Lane Sharing and the Lane-Splitting Question
You are riding a motorcycle on a six-lane freeway in the Phoenix area during rush hour. Traffic in your direction is moving at about 15 mph, and you are in the number 2 lane of three. The lane to your left is moving slightly faster, about 20 mph, and the lane to your right is stop-and-go. You see a gap between the number 1 and number 2 lanes and consider riding between them to reach your exit a mile ahead. Your lane position is currently in the left portion of your lane, about 3 feet from the lane line. A white SUV in the number 1 lane is drifting slightly toward the line.
1. Evaluate the lane-sharing idea against Arizona law and against the risk picture in this specific traffic.
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Arizona law does not permit lane splitting, meaning riding between lanes of moving traffic or sharing a lane with another vehicle in a way that is not authorized. Arizona does allow a motorcycle to use a full lane, and it does not permit two motorcycles to share a lane unless the law allows it; in general, a rider should occupy a lane as a vehicle would. Riding between the number 1 and number 2 lanes here would be lane splitting and is not legal in Arizona.
Risk picture even setting legality aside:
- The speed differential is small, but the right lane is stop-and-go, so a car could change lanes into the gap without warning.
- The white SUV is drifting toward the line, which is exactly the failure mode that makes lane sharing dangerous.
- The gap between lanes is narrow, and your mirrors and bars would be close to both vehicles.
- A mile to the exit is not worth the exposure.
Judgment: do not ride between the lanes. Stay in your lane, maintain space, and plan the exit early.
2. Given that you cannot split lanes, how should you position and manage the ride to the exit?
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Plan:
- Pick the lane you need for the exit and get there early, using normal lane changes with signals and mirror and blind-spot checks.
- In slow traffic, keep a cushion ahead and to the sides. Avoid riding directly beside a vehicle in an adjacent lane, since that is where a lane change will put you.
- Watch the white SUV. If it continues drifting, drop back or move right within your lane to create space, and do not linger in its blind spot.
- Maintain a visible position in your lane, with headlight on, and avoid hugging the lane line where you are least visible and most exposed.
- Watch for brake lights several cars ahead, and cover the brakes in stop-and-go.
- Do not use the shoulder or the gap between lanes to bypass traffic.
Being visible and predictable matters more than gaining a few car lengths.
3. What lane-positioning principles apply when traffic is moving at very different speeds across lanes?
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Principles:
- Occupy a lane as a vehicle would, and choose a position within it that maximizes space from adjacent traffic and keeps you visible in mirrors.
- Avoid riding in the door zone of adjacent lanes, meaning directly alongside another vehicle where a lane change would hit you.
- When adjacent lanes move at different speeds, expect lane changes from the faster lane into the slower one and vice versa. Position to have an escape path.
- Increase following distance in stop-and-go so you are not trapped against the vehicle ahead.
- Use your headlight and lane position to be seen, but do not rely on being seen.
- Plan exits early so you are not making a hurried multi-lane move near the gore point.
In this traffic, the safest choice is a stable lane position with space on both sides and an early exit plan.