The ‘Form One Lane’ rule requires a driver to give way to a vehicle in another lane is that vehicle is in front of the driver’s vehicle as the lanes merge. ‘The driver in front has Right of Way’.
I can’t find anything about South African law on this rule.
Our legislation does not have a specific provision addressing this. However if the left lane is closing the driver on the left would be at fault as he would be attempting to pass the driver on the right. Reg 298 applies. There is also a prohibition to drive on the shoulder of a public road. Vehicle A will be transgressing reg 298A if B does not slow down so he can enter the roadway.
Passing of vehicle
Reg 298. (1) Subject to the provisions of subregulation (2) and (4) and regulation 296, the driver of a vehicle intending to pass any other vehicle proceeding in the same direction on a public road shall pass to the right thereof at a safe distance and shall not again drive on the left side of the roadway until safely clear of the vehicle so passed:
Provided that, in the circumstances as aforesaid, passing on the left of such vehicle shall be permissible if the person driving the passing vehicle can do so with safety to himself or herself and other traffic or property which is or may be on such road and—
(a) the vehicle being passed is turning to its right or the driver thereof has signalled his or her intention of turning to his or her right;
(b) such road is a public road in an urban area and—
(i) is restricted to vehicles moving in one direction; and
(ii) the roadway is of sufficient width for two or more lines of moving vehicles;
(c) such road is a public road in an urban area and the roadway is of sufficient width for two or more lines of moving vehicles moving in each direction;
(d) the roadway of such road is restricted to vehicles moving in one direction and is divided into traffic lanes by appropriate road traffic signs; or
(e) he or she is driving in compliance with the directions of a traffic officer or is driving in traffic which is under the general direction of such officer, and in accordance with such direction:
Provided further that in no event shall any passing referred to in paragraph (a), (b), (c) or (d) be done by driving on the shoulders of the roadway or on the verge of the public road concerned.
(2) The driver of a vehicle shall not pass other traffic proceeding in the same direction on a public road when approaching—
(a) the summit of a rise;
(b) a curve; or
(c) any other place,
where his or her view is so restricted that any such passing could create a hazard in relation to other traffic which might approach from the opposite direction, unless—
(i) he or she can do so without encroaching on the right‑hand side of the roadway; or
(ii) the roadway of such road is restricted to vehicles moving in one direction.
(3) The driver of a vehicle on a public road shall, except in the circumstances referred to in the first proviso to subregulation (1), upon becoming aware of other traffic proceeding in the same direction and wishing to pass his or her vehicle, cause his or her vehicle to travel as near to the left edge of the roadway as is possible, without endangering himself or herself or other traffic or property on the roadway, and shall not accelerate the speed of his or her vehicle until the other vehicle has passed.
(4) When about to pass oncoming traffic, the driver of a vehicle on a public road shall ensure that the vehicle driven by him or her does not encroach on the roadway to his or her right in such manner as may obstruct or endanger such oncoming traffic.
(5) The driver of a vehicle intending to pass a stationary bus on a public road shall do so with due care for the safety of persons who are approaching or leaving or may approach or leave such bus.
Prohibition on driving on shoulder of public road, except in certain circumstances
Reg 298A.(1) Subject to subregulation (2) and regulation 298(1)(e), no person shall drive a motor vehicle on the shoulder of a public road.
(2) Notwithstanding subregulation (1), the driver of a motor vehicle may, during the period between sunrise and sunset, drive such motor vehicle on the shoulder of a public road which is designated for one lane of traffic in each direction—
(a) while such motor vehicle is being overtaken by another vehicle; and
b) if he or she can do so without endangering himself or herself, other traffic, pedestrians or property on such public road;
(c) if persons and vehicles upon a public road are clearly discernible at a distance of at least 150 metres.
Alta Swanepoel and Associates