Indiana Lane Splitting: No Statute Either Way, but Two Riders May Share a Lane

The starting point is that Indiana legislated lane sharing and left lane splitting alone. Ind. Code § 9-21-10-6 opens by declaring that a motorcycle is entitled to the full use of a traffic lane, and that a vehicle may not be driven or operated in a manner that deprives another vehicle of the full use of a traffic lane. That sentence protects a rider from being crowded by a car sharing the lane, and it cuts both ways, since a motorcycle is a vehicle too. It says nothing about a rider moving between two lines of stopped or slow traffic.

The second sentence is the unusual part. Motorcycles, other than autocycles, may, with the consent of both persons who operate the motorcycles, be operated with not more than two abreast in a single traffic lane. Two riders may therefore legally occupy one lane side by side in Indiana, but only two, and only if both of them agree to it. The autocycle exclusion and the consent language both arrived with P.L.82-2015, the act that also created the autocycle category at Ind. Code § 9-13-2-6.1: a three wheeled motor vehicle with an enclosed or partly enclosed seating area, a rollcage or roll hoops, safety belts for each occupant, antilock brakes, and steering wheel and pedal controls. Ind. Code § 9-13-2-108 folds an autocycle into the definition of motorcycle generally, so § 9-21-10-6 has to carve it back out to stop two of them from claiming a shared lane.

Nothing in Title 9 either authorises or forbids passing between lanes. A full text search of the General Assembly's own corpus returns no occurrence of lane splitting, lane filtering or between lanes in any Indiana Code section, while control phrases from the same subject matter return real results: two abreast returns Ind. Code § 9-21-11-6, the bicycle provision, and low speed vehicle returns § 9-21-5-8.5 and § 9-13-2-94.5. The absence is in the code, not in the search.

Because there is no special rule, the ordinary lane discipline provisions govern, and Ind. Code § 9-21-10-7(a) makes that explicit: all traffic regulations, and all rights and duties inured from them, that apply to a driver of a motor vehicle apply to a motorcycle operator, except regulations that expressly do not apply and regulations that by their nature have no application. The controlling one is Ind. Code § 9-21-8-11.5, added by P.L.164-2018, SEC.17: on a roadway divided into two or more clearly marked lanes, a vehicle shall be driven as nearly as practicable entirely between the lines marking the single lane, and may not be moved from the lane until the driver has first ascertained that the movement can be made with safety. A rider straddling a lane line to pass a queue is not driving entirely between the lines, which is where a citation would come from.

Overtaking on the right, the manoeuvre a filtering rider is really performing, has its own limits. Ind. Code § 9-21-8-6(a) permits passing on the right only when the vehicle being overtaken is making or about to make a left turn, or upon a roadway with unobstructed pavement of sufficient width for two or more lanes of vehicles moving lawfully in the direction being travelled. Subsection (b) adds that overtaking on the right may not be made by driving off the roadway. Ind. Code § 9-21-8-24 bars slowing, turning from a direct course, or changing from one traffic lane to another unless the movement can be made with reasonable safety, and requires an appropriate signal first. On a three lane road, Ind. Code § 9-21-8-11 restricts use of the centre lane to overtaking with a clear view, preparing a left turn, or where the lane is signposted for the direction being travelled.

One Indiana provision turns a cluster of these into something worse than an infraction. Ind. Code § 9-21-8-55 defines aggressive driving as committing at least three of nine listed acts during one episode of continuous driving, and the list includes following too closely under § 9-21-8-14, unsafe operation under § 9-21-8-24, overtaking on the right by driving off the roadway under § 9-21-8-6, failure to obey a traffic control device under § 9-21-8-41, and driving at an unsafe speed under IC 9-21-5. A person who does three of those with the intent to harass or intimidate someone in another vehicle commits aggressive driving, a Class A misdemeanor. A rider weaving up a stopped queue can accumulate those elements quickly.

A violation of the motorcycle chapter is a Class C infraction under Ind. Code § 9-21-10-13, and a violation of the traffic movement chapter is a Class C infraction under Ind. Code § 9-21-8-49(a). Ind. Code § 34-28-5-4(c) caps a Class C infraction judgment at five hundred dollars ($500) plus court costs. Indiana then adds a step most states do not: under § 9-21-8-49(b), a person who violates the traffic movement chapter in a manner that results in bodily injury to a person commits a Class A infraction instead, and § 34-28-5-4(a) allows a judgment of up to ten thousand dollars ($10,000) for a Class A infraction.

So the same lane change that costs $500 when nothing happens carries twenty times the exposure if the rider or a driver is hurt. 50) plus court costs, and a court in Marion County must impose at least thirty-five dollars ($35) under § 34-28-5-4(h). Aggressive driving under § 9-21-8-55 leaves the infraction system entirely and is charged as a Class A misdemeanor.