A company based in the West Midlands carries groupage all over Europe from its base in Birmingham. It runs a fleet of 3-axle artic units and a variety of 2 and 3 axle semi-trailers. All of the tractor units are plated at 44 tonnes.
The company is actively looking for ways in which it can become more fuel efficient as fuel is one of its largest outgoings and has a big impact on its profit margins.
The company is actively looking for ways in which it can become more fuel efficient as fuel is one of its largest outgoings and has a big impact on its profit margins.
There are 5 multiple choice questions in this case study. Read this carefully and ensure you fully understand the scenario before starting the test. You need to score 4 out of 5 to pass.
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1. What is the maximum permissible train weight of these vehicles when pulling a 2 axle semi-trailer in the UK?
Mark one answer
B
C
D
Correct Answer: B
Explanation: • 44 tonnes: No, it would have to be a 3-axle tractor unit pulling a 3-axle semi-trailer to operate at this weight.
• 42 tonnes: No, this vehicle cannot go to this weight as a 3 + 2 axle configuration.
• 38 tonnes: No, this is not the maximum permitted train weight for this vehicle combination.
• 40 tonnes: Yes, this would be the maximum train weight for a 5 axle combination
Explanation: • 44 tonnes: No, it would have to be a 3-axle tractor unit pulling a 3-axle semi-trailer to operate at this weight.
• 42 tonnes: No, this vehicle cannot go to this weight as a 3 + 2 axle configuration.
• 38 tonnes: No, this is not the maximum permitted train weight for this vehicle combination.
• 40 tonnes: Yes, this would be the maximum train weight for a 5 axle combination
2. What is the maximum weight that could be loaded onto the upper deck of the semi-trailer?
Mark one answer
B
C
D
Correct Answer: C
Explanation: • 12 tonnes: No, it would vary depending on manufacturer, construction and design.
• 10 tonnes: No, it would vary depending on manufacturer, construction and design.
• It would be stated on the trailer Ministry Plate: No, the Ministry plate would only give details of the maximum weight for the semi-trailer and individual axle maximum weights.
• It would be stated on the deck frame: Correct.
Explanation: • 12 tonnes: No, it would vary depending on manufacturer, construction and design.
• 10 tonnes: No, it would vary depending on manufacturer, construction and design.
• It would be stated on the trailer Ministry Plate: No, the Ministry plate would only give details of the maximum weight for the semi-trailer and individual axle maximum weights.
• It would be stated on the deck frame: Correct.
3. Which two of the labelled features could be said to make this vehicle more "environmentally friendly"?
Mark two answers
B
C
D
Correct Answer: C, D
Explanation: • The tear-drop shape to the trailer and the wind deflector on the cab roof helps deflect the wind more smoothly over the cab roof towards the semi-trailer, thereby reducing drag and improving fuel consumption.
• The lift axle raises when there is less weight over this part of the tractor unit {e.g. when the semi-trailer is lightly laden or empty, thus reducing drag and improving fuel consumption and also reduces tyre wear and the need for more frequent tyre replacement.
• The under-run protection and flexible curtain-side sheeting do not improve fuel consumption.
Explanation: • The tear-drop shape to the trailer and the wind deflector on the cab roof helps deflect the wind more smoothly over the cab roof towards the semi-trailer, thereby reducing drag and improving fuel consumption.
• The lift axle raises when there is less weight over this part of the tractor unit {e.g. when the semi-trailer is lightly laden or empty, thus reducing drag and improving fuel consumption and also reduces tyre wear and the need for more frequent tyre replacement.
• The under-run protection and flexible curtain-side sheeting do not improve fuel consumption.
4. Which one of the following answers is likely to have the most positive effect on vehicle fuel economy?
Mark one answer
B
C
D
Correct Answer: C
Explanation: • Carrying as much weight as possible to cut the number of journeys: No, although maximising payload is always the goal, the more weight carried the more fuel the vehicle will use to move it. Trying to get as much weight on as possible may also lead to overloading the vehicle, particularly where there is a high cubic capacity for goods as there is in this double-deck semi-trailer.
• Advising the drivers to coast downhill whenever they can: No, this is potentially very dangerous and could lead to brake fade (where the brakes overheat and lose all stopping power) as there is no assistance to slow the vehicle via engine braking and because the engine will be running at very low revs, the compressor may not be building sufficient air pressure in its tanks to supply the braking system.
• Using red diesel because it is significantly cheaper than white: No, the use of red diesel in a road engine is illegal as it means that the correct level of duty has not been paid. Using red diesel can lead to the confiscation of the vehicle by HMRC and a very heavy fine or other monetary penalty.
• Keeping the rev counter in the green zone: Yes, this is the best answer here. Keeping the rev counter in the green zone means that the engine is working most efficiently.
Explanation: • Carrying as much weight as possible to cut the number of journeys: No, although maximising payload is always the goal, the more weight carried the more fuel the vehicle will use to move it. Trying to get as much weight on as possible may also lead to overloading the vehicle, particularly where there is a high cubic capacity for goods as there is in this double-deck semi-trailer.
• Advising the drivers to coast downhill whenever they can: No, this is potentially very dangerous and could lead to brake fade (where the brakes overheat and lose all stopping power) as there is no assistance to slow the vehicle via engine braking and because the engine will be running at very low revs, the compressor may not be building sufficient air pressure in its tanks to supply the braking system.
• Using red diesel because it is significantly cheaper than white: No, the use of red diesel in a road engine is illegal as it means that the correct level of duty has not been paid. Using red diesel can lead to the confiscation of the vehicle by HMRC and a very heavy fine or other monetary penalty.
• Keeping the rev counter in the green zone: Yes, this is the best answer here. Keeping the rev counter in the green zone means that the engine is working most efficiently.
5. What is the maximum permissible train weight of these vehicles when pulling a 3 axle semi-trailer in the UK?
Mark one answer
B
C
D
Correct Answer: D
Explanation: • 42 tonnes: No, this is not the maximum permitted weight for this vehicle combination.
• 40 tonnes: No, but this would be the maximum train weight for a 5 axle combination.
• 38 tonnes: No, although this weight is permitted for certain 2 + 2 articulated vehicle combinations meeting specific requirements.
• 44 tonnes: Yes, correct.
Explanation: • 42 tonnes: No, this is not the maximum permitted weight for this vehicle combination.
• 40 tonnes: No, but this would be the maximum train weight for a 5 axle combination.
• 38 tonnes: No, although this weight is permitted for certain 2 + 2 articulated vehicle combinations meeting specific requirements.
• 44 tonnes: Yes, correct.