Fwd: The La Costa Rear End Collision
Jim Baross
From: Principled Bicycling <principle...@substack.com>
Date: Sun, Jul 20, 2025 at 10:08 AM
Subject: The La Costa Rear End Collision
To: <jimb...@gmail.com>
The La Costa Rear End CollisionThis wasn’t a problem of the cyclist's existence on the road—it was a human attention problem made worse by inappropriate equipment.
This video is making the rounds on social media showing a solo bicyclist riding in a wide, green painted, buffered bicycle lane colliding with a motorcycle cop and then an SUV stopped in the bicycle lane. In front of that SUV is a tow truck.  Naturally, when it comes to such videos and the commentary imagine yourself as the protagonist in the movie Idiocracy.
While missing from these comments is the usual “bikes vs two ton vehicles” blabber - a profound misunderstanding of basic physics. The original video appears to come from the r/SanDiego subreddit and according to the person who posted the video it taken at 3:18 PM on La Costa Boulevard in Carlsbad. La Costa is a popular cycling route both for recreation and commuting. It’s in fact perhaps one of the most popular in the country given that it’s an East to West connection between the inland neighborhoods of Carlsbad and cycling in the San Diego climate is amenable year around. It’s one of the only such connections due to the area’s unique topography.
La Costa is a road where a wide bicycle lane not only fit without having to change the configuration of the general-use traffic lanes (incorrectly called “car lanes”), but also one where wide, buffered bicycle lanes for the most part absolutely make sense. But this doesn’t mean bicyclists using them makes them immune to issues, and that’s exactly what happened with this bicyclist here. The crash location as can be seen in the video and in Google Streetview occurred right at the termination of the green paint.
Perhaps this is another opportunity to point out that often times green paint in a bike lane is an indication of a hazard - something John Schubert noted in his 2018 article on door zone bike lanes. This portion of Eastbound La Costa is a long, but relatively subtle curve next to a steep hill making it difficult for bicyclists to see sufficiently ahead and around the curve. Rumor has it the bike lane was painted green on this curve not for the bicyclists but to discourage motorists driving the curve too fast for conditions from drifting into the bike lane as they drive around the curve. This is actually a legitimate concern for bicyclists and why many want “protection.” But it really doesn’t help either that this bicyclist was using aero bars. Aero, also sometimes called time trial (TT) or tri-bars are popular with triathlon cyclists. Anecdotally, triathlon cyclists are among the most difficult sub-type of cyclists to understand basic cycling safety including Cycling Savvy type lessons instead substituting their athletic prowess for true traffic skill. In other words, they can be the “Underwear Tribe” on steroids (no pun intended). Whether this particular cyclist belongs to that group is unknown, of course. Aero bars allow bicyclists to get into a highly aerodynamic position yet with massive tradeoffs of cyclist visibility and maneuverability not present with standard road drop bars or other bar configurations. Some aero bar configurations, usually installed on dedicated tri-bikes include a second set of brake levers on the bars, but most of the “clip-on” aftermarket bars do not include these extra brake levers. This makes their use even more hazardous since the cyclist will have to rapidly change positions to brake (or to shift gears). These issues are in part why aero bar use is banned from most formal road bicycle races. Bicycle clubs too either restrict their use or outright prohibit them during their group rides.  The flood of responses to the La Costa crash reveals more about the public’s misperceptions of human attention than it does about the crash itself. Some reactions, like those from IfindRetards or ConcernedforColorado, are little more than dehumanizing mockery for internet narcissism points and proof that Idiocracy is a documentary, not a movie that takes place in the future. Others—like dovgvlad’s blanket dismissal of cyclists as “dangerous”—reflect a crude tribalism that frames bicyclists as cultural intruders rather than fellow road users. Underlying much of this hostility is negativity bias: the well-documented psychological tendency to more vividly recall negative interactions over positive or neutral ones. One careless cyclist seen running a stop sign or red light tends to imprint far more deeply than the hundreds who navigate legally and safely. But compounding this is widespread ignorance of traffic law, including with licensed and insured motorists, and especially where cyclists are concerned. Many people assume that “bad” cycling behavior - anything that inconveniences them and often ignoring all the delay other motor traffic causes is illegal or unsafe when it often isn’t. Lane control, yielding decisions, and even riding two abreast are frequently misjudged not because they’re unsafe, but because other road users simply don’t understand what the law allows. And in turn, they fill that gap with resentment towards an out-group which has just as much intellectual and skills diversity as motorists. Still others, like svstartupguy or LM21Spotter, invoke what they assume is common sense: that if something was "in view," it should have been seen. In the case of this cyclist, there’s zero chance he should not have had any issues not seeing the impending obstacles in the bike lane. Thes Redditors came to a similar conclusion.
But these assumptions are wrong too. And this reveals a deeper problem: an unwillingness to understand that attentional limits are not a cyclist problem, but a human one. Perception science—especially Marc Green’s work on inattentional blindness, conspicuity, and attentional filtering shows how dangerously naive these takes are. Green has an entire library of articles on his website Visual Expert including: Green’s articles point out that we do not perceive the world as it is. We perceive what we expect, via schemas and filtered through the narrow bandwidth of attention. This is why people even who aren’t doing something as egregious as texting and driving or intoxicated crash into fire trucks, drive off piers, or yes, ride straight into stopped vehicles in broad daylight. Not because they’re necessarily reckless, but because attention is selective, limited, and easily misallocated—especially when expectation overrides vigilance. But cyclist in this video made a critical mistake: he was using TT/aero bars on an open road. These bars compromise situational awareness in two ways:
In essence, aero bars magnify the these human limits of attention, making perceptual failures more likely. This is not a cyclist issue, it’s a cyclist with a particular type of equipment issue and possibly a cyclist with the stereotypical “tri-dork”/”underwear tribe” schema. But this situation on La Costa could happen to any road user. And the solution is not to scapegoat cyclists or double down on false infrastructure salvation. In fact, this crash shares key dynamics with failures we see in so-called “protected” bike lanes and door zone bike lanes—designs that confine cyclists into narrow, visibility-compromised spaces and create a false sense of security. Whether it's a “protected” or door zone bike or an aero-bar position in any situation outside a formal closed course, the outcome is the same: diminished time to see, assess, and react. The La Costa incident doesn’t prove that cyclists (the people) or cycles (the inanimate object) are dangerous by default. It proves that perception is limited, context matters, and of course - “design-for-feelings” fails. The hard truth is this: bike lanes don’t automatically create safety. Nor does simply riding legally in a bike lane. True safety depends on understanding how human attention really works—and building both personal behavior and infrastructure that respects those limits. Whether you’re a motorist, a pedestrian, or a cyclist: if your position on the road prevents you from seeing or being seen—especially in time to act—you’re already courting danger. This is why cyclists must not only claim space but learn to drive their bikes—as taught by CyclingSavvy who rejects passive, edge-riding norms by default. And it’s why cyclists using aero bars on open roads are making a serious miscalculation: they are turning themselves into the very inattentive road users criticized everywhere. So let’s skip the moral panic and learn the real lesson: Blame is easy. Attention is limited. And safety, like freedom, requires knowledge, not illusions. You're currently a free subscriber to Principled Bicycling. For the full experience, upgrade your subscription.
© 2025 Principled Bicycling
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John Eldon
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