Take LK DMT Heavy Vehicle Written Practice Questions - Sri Lanka Department of Motor Traffic Heavy Vehicle Written Test Exam

QUESTION 1 / 25

At what air pressure should the low air pressure warning buzzer or light activate in a heavy vehicle equipped with air brakes?

Choose one answer below.

AAround 20 to 30 psi✓BAround 55 to 60 psi✓CAround 100 to 120 psi✓DAround 150 to 180 psi✓

QUESTION 2 / 25

Why must the air brake reservoir tanks on a heavy commercial lorry be drained daily by the driver?

Choose one answer below.

ATo prevent the air pressure from escaping through the tires✓BTo remove water and oil that can freeze or corrode the brake system✓CTo adjust the tension of the brake pedal mechanism✓DTo clean the internal air filter of the diesel engine✓

QUESTION 3 / 25

What is the primary safety function of a dual air brake system in a heavy passenger bus?

Choose one answer below.

ATo double the braking power when descending steep hills✓BTo provide separate front and rear brake circuits in case of a system leak✓CTo allow the passenger bus to travel at higher speeds safely✓DTo automate the parking brake release process during departures✓

QUESTION 4 / 25

Under Sri Lankan Motor Traffic Regulations, what is the default maximum height allowed for a heavy lorry or bus, including its load?

Choose one answer below.

A2.8 meters✓B3.8 meters✓C4.6 meters✓D5.5 meters✓

QUESTION 5 / 25

What is the normal operating air pressure range for a heavy vehicle's air brake system?

Choose one answer below.

A20 to 40 psi✓B50 to 75 psi✓C85 to 120 psi✓D150 to 200 psi✓

QUESTION 6 / 25

What is the minimum legal tire tread depth required for a heavy lorry or motor coach in Sri Lanka?

Choose one answer below.

A0.8 mm✓B1.6 mm✓C3.0 mm✓D4.5 mm✓

QUESTION 7 / 25

When draining moisture from the air brake tanks of a heavy lorry, which tank should be drained first?

Choose one answer below.

AThe primary reservoir tank✓BThe secondary reservoir tank✓CThe wet tank (supply tank)✓DThe emergency spring brake chamber tank✓

QUESTION 8 / 25

During a pre-trip inspection of a heavy lorry, what indicates a critical leaf spring suspension defect?

Choose one answer below.

ALeaf springs are covered in road dust or light grime✓BMore than one-fourth of the leaves in a spring stack are broken or shifted✓CThe springs have a black coat of protective paint from the factory✓DThe spring shackle bolts are tightly secured to the frame✓

QUESTION 9 / 25

How should a heavy vehicle driver check the slack adjusters on an air brake system during a pre-trip inspection?

Choose one answer below.

ABy visual inspection from the driver's cab while moving slowly✓BBy releasing the parking brake, pulling hard on each slack adjuster, and checking for movement exceeding 1 inch✓CBy pumping the brake pedal 20 times and checking if it gets stiff✓DBy checking if the brake drums are hot to the touch when parked✓

QUESTION 10 / 25

What is the primary reason for performing a systematic, step-by-step pre-trip inspection of a heavy passenger bus?

Choose one answer below.

ATo satisfy the operator's cleaning and washing requirements✓BTo ensure the mechanical safety and roadworthiness of the bus before passengers board✓CTo reduce the fuel consumption of the vehicle during the trip✓DTo adjust the passenger seat belts and headrests✓

QUESTION 11 / 25

Why should a heavy truck driver turn off the engine retarder (exhaust or Jake brake) in wet or slippery road conditions?

Choose one answer below.

AThe retarder can overheat the engine cooling system in rainy weather✓BThe retarder can cause the drive wheels to skid and lose traction✓CThe retarder uses excessive diesel fuel when roads are wet✓DThe retarder increases the wear on the service brake pads✓

QUESTION 12 / 25

What is the cause of 'brake fade' when driving a heavy lorry down a long, steep gradient?

Choose one answer below.

AThe air compressor fails to pump enough air to the chambers✓BThe brake drums or discs overheat from constant use, reducing friction✓CThe brake pedal mechanism gets jammed by road debris✓DThe thickness of the brake linings increases temporarily✓

QUESTION 13 / 25

On a heavy passenger bus in Sri Lanka, what is a key safety rule regarding emergency exit doors?

Choose one answer below.

