Basic Vehicle Anatomy and Why It's Important to Fleet Maintenance Consulting
1. Front of the Bus:
- Headlights: Found on either side, toward the lower front. Headlights light the road ahead for the driver to safely operate the vehicle. Headlights also act as a safety beacon of sorts for other drivers on the road. For a vehicle to be in compliance, both headlights must work, be aimed in the right direction and be capable of switching between high and low beam.
- Grille: Center front, covering the radiator. While grilles are minimized on buses that have rear engines, they still can provide essential air to various functions like ventilation or HVAC intake. On vehicles with forward engines, they provide protection from direct impact for heat exchangers like the radiator, charge-air coolers, some HVAC applications, and help direct air to cool the other front engine compartment components, in a addition to allowing air to flow freely into the air filter housing.
- Windshield: Large glass at the front, providing visibility for the driver. These are among the most important pieces of equipment on the front of the bus. Obviously, the windshield provides deflection of wind for the entire vehicle - otherwise buses would be incredibly less efficient and act more like parachutes than a vehicle used for mass transportation. In cold weather, the windshield is most responsible for creating the barrier between the elements and passengers. Windshields must be free of cracks and chips that can obscure a driver's vision, and windshield wipers and washers must be operational so that if the driver needed to clear the windshield of debris or rain, she could do so and the windshield would be sufficiently cleared to see the road and hazards ahead.
- Destination Display: Usually above the windshield, displaying the bus's route or destination. The destination sign is an essential tool to signal the bus's destination or another message to riders and others on the road. A working destination sign decreases the time a driver must spend at a stop, and assures riders that they are boarding the correct bus for their desired route. Destination signs can also be used to signal emergencies. For example, if a bus is overtaken by a hijacker, the driver can push a button that may enable the sign to display a message like, "Call 911."
2. Sides of the Bus:
- Entrance and Exit Doors: Typically on the right side (in countries with left-hand traffic) or left side (in countries with right-hand traffic). 40' transit buses will have a front and rear passenger door, while shorter shuttle buses commonly used in airports may only have a single front entrance. Doors are opened with a switch operated by the driver, and modern doors are equipped with a sensitive strip of rubber that prevents the doors from remaining closed in the event that.an object more than 1 inch in diameter becomes stuck.
- Windows: Large, often rectangular, and run along the length of the bus on both sides. Windows serve multiple purposes on transit buses - shade and insulation from the outside elements, discretion and privacy for riders, and a large viewing area so riders can see the sights as they are on their route. They also can serve an important safety purpose - emergency exits.
- Fuel Door and Cap: Positioned usually towards the rear on one of the sides, covering the entrance to the fuel tank. A fuel door provides essential access for maintenance workers to fill the fuel tank(s) with gasoline, diesel, CNG, or hydrogen. A similar door may also provide access to a charging port for a battery electric bus. In any case, a working door that is properly labeled and equipped is required to keep the bus making revenue.
- Exterior Mirrors: Mounted near the front on both sides, aiding the driver in viewing the sides and rear of the bus. Exterior mirror can vary in size depending on the size and specification of the bus. All buses are equipped with both convex and flat mirrors for blind spots, and most modern transit buses have exterior mirrors that can be put into position while the driver sits in the driver seat.
3. Rear of the Bus:
- Tail Lights: Found on either side of the bus's rear. Tail lights are an essential safety item on the back of the bus. When illuminated, they provide visibility of the entire rear of the bus from right to left, and are typically operated by the same switch the turns on the headlights. Some tail lights also incorporate the brake lights, which are illuminated when the driver presses down the brake pedal to slow the vehicle. This serves as a warning to other drivers that the vehicle is slowing down, and they should also. Both brake lights and tail lights must be operational in order for the bus to be in compliance with local and federal DOT regulations.
- Engine Compartment: Many transit buses have rear engines, so there's often a large compartment or panel here. Nearly all transit buses have one or two doors that open up to expose the components housed in the rear of the bus. In some cases the lower door will open to expose an engine, but in more recent years have seen a shift toward more Battery Electric Vehicles (BEV) which do not have engines, but large electrical components. There may also be another compartment above the engine where the main HVAC unit is kept. Transit bus engine compartments must by design have operational lights, pressure gauges, and a rear start switch.
- Exhaust: Depending on the design, the exhaust tip could be located towards the bottom, either on one of the sides or at the rear. Modern Internal Combustion Engine (ICE) buses have additional emissions abatement equipment that require additional space, running up the side of the bus, with an exhaust tip at the top. .
