top 5 Corridors, the Vision Zero School Safety Study, and the high-injury intersections in Sacramento that have been missed through a focus on corridors.

prudent drivers as traffic calming

Dan AllisonLeave a comment

Now, on to why I brought up the topic of prudent drivers. A prudent driver on a two lane (one lane in each direction) roadway largely controls the behavior of irresponsible drivers. On wider roads, with two lanes or more in a direction, whether a one-way or two-way, the irresponsible driver can do as they wish, violating laws and endangering others. On the narrower roadway, the irresponsible drivers get irritated, and honk and cuss, but there isn’t much they can do about it. This difference in large part explains why fatality and severe injury crashes are rare on residential streets within neighborhoods, and are common on arterial streets with multiple lanes. It also explains why rural roads have such high crash rates, because the prudent driver there can’t really control other drivers. On two lane streets, prudent drivers set the tone; on multiple lane streets, irresponsible drivers set the tone.

We have proven, over the history of motor vehicle use in the US, that is is not possible to significantly change the behavior of drivers. Education doesn’t do it, enforcement (even when that used to be more common) doesn’t do it. Nearly all of the improvement in roadway deaths has been due to safer cars, not to safer drivers or safer roads, and now that improvement is reversing itself as more and more walkers and bicyclists are killed by irresponsible drivers.

I am not against education, if it is directed at the most dangerous behaviors, which it is not, and I am not against enforcement, if it is done in an unbiased manner, which it is not. Each state has an agency, usually called the Office of Traffic Safety (OTS), whose mission is to obscure the real causes of crashes and to blame walkers and bicyclist for their death and injury, and at the federal level, the National Highway Traffic Safety Administration (NHTSA) fulfills this function admirably. In this, they are often aided and abetted by the law enforcement agencies. The reason CHP is California is so opposed to automatic speed enforcement is because it would remove the mis-focus and bias that they otherwise rely upon.

Driver behavior must be controlled by roadway design. That is why I strongly believe that all multiple lane roads must be reduced. Two lane one-way streets must be converted to two-ways streets with only one lane in each direction (and any other lanes converted to pedestrian, bicyclist or transit use). Two-way roadways with two or more lanes in the same direction must be reallocated to other uses. Again, excess capacity would be converted to pedestrian, bicyclist, or transit use, or even to development as overly wide streets shrink to fit the real need.

I have no illusions about the huge change in traffic flow. Those drivers who have gotten used to having plenty of space for themselves (their cars) would have to figure out how to use less: fewer trips, shorter trips, slower trips. People would make different decisions about where they live, where they work, where they shop and recreate. As far as I am concerned, this is all to the good.

Our freeways are designed by the ‘best and brightest’ engineers to be as safe as possible, allowing errant vehicles extra space, protecting hard objects with guard rails and impact attenuators (crash barriers), and using ridiculously wide travel lanes, yet still have very high crash rates. Spending more money apparently doesn’t make freeways safer, and the explanation for this is risk compensation, the proven effect that irresponsible drivers will increase their unsafe behavior to maintain the same level of risk. Think about the daily news items about crashes that close freeways for significant periods of time, and how often they happen. None of these need to happen, and I’d argue that an irresponsible drivers is the primary cause of each and every one of them. This post is about local streets, not freeways, but it is worth remembering that irresponsible drivers are everywhere.

I don’t believe that one single death or severe injury for a walker or bicyclist is worth any amount of convenience for motor vehicle drivers. Not one.

So, I ask every transportation agency in the Sacramento region to:

  • cease widening roads, forever
  • analyze all one-way roads with three or more lanes to determine the most dangerous ones, and convert these within two years
  • analyze all two-way streets with more than one lane per direction for the most dangerous ones, and convert these within five years
  • analyze the remaining roads that are not one lane per direction, for the most dangerous ones, and convert these within ten years
  • complete conversion of all roads within twenty years
  • stop victim blaming

the city could do this now

Dan AllisonLeave a comment

Some things the City of Sacramento could do today, and this week, to improve transportation and safety now and in the future:

  • Paint red curb offsets for all marked and unmarked crosswalks. These are upstream offsets, which have a strong safety value of increasing the visibility of drivers and walkers to each other. Downstream offsets, beyond the crosswalk, are much less important. Paint is cheap! Yes, maintenance of paint is more expensive, but this is important enough to make the investment.
  • Set all pedestrian signals to auto-recall, city-wide. Later we can have a discussion about whether to leave them this way, and how this interacts with the audible signals for limited vision people. I’m NOT saying disconnect the buttons, they would work if you pressed them, rather, that you no longer need to press them.
  • Convert the southbound light rail lane on 12th Street from a shared general purpose travel lane to a transit lane, from C Street to K Street. Having drivers interfere with light rail should never be OK. Consider doing the same for the portions of 7th Street and 8th Street where there is excess vehicle capacity.
  • Enforce, with a vengeance, speeding and failure to yield to pedestrian laws. Impound the cars and revoke the licenses of anyone who has more than one of these violations in a week. Our streets have been taken over by lawless joy-riders, and we need to take them back, for the safety of walkers, bicyclists, and other people in vehicles, and yes, people in adjacent buildings. Yes, these situations will end up in court, about whether the city has the power to do this, but in the meanwhile, we get these people off the street. This is an emergency, after all, and this seems a reasonable use of police emergency powers.
  • Close at least one street of at least a eighth mile length in every census tract. Since census tracts vary by population size, in a very rough way, this distributes the closed streets in the fairest manner. It provides people safe walking space in their neighborhoods, to ensure physical distancing.
  • Close the extra lanes on any street that has more than two lanes per direction, and re-allocate that space to either pedestrians or bicyclists, as demand seems to indicate.

There is construction going on right now on N Street adjacent to Capitol Park. The street has been narrowed from three lanes to one lane, and it is working just fine. The prudent driver, the one following speed limits, or at least in the range, now sets the speed of the roadway, and the egregious violators have to live with it. Which is, I think, why I’m not seeing problems on N Street right now, and am still seeing it on other wide roadways.

What else would you recommend, actions that could take place almost immediately and would not cost much?