Wednesday, August 01, 2012

2010-2011 San Francisco Collisions Report

The just released San Francisco Collisions Report confirms the trends shown in previous reports: Our streets have been getting consistently safer over the years, thanks to the MTA's focusing on the city's most dangerous streets and intersections and making them safer.

You can't count on the Bicycle Coalition or Walk SF to tell you that. The latter's website demagogues the pedestrian safety issue, while ignoring reports like this. Neither special interest group will deign to do an analysis of the latest report, which puts the lie to the sense of a chronic safety crisis on city streets that they foster to push their anti-car agenda.

Walk SF and the Bicycle Coalition push their agenda by promoting the sense that there's a bloodbath happening on city streets caused of course by motor vehicles, aka "death monsters."

When you look at the numbers from previous years, there surely used to be something like a traffic bloodbath on city streets. See page 4 of this collisions report, where we learn that there were 5,804 injury collisions/accidents in 1990, a number down to 3,111 in 2011. There's been progress too in reducing fatal accidents on city streets. 64 people died on city streets in 1990, and that number was down to 28 in 2011.

See a MTA report from 2010, New York City's Pedestrian Safety Study and San Francisco Data, for more historical information on accidents on SF's streets. From early in the 20th Century up through the 1960s, more than 100 traffic deaths a year were common on city streets (pages 5-7).

The collision report is overly cautious about this positive trend:

The number of collisions resulting in fatalities in 2010, 23, was one of the lowest that San Francisco has recorded (Figure 2). The number of collisions resulting in fatalities in 2011 was 28. In general, injury collisions are a more reliable indicator of collision trends because fatal collisions, being fewer in number, are subject to sharper fluctuations from year to year...Since 2004 annual fatal collision totals below 30 have been more common, a possible indication of an improving trend (page 4).

Cyclists are the only group that has an increasing number of injury accidents:

Injury collisions involving bicycles, however, have increased as a share of the City’s reported injury total. From 2000 to 2004, ten percent of collisions involved a person riding a bicycle. Eleven years later that percentage has doubled to 21 percent as bicycle collisions have increased while other types of collisions have not (page 17).

More cyclists are getting injured on city streets because there are more of them. The report cautiously endorses that view:

There were 630 injury collisions in 2011 involving a bicycle as a party, up 5 percent from the 599 total recorded in 2010. The 2011 injury collision total is the highest in the past ten years. Bicycle-involved collisions have been steadily increasing since 2002. While the exact reasons for this increase are not known, it has coincided with a statistically significant increase in the number of bicyclists riding on various city streets, as measured by annual counts taken by the SFMTA. Table 8[on page 22] suggests there may be some relationship between the increases in recorded bicycle activity and resulting bicycle-involved collisions. The "safety in numbers" effect of decreasing collisions as bicycle riding becomes more prevalent does not appear to be the case so far in San Francisco (page 21).

When there's an effort to determine who's at fault for these accidents, the report (page 24) finds that cyclists are responsible for more than half of their own injury accidents, primarly because of speeding, running stop signs/stop lights, and riding the wrong way and against traffic on city streets. In other words, the "scofflaw" behavior that even the Bicycle Coalition admits is common among city cyclists:

Fault for collisions seems to be evenly split among bicycle riders and motorists according to the SFPD collision reports. The most common violation cause by the bicyclist was unsafe speed (16 percent of total), and on the part of motorists it was not signaling a turn (8 percent of total). The second most common collision cause on the part of motorists involved not checking for bicycles before opening a door (8 percent of total) closely followed by failure to yield right of way when making a turn (8 percent of total). The second and third most common collision cause on the part of bicycle riders was violation of traffic control devices such as STOP signs and traffic signals (10 percent of total).

Pedestrian injuries were up slightly from the previous year, but the overall trend is fewer pedestrians injured every year on city streets ("Focusing on multi-year trends can help reduce the effects of short-term fluctuations," page 3):

The 2011 total of 807 injury collisions involving a pedestrian is up 3 percent from the 784 injury collisions reported in 2010. Up to 2004 pedestrian collisions continued a steady decline from the over 1,000 incidents that were recorded annually in the 1990’s. Since 2004 pedestrian injury collisions have been relatively unchanged. Though 2009 recorded the lowest San Francisco pedestrian injury total in the past decades, collisions in 2010-2011 unfortunately increased (page 18)...The recent trend among pedestrian fatal collisions appears to be slightly down, with the four lowest annual totals reported after 2004 (page 19).

Like cyclists pedestrians are often the cause of their own injuries: "...typically the SFPD will determine through witness and party statements the most likely cause of the collision (page 20)." Of the 807 pedestrian injury accidents in 2011, 266 were the fault of pedestrians and 541 were the fault of motorists.

A dramatic decline in motor vehicle-to-motor vehicle injury collisions continues. There were 2,547 such collisions in 2000, which dropped to 1,321 in 2011 (page 29). That decline was due in part to a similar decline in "red light violation collisions":

Traffic signal hardware and timing improvements described in this report appear to have helped reduce these types of collisions at certain intersections. This decrease also coincides with the city's deployment of red light photo enforcement starting in 1997 and other efforts aimed at reducing the incidences of red light running (page 7).

Which brings us to District 5's most controversial intersection, Fell and Masonic:

2009-2011 injury collisions: 20...In 2008 SFMTA installed a bicycle signal treatment that separated Fell Street left-turning motor vehicles from bicycles and pedestrians crossing Masonic Avenue on the south side of Fell Street. Red light camera was activated in late 2011. Further signal design changes are to be completed in the summer of 2012. Collision trend: 2011 saw the highest collision totals for the intersection, with 11 total reported, five of those being vehicle-bicycle collisions.

Actually, as the numbers between 2000 and 2011 show, the accident trend at this intersection, in the words of last year's collision report has been stable: "This location has had a stable pattern since 2006 of 6 to 5 reported intersection collisions a year (page 16)." Last year's spike was probably an anomaly, like way back in 2001, when there were also 11 injury accidents there.

As I predicted more than four years ago, the changes at that intersection haven't made any difference in safety, though the traffic light and the separate left-turn lane were both sensible changes. Not surprisingly, some motorists and cyclists still make mistakes and/or behave recklessly at this intersection, rushing to beat the light. Traffic engineering can do a lot to make our streets safer, but it will never trump human nature.

Good to see that the report notes a real improvement at the Grove Street and Divisadero intersection, since a much-needed traffic signal has been installed at that dangerous intersection (page 30). As a pedestrian, I either sprinted across the street there or walked to the next block to cross.

The report has an odd lapse in interpretation on the Duboce Avenue and Valencia Street intersection: "Collision Trend: Sustained increase in collisions since 2006-2011." But the numbers at the bottom of the page show a remarkably stable pattern of accidents at that intersection since 2000. Eight of the 17 injury accidents there between 2008 and 2010 were to cyclists. Maybe that's what the writer had in mind, but "SF MTA staff will review pattern of bicycle-vehicle collisions..."

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At 3:58 PM, Blogger Rob Anderson said...

Michael Helquist: From now on you can only comment on this blog using your own name. No more pseudonyms or anonymity.


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