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If you ride a motorcycle in Massachusetts, you have probably been stuck in bumper-to-bumper traffic on I-93 or Route 128 and thought about threading between the cars. In states like California, that maneuver is legal. In Massachusetts, it is not.
Lane splitting, the practice of riding a motorcycle between two lanes of stopped or slow-moving traffic, is not explicitly permitted under Massachusetts law. Neither is lane filtering, which is a similar practice at lower speeds or at a standstill. Riders who split lanes in Massachusetts risk traffic citations, and if an accident occurs while lane splitting, it can significantly affect their ability to recover compensation.
Kiley Law Group has represented injured motorcyclists across Massachusetts and New Hampshire for more than 50 years. If you were involved in a motorcycle accident while lane splitting or in any other circumstance, call 978-474-8670 for a free consultation.
Lane splitting refers to a motorcycle riding between two lanes of traffic traveling in the same direction. The motorcycle passes between cars rather than following behind them in a single lane. Lane splitting most commonly occurs on highways and multi-lane roads during congestion, when traffic is moving slowly or is completely stopped.
Lane filtering is a related but slightly different maneuver. Filtering typically refers to moving between stopped vehicles at a traffic light or intersection, often at very low speeds or from a standstill. Some states that prohibit lane splitting at highway speeds still allow filtering at intersections. Massachusetts does not make this distinction.
Lane splitting should not be confused with lane sharing, which is when two motorcycles ride side by side in the same lane. Lane sharing between two motorcycles is legal in Massachusetts. What is not legal is a motorcycle sharing a lane with a car or passing between two cars occupying adjacent lanes.
Massachusetts does not have a statute that mentions lane splitting by name. Instead, lane splitting is effectively prohibited by the state's general traffic laws governing lane usage and overtaking.
Mass. Gen. Laws Ch. 89, §4A requires that vehicles, including motorcycles, travel within a single marked lane and prohibits moving from that lane until the driver has determined that the movement can be made safely. Riding between two lanes of traffic violates this requirement.
Mass. Gen. Laws Ch. 89, §2 governs overtaking and passing. Vehicles may only pass on the left, and only when the left side of the roadway is clearly visible and free of oncoming traffic. Passing between lanes does not satisfy this requirement.
Additionally, the Massachusetts Motorcycle Operator Manual, published by the RMV, specifically warns riders against lane splitting and advises against riding between rows of stopped or moving vehicles.
Bottom line: there is no circumstance in which lane splitting is legal in Massachusetts. Riders who split lanes can be cited for improper lane usage, and the violation can be used against them in an accident claim.
Lane splitting laws vary significantly across the United States. Understanding the broader landscape helps riders who travel across state lines.
If you ride in New Hampshire, where Kiley Law Group also represents injured riders, lane splitting is similarly not permitted under NH RSA 265:22 and RSA 265:16, which govern lane usage and passing.
Riders who lane split are not always doing it recklessly. In heavy traffic, motorcycles are particularly vulnerable to rear-end collisions. A distracted driver who fails to stop in time can crush a motorcycle between two vehicles. Some riders believe that moving between lanes is actually safer than sitting in stopped traffic.
There is research to support this perspective. A 2015 study by the University of California Berkeley found that lane-splitting motorcyclists were significantly less likely to be rear-ended in traffic compared to motorcyclists who stayed in their lane. The study also found that lane splitting at speeds below 50 mph, with a speed differential of less than 15 mph above surrounding traffic, was relatively safe.
However, this research was conducted in California, where lane splitting is legal and drivers are accustomed to motorcycles moving between lanes. In Massachusetts, where lane splitting is rare and drivers do not expect it, the risks are different. Drivers may change lanes without checking for motorcycles, open doors in stopped traffic, or make sudden lateral movements that leave a lane-splitting rider with nowhere to go.
This is where lane splitting has the most serious consequences for riders. If you are involved in a motorcycle accident while lane splitting in Massachusetts, the insurance company will almost certainly use it against you.
Massachusetts follows a modified comparative negligence rule under Mass. Gen. Laws Ch. 231, §85. If you are found to be partially at fault for the accident, your compensation is reduced by your percentage of fault. If you are more than 50% at fault, you recover nothing.
Lane splitting alone does not mean you caused the accident. A car that changes lanes without signaling or checking mirrors can still be primarily at fault, even if the motorcycle was between lanes at the time. But the lane splitting gives the insurance company leverage to argue shared fault, and adjusters will push for the highest possible fault percentage against the rider.
