Access Controls
Regulations by which access to a road facility from individual driveways, minor streets or major streets may be limited for the purpose of increasing roadway capacity and improving safety
Arterial
A roadway for through traffic with partial control of access linking major traffic generators and communities to regional highway facilities
At-Grade Intersection
The location at which two roadways cross and join at the same vertical elevation; access through the intersection may be controlled by traffic signals or stop/yield signs
Average Daily Traffic (ADT)
The total traffic volume passing a point or segment of a roadway in both directions during an average 24-hour period
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Background Traffic
In a traffic analysis, current traffic in accordance with recent traffic counts + traffic generated by pipeline development + growth in through traffic on the current road network + all roadway improvements which are fully funded by the state, the county or another party
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Capacity
On a roadway link, the maximum number of vehicles which can pass a given point during one hour under prevailing roadway and traffic conditions
Collector
A roadway with no control of access linking residential communities with the arterial system
Critical Lane Volume (CLV)
At an intersection, the sum of the critical movements in the north-south direction and the east-west direction
Critical Movement
At an intersection, the highest total of the through movement + its opposing left-turn movement in one direction on an hourly, per-lane basis (for example, the critical movement in the north-south direction is the higher of the northbound through movement + the southbound left-turn movement, computed on an hourly per-lane basis, and the southbound through movement + the northbound left-turn movement, computed on an hourly per-lane basis)
Cycle
The time period required for one complete sequence of traffic signal indications
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De Minimus Development
A development which generates five or fewer peak hour trips
Design Speed
The maximum safe speed for which the various physical features of the roadway are designed
Diverge Point
A location at which a single lane of traffic separates into two separate lanes, such as where a ramp leaves a highway
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Existing Traffic
In a traffic analysis, current traffic in accordance with recent traffic counts on the current road network
Expressway
A divided highway for through traffic with full control of access using grade-separated interchanges and some well-spaced at-grade intersections
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Freeway
A divided highway for through traffic with full control of access using grade-separated interchanges exclusively
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Grade Separation
A location where two roadways cross, with one passing over the other on an overpass, but lacking a direct connection via a system of ramps
Grade-Separated Interchange
A location where two roadways cross, with one passing over the other on an overpass, and with a system of ramps joining the two roadways
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Level of Service (LOS)
A qualitative measure using a sequence of letters from A through F to describe the quality of operational conditions within an intersection or a roadway link. The LOS standards used in the guidelines are based on the Prince George's County General Plan, approved by the County Council in 2002
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Merge Point
A location where a ramp enters a highway, allowing traffic to enter the main traffic flow on the highway
Modal Split
The percentage of people using a particular means of transport, such as auto, transit, or walk, to make a trip
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Operating Speed
The maximum average observed speed for a given set of roadway and traffic conditions
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Pass-By Trip
A trip generated by a land use which is already using the road adjacent to the land use; most frequently associated with land uses such as retail centers, service stations and fast-food restaurants
Peak Hour
The one-hour period of greatest utilization of a transportation facility; weekdays normally have two peaks, one in the morning and one in the afternoon
Peak Period
A three-hour period during which a transportation facility has significantly increased levels of use; includes the peak hour
Phase
A portion of a traffic signal cycle allocated to any traffic movement or combination of traffic movements
Pipeline Development
Development having an approved and valid Preliminary Plan of Subdivision, Final Plat or Record Plat
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Ramp
A length of roadway providing an exclusive connection between two highway facilities
Roadway Link
A segment of roadway between two points
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Through Traffic
Trips which begin and end outside of a given study area which pass through the study area
Total Traffic
In a traffic analysis, background traffic plus traffic generated by the development under consideration
Traffic Control Device
Any sign, signal, pavement marking or device placed or erected for the purpose of regulating, warning or directing traffic and/or pedestrians
Transportation Staff
The Transportation Planning staff located in the Transportation Planning Section (TPS) in the Countywide Planning Division of M-NCPPC, or such other staff persons who may be designated to advise the Planning Board on transportation issues
Trip
A one-way movement by a person or a vehicle having an origin and a destination
Trip Assignment
The process of allocating vehicle travel generated within a land parcel to each link of the roadway network
Trip Distribution
The process of estimating the direction of travel and the length of vehicle trips originating from or destined for the uses on a land parcel
Trip Generation
The process of estimating the number of vehicle trips originating from or destined for the uses on a land parcel
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Volume-to-Capacity Ratio (V/C)
A performance measure computed using the ratio of an actual roadway volume to the capacity of a roadway link
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Weaving Section
A highway section where the pattern of traffic entering and leaving at adjacent points of access results in vehicle paths crossing each other
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