AThey must be padlocked from the outside during the trip✓BThey must be kept unlocked, clearly labeled, and completely unobstructed✓CThey must only be opened by a police officer or PHI✓DThey must be blocked by luggage to prevent accidental opening✓

QUESTION 14 / 25

After starting a heavy bus engine, what is the maximum time within which the engine oil pressure gauge should show normal pressure?

Choose one answer below.

AWithin 3 to 5 seconds✓BWithin 30 to 60 seconds✓CWithin 3 to 5 minutes✓DWithin 10 minutes✓

QUESTION 15 / 25

During a walkaround inspection of a heavy vehicle, what visual sign indicates that wheel lug nuts may be loose?

Choose one answer below.

AClean, painted surfaces around the lug nuts✓BRust streaks trailing from the lug nuts on steel wheels, or shiny metal on aluminum wheels✓CA thin layer of dry dust covering the wheel rim✓DThe tires are inflated to their maximum pressure✓

QUESTION 16 / 25

What does a single solid white line painted down the center of a two-lane road in Sri Lanka mean?

Choose one answer below.

AOvertaking is permitted at any time if the road ahead is clear✓BOvertaking or crossing the line is prohibited, except when turning off the road✓CThe lane is reserved for public passenger buses only✓DDrivers must stop and wait for a green signal before passing✓

QUESTION 17 / 25

What do double solid white lines in the center of a road in Sri Lanka indicate?

Choose one answer below.

AOvertaking is permitted only for light passenger vehicles✓BCrossing or overtaking across these lines is strictly prohibited from both directions✓CIt is a designated lane for public transport vehicles✓DYou may cross the lines to park on the opposite shoulder✓

QUESTION 18 / 25

What does a broken white line down the center of a road indicate in Sri Lanka?

Choose one answer below.

AOvertaking is prohibited under all circumstances✓BOvertaking or lane changes are permitted when it is safe to do so✓CParking is allowed in the middle of the road✓DThe road ahead is a one-way street only✓

QUESTION 19 / 25

What do yellow zigzag line markings on the side of the road or curb in Sri Lanka indicate?

Choose one answer below.

AA designated school bus parking zone✓BStopping or parking is prohibited in this area, typically near pedestrian crossings✓CA zone where heavy vehicles must drive at their maximum speed✓DA parking area reserved exclusively for three-wheelers✓

QUESTION 20 / 25

What is the rule when approaching a yellow box junction painted at an intersection in Sri Lanka?

Choose one answer below.

AHeavy vehicles have the right of way to enter and block the box at any time✓BDo not enter the box unless your exit road or lane is entirely clear✓CStop inside the box to wait for the green traffic light✓DYou must speed up to cross the box before the light turns red✓

QUESTION 21 / 25

What does a double solid yellow line painted along the edge of a road in Sri Lanka mean?

Choose one answer below.

AParking is allowed for less than 10 minutes✓BStopping or parking is prohibited at all times✓COnly heavy buses are allowed to park here✓DOvertaking from the left side is permitted✓

QUESTION 22 / 25

What does a single broken yellow line painted along the edge of a road in Sri Lanka mean?

Choose one answer below.

ANo stopping at any time under any circumstances✓BParking is prohibited, but temporary stopping to load or unload passengers is allowed✓CA designated lane for three-wheelers and motorcycles✓DThe speed limit is restricted to 20 km/h in this area✓

QUESTION 23 / 25

What does a solid white line next to a broken white line in the center of the road mean?

Choose one answer below.

AVehicles on both sides may cross the lines to overtake✓BOvertaking is permitted only for the side with the broken line✓COvertaking is permitted only for the side with the solid line✓DBoth sides are strictly prohibited from overtaking✓

QUESTION 24 / 25

What do white diagonal stripes (chevron markings) painted inside a traffic island area indicate?

Choose one answer below.

AAn area reserved for parking heavy buses✓BA safety zone that drivers must not enter or cross except in an emergency✓CA turning lane for heavy trucks and trailers✓DA zone where speed limits are not enforced✓

QUESTION 25 / 25

What do transverse yellow bars painted across a lane before a pedestrian crossing or roundabout indicate?

Choose one answer below.

AA warning to slow down as you are approaching a hazard✓BAn area where stopping is prohibited at all times✓CA lane reserved for public transport only✓DA point where you must stop and yield to all traffic✓