O

 

 

OBLIQUE COLLISION

An oblique collision is a collision between two vehicles in which the velocities of the vehicles prior to collision were not parallel.

 

OBSOLESCENCE PREVENTION

A system that provides data (via computer) compiled from the BAO Obsolescence Reporting System, the Kentucky truck releasing system, BAO general office releasing system, and the assembly plants inventories for purposes of identification of parts representing a potential obsolescence risk.

 

OBTUSE ANGLE

An angle that is greater than a right, 90 degree angle

 

OCCUPANT

Any person who is in or upon a motor vehicle in transport, including the driver, passengers and persons riding on the exterior of the motor vehicle.

 

OCCUPANT KINEMATICS

An analysis of the motion of occupants during a collision for the purpose of correlating occupant injuries to interior vehicle contact damage, and determination of relative seating position

 

OCCUPANT PROTECTION

The degree of crashworthiness of a vehicle.

 

OCCUPANT STRETCH

The distance traveled by the occupant's appendages after restraint system loading is achieved.  This distance varies for different appendages and is most important for the head.  Occupant stretch can be as little as 0cm for an airbag restraint system or 50 cm (20 in) for some child car seats.

 

OCTANE

Rating applied to gasoline.

 

OD

(Operation Description Sheets) Description of assembly operations used by assembly plants.

 

ODD

(Outside Design and Development) A part, assembly or vehicle sub-system designed, developed, tooled and produced by an outside supplier. (Chrysler derived)

 

ODDO

(Operation Description Sheet Distribution Order) Used for distribution of O/Ds to assembly plants.

 

ODOMETER

An instrument that measures the total number of miles traveled by a vehicle.

 

Odometer
Odometer value at the time of the data extraction ( Detroit )

 

OEM

Original Equipment Manufacturer. Refers to the truck manufacturer.

 

OFF LINE

Area designated for sub-assembly operations not performed on main body conveyer.

 

OFF TRACKING

A term used to refer to the path taken by the rear end of a vehicle when turning.  The path of the rear wheels is shorter than the path of the front.  The off-track is much shorter on a tractor-trailer.  Drivers must compensate for off-tracking in turns and on curves.

 

OFF TRACKING OFFSET

Offset is the measure of the degree to which the centerlines of two vehicles in a head-on, or rear end, collision do not coincide

 

OFF-HIGHWAY

Refers to trucking usually performed on private logging roads, construction sites, mining locations, etc. Off-highway trucks are always constructed much more ruggedly as they are subjected to severe stresses.

 

OFFICE CAR

Car used by railway officials while traveling.

 

OGEE

A long, S-shaped curve.

 

OHM

A unit of measurement of electrical resistance that allows an electromotive force of one volt to produce a current flow of one ampere.

 

OHMMETER

An instrument that measures the amount of resistance (in Ohm's) in a circuit or in an electrical component outside the circuit.

 

OHM'S LAW

Voltage (in volts) is equal to the current (amps) multiplied by resistance (ohms).  E = IR  (E = volts or voltage;  I = amperes or current;  R = ohms or resistance).

 

OIL CANNING

Loose or extra metal in large panel.

 

OIL FIELD BODY

Heavily constructed platform type truck body equipped with instruments for oil defiling.

 

OIL FILTER

Device for cleaning and purifying the engine lubricating oil.

Oil Monitor
User configurable service interval reminder in ProDriver. ( Detroit )

Oil Pressure
Pressure of the engine oil in the lubrication system. ( Detroit )

OIL PRESSURE GAUGE

Measures pressure of engine lubricating oil. Pressure varies with engine speed and oil viscosity.  Sudden drop of pressure indicates a problem.

 

OIL SEAL

A device used to retain lubricant in the bearing area of the wheel.  The sealing part of the seal is usually made of a resilient material such as synthetic rubber or leather, which is assembled into a wheel or the hub bore.

 

ON THE GROUND

(slang) Railroad wheels of a train on the ties, not on the rails, as derailed in train.

 

ON-OFF ROAD VEHICLE

A motor vehicle designed for use on irregular terrain (off-road) as well as on the roadway.  Typical of this is timber haulage wherein logs are hauled on forest tracks or roads and then on the highway to a mill or rail siding. Also livestock haulage when the loading point is some distance along a rough road, and the load is then moved to abattoirs or elsewhere on a highway or similar road. Such vehicles typically have a four wheel drive capability and, as a result of design constraints and ground clearance requirements, have a higher center of mass than cars.  Only those vehicles based on truck components are categorized as on-off road vehicles in NASS.

