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 )
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
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