Turn signals should be used any time you change direction or position on the road. That includes turns at intersections, lane changes, merging, pulling away from a curb, entering or exiting a driveway, and even pulling over to park. Most states require you to signal at least 100 feet before making any turning movement, and failing to signal is linked to more crashes than many drivers realize.
The 100-Foot Rule
Across most of the United States, the standard legal requirement is to activate your turn signal at least 100 feet (about 30 meters) before you turn or change lanes. That’s roughly six to seven car lengths. Some states set the threshold higher, around 200 feet, so it’s worth checking your local vehicle code. In practical terms, 100 feet at city speeds gives drivers behind you about two seconds of warning, which is the minimum needed for them to react and adjust.
On highways, 100 feet passes in about one second at 65 mph, so signaling earlier is both safer and, in many jurisdictions, expected. A good habit is to activate your signal three to five seconds before any maneuver on higher-speed roads.
Turns at Intersections
This is the most obvious use, yet one of the most neglected. Signal before every right or left turn, whether you’re at a stoplight, a stop sign, or an uncontrolled intersection. Your signal should go on before you begin braking for the turn so the driver behind you understands why you’re slowing down. If you brake first and signal second, the person following you has already lost reaction time.
The same applies to turning into driveways, parking lots, and private roads. Even if no one appears to be around, consistent signaling builds the kind of muscle memory that protects you when it matters most.
Lane Changes and Highway Merging
Any lateral movement on the road requires a signal. That means every lane change on a multi-lane road, every highway merge, and every time a lane ends and forces you into adjacent traffic. California’s Vehicle Code, which mirrors many other states, requires a turn signal whenever your movement would affect another vehicle in close proximity. The minimum distance is the same 100 feet, but on a freeway that translates to barely a blink. Signal well before you start drifting over.
When merging onto a highway from an on-ramp, activate your signal as you begin matching the speed of traffic and looking for a gap. Keep it on through the merge, then cancel it once you’re established in your lane. Drivers already on the highway can’t read your mind, and a signal gives them the chance to create space for you.
Pulling Over, Parking, and Leaving a Curb
Signaling isn’t just for moving through traffic. You need to signal when pulling to the curb to park, when leaving a parallel parking spot, and when exiting a parking lot onto a street. The New York DMV, for example, specifies that any vehicle entering a roadway from a driveway, alley, or other non-roadway location must stop and yield to traffic. Your signal tells approaching drivers which direction you intend to go, helping them decide whether to slow down or maintain speed.
When parallel parking, signal right to let drivers behind you know you’re about to slow and pull in. When pulling back out into traffic, signal left and wait for a safe gap. Skipping the signal in either situation creates confusion, especially in urban areas where drivers, cyclists, and pedestrians are all sharing tight space.
U-Turns and Three-Point Turns
Multi-point maneuvers require signaling at each stage. For a three-point turn, start by signaling right and pulling to the right side of the road. Then activate your left signal before turning sharply left across the road. After reversing toward the opposite curb, signal left again before pulling forward into your new lane of travel. Each signal communicates a different movement to anyone approaching from either direction.
For a U-turn at an intersection where it’s legal, treat it like a left turn: signal left well in advance, move into the leftmost lane or turning lane, and complete the turn when the way is clear.
Roundabouts and Traffic Circles
Roundabouts confuse a lot of drivers when it comes to signaling. The general rule is to signal right as you approach the exit you plan to take. If you’re turning right at the first exit, signal right before you enter. If you’re going straight through (taking the second exit), signal right as you pass the first exit. If you’re making a left or full loop, signal left as you enter, then switch to a right signal as you approach your exit. The goal is always the same: let other drivers, cyclists, and pedestrians know where you’re headed.
Why It Matters More Than You Think
Skipping a turn signal feels harmless in the moment, but the crash data tells a different story. Research published in Transportation Research Part F found that roughly 15% of car drivers and nearly 18% of motorcyclists reported being involved in at least one crash caused by failure to signal over a three-year period. The most common types of crashes tied to signal neglect are rear-end collisions and T-bone impacts at intersections. One analysis found that signal neglect may actually cause more crashes than distracted driving behaviors like phone use behind the wheel.
The reason is straightforward. Every other road user, including drivers, cyclists, and pedestrians, relies on your signal to predict what you’re about to do. Without it, they’re guessing. A pedestrian stepping into a crosswalk assumes a car approaching from the side will continue straight. A motorcyclist in your blind spot assumes you’ll stay in your lane. A signal changes those assumptions and gives everyone time to respond safely.
When Signals Are Easy to Forget
Most drivers remember to signal at busy intersections. The lapses tend to happen in lower-stakes situations: changing lanes on a quiet highway, turning into your own driveway, pulling out of a gas station, or navigating an empty parking lot. These are exactly the moments when a cyclist, jogger, or another driver you didn’t notice can appear. Building the habit of signaling every single time, regardless of how empty the road looks, means you’ll never have to decide in a split second whether it’s “worth it.” It always is.