 

OPEN TOP

(trailer)    A truck or trailer body with sides but without any permanent top, often used for heavy equipment that mutt be lowered into place by crane.  Nicknamed rag top.

 OPEO

Overseas Product Engineering Office

 

OPERATIONAL FACTOR

Functional failures of the highway transportation system that contribute to the cause of a traffic accident.  The failures may be malfunctions of perception, decision or performance in trip planning, driving strategy, or evasive tactics.

 

OPERATOR

A motor vehicle driver.

 

OPINION

Belief based on grounds insufficient for certainty; conclusions, inferences, and conjectures concerning events and conditions which were not sufficiently well observed or recorded to be accepted facts.

 

OPPOSING SIGNALS

Signals which govern movements in opposite directions on the same track.

 

OPPOSITE DIRECTION COLLISION

A collision between two traffic units moving in opposite directions on the same roadway.  Sometimes called head-on collisions.

 

OPTICS

The quantitative measure of brightness of a light source or an illuminated surface, equal to luminous flux per unit solid angle emitted per unit projected on the surface.

Optimized Idle
Detroit Diesel DDEC feature to reduce idle time while, maintaining engine temperature, battery voltage, or cab temperature. ProDriver records Optimized Idle data for reporting in ProDriver Reports. ( Detroit )

Optimized Idle Time, Active
The total time during which Optimized Idle is active. This time is the sum of Run time and any time the engine is not running but the system is active. ( Detroit )

Optimized Idle Time, Battery
The time the engine is running in response to the battery voltage dropping below 12.2 volts DC. After the engine runs for 20 minutes in this mode, the engine shuts off and the time in this category stops collecting. ( Detroit )

Optimized Idle Time, Continuous
The time the engine is running in Continuous Mode. This Continuous mode is entered if the truck body skin temperature sensor is less than 24 F or greater than 100 F and the thermostat set point is not satisfied. The engine will run continuously until the external temperature moves out of the extreme bands and/or the thermostat is satisfied. ( Detroit )

Optimized Idle Time, Engine Temp.
The time the engine is running in response to the engine oil temperature dropping below 60 F. When the oil temperature reaches 104 F, the engine shuts off and the time in this category stops collecting. ( Detroit )

Optimized Idle Time, Extended Idle
The time the engine is running in Extended Idle Mode. This mode is entered if the thermostat set point is not satisfied within 45 minutes and the external temperature is not in the extreme temperature bands. The engine runs in a cycle of on for 15 minutes and off for 15 minutes. ( Detroit )

Optimized Idle Time, Run
The time the engine is running for any reason under Optimized Idle. This time is the sum of the sub-category times: Battery , Engine Temp., Thermostat, Extended Idle and Continuous. ( Detroit )

Optimized Idle Time, Thermostat
The time the engine is running in response to a request from the in-cab thermostat. When the thermostat set point is satisfied, the engine shuts off and time in this category stops collecting . ( Detroit )

OPTIMUM ANGLE

(o): The launch angle for a vault requiring the minimum  velocity for the distances involved.

 

ORDERS

Train orders, telegraph or telephoned to an operator from a dispatcher, delivered to the conductor for himself and crew.

 

OSCAR

The two-dimensional movable manikin used by designers and engineers to represent the size and shape of most drivers or passengers and the limitations of their movements.

 

OSCILLATORY INSTABILITY

Oscillatory instability exists if a small temporary disturbance or control input causes and oscillatory vehicle response without oscillation.

 

OSCILLOGRAPH

A recording instrument electronically operated to record a trace of one or more channels from sending units.

 

OSHA

Federal Occupational Safety and Health Administration

 

OSM

Outside of Metal

 

OUTER CUSHION

The primary air cushion restraint for the occupant.

 

OUT-OF-SEQUENCE CONDITION

In the initial start mode of the ignition interlock system, a condition where the belt is fastened before the seat is occupied, which prohibits starting.

 

OUT-OF-SERVICE DRIVER

Driver declared out-of-service by a government representative because of hours of service violations.  The out-of-service form indicates when such a driver may commence driving again.

 

OUT-OF-SERVICE VEHICLE

A vehicle that cannot pass the government safety inspection and is declared out-of-service.  Cannot be driven until the problem or problems are corrected or repaired.

 

OUTRIGGERS

Devices used for increasing width of low boy trailer.

 

OUTSERT

Reinforcing metal channel pressed over main frame rail.

 

OUTSIDE DIAMETER

The maximum diameter of the new unloaded tire inflated to the normal recommended pressure and mounted on a specified rim.  (See Airplane Section, Tire and Rim Association Year Book.)

