When the LADOT proposes a road diet (also known as a roadway reconfiguration) on a street, it primarily does so with the intent of improving traffic safety. As it happens, road diets are frequently opportunities to specifically enhance conditions for people walking and bicycling – the most vulnerable users of our streets – while improving overall safety for all. After decades of study on the national level, road diets are officially acknowledged by the FHWA as a proven means to improve safety and the logistics of why road diets succeed in doing this have previously been laid out on this blog.

York Boulevard – A Local Success Story

While the LADOT frequently cites road diet studies from other cities to demonstrate their effectiveness in improving traffic safety, seldom are local road diet success stories discussed. It is for this reason we would like to share some positive results from reviewing traffic collision data (available via the Statewide Integrated Traffic Records System) on a portion of York Boulevard, between Eagle Rock Boulevard and Avenue 54, that was placed on a road diet in 2006.

We’ll dive into the details demonstrating this particular road diet’s success, but here’s the short version for those of you that can’t wait: before the road diet, this portion of York Boulevard experienced 27 collisions and 28 injuries per mile per year. After the road diet, this portion of York Boulevard experienced 21 collisions and 20 injuries per mile per year, reflecting 23% and 27% reductions, respectively.

Context and Background

Implemented in 2006, the road diet on the 1.3 mile segment of York Boulevard between Eagle Rock Boulevard and Avenue 54 is one of a few high profile roadway re-configurations in recent memory that has been around long enough to be studied extensively. The road diet converted this segment of York Boulevard from two lanes in each direction to a single lane in each direction with a center turn lane– bike lanes were not added until four years later in 2010.

In this analysis we will compare the five years of data available prior to the road diet with the five years following the road diet. We will also compare these results to a 0.9 mile segment of York Boulevard to the east, between Avenue 54 to North Figueroa Street. This segment was not road dieted during the same time period, allowing us to compare the road dieted portion of York Boulevard against a portion that went unchanged in its configuration.

The Big Picture

From 2001 through 2005, York Boulevard between Eagle Rock Boulevard and Avenue 54 experienced a total of 176 traffic related collisions that caused 181 injuries. This means this portion of York Boulevard experienced approximately 27 collisions and 28 injuries per mile per year during this time period.

From 2006 through 2010, after the road diet was implemented, this same segment of York Boulevard experienced a total of 135 collisions, resulting in 131 injuries. This works out to about 21 collisions and 20 injuries on a per mile per year basis. Comparing the street before and after the road diet, we see collisions dropped 23.3% while injuries dropped 27.6%.

Meanwhile, on the segment of York Boulevard between Avenue 54 and North Figueroa Street, which went unchanged, the number of collisions dropped by only 3.9%, from 77 to 74 during the same time period. The number of injuries in this segment dropped by 16.4% from 73 to 61. On a per mile per year level, collisions in this segment dropped from approximately 17.1 to 16.4, while injuries dropped from about 16.2 to 13.55.

While both segments of York Boulevard saw decreases in the number of collisions and injuries, it is clear far more dramatic safety improvements occurred in the western portion of York Boulevard between Eagle Rock Boulevard and Avenue 54 that was road dieted in 2006. For a visualization of this difference, see the below graphs:

A Look at Bicycle and Pedestrian Related Collisions

Dramatic drops in the overall number of collisions and injuries are of course great news, but there are more facets that can be analyzed. Of interest to readers of this blog are probably how pedestrian and bicycle related collisions changed after the road diet.

From 2001 through 2005, before the road diet, seven reported collisions involved people walking on York Boulevard between Eagle Rock Boulevard and Avenue 54. From 2006 through 2010, after the road diet, people walking were involved in nine reported collisions in this segment, a 28.5% increase. This translates to a modest shift from 1.07 collisions to 1.38 collisions per mile per year, showing little change.

The number of bicycle related collisions increased 100% after the road diet. From 2001 through 2005, people bicycling were involved in three reported collisions. In the post- road diet years, from 2006 through 2010, people bicycling were involved in six reported collisions, a change from 0.46 to 0.92 collisions per mile per year. However, bicycle counts conducted by the Los Angeles County Bicycle Coalition on York Boulevard observed a 150% 93%* increase in the number of people bicycling from 2009 to 2011 alone. In other words, the increase in collisions in recent years has likely not been proportional to the increase in levels of bicycling on the street.

In the 0.9 mile segment of York Boulevard east of the road diet, between Avenue 54 and North Figueroa Street, pedestrian related collisions went essentially unchanged. There were five pedestrian related collisions reported between 2001 and 2005 and four reported between 2006 and 2010, a 20% drop or a change from 0.7 to 0.6 pedestrian related collisions per mile per year. Bicycle related collisions increased 100% from two reported between 2001 and 2005 to four reported between 2006 and 2010, a shift from 0.44 to 0.88 collisions per mile per year.

Hit-and-Runs

Unanticipated, but welcomed news, is that the number of hit-and-runs have also decreased drastically on York Boulevard between Eagle Rock Boulevard and Avenue 54 since the road diet was implemented. In the five years studied before the road diet, 63 of the 176 reported collisions were hit-and-runs; 42 were classified misdemeanor and 21 felony. In the five years following the road diet, 39 of 135 reported collisions were hit-and-runs, of which 28 were misdemeanor and 11 were felony. Misdemeanor hit-and-runs decreased by 33.3% and felony hit-and-runs decreased by 47.6%, meaning hit-and-runs overall dropped by 38.1%– a huge win for neighborhood safety! On a per mile per year basis, this means hit-and-runs dropped from 9.7 to to 6.

The segment of York Boulevard between Avenue 54 and North Figueroa Street also saw improvements, but again not on the level seen in the road dieted section. From 2001 through 2005 there were 18 misdemeanor and and four felony hit-and-runs in this segment of York Boulevard. From 2006 through 2010 this segment experienced 18 misdemeanor and one felony hit-and-runs. There was a minor drop in the number of felony hit-and-runs while the number of misdemeanor hit-and-runs stayed the same. In all, this means hit-and-runs only dropped by 13.6%, from 22 to 19 (or from 4.8 to 4.2 on a per mile per year basis) in the portion of York Boulevard that was not road dieted.

Looking Ahead

After taking a careful analytic look at the collision history along York Boulevard for the past decade, it seems the road diet between Eagle Rock Boulevard and Avenue 54 is doing exactly what road diets are intended to do, improve traffic safety. The LADOT has implemented over 20 miles of road diets this past fiscal year, (we’ll have more on that in a separate post!) and it is anticipated similar improvements in safety will become measurable in the coming years.

Road diets aren’t without their critics, but these projects ultimately make us all safer and everyone is a beneficiary of a street made safer in their neighborhood. Not only does it mean fewer collisions are happening when streets are reconfigured to be made safer, but it also means the city resources that would otherwise go towards responding to traffic collisions can now aid other emergencies and neighborhood needs.

So let’s hear it for making our communities safer through road diets!

*A comment on EastsiderLA’s coverage of our post correctly points out there was actually a 93% increase in levels of cycling observed, not 150%

(Note: the 0.9 mile segment of York Boulevard between Avenue 54 and North Figueroa Street went on an “asymmetrical road diet” in October 2012 in which only the westbound traffic was reconfigured.)