- Bumper: Lower body, under the engine compartment door. Another essential safety feature, the bumper is responsible for absorbing the shock of impact by a vehicle approaching from the rear. A bumper that is improperly mounted, or has been in a small accident and not repaired, will not act as designed, and can cause additional injury to the driver or passengers riding the bus.
4. Top of the Bus:
- Emergency Exit: All transit buses must have two roof hatches. Most roof hatches can serve a dual purpose - ventilation and egress in the event of a roll over.
- Air Conditioning Units: If equipped, usually located on the roof towards the center or rear. To free up space in the back of the bus for extra seating, many buses are built with roof-mounted HVAC units. These units can provide better cooling throughout the entire bus when compared to rear-mount units because they are often centrally located, meaning cooled air has less distance to travel before exiting the duct into the passenger area.
5. Undercarriage/Chassis:
- Wheels: Four or more, depending on the bus size. Dual wheels are often found on the rear axle. Wheels on the bus go 'round and 'round. Wheel are responsible for transferring mechanical power produced by the propulsion system to the pavement, thus moving the bus in the desired direction. Wheels (tires, rims, bearings, brakes) absorb all of the bumps in the road, while the suspension does its best to keep the bus's wheels in touch with the pavement.
- Suspension System: Found near the wheels, it's the system of springs, shock absorbers, and linkages that connects the bus to its wheels. Suspension maintenance is underrated as far as safety goes. Shock absorbers can look "ok" on the outside, but have no gas left internally, leading to lack of contact with the ground and loss of traction during emergency braking.
- Transmission: Located between the engine and the drive wheels, it transmits power from the engine to the drive wheels. A properly maintained transmission can decrease fuel consumption. The transmission is a precision piece of equipment, and newer transmission with higher gear counts can be finicky if improperly maintained. Most manufacturers are happy to help train your maintenance staff on their specific secret sauce if you ask.
- Exhaust System: Runs from the engine towards the back, culminating in the exhaust pipe. Exhaust systems are often overlooked. They begin with the engine's exhaust headers and can run either the length or height of the bus depending on the engine's location. Almost all modern exhaust systems have a catalytic converter - an inline device that converts carbon emissions to a less harmful emission using a combination of metals and sensors.
- Fuel Tank/Energy Storage: Typically positioned towards the center or rear of the bus on gas or diesel applications, or on the roof for CNG, Hydrogen Fuel Cell, and battery electric applications. All of the energy used for propulsion is stored in these places.
6. Inside the Bus:
- Driver's Cabin: Front-left position (or front-right, depending on the country). Contains the steering wheel, instrument panel, controls, and driver seat. The driver's are has evolved over the years to help the driver operate the vehicle more efficiently and safely. Drivers behavior can now be monitored by equipment often found in or near the driver's area, creating a much safer and more accountable overall. That said, this area is used the most and often will have broken or non-functioning buttons and indicators as a result of general wear and tear.
- Passenger Seats: Rows of seating, often in pairs, running along the length of the bus. This is perhaps the most essential part of the bus, since the bus's intended use is to move people. While we generally would prefer people sit in seats, there may be instances when all of the seats are in use and riders need to stand use stanchions and handrails to stabilize themselves. Seats can come in a few different configurations based on the customer spec. Some seats are designed with no pad or fabric in order to enable easier cleaning, while some larger commuter buses may have full captains chairs wrapped in luxurious leather.
- Aisle: Central walkway allowing passengers to move from the front to the rear. The aisle is place where people move lengthwise throughout the bus, and generally runs down the center of the bus. A clear aisle helps passengers quickly enter the bus to find their seats and exit the bus once they reach their destination. Generally, aisles are wide enough to allow a wheelchair to move to the designated wheelchair securement area, but can also be more narrow in other parts of the bus designed to accommodate more passenger seating.
- Stanchions and Handrails: Vertical poles and overhead rails for standing passengers to hold onto. Stanchions are a major touch point in any bus - even when the bus is not in motion. Stanchions are attached at the floor and ceiling, while handrails typically are in the overhead and are attached both to the overhead and between stanchions. Because these are major touchpoint, they must be cleaned regularly and inspected for sharp edges and secure attachment. An unsecured stanchion has the potential to cause a rider to become injured if it becomes unattached.
- Stop Request Buttons or Cords: Found near seats or overhead, allowing passengers to signal the driver to stop. Stop requests are another essential piece of equipment on all transit buses. A stop request is a much more convenient way for a driver to become aware that a passenger desires to exit the bus at the next stop. It's also a discreet way for a passenger to exit the bus without disturbing other passengers.