 

OVER DEFLECTED

A condition of a tire in which the pressure on the road is greater at the edges of the tread than in the middle; an overloaded or under inflated tire condition.

 

OVER DRIVING THE HEADLIGHTS

Driving at a speed that will not permit you to stop your vehicle within the distance you see ahead.

 

OVER FREIGHT

Freight separated from its waybill and displaying no identifying marks.  See astray freight.

 

OVER ON BILL

Freight in excess of that specified by the freight bill or the bill of lading.

 

OVER REACTION

A driver's evasive reaction to a hazardous situation that produces another, or additional, hazard.  Overreaction is usually a matter of too much steering at high speed, and often results in yaw.

Over Rev Time
Time accumulated when the engine RPM is greater than the setup parameter RPM Limit, in HH:MM:SS format. ( Detroit )

Over Rev Percentage
Over Rev Time divided by Trip Time. ( Detroit )  

OVER STEER

A characteristic of a motor vehicle that results in a tendency to steer toward the inside of a curve, especially at high speed.  Motor vehicles with more weight on the rear wheels than on the front, and with too little pressure in the rear tires are like it. to over steer.

 

OVER THE ROAD

(OTR) See line haul operation.

 

OVER WITHOUT BILL

When a terminal has freight without its bill of lading or freight bill.

 

OVER, SHORT AND DAMAGED

(OS&D)  Discrepancies between freight on hand and freight shown on the bill.  Freight not covered by billing is "over".  If some is missing, it is "short".  Freight received in bad condition, is "damaged".  Freight agents file an OS&D report showing these discrepancies.

Overall Economy
Trip Distance divided by Trip Fuel. ( Detroit )

OVERALL LENGTH
(OAL) Front-to-rear measurement of vehicle, including bumpers, etc  

OVERALL RATIO

Ratio of the lowest to the highest forward gear in the transmission.

 

OVERALL STEERING RATIO

The rate of change of steering wheel angle at a given steering wheel trim position, with respect to change in average steer angle of a pair of steered wheels, assuming an infinitely stiff steering system with no roll of the vehicle.

 

OVERALL VEHICLE WIDTH

(OAW) Overall vehicle width means the nominal design dimension of the widest part of the vehicle, exclusive of signal lamps, marker lamps, outside rearview mirrors, flexible fender extensions, and mud flaps, determined with doors and windows closed ant the wheels in the straight-ahead position

 

OVERALL WIDTH

(of a tire) Overall width is the linear distance between the exteriors of the side walls of an inflated tire, including elevations due to labeling, decorations, or protective bands or ribs

 

OVERALL HEIGHT

(OAH) Height from ground to highest point of vehicle.

 

OVERBEND

Forming a part beyond design shape.

 

OVERDRIVE

Refers to a condition in which the vehicle's transmission is in a gear having a ratio greater than 1:1, that is, the engine crankshaft turns at a slower rate than the vehicle drive shaft.  Opposite of under drive.  (Also see direct drive).

 

OVERHANG, FRONT

Distance from centerline of front axle to front of vehicle or BA dimension.

 

OVERHANG, REAR

Distance from centerline of rear axle to rear of vehicle frame or AE dimension.

 

OVERLAP

The measurement of the extent of engagement of two objects in contact with one another

 

OVERLAY

A sheet of translucent paper laid over an original drawing to sketch an alternate version or design. Used for comparing two or more designs.

 

OVERRIDE SYSTEM

An underhood device which allows one free start (regardless of the belt condition) for each operation of the device.

 

OVERRIDING THE GOVERNOR (OVERSPENDING)

When the weight of the vehicle drives the engine beyond governed speed.  Happens on hills when vehicle is not in a low enough gear and is not supplemented as necessary by light, steady brake application.  The governor does not control the engine speed when the vehicle is driving the engine.

 

OVERSIZED VEHICLE

Any vehicle whose weight And or dimensions exceeds State regulations.

 

Overspeed
A, B See Speeding Time> MPH A,B. ( Detroit )

 

OVERSTEER

A vehicle is oversteer at a given trim if the ratio of the steering wheel angle gradient to the overall steering ratio is less than the Ackerman steer angle gradient.

 

OVERTURNING COUPLE

The overturning moment on the vehicle with respect to a central, longitudinal axis in the road plane due to lateral acceleration and roll acceleration.

 

OVERTURNING COUPLE DISTRIBUTION

The distribution of the total overturning couple between the front and rear suspensions expressed as the percentage of the total.

 

OWNER OPERATOR

A trucker who both owns and drives his tractors

References

Detroit Diesel

Caterpillar User's Manual