You should not drive for at least 24 to 48 hours after a concussion, even a mild one. Consensus guidelines recommend complete cognitive and physical rest during that initial window, followed by a gradual return to normal activities including driving. After that period, whether you’re safe to get behind the wheel depends entirely on which symptoms you still have and how severe they are.
Why a Concussion Makes Driving Dangerous
A concussion temporarily changes how your brain processes information, and driving is one of the most cognitively demanding things most people do every day. It requires you to track multiple objects, react instantly to unexpected changes, divide your attention between mirrors and the road ahead, and make rapid judgments about speed and distance. All of these abilities take a measurable hit after a concussion.
In a driving simulation study comparing young concussed drivers to uninjured ones, those with concussions had 26% slower reaction times when responding to a cue while driving. Their average response took 963 milliseconds compared to 767 milliseconds for the control group. At highway speeds, that extra 200 milliseconds translates to several additional feet of travel before you even begin to brake. Concussed drivers were also twice as likely to completely miss a cue altogether, meaning they didn’t respond at all.
Even a month after the injury, reaction times were still 16% slower than those of uninjured drivers. The gap narrowed but didn’t close, which is worth keeping in mind if you’re feeling mostly better but not quite right.
The Real-World Crash Risk
A large retrospective study in Ontario, Canada tracked motor vehicle crashes among people who had visited an emergency department. The general population crash rate was about 4.6 per 1,000 people annually. For people who had sustained a concussion, the rate jumped to 10.58 per 1,000, more than double the population average. After adjusting for age, sex, and other factors, people with a prior concussion had a 49% higher crash risk compared to a control group with ankle sprains. That elevated risk reflects the lingering cognitive effects that concussions can produce well beyond the first couple of days.
Symptoms That Mean You Shouldn’t Drive
The 24 to 48 hour rest period is a minimum, not a finish line. If you still have active symptoms after that window, you’re not ready. The specific symptoms that make driving unsafe include:
- Slower reaction time. If you feel like you’re processing things a beat behind, your ability to brake or swerve in time is compromised.
- Trouble paying attention. Driving requires sustained focus and the ability to split your attention between multiple inputs. Brain fog or difficulty concentrating is a clear sign you’re not ready.
- Sensitivity to bright lights. If lights trigger headaches or worsen your symptoms, nighttime driving is especially dangerous. Oncoming headlights can set off symptoms mid-drive, leaving you impaired at the wheel.
- Dizziness with head movement. If turning your head or changing position triggers symptoms, you’ll either instinctively avoid scanning the road (creating blind spots) or trigger symptoms that distract you. Both make it harder to detect and avoid hazards.
- Poor coordination or balance. Physical coordination matters for steering, pedal control, and quick corrections.
- Impaired judgment. This one is tricky because poor judgment makes it harder to accurately assess whether your judgment is impaired. If people around you are saying you seem off, take that seriously.
How Doctors Evaluate Fitness to Drive
There’s no single standardized test that clears someone to drive after a concussion. What doctors typically do is assess a combination of physical and cognitive abilities. On the physical side, they look at range of motion, coordination, balance, and reaction speed. On the cognitive side, they evaluate attention, processing speed, visual-spatial perception, and executive functioning, which is your ability to plan, switch between tasks, and make quick decisions.
Vision testing goes beyond the standard eye chart. Contrast sensitivity (how well you see in low-light or glare conditions), visual field width, and your ability to process visual information quickly all matter for safe driving. A standard vision screening at a DMV won’t catch the subtle deficits a concussion can cause.
In some cases, a doctor may recommend an on-the-road evaluation with a driving rehabilitation specialist. This tests real-world skills like turning, stopping at intersections, adjusting speed, scanning surroundings, and recognizing signs. Based on these assessments, a clinician will either clear you to drive without restrictions, recommend driving rehabilitation, or determine that you don’t yet meet safe driving criteria.
A Practical Timeline for Getting Back on the Road
For most people with a mild concussion, the path looks like this: rest for the first 24 to 48 hours, then begin a gradual return to daily activities. Driving fits into that gradual return, but only once your symptoms have meaningfully improved. You don’t need to be 100% symptom-free in every situation, but you should be able to concentrate, turn your head freely, tolerate bright lights, and feel confident in your reaction speed.
Start with short, familiar routes during low-traffic times if you’re unsure. A five-minute drive to a nearby store in daylight is a very different challenge than a 40-minute highway commute during rush hour. If the short drive goes fine with no symptom flare-ups, you can gradually increase distance and complexity. If you notice headaches building, difficulty focusing, or any symptom worsening while driving, pull over. That’s your brain telling you it’s not ready yet.
Most people with mild concussions recover enough to drive safely within a few days to a couple of weeks. If symptoms persist beyond two to four weeks, a formal driving evaluation through your healthcare provider can help identify specific deficits and whether targeted rehabilitation would help.