Injury Accidents on Marin Avenue Rise After Safety Fix

Marin Avenue saw more injury accidents after a "road diet" was undertaken to make it safer.

In 2005, Marin Avenue went on a diet. In the jargon of urban planners that means a stretch of the road that follows the course of an old creek from the Berkeley Hills to San Pablo Avenue was narrowed from four travel lanes to two. A two-way turn lane and bicycle lanes were added to make the street safer for motorists, bicyclists, and pedestrians. 

A year after the work between The Alameda and San Pablo Avenue was finished, engineers hired by the cities of Berkeley and Albany . While travel speeds inched up slightly by an extra mile or two per hour, traffic volumes dropped by more than 10 percent. Pedestrians had to wait longer to cross the street, but they were safer. Travel times didn’t change.

Public attention returned to traffic safety on Marin Avenue after as he skateboarded down Marin Avenue after dark on January 30. Commenters on Albany Patch remarked that the intersection of Marin and Tulare avenues remained treacherous for pedestrians and motorists alike. Patch staff looked at 10 years of traffic records to learn if Marin Avenue was safer after it was reconfigured in 2005.

Public records from the California Highway Patrol show that the number of injury collisions on Marin Avenue increased after 2005. The records also show that the number of injury accidents where unsafe speed was a factor rose during the same period.

On the Berkeley stretch of Marin Avenue, between Ventura Avenue and Grizzly Peak Boulevard there were 25 collisions in the five years before the diet and 29 in the five years following, even though traffic volume dropped by 14 percent in the blocks where the road was adjusted. 

Overall on Marin, there were 58 injury collisions from the start of 2001 to the time when the roadwork was finished in the fall of 2005. Between 2006 and 2010, 91 injury collisions were recorded on the same section of road.  

Between 2001-2006, unsafe speed was a factor in 22 percent of the injury collisions. After the road was converted, unsafe speed was a factor in 53 percent of injury collisions.

The has not made public the report from the fatal accident in January on Marin and Tulare Avenues. 

Farid Javandel is the mayor of Albany and transportation manager for Berkeley. Javandel said that Berkeley has not conducted another traffic safety study on Marin Avenue since 2006. He said that increased traffic volume on Marin Avenue could account for the rise in injury collisions, but that he has not heard evidence of traffic increasing on the road. "If something anecdotally seems to be coming up or the police department brings something to our attention," Javandel said, “then we would look at that."

 Top Intersections on Marin Avenue for Injury Collisions between 2001-2010 Ramona (Albany) 13 Masonic (Albany) 11 The Circle (Berkeley) 8 Curtis (Albany) 8 Colusa (Berkeley) 7 San Pablo (Albany) 7 Santa Fe (Albany) 7 The Alameda (Berkeley) 7
Emily Henry March 14, 2012 at 04:16 PM
Severin, according to Berkeley's transportation manager, the city doesn't do traffic measuring regularly (more like once or twice a decade) so there is no data to indicate whether or not the number of cyclists using Marin Avenue has increased. It would seem that crashes have indeed been more severe since the road diet, as there are more collisions resulting in injuries.
Emily Henry March 14, 2012 at 04:30 PM
Moe, thanks for the suggestion. As you can probably imagine, it takes a lot of time to compile this type of data. Each of the incidents on Marin Avenue had to be identified and recorded from a list of hundreds of incidents provided by the CHP. We have tried to present the information in the clearest way, without overwhelming the story with charts and numbers. However, in response to your request, I have added a table showing the year-by-year numbers. You can find it in the media box on the top right of the page.
Moe Hong March 14, 2012 at 04:30 PM
Emily, since there's no way to tell if these crashes have anything whatsoever to do with the road diet (obviously, as a journalist you must realize that correlation is not causation) and not some other factor, it would be irresponsible to relate the two in this article.
Emily Henry March 14, 2012 at 04:49 PM
Moe, as you can see from the numbers, there were fewer severe collisions (those causing injury or death) prior to 2005. This is a fact. There was an obvious dip in the number of incidents the year the road diet was being put in place (bearing in mind that there would have been road closures while construction was being done, as well as increased surveillance). In the years since 2005, there has been an increase in severe collisions, and speeding has become the primary cause for these incidents. While correlation does not automatically imply causation, this is no reason to ignore the correlation itself, especially when no other explanations can be offered by the city and anecdotal evidence from residents, drivers, pedestrians and cyclists suggest that the road diet was a catalyst for this change. As journalists, we present the information and invite readers to draw their own conclusions.
Alex Gronke March 14, 2012 at 04:50 PM
Moe, The article does not claim that the road diet caused the crashes. It merely points to the stats showing that injury collisions increased after the road diet was finished.


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