Causes of bike accidents in Long Beach — 10 years worth of data

Posted on December 6th, by admin in Safety. 9 comments

As Long Beach becomes more and more bike friendly…and as we get more and more people to bicycle, we are also seeing an increase in the number of bike related accidents.  Through our Share our Streets campaign we have been working to make both bicyclists and motorists more safety aware.  You may have seen our banners…and our bus ads.  Hopefully you have toured our website and looked at many of the safety related tips.

To help make our campaign more effective we want to make people aware of the primary causes of bike related accidents in the city….and to let them know what they can do to be safer as a bicyclist and as a driver.

The number of bike related accidents is increasing – at a rate about equal to the rate of growth in bicycling.

As you can see from the chart below…the number of bike related accidents has increased over past 5 years.  This is increase is coincident with the growth rate of cycling in Long Beach…which based on our bike counts doubled between 2008 and 2010.

While we have not done the statistical analysis it looks like the growth rate of accidents is slightly below the rate of growth in the number of riders, which is what we would expect.  In other words while the number of accidents is increasing the actual rate is decreasing.  This is certainly what is seen in other cities – when you get more bicyclists on the road…it is safer because drivers are more aware of the bicyclists and treat them with more respect.  We are anxious to see our 2012 data to see whether this trend holds.

Major causes of bike related accidents

An analysis of Long Beach traffic accident data since 2002 has revealed five leading causes that make up more than 80 percent of all automobile-bicycle incidents:

  1.   Bicyclist riding on the wrong side of the road against oncoming traffic;
  2.   Bicyclist making an unpredictable and hazardous move (e.g., darts in front of a moving vehicle);
  3.   Bicyclist running a stop light or stop sign;
  4.   Motorist running a stop light or stop sign; or
  5.   Motorist making a right or left turn in front of a moving bicycle.

Major causes of accidents are wrong way riding by bicyclists, right turns by cars and failing to yield by both  


According to the Long Beach data about 45% of the bike related accidents in the city are caused by the bicyclist (35% are driver related and 20% undetermined).





As you can see from the chart below the number one cause of accidents where the bicyclist is attributed to be at fault is riding on the wrong side of the road.  Over 30% of the accidents where the bicyclists is a fault can be attributed to this one cause.

The second cause is what is referred to as Auto Right-of-way violation.  In this case it means the bicyclist pulled in front of the vehicle.  This makes up just under 30% of the accidents.

The third largest cause, making up  15% of the accidents, is running a stop light or stop sign.

The forth major cause is what is termed “other hazardous movement.” This is the primary cause of about 12%  of the accidents. That means the bicyclist most likely did something unpredictable…and got hit by the car.

These four behaviors are attributed to be the primary causes of over 75% of the bicyclist “caused” accidents. The other 25% is made up of things such the two shown here (improper turning and unsafe speed).  Two of the others that do show up lower on the list are BUI (biking under the influence) and no brakes…presumably fixies with no breaks).

Accident caused by drivers

The Long Beach data suggests that about 1/3 of the bike related accidents in the city are caused by the motorist. As you can see from the adjacent chart over 40% of these accidents are categorized as either Auto Right-of-way violation or Pedestrian Right-of Way violation.  In other words the driver pulled in front of the bicyclists (I’m implying here that when the report refers to pedestrian..they in fact are referring to the bicyclist).  Another 15% is related to improper turning. And finally 12% is related to running a stop light or stop sign.


Another interesting piece of data is that in over 40% of all bike related accidents…whether they were attributed to the bicyclist or the driver… the driver was turning or entering the roadway.  Almost 30% of the time the car was making a right turn and 10% a left turn.  When combined with the data from the table above this strongly suggests that the single biggest cause of driver caused accidents is making right turns and in the process cutting of the bicyclist.

A final note – in just under 7% of the total accidents..the driver was stopped … which based on the data most often means that the bicyclists hit a parked car (oops).


From a safety perspective…bicyclists can at times be our own worst enemy.  Almost 50% of all accidents that are caused by the bicyclist are related to either riding the wrong way or failing to yield the right-of-way to a vehicle.  Our Share-our-Streets campaign has a big focus on these two issues.  Clearly we are headed the right direction with the message “ride with the flow of traffic” and “courtesy counts.”  This is also an area where we need to work with our law enforcement personnel to help change this behavior.

Recommendation to bicyclists…never ride against the flow of traffic!!!!  And…yield to cars trucks….don’t assume they will see you.

