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.
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.
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.
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.
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.
This information from the City of Sacramento via email.
We have added and updated upcoming outreach events for the Vision Zero Top 5 Corridors.
Join us to learn more about the Vision Zero Top 5 Corridors Study and share your experience biking, walking and driving along these streets at one of the following events:
Date and Time
Corridor of Interest
Monday, November 5th
Peter Burnett Elementary School
6032 36th Ave.
South Stockton Blvd.
Wednesday, November 7th
Transit stop at Broadway and Stockton near Food Source (4401 Broadway)
Saturday, November 10th
Old North Sacramento/Dixieanne Community Association
701 Dixieanne Ave.
El Camino Ave.
Thursday, November 15th
Luther Burbank High School
3500 Florin Rd.
Thursday, November 15th
Gardenland/Northgate Neighborhood Association
Stanford Settlement Conference Room
450 W. El Camino Ave.
El Camino Ave.
Friday, November 16th
2308 Del Paso Blvd.
El Camino Ave.
Wednesday, December 5th
Hagginwood Community Association
William J. Kinney Police Facility
3550 Marysville Blvd.
About the Study
In 2017, the City of Sacramento identified the five corridors in Sacramento with the highest numbers of fatal and serious crashes involving pedestrians, bicyclists, and motorists.
The Vision Zero Top Five Corridor Study will analyze the factors that contribute to these corridors’ high crash rates. Based on technical analysis, community input, and best practices in roadway safety and design, the study will identify improvements for each of these corridors that can be implemented in the near-term.