DTT HGV Passenger Safety and Air Brakes 1 — Questions and Answers
Question 1: What is the driver of a bus or coach primarily responsible for regarding passenger safety?
- Ensuring passengers board and alight safely, are seated before moving, do not stand in unauthorised areas, and are not endangered by the driver's actions (Correct answer)
- Selling tickets and managing the timetable
- Checking luggage for prohibited items
- Keeping to the timetable — passenger safety is a conductor's responsibility
Correct answer: Ensuring passengers board and alight safely, are seated before moving, do not stand in unauthorised areas, and are not endangered by the driver's actions
The driver is ultimately responsible for passenger safety. This includes ensuring all passengers are properly seated or holding before moving, maintaining safe driving conduct, and managing emergency situations.
Question 2: What is the maximum standing capacity in a standard single-deck urban bus?
- Determined by the vehicle's type approval — standing passengers must have adequate handholds and space per person (Correct answer)
- 10 standing passengers for any urban bus
- Equal to the seated capacity — standing and seated numbers are always equal
- Standing is prohibited on all service buses in Ireland
Correct answer: Determined by the vehicle's type approval — standing passengers must have adequate handholds and space per person
Standing passenger capacity is set by the vehicle's type approval certificate. The number is calculated based on floor space, handrail provision, and safety standards. It varies by vehicle type and is marked in the vehicle.
Question 3: When must a bus driver not allow a passenger to board?
- When the vehicle is at its certified maximum capacity, or the passenger's behaviour poses a safety risk (Correct answer)
- Whenever the driver considers the passenger unsuitable
- When the passenger lacks the correct fare and no alternative payment is available
- Boarding refusal is only at the discretion of the transport company
Correct answer: When the vehicle is at its certified maximum capacity, or the passenger's behaviour poses a safety risk
A driver must refuse boarding when the vehicle is at maximum capacity (standing or seated, per type approval). A driver may also refuse a passenger who is intoxicated, threatening, or whose presence endangers other passengers.
Question 4: What is an air brake system and why is it used on heavy vehicles?
- A braking system powered by compressed air — used on heavy vehicles because air provides the force needed to apply large drum or disc brakes on multiple axles (Correct answer)
- A brake system that uses air cooling to prevent brake fade
- An electrically operated braking system for large vehicles
- A braking system that vents brake heat through air ducts
Correct answer: A braking system powered by compressed air — used on heavy vehicles because air provides the force needed to apply large drum or disc brakes on multiple axles
Air brakes use compressed air to apply braking force to all axles simultaneously. The air pressure provides the power needed to brake very heavy vehicles — hydraulic systems do not generate sufficient force for multi-axle trucks and buses.
Question 5: What is the 'spring brake' (parking brake) on an air brake system?
- A spring-loaded device that applies the brakes automatically when air pressure is lost — it holds the vehicle when parked (Correct answer)
- A soft application brake for gentle deceleration in traffic
- A brake applied only to the front axle for directional stability
- An emergency brake operated by a separate foot pedal
Correct answer: A spring-loaded device that applies the brakes automatically when air pressure is lost — it holds the vehicle when parked
The spring brake (parking or emergency brake) on an air brake system is spring-loaded. When air pressure is released or lost, the spring force automatically applies the brakes — providing both parking and emergency brake functions.
Question 6: What is the minimum air pressure required before driving an air-braked vehicle?
- The pressure must reach the cut-in pressure shown in the vehicle manual — typically around 5-6 bar — and brake warning lights must extinguish (Correct answer)
- Any reading above 0 bar — the system builds pressure while driving
- 3 bar minimum — this is the emergency brake activation threshold
- 7 bar — the maximum operating pressure before a safety valve opens
Correct answer: The pressure must reach the cut-in pressure shown in the vehicle manual — typically around 5-6 bar — and brake warning lights must extinguish
Air pressure must build to the system's cut-in or 'green zone' pressure before driving. Warning lights on the dashboard extinguish when safe pressure is reached. Driving with insufficient air pressure risks brake failure.
DTT HGV Passenger Safety and Air Brakes 1
What is the driver of a bus or coach primarily responsible for regarding passenger safety?