In practice, a rider who was lane splitting at the time of an accident will need stronger evidence to overcome the fault argument. Dash cam footage, witness testimony, and expert reconstruction can demonstrate that the other driver's negligence was the primary cause, regardless of the rider's lane position.
An experienced motorcycle accident attorney can frame the evidence to minimize the fault assigned to the rider and maximize recovery. This is not a case where you want to negotiate with the insurance company on your own.
The most common lane-splitting accident occurs when a driver changes lanes without checking blind spots and collides with a motorcycle passing between lanes. In this scenario, the driver is at fault for the unsafe lane change, but the insurance company will argue the motorcycle should not have been between lanes. Fault is typically shared, with the split depending on the specific facts.
In heavily congested areas, drivers or passengers sometimes open car doors while traffic is stopped. A motorcycle filtering between lanes can strike an opened door with devastating consequences. Massachusetts has a dooring law (Mass. Gen. Laws Ch. 90, §14) that prohibits opening a vehicle door into traffic, but the rider's lane position may still factor into the fault analysis.
When a vehicle in one of the adjacent lanes brakes suddenly, the motorcycle riding between lanes has extremely limited room to maneuver. The close proximity inherent to lane splitting means reaction time and stopping distance are both compressed. Even experienced riders can be caught off guard.
If you were involved in an accident while lane splitting in Massachusetts, the steps you take afterward are the same as any motorcycle accident, but the stakes are higher because your lane position will be scrutinized.
There have been periodic legislative efforts to legalize lane filtering in Massachusetts, but none have gained significant traction. Bills have been filed in the Massachusetts General Court that would allow motorcycles to filter between stopped traffic at intersections under specific speed limits, similar to the laws in Utah and Arizona. As of 2026, none of these bills have passed.
The Massachusetts Motorcycle Association and rider advocacy groups continue to push for lane filtering legislation, citing the safety benefits demonstrated in other states. Opponents raise concerns about driver awareness and the narrow, congested roads common in the Boston metro area.
Until the law changes, lane splitting and lane filtering remain prohibited in Massachusetts, and riders who engage in these practices do so at their own legal risk.
No. Lane splitting is not legal in Massachusetts. While there is no statute that uses the term "lane splitting" specifically, the practice is prohibited by Mass. Gen. Laws Ch. 89, §4A (lane usage) and Ch. 89, §2 (passing regulations). Riders who split lanes can be cited and may face fault arguments if an accident occurs.
No. Lane filtering, which involves moving between stopped vehicles at an intersection or in a traffic jam at low speed, is also not permitted in Massachusetts. Some states like Utah and Arizona have legalized filtering under specific conditions, but Massachusetts has not adopted similar legislation.
Yes, in many cases. Lane splitting does not automatically bar you from recovering compensation. Massachusetts uses comparative negligence, meaning your compensation is reduced by your percentage of fault but not eliminated unless you are more than 50% at fault. If the other driver's negligence, such as an unsafe lane change, was the primary cause, you can still recover. An experienced attorney is critical in these cases.
Lane splitting is treated as an improper lane usage violation. Penalties typically include a fine and may result in points on your license. The larger consequence is the impact on an accident claim: if you are injured while lane splitting, the violation can be used to argue you were at fault, which reduces or eliminates your ability to recover compensation.
Research from the University of California Berkeley suggests that lane splitting at moderate speeds with a small speed differential is associated with lower rates of rear-end collisions for motorcyclists. However, that research was conducted in California, where lane splitting is legal and drivers expect it. In Massachusetts, where drivers are not accustomed to motorcycles between lanes, the risks may be different. Regardless of the safety argument, lane splitting remains illegal in Massachusetts.
Whether you were lane splitting, riding in your lane, or stopped at a red light when the accident happened, Kiley Law Group is here to help. We have spent over 50 years fighting for injured motorcyclists across Massachusetts and New Hampshire, and we have recovered more than $1 billion for our clients. We handle motorcycle accident cases on a contingency basis, so you pay nothing unless we win.
Call 978-474-8670 today for a free consultation, or contact us online.
This page is for general informational purposes only and does not constitute legal advice. Massachusetts law cited includes Mass. Gen. Laws Ch. 89, §4A (lane usage), Ch. 89, §2 (passing), Ch. 231, §85 (comparative negligence), and Ch. 90, §14 (dooring). Laws change; consult a licensed Massachusetts attorney for advice specific to your situation.
