1.1 Keeping Left, Lane Use and Moving Off Safely

1.1 Keeping Left, Lane Use and Moving Off Safely

Lane discipline questions test whether you know the actual wording of the rules of the road in section 148 of the Motor Traffic Act (Chapter 203) and the lane-marking rules in the Motor Traffic (Signs, Signals, Symbols and Road Markings) Regulations No. 02 of 2015. Section 147 makes it an offence to drive in breach of any part of section 148, and these offences can be dealt with by spot fine under section 215A.

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1. The Basic Rule: Keep to the Left

Section 148(1) states the rule:

A motor vehicle being driven shall be kept to the left or near side of the road, except when such vehicle is overtaking other traffic or turning right.

Sri Lanka drives on the left, so ordinary cars are right-hand drive: the driver sits on the right, next to the centre of the road. That position gives the best view of oncoming traffic when you plan an overtake, and it is why every arm signal is given with the right arm (section 4.3).

The rest of section 148 builds on this:

• s.148(2): when you are being overtaken, drive so as to let the other vehicle pass. Keep left and do not speed up.
• s.148(5): do not drive alongside, or overtake, traffic in a way that obstructs oncoming traffic.
• s.148(6)–(8): do not cross a road, turn in it, or enter or leave it from a place that is not a road in a way that obstructs traffic.

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2. Roads With Several Lanes

What the Act says

The first proviso to section 148(1) deals with wide roads:

On a road which permits the flow of traffic in the same direction in three or more parallel lanes which are demarcated, vehicles may be driven along two parallel lanes in the same direction except the lane closest to the centre of the road.

The second proviso adds that vehicles on parallel lanes must not move from one lane to another in a way that obstructs other traffic.

What the 2015 regulations add

Regulation 27(5) applies where lane lines (road marking RM-13) divide a road into four or more lanes:

• all vehicles must be driven within the lanes;
• lane lines may be crossed or straddled only to overtake or to turn left or right; and
• vehicles are to be driven on the outside lanes, while the inside lanes are used for overtaking or turning right.

The RDA's expressway rules say the same thing: use the outer (left) lane for normal driving and the inner lane only for overtaking, then return to the outer lane.

Weaving from lane to lane so as to obstruct others breaks the second proviso to section 148(1). Weaving that endangers people can also be charged as reckless or negligent driving under section 151(2)–(3).

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3. Bus Lanes

Some city roads have lanes reserved for buses, marked with the words BUS LANE (RM-40), a lane line (RM-44) and the OSD-07 "Bus only lane begins" sign, ending at OSD-08. Regulation 27(6) allows only public transport vehicles to use or cross them, except:

• to avoid an accident, without endangering bus-lane users;
• where your own part of the road is blocked and the bus lane is the most convenient way past, returning as soon as possible;
• when a police officer directs you to turn across it or use it;
• for pedestrians crossing, people getting in or out of a vehicle, and loading or unloading where loading is not prohibited.

An additional panel may limit the lane to certain hours or days (regulation 27(9)). Outside those times, the lane is an ordinary lane.

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4. Moving Off From the Kerb: Observe, Decide, Act

Moving off must not force anyone else to brake or swerve (s.148(6)–(7)). DMT sample questions treat observation as the first step of any manoeuvre (for example, the first action before overtaking is to observe the road). The safe sequence is observe, decide, then act, and the familiar Mirror–Signal–Manoeuvre routine puts it into practice:

1. Mirrors: check the interior mirror, then the right exterior mirror for traffic coming up behind, and the left mirror for cyclists or pedestrians beside you.
2. Blind spot: turn your head and look over your right shoulder. Mirrors do not show a motorcycle or three-wheeler right beside your rear door.
3. Signal: indicate right if anyone could benefit from knowing.
4. Decide: move only when there is a safe gap.
5. Act: release the handbrake, move off smoothly and settle into the left of the lane.

  OBSERVE (mirrors + right shoulder) -> DECIDE (safe gap?) -> ACT (signal, move off, keep left)

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5. Positioning for Turns (Section 148(12)–(13))

Turning left

Section 148(12) requires a vehicle turning left into another road to be kept as near as possible to the left edge of the road, unless a police officer directs otherwise. Before the turn, check your left mirror and left shoulder: motorcycles and three-wheelers often try to pass on the inside. Do not swing out to the right before turning left.

Turning right

Section 148(13) sets out the right turn:

1. Position the vehicle nearly parallel to the centre of the road, signalling right at the same time.
2. Drive to the point of turn, which should be close to the centre of the intersection.
3. Turn into the other road only after checking that your path is clear of oncoming traffic.
4. If there is a structure (an island or roundabout) in the middle of the junction, complete the turn keeping it on your right, unless a police officer directs otherwise.

While you wait for a gap, keep your front wheels pointing straight ahead. If a vehicle hits you from behind, you will then be pushed forward instead of into the path of oncoming traffic.

Stop lines

Section 148(14): a vehicle coming from any place onto a road must stop before entering the road where stop lines are painted.

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6. Common Exam Traps

• "The right-hand lane of a three-lane road is for cruising." False. It is for overtaking and turning right only.
• "You may straddle lane lines if traffic is heavy." False. You may cross them only to overtake or turn.
• "A private car may drive in a bus lane during its hours if the other lanes are congested." False. Congestion is not one of the exceptions; a blocked lane or obstruction ahead is.