- Headlights: Found on either side, toward the lower front. Headlights light the road ahead for the driver to safely operate the vehicle. Headlights also act as a safety beacon of sorts for other drivers on the road. For a vehicle to be in compliance, both headlights must work, be aimed in the right direction and be capable of switching between high and low beam.
- Grille: Center front, covering the radiator. While grilles are minimized on buses that have rear engines, they still can provide essential air to various functions like ventilation or HVAC intake. On vehicles with forward engines, they provide protection from direct impact for heat exchangers like the radiator, charge-air coolers, some HVAC applications, and help direct air to cool the other front engine compartment components, in a addition to allowing air to flow freely into the air filter housing.
- Windshield: Large glass at the front, providing visibility for the driver. These are among the most important pieces of equipment on the front of the bus. Obviously, the windshield provides deflection of wind for the entire vehicle - otherwise buses would be incredibly less efficient and act more like parachutes than a vehicle used for mass transportation. In cold weather, the windshield is most responsible for creating the barrier between the elements and passengers. Windshields must be free of cracks and chips that can obscure a driver's vision, and windshield wipers and washers must be operational so that if the driver needed to clear the windshield of debris or rain, she could do so and the windshield would be sufficiently cleared to see the road and hazards ahead.
- Destination Display: Usually above the windshield, displaying the bus's route or destination. The destination sign is an essential tool to signal the bus's destination or another message to riders and others on the road. A working destination sign decreases the time a driver must spend at a stop, and assures riders that they are boarding the correct bus for their desired route. Destination signs can also be used to signal emergencies. For example, if a bus is overtaken by a hijacker, the driver can push a button that may enable the sign to display a message like, "Call 911."
2. Sides of the Bus:
- Entrance and Exit Doors: Typically on the right side (in countries with left-hand traffic) or left side (in countries with right-hand traffic). 40' transit buses will have a front and rear passenger door, while shorter shuttle buses commonly used in airports may only have a single front entrance. Doors are opened with a switch operated by the driver, and modern doors are equipped with a sensitive strip of rubber that prevents the doors from remaining closed in the event that.an object more than 1 inch in diameter becomes stuck.
- Windows: Large, often rectangular, and run along the length of the bus on both sides. Windows serve multiple purposes on transit buses - shade and insulation from the outside elements, discretion and privacy for riders, and a large viewing area so riders can see the sights as they are on their route. They also can serve an important safety purpose - emergency exits.
- Fuel Door and Cap: Positioned usually towards the rear on one of the sides, covering the entrance to the fuel tank. A fuel door provides essential access for maintenance workers to fill the fuel tank(s) with gasoline, diesel, CNG, or hydrogen. A similar door may also provide access to a charging port for a battery electric bus. In any case, a working door that is properly labeled and equipped is required to keep the bus making revenue.
- Exterior Mirrors: Mounted near the front on both sides, aiding the driver in viewing the sides and rear of the bus. Exterior mirror can vary in size depending on the size and specification of the bus. All buses are equipped with both convex and flat mirrors for blind spots, and most modern transit buses have exterior mirrors that can be put into position while the driver sits in the driver seat.
3. Rear of the Bus:
- Tail Lights: Found on either side of the bus's rear. Tail lights are an essential safety item on the back of the bus. When illuminated, they provide visibility of the entire rear of the bus from right to left, and are typically operated by the same switch the turns on the headlights. Some tail lights also incorporate the brake lights, which are illuminated when the driver presses down the brake pedal to slow the vehicle. This serves as a warning to other drivers that the vehicle is slowing down, and they should also. Both brake lights and tail lights must be operational in order for the bus to be in compliance with local and federal DOT regulations.
- Engine Compartment: Many transit buses have rear engines, so there's often a large compartment or panel here. Nearly all transit buses have one or two doors that open up to expose the components housed in the rear of the bus. In some cases the lower door will open to expose an engine, but in more recent years have seen a shift toward more Battery Electric Vehicles (BEV) which do not have engines, but large electrical components. There may also be another compartment above the engine where the main HVAC unit is kept. Transit bus engine compartments must by design have operational lights, pressure gauges, and a rear start switch.
- Exhaust: Depending on the design, the exhaust tip could be located towards the bottom, either on one of the sides or at the rear. Modern Internal Combustion Engine (ICE) buses have additional emissions abatement equipment that require additional space, running up the side of the bus, with an exhaust tip at the top. .
