Mont. Code Ann. § 61-8-321
Drive on right side of roadway -- exceptions
En. Sec. 48, Ch. 263, L. 1955; R.C.M. 1947, 32-2151; amd. Sec. 6, Ch. 352, L. 2003; amd. Sec. 1, Ch. 236, L. 2017; amd. Sec. 31, Ch. 299, L. 2019; amd. Sec. 8, Ch. 567, L. 2023.
(1) Upon all roadways of sufficient width, a vehicle must be operated upon the right half of the roadway, except as follows:
- (a) when overtaking and passing another vehicle proceeding in the same direction under the rules governing the passing movement;
- (b) when the right half of a roadway is closed to traffic while under construction or repair;
- (c) upon a roadway divided into three marked lanes for traffic under the rules applicable on a divided roadway;
- (d) upon a roadway designated by official traffic control devices for one-way traffic;
- (e) when the operator of a vehicle is complying with the provisions of 61-8-387 or 61-8-388;
- (f) when an obstruction exists that makes it necessary to drive to the left of the center of the roadway; or
- (g) when a police vehicle or authorized emergency vehicle is performing a job-related duty as provided in 61-8-107.
- (2) A person operating a vehicle to the left of the center of the roadway for any of the reasons provided in subsection (1) shall yield the right-of-way to all vehicles traveling in the proper direction upon the unobstructed portion of the roadway that are within a distance that constitutes an immediate hazard.
(3)
- (a) Except as provided in subsection (3)(b) and subject to subsection (4), upon all roadways having two or more lanes for traffic moving in the same direction, a vehicle must be driven in the right-hand lane.
(b) A vehicle being operated upon a roadway having two or more lanes for traffic moving in the same direction is not required to be driven in the right-hand lane when:
- (i) overtaking and passing another vehicle proceeding in the same direction;
- (ii) traveling at a speed greater than the traffic flow;
- (iii) moving left to allow traffic to merge;
- (iv) traveling on a roadway within the official boundaries of a city or town, except as provided in subsection (4);
- (v) preparing for a left turn at an intersection or into a private road or driveway when a left turn is legally permitted;
- (vi) exiting onto a left-hand exit from a controlled-access highway;
- (vii) an obstruction or hazardous conditions make it necessary to drive in a lane other than the right-hand lane;
- (viii) road or vehicle conditions make it safer to drive in a lane other than the right-hand lane; or
- (ix) authorized snow-removal equipment is operating on the roadway.
- (4) When traveling upon an interstate highway, as defined in 60-1-103, within the official boundaries of a city or town, a vehicle must be driven in the right-hand lane unless otherwise directed or permitted by an official traffic control device.
History: En. Sec. 48, Ch. 263, L. 1955; R.C.M. 1947, 32-2151; amd. Sec. 6, Ch. 352, L. 2003; amd. Sec. 1, Ch. 236, L. 2017; amd. Sec. 31, Ch. 299, L. 2019; amd. Sec. 8, Ch. 567, L. 2023.