PCV Environmental Awareness and Fuel Efficiency 1 — Questions and Answers
Question 1: What driving technique most effectively reduces fuel consumption on a bus route?
- Accelerating hard to reach speed quickly then braking sharply
- Smooth, progressive acceleration and anticipatory braking (eco-driving) (Correct answer)
- Driving at maximum speed between stops
- Keeping the engine at a constant high RPM
Correct answer: Smooth, progressive acceleration and anticipatory braking (eco-driving)
Smooth, eco-driving — gentle acceleration and anticipatory braking — minimises fuel consumption and emissions.
Eco-driving techniques for PCV drivers include: accelerating gently, reading the road ahead to coast to junctions rather than braking late, selecting the highest appropriate gear, maintaining a steady speed, and switching off unnecessary auxiliaries. DVSA research shows eco-driving can reduce fuel consumption by up to 10–15% on urban routes.
Question 2: How does excessive engine idling affect a bus's fuel consumption and emissions?
- It has no measurable effect on fuel use
- It wastes fuel and produces unnecessary exhaust emissions including NOx and particulates (Correct answer)
- It keeps the engine warm, improving efficiency overall
- It reduces wear on the starter motor
Correct answer: It wastes fuel and produces unnecessary exhaust emissions including NOx and particulates
Prolonged idling wastes fuel and emits unnecessary pollutants — engines should be switched off during prolonged stops.
A bus idling for 10 minutes uses roughly 0.5–1 litre of fuel unnecessarily. Prolonged idling produces NOx, PM10, and CO2 without serving any transport purpose. Many operators have a '2-minute rule' — if stationary for more than 2 minutes (except in traffic), the driver should switch off the engine. This is especially important at termini and in urban areas with Clean Air Zones.
Question 3: What does 'regenerative braking' do in a hybrid or electric bus?
- It uses the engine to generate compressed air for the air brakes
- It captures kinetic energy during braking and converts it into electrical energy stored in batteries (Correct answer)
- It automatically applies the brakes when the bus exceeds the speed limit
- It recirculates exhaust gases to reduce emissions
Correct answer: It captures kinetic energy during braking and converts it into electrical energy stored in batteries
Regenerative braking recovers kinetic energy during deceleration and stores it as electricity to be reused for propulsion.
In hybrid and electric buses, regenerative braking uses the electric motor as a generator when the vehicle decelerates. The kinetic energy that would otherwise be lost as heat in conventional brakes is converted to electrical energy and stored in a battery pack. This can significantly extend range and improve energy efficiency, particularly on urban routes with frequent stops.
Question 4: Which of the following actions by a PCV driver contributes most to reducing tyre wear and fuel consumption?
- Checking and maintaining correct tyre pressures regularly (Correct answer)
- Using wider tyres than specified
- Driving in the highest gear at all times
- Avoiding use of the air conditioning system
Correct answer: Checking and maintaining correct tyre pressures regularly
Correct tyre inflation reduces rolling resistance, improving fuel economy and extending tyre life.
Under-inflated tyres have greater rolling resistance, which increases fuel consumption and generates excess heat, accelerating tyre wear. DVSA and manufacturer guidelines state that tyres should be checked cold (before driving) and inflated to the specified pressure. A tyre that is 20% under-inflated can increase fuel consumption by around 3–5% and significantly shortens tyre life.
Question 5: What is a Low Emission Zone (LEZ) and how does it affect PCV operators?
- A zone where buses must travel at reduced speed to lower emissions
- A designated area that restricts or charges older, more polluting vehicles including buses that do not meet emission standards (Correct answer)
- An area where electric vehicles have priority lane access
- A zone where PCV operators are exempt from congestion charges
Correct answer: A designated area that restricts or charges older, more polluting vehicles including buses that do not meet emission standards
LEZs restrict entry by vehicles that do not meet specified emission standards, potentially charging or prohibiting older buses.
Low Emission Zones (LEZs) and Clean Air Zones (CAZs) are designated urban areas where vehicles must meet minimum emission standards (typically Euro VI for buses and coaches) to enter free of charge. Vehicles not meeting the standard face a daily charge or prohibition from entry. Operators running non-compliant vehicles in these zones can face significant financial penalties. Major UK cities including London, Birmingham, and Edinburgh operate such schemes.
Question 6: What is the primary benefit of route optimisation for reducing a bus fleet's environmental impact?
- It allows buses to travel faster on all routes
- It reduces unnecessary mileage, cutting fuel consumption and emissions (Correct answer)
- It reduces driver wages by shortening shifts
- It allows operators to avoid congestion charges
Correct answer: It reduces unnecessary mileage, cutting fuel consumption and emissions
Route optimisation reduces total distance travelled, directly cutting fuel use, emissions, and operating costs.
Route optimisation analyses bus routes to eliminate unnecessary dead mileage (empty running), improve scheduling to reduce waiting time at termini with idling engines, and ensure vehicles are correctly matched to demand. By minimising total vehicle kilometres, operators reduce fuel consumption, CO2 emissions, and operating costs — while improving service reliability.
PCV Environmental Awareness and Fuel Efficiency 1
What driving technique most effectively reduces fuel consumption on a bus route?