People skip their turn signals for a mix of laziness, habit, distraction, and a sense that nobody’s watching. A landmark study by the Society of Automotive Engineers observed 12,000 vehicles making turns and lane changes and found that neglected turn signals cause more crashes than distracted driving. The problem is widespread, persistent, and rooted in both psychology and road design.
How Common the Problem Actually Is
The SAE study remains the most comprehensive observational research on turn signal use. Researchers watched thousands of everyday drivers in situations that clearly required a signal, such as turning at intersections and changing lanes, then simply recorded whether the signal was on or off. The neglect rates were high enough that the study’s authors described the current turn signal system, which relies entirely on the driver choosing to flip a lever, as “defective.” Lane changes showed even worse compliance than turns, likely because many drivers view lane changes as less of a “real” maneuver than a full turn.
NHTSA data backs this up from a different angle. In a study comparing safe and unsafe drivers, failure to signal was categorized as a primary contributing factor in crashes and near-crashes. Safe drivers had essentially zero events where skipping a signal led to a dangerous situation. Moderately safe and unsafe drivers averaged close to one such event per person during the study period. That might sound small, but scaled across millions of drivers making dozens of lane changes a day, the math gets alarming fast.
Laziness and Autopilot Driving
The most honest reason people skip signals is that it feels unnecessary in the moment. Driving is a highly practiced skill, and once you’ve done it for years, large portions of it shift into autopilot. Your brain conserves energy by running familiar sequences without conscious thought. Signaling requires a small but real interruption to that autopilot: you have to think ahead, move your hand, and maintain the signal for long enough to communicate your intent. When traffic is light or the turn feels obvious, many drivers judge that the effort isn’t worth it.
This is a form of cognitive shortcuts at work. Your brain constantly evaluates which tasks “matter” based on perceived risk, and if you’ve changed lanes a thousand times without signaling and nothing bad happened, the brain files signaling as optional. Over time, not signaling becomes the habit rather than signaling. Breaking that pattern requires conscious effort, which is exactly what autopilot driving avoids.
The Anonymity Effect
Inside a car, you’re shielded from social pressure in a way you almost never are in other public spaces. If you cut in front of someone in a grocery line, you’d see their face and feel the social consequences immediately. In traffic, other drivers are faceless vehicles. This sense of anonymity loosens the grip of social norms. Signaling is fundamentally a communication act, a courtesy meant for other people, and when those people feel abstract, the motivation to communicate drops.
Research on pedestrian interactions highlights just how much communication matters on the road. One study found that when pedestrians made eye contact with approaching drivers, about 68% of drivers stopped for them. Without that eye contact, only about 45% stopped. The same principle applies to signaling: when drivers feel “seen” by other road users, they behave more cooperatively. Enclosed in a car, surrounded by tinted glass and steel, that feeling of being seen vanishes.
Social Modeling Makes It Contagious
One of the more striking findings in turn signal research is the modeling effect. Drivers who followed a vehicle that used its turn signal were significantly more likely to activate their own signal. Drivers following someone who didn’t signal were more likely to skip theirs too. In other words, not signaling is socially contagious. If you’re driving in an area where signal use is already low, you’re surrounded by a constant demonstration that it’s acceptable to skip it. This creates a self-reinforcing cycle: fewer signals lead to fewer signals.
This also helps explain regional differences. If you’ve ever noticed that drivers in one city seem far worse about signaling than drivers in another, you’re not imagining it. Local driving culture is real, and it’s shaped in part by this monkey-see, monkey-do dynamic.
Distraction and Cognitive Load
Sometimes people intend to signal and simply forget. Adjusting GPS directions, managing a phone call, monitoring a complicated intersection, or dealing with kids in the backseat all consume the mental bandwidth that signaling requires. The signal lever is low on the priority list when your attention is being pulled in multiple directions. This is especially true during lane changes on highways, where drivers are simultaneously checking mirrors, judging speed gaps, and watching traffic ahead. Adding “flip the signal” to that mental checklist is one more step, and it’s the easiest one to drop.
Distraction also explains why the same driver might signal reliably in some situations but not others. A calm, familiar commute with light traffic leaves plenty of mental room. A stressful merge in heavy traffic or an unfamiliar interchange does not.
Intentional Skipping
Some drivers deliberately choose not to signal, particularly during lane changes in dense traffic. The reasoning, sometimes stated outright, is that signaling your intention to merge gives the driver in the next lane a chance to close the gap and block you. Whether or not this is rational (it often isn’t), the perception is real enough to shape behavior. These drivers see signaling as a competitive disadvantage rather than a safety tool.
Others skip signals out of a belief that no one is around to benefit from them. A late-night turn on an empty road, a lane change with no visible cars nearby. The logic is that signals exist to communicate, and if there’s no audience, there’s no point. The problem is that the cars you don’t see, motorcycles in your blind spot, cyclists approaching from behind, pedestrians about to step off a curb, are exactly the ones who need the information most.
Why It Matters More Than People Think
Misinterpretation of a driver’s intent is one of the most common factors in pedestrian crashes. When you don’t signal, every other road user near you has to guess what you’re about to do. Cyclists are especially vulnerable because they’re sharing the road with vehicles that outweigh them by thousands of pounds. A cyclist approaching an intersection has no way to know you’re about to turn right unless you tell them. Pedestrians face similar risks, relying on signals to judge whether it’s safe to cross.
The SAE study’s conclusion that neglected signals cause more crashes than distracted driving puts the stakes in perspective. Distracted driving gets national awareness campaigns, dedicated laws, and widespread public concern. Failure to signal gets a shrug. Yet the crash data suggests it deserves the same level of attention.
How Modern Cars Are Adapting
Automakers and safety regulators have started designing around the assumption that drivers won’t always signal. Blind spot warning systems, now being standardized through NHTSA’s New Car Assessment Program, are specifically tested under both conditions: with the turn signal on and with it off. When a driver activates their signal before changing lanes, the system provides an escalated warning, such as a flashing light instead of a steady one, if a vehicle is detected in the blind spot. When no signal is used, the system still provides a basic visual alert, typically in the side mirror or near the windshield pillar.
Lane keeping assist and lane centering systems also operate independently of turn signal input. These technologies nudge the car back into its lane if it starts to drift, regardless of whether the driver signaled. The fact that safety engineers test every scenario both with and without turn signal use tells you something important: the industry has accepted that a significant percentage of lane changes happen without a signal, and the safety net has to work anyway.
None of this makes skipping your signal safe or acceptable. These systems are backup layers, not replacements for clear communication. A blind spot monitor can warn you about the car next to you, but it can’t tell the driver behind you which direction you’re headed.