- Bumper: Lower body, under the engine compartment door. Another essential safety feature, the bumper is responsible for absorbing the shock of impact by a vehicle approaching from the rear. A bumper that is improperly mounted, or has been in a small accident and not repaired, will not act as designed, and can cause additional injury to the driver or passengers riding the bus.
4. Top of the Bus:
- Emergency Exit: All transit buses must have two roof hatches. Most roof hatches can serve a dual purpose - ventilation and egress in the event of a roll over.
- Air Conditioning Units: If equipped, usually located on the roof towards the center or rear. To free up space in the back of the bus for extra seating, many buses are built with roof-mounted HVAC units. These units can provide better cooling throughout the entire bus when compared to rear-mount units because they are often centrally located, meaning cooled air has less distance to travel before exiting the duct into the passenger area.
5. Undercarriage/Chassis:
- Wheels: Four or more, depending on the bus size. Dual wheels are often found on the rear axle. Wheels on the bus go 'round and 'round. Wheel are responsible for transferring mechanical power produced by the propulsion system to the pavement, thus moving the bus in the desired direction. Wheels (tires, rims, bearings, brakes) absorb all of the bumps in the road, while the suspension does its best to keep the bus's wheels in touch with the pavement.
- Suspension System: Found near the wheels, it's the system of springs, shock absorbers, and linkages that connects the bus to its wheels. Suspension maintenance is underrated as far as safety goes. Shock absorbers can look "ok" on the outside, but have no gas left internally, leading to lack of contact with the ground and loss of traction during emergency braking.
- Transmission: Located between the engine and the drive wheels, it transmits power from the engine to the drive wheels. A properly maintained transmission can decrease fuel consumption. The transmission is a precision piece of equipment, and newer transmission with higher gear counts can be finicky if improperly maintained. Most manufacturers are happy to help train your maintenance staff on their specific secret sauce if you ask.
- Exhaust System: Runs from the engine towards the back, culminating in the exhaust pipe. Exhaust systems are often overlooked. They begin with the engine's exhaust headers and can run either the length or height of the bus depending on the engine's location. Almost all modern exhaust systems have a catalytic converter - an inline device that converts carbon emissions to a less harmful emission using a combination of metals and sensors.
- Fuel Tank/Energy Storage: Typically positioned towards the center or rear of the bus on gas or diesel applications, or on the roof for CNG, Hydrogen Fuel Cell, and battery electric applications. All of the energy used for propulsion is stored in these places.
6. Inside the Bus:
- Driver's Cabin: Front-left position (or front-right, depending on the country). Contains the steering wheel, instrument panel, controls, and driver seat. The driver's are has evolved over the years to help the driver operate the vehicle more efficiently and safely. Drivers behavior can now be monitored by equipment often found in or near the driver's area, creating a much safer and more accountable overall. That said, this area is used the most and often will have broken or non-functioning buttons and indicators as a result of general wear and tear.
- Passenger Seats: Rows of seating, often in pairs, running along the length of the bus. This is perhaps the most essential part of the bus, since the bus's intended use is to move people. While we generally would prefer people sit in seats, there may be instances when all of the seats are in use and riders need to stand use stanchions and handrails to stabilize themselves. Seats can come in a few different configurations based on the customer spec. Some seats are designed with no pad or fabric in order to enable easier cleaning, while some larger commuter buses may have full captains chairs wrapped in luxurious leather.
- Aisle: Central walkway allowing passengers to move from the front to the rear. The aisle is place where people move lengthwise throughout the bus, and generally runs down the center of the bus. A clear aisle helps passengers quickly enter the bus to find their seats and exit the bus once they reach their destination. Generally, aisles are wide enough to allow a wheelchair to move to the designated wheelchair securement area, but can also be more narrow in other parts of the bus designed to accommodate more passenger seating.
- Stanchions and Handrails: Vertical poles and overhead rails for standing passengers to hold onto. Stanchions are a major touch point in any bus - even when the bus is not in motion. Stanchions are attached at the floor and ceiling, while handrails typically are in the overhead and are attached both to the overhead and between stanchions. Because these are major touchpoint, they must be cleaned regularly and inspected for sharp edges and secure attachment. An unsecured stanchion has the potential to cause a rider to become injured if it becomes unattached.
- Stop Request Buttons or Cords: Found near seats or overhead, allowing passengers to signal the driver to stop. Stop requests are another essential piece of equipment on all transit buses. A stop request is a much more convenient way for a driver to become aware that a passenger desires to exit the bus at the next stop. It's also a discreet way for a passenger to exit the bus without disturbing other passengers.