The legality of a motorcycle moving between lanes of traffic, often called lane splitting or lane filtering, depends entirely on the state you're in. Currently, only Utah, Montana, Arizona, and Hawaii have legalized some form of the practice, each with specific restrictions. In all other states, it remains illegal. Even where legal, it's a controversial maneuver that requires extreme caution, specific road conditions, and proper technique to be performed safely. The primary argument for it is that it can reduce motorcycle congestion and lessen the risk of a rear-end collision for the rider.
The key distinction lies in the terminology. Lane splitting typically refers to riding between lanes of moving traffic, while lane filtering describes moving between stationary or slow-moving vehicles to get to the front of an intersection. States that allow it have strict rules; for example, Utah only permits filtering when traffic is stopped and at speeds under 15 mph.
Safety is the paramount concern. Proponents cite a 2015 UC Berkeley study which found that lane splitting can be safe if done at speeds no more than 15 mph faster than surrounding traffic and at overall speeds below 50 mph. However, the risks are significant. Car drivers often don't expect a motorcycle to appear beside them in the same lane, and a sudden door opening or lane change can be catastrophic.
If you are in a state where it is legal and choose to do it, follow these best practices:
- Speed Differential: Never go more than 10-15 mph faster than the flow of traffic.
- Traffic Speed: Only consider it when traffic is moving at 30 mph or less.
- Heightened Awareness: Watch for turning vehicles, gaps in traffic where a car might switch lanes, and car doors.
- Avoid Blind Spots: Do not linger beside a vehicle where the driver cannot see you.
The following table summarizes the legal status and key rules in the states where some form of lane filtering is permitted.
| State | Legal Status | Key Restrictions |
|---|
| Utah | Legal (Lane Filtering) | Only when traffic is stopped; max speed of 15 mph. |
| Montana | Legal (Lane Filtering) | Only when traffic is stopped; must be done safely. |
| Arizona | Legal (Lane Filtering) | Only on roads with speed limits of 45 mph or less; traffic must be stopped. |
| Hawaii | Legal (Lane Splitting) | Motorbikes with engine size under 50cc only; specific roads. |