For vehicle caused accidents the major issue is failing to yield right of way to the bicyclists and this is most evident when are turning and/or entering traffic.  In other words driver cut off bicyclists and in doing so actually hit the bicyclists.   Facilities such as our separated lanes go a long way to alleviate this problem.  This is demonstrated by a drop of almost 40% in bike related accidents on the Broadway and 3rd bicycle corridor since the lanes have been installed.  Our Share-our-Streets messaging of “slow when passing” and “courtesy counts” also target this issue.

Recommendation to drivers…don’t try and jump in front a bicyclists when entering traffic or when making a right or left turn.  Be respectful and let them go before making your turn or moving into traffic.

9 responses to “Causes of bike accidents in Long Beach — 10 years worth of data”

  1. TomTrottier says:

    For your first graph, it would be nice if the scales were comparable logwise, eg, line up 2000 cyclists with 200 accidents, 3000 cyclists with 300 accidents.

    But I’m glad to see that cycling is on the increase! Wait ’til gas reaches $10/gallon!

  2. This is great to see some analysis and efforts to determine exposure and thus risk. I’d be interested to see how things change once you get hold of Sherry Ryan’s data (SDSU). Also, be sure to check out our crash\mapping site if you haven’t already:

  3. Let’s not forget that cyclist right of way violations are determined by police at the scene. Many police – perhaps the vast majority – have no idea that cyclists have the same rights as other vehicle operators. I expect at least half of those are actually motorist right of way violations that have been falsely blamed on the cyclist.

    Also, if cycling casualties have gone up the actual rate may NOT be decreasing! Before we can make a proper finding on that, it’s important to know where the rise in cycling is coming from. If motorists are taking up cycling, then fine – casualties are probably decreasing because the new cyclists come from a transportation mode that is less safe than cycling. If, however, the new cyclists are coming to cycling from public transportation, which has a much lower casualty rate, then the actual rate of cyclist casualties is not decreasing at all – in fact it’s probably greatly INCREASING!

  4. “in just under 7% of the total accidents..the driver was stopped … which based on the data most often means that the bicyclists hit a parked car (oops).”

    Be aware: many of these are probably doorings.

    • allancrawford says:

      Ian…that is certainly a possibility that some of these are related to doorings. I’ll go back and check the data and see if there is any way we can see if that was the case. Unfortunately that is not one of the categories the police use.

      • John Duval says:

        How do we get the police to use dooring as a category? I am very concerned because I commute along Wardlow where I ride on the white line and in traffic lane to avoid frequent near misses. Most cyclists do not take such precautions. There are two issues with this being categorized as cyclist striking a parked car:

        1) cyclist is held liable for the careless act of a motorist / motorist not held responsible for likely injury and property damage.
        2) poor design of infrastructure is not identified and corrected in the future.

  5. Ron says:

    “pedestrian right-of-way” is the sidewalk area or maybe crosswalk area. So the driver violation would have probably been related to either – i.e. at driveways crossing sidewalks or at crosswalks (and the cyclist happened to be in that area)

  6. Garry Walden says:

    As an avid rider, born, raised, riding bikes forever in Los Angeles and Long Beach, the fundamental mistake I see in rider behavior is that they trust the laws to protect them rather than their own better judgement.

    I have seen countless occurrences where bicyclists will ride in high traffic lanes (thinking the law will protect them from being plowed over), instead of bouncing a couple of streets over to lesser traveled streets to reduce risk.

    Long Beach has made great efforts in creating a bike conscious community, however, I believe more effort needs to be made in educating bicyclists on being smarter on the road; instead of thinking you can ride down the street with no hands (and the law will protect you), start thinking about using designated bike paths, lights, helmets, reflective gear, and learning more than just the laws related to biking, but also the laws related to surviving.

  7. D K says:

    Any cyclist who believes they can ride in traffic and not have to be concerned that they won’t get hit by a vehicle is a fool. Some bikers act as though they’ve never driven a car. Bikers tend to dart in front of cars, don’t have any sheet metal to protect them, ride in blind spots, often sit lower than a vehicle so they’re not as easily seen, and frankly, bikers tend to have an arrogance in their riding style that is only serving to create danger for themselves. Garry Walden’s advice is solid. Just because this town is more bike friendly than others doesn’t mean you don’t have to consider YOURSELF as your first line of defense. And defensive bike riding is the order of the day. So when you dart in front of me and when you are in the middle of 35 MPH traffic going 10 MPH don’t be suing me or anyone else because you felt you had a right to tangle with a 3,,000 lb vehicle.

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