Is Motorcycle Lane Splitting Safe? An Analysis

You’ve probably heard figures bandied about that lane filtering is four, six or 10 times safer than sitting in stationary traffic in your lane. But how true is that? Is it safer to filter while on a motorcycle or is it just a good way to get through traffic faster? We’ve taken a look at research and studies going back as far as 1981 and as early as last year to see whether or not filtering will make your riding experience safer or more dangerous.

A landmark document in motorcycle safety which we will first look at is the Hurt Report which was begun 1976 and published in 1981. It was and still is regarded as one of the most comprehensive and important motorcycle safety studies of last century. It’s a broad ranging document that came to various conclusions, such that two-thirds of motorcycle-car crashes occurred when the car driver failed to see and give way to the approaching motorcycle at an intersection and that helmets significantly reduce the risk of brain injury and death but with no increased risk of crash involvement or neck injury.

It did not however look at the effects of lane splitting and any claims that it did are people’s interpretation of the data provided. In fact, a co-author of the Hurt report, Dave Thom was quoted as saying that “Lane splitting is theoretically advantageous but there’s no way to statistically disprove it’s safer because there’s been no study from which to pull the information from”.

Is Motorcycle Lane Splitting Dangerous?

Where people have used the Hurt report to claim lane splitting is safe is this:

“Moderate or heavy traffic was the situation at 59.2% of the accidents.”

However, that does not describe what occurred in enough detail to draw any inferences from. Did the motorcycle run into the car? Was it from behind or at the side? Was the rider actually lane splitting at the time of the accident? The report does not say. In fact, the Hurt report does not even mention the term lane splitting once.

The largest report to follow the Hurt report was a European study titled Motorcycle Accidents In Depth Study, or MAIDS. First published in 2009, the report looked at 921 accidents from France, Germany, the Netherlands, Spain and Italy. It is in the MAIDS report that you will often hear the quote that lane-splitting is six (or some other similar number) times more safer than not splitting.

Again however, there is no specific analysis of lane splitting or filtering. In fact, the word filtering only occurs a handful of times in two data tables. That data shows the following frequency and percentage of crashes involving a car hitting a rider from behind when the rider is stopped, and lane filtering:

Stopped in traffic, speed is zero262.8

Therefore as a mathematical result, one could say that as 26 divided by four equals 6.5, filtering must be six and a half times safer than not doing so. From a statistical point of view however, it’s a very long bow to draw. The other issue is that out of the five countries included in the MAIDS report, one doesn’t allow filtering and yet there was no mention of whether that had any impact on the results. For all we know, those 26 “Stopped in traffic, speed is zero” accidents could have occurred in the four countries where splitting was legal and the four filtering accidents could have occurred in the one where it isn’t. The details just aren’t there.

Is Motorcycle Lane Splitting Dangerous?

So has there actually ever been a study that specifically looks at lane filtering?

Thankfully, yes. A preliminary report conducted by the University of California, Berkeley and the California Highway Patrol looked at 8,000 motorcycle accidents occurring between June 2012 and August 2013 and what the effect of lane splitting was on riders. The report found the following (note, LSM stands for Lane Splitting Motorcyclist):

  • LSM were less likely to be rear-ended by another vehicle (2.7%) than were other motorcyclists (4.6%).
  • Patterns of injury were significantly different comparing LSM and other motorcyclists. LSM were notably less likely to suffer head injury (9.1% vs 16.5%), torso injury (18.6% vs 27.3%), or fatal injury (1.4% vs 3.1%) than other motorcyclists.
  • The occurrence of neck injury and arm/leg injury did not differ meaningfully by lane-splitting status.

The other interesting data is that motorcyclists who lane-split seem to be more safety conscious as indicated by the following findings:

  • LSM were more likely to be wearing a full-face helmet than other motorcyclists (79% and 64%, respectively) and less likely to be wearing a novelty helmet (1.9% and 4.1%, respectively).
  • Motorcyclists who were not lane-splitting were more likely to wearing a 1/2- or 3/4-helmet (23%) than LSM (13%).
  • The prevalence of alcohol use was lower among LSM (1.3%) than it was among other motorcyclists (3.3%).
  • The proportion of motorcyclists that were unlicensed was moderately lower among LSM (18%) than among other motorcyclists (22%).
Is Motorcycle Lane Splitting Dangerous?

There is one other statistic that stands out, however:

  • LSM, on the other hand, were much more likely to have rear-ended another vehicle (36.4%) than were other motorcyclists (14.9%) due to lane splitting.

Which unfortunately almost puts us back to square one. You’re less likely to be hit by a car from behind if you don’t lane split, but more likely to run into a car from behind yourself if you do lane split.

But for a moment, let’s forget about the reports and apply the common sense test. What is likely to be worse? Being hit from behind by a two ton car while you’re sitting stationary, or running into the back of a car on a motorcycle at low filtering speeds? The answer should be pretty clear that the latter is the preferable type of accident.

And that’s supported by the UC Berkeley report, which showed that head and torso injuries were far worse for riders that didn’t split and that those riders who didn’t split were nearly three times more likely to be involved in a fatal accident.

As it stands, the research tells the following story:

  • Splitting is not less safe than not splitting.
  • It is highly likely, given research conducted that it is safer to lane split as opposed to not lane split.

Of course, it’s up to the individual rider to be comfortable with the idea of lane splitting. But here, we’re strong advocates of filtering from a safety perspective. Doing it correctly and at sensible speeds should mean there’s no reason to run into another car, and doing so prevents the possibility of being cleaned up from behind.

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