Note:
a - These definitions are modified from the Glossary of TAC Geometric Design Guide for Canadian Roads - June 2017.
b - These definitions are in addition to the Glossary of TAC Geometric Design Guide for Canadian Roads - June 2017.
A. B. C. D. E. F. G. H. I. J. K. L. M. N. O. P. Q. R. S. T. U. V. W. Y. Z
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A.
Acceleration Lane
An auxiliary lane to enable a vehicle entering a roadway to increase speed to merge with through traffic as applied at channelized intersections, or as a speed-change lane at interchanges.
Access Control
See “Controlled Access”.
Access Management
The management of the location and basic dimensions of access to property, from a roadway.
Accident
Not used. See “Collision”
Adverse Crowna
A section with the cross-slope removed to a zero slope. This change in cross-slope is accomplished over the tangent runout.
Ancillary Space
The part of the roadway, between the travel lanes and the curb or pavement edge.
Approach Nose
The end of a median or island that faces approaching traffic.
Approach Taper
The taper required in advance of an intersection to shift the through lanes laterally to the right to provide the width for a left-turn auxiliary lane.
Area of Concernb
An area within the roadside environment and within the desirable clear zone that has a higher severity index than a barrier system.
Area of Contents
An object or roadside condition that may warrant safety treatment.
Arterial Road
A road primarily for through traffic.
Assumed Speedb
The assumed speed for calculating minimum stopping sight distance is based on the 85th percentile wet weather speeds as derived from a traffic study.
Assured Passing Opportunityb
A condition in which a vehicle can safely pass another without restriction either by visibility or opposing traffic.
Auxiliary Lanea
A lane in addition to, and placed adjacent to, a through lane intended for a specific maneuver such as turning, merging, diverging, weaving, and for slow vehicles, but not parking.
Annual Average Daily Traffic (AADT)
The total volume of traffic passing a point or segment of a roadway, in both directions for one year, divided by the number of days in the year.
Average Daily Trafficb (ADT)
The total volume of traffic during a given time period (in whole days) greater than one day and less than one year divided by the number of days in that time period.
B.
Back Slopeb
Where the roadway is in cut, the slope between the drainage channel and the natural ground is referred to as a back slope.
Barrierb
A device which provides a physical limitation through which a vehicle would not normally pass. It is intended to contain or redirect an errant vehicle of a particular size range, at a given speed and angle of impact.
Barrier Systemb
A system which provides a physical limitation through which an errant vehicle would not normally penetrate or vault over. It is intended to contain or redirect an errant design vehicle of a particular size range, at a given speed and angle of impact.
Barrier Transition
A method by which a change in longitudinal barrier type provides continuous protection to adjacent traffic.
Barrier Warrant
A criterion that identifies a potential need for a traffic barrier.
Bifurcation Pointb
The point or area at which a roadway divides into two branches or parts.
Bike Lane
A lane intended for the exclusive use of bicycles, within a roadway used by motorized vehicles.
Bike Path
A bicycle facility physically separated from roadways, where motor vehicle traffic, except maintenance vehicles, is excluded.
Bike Route
Any roadway signed specifically to encourage bicycle use.
Bikeway
A roadway, or part of a roadway, intended for the use of bicycles, either exclusively or shared with other vehicular traffic or pedestrians.
Border
The area adjoining the outer edge of the sidewalk.
Boulevarda
A reserve which separates the roadway and sidewalk. It provides some protection to the pedestrian and can accommodate street accessories such as traffic signs the fire hydrants. It is a suitable location for underground utilities and may be used for illumination poles. It also provides an area for snow storage.
Brake Reaction Timeb
The time that elapses from the instant the driver decides to take remedial action, to the instant that remedial action begins (contacts brake pedal).
Braking Distance
The distance travelled from the instant that braking begins to the instant the vehicle comes to a stop.
Break Point
The outer extremity of the shoulder where the side slope begins.
Breakaway
A design feature that allows a device such as a sign, luminaire or traffic signal support to yield or separate upon impact.
Bridge Railing
A longitudinal barrier whose primary function is to prevent an errant vehicle from going over the side of the bridge structure.
Broken Back Curve
An arrangement of curves in which a short tangent separates two curves in the same direction.
Building Line
A line prescribing the nearest limits for the erection of buildings in relation to a roadway.
Bulbing
A widened portion of the median or outer separation, usually at an intersection.
Bullnoseb
Location where edge of highway and edge of ramp meet each other. Bullnose may include or exclude curb and gutter.
Bus Only lane (BOL), busway, or transitwayb
Managed lane dedicated primarily to buses
C.
Centreline Kilometres
A linear measurement on the length of a highway or network of highways without considering the number of lanes.
Channelization
The separation and direction of traffic movements and pedestrians into defined paths at an at-grade intersection through the use of geometric features, pavement markings and traffic control devices.
Choker (Curb Bulb)
A narrowing of a roadway, either at an intersection or mid-block, in order to reduce the width of the roadway surface.
Clear Zonea
The unobstructed, traversable area provided beyond the edge of the through travelled way available for use by errant vehicles. The clear zone includes shoulders, bike lanes, and auxiliary lanes, except those auxiliary lanes that function like through lanes. The clear zone also includes recoverable slopes, and non-recoverable slopes with a clear run-out area. The selected clear zone width is dependent upon traffic volumes and design speed, and roadside geometry.
Climbing Lane
A lane added on the right side of a roadway on an upgrade intended for use by trucks and other slow vehicles to discourage these vehicle types from using the through lanes.
Collector Lanesa
Those lanes of an express/collector system separated from express lanes by an outer separation.
Collector Road
A road on which traffic movement and access have similar importance.
Collision
An event in which travel by a vehicle results in the vehicle being in an inappropriate location, or in an appropriate location at an inappropriate time, culminating in unwanted contact with a fixed object, vehicle, other roadway user or other obstacle.
Collision-Free
Circumstances under which a collision will never occur, i.e. "absolute" safety.
Comment Status
We review all the comments we receive and decide whether they can be posted for others to see. When you submit your comment, it will be ready for review until someone has decided if it can be posted. A comment is approved if it can be posted online. We will not publish your comment for others to see if it:
- contains inappropriate or offensive content (language or links)
- is off topic
- contains personal information
This will be noted in the comment status. There is no time limit for the review stage.
Commercial Motor Vehicle (CMV)b
A motor vehicle having a permanently attached truck or delivery body, including fire apparatus, busses, and truck tractors and trailers (combination units) used for hauling purposes on the highways, and requiring a Commercial Vehicle Operating Registration (CVOR)
Consultation
This is the process of asking for your feedback on what we're doing with regards to technical documents underway. We first post a proposal on the portal that explains what we want to do. You usually have a minimum amount of days to comment. We then make a decision and let you know how we took your feedback into consideration.
Continuous Right-Turn Auxiliary Lane
A right-turn lane that is continuous for a significant distance serving a number of driveways.
Controlled Access
The condition where the opportunity for access to a roadway is controlled by public authority.
Corner Clearance
The distance between the near curb of a street intersection and the near edge of a driveway throat or public lane.
Crash
Not used. (See “Collision”)
Crash Cushiona
An energy attenuating system which provides a physical limitation through which an errant vehicle would not normally penetrate. It is intended to contain or redirect or stop an errant design vehicle of a particular size range, at a given speed and angle of impact.
Crest Vertical Curve
A vertical curve having a convex shape in profile viewed from above.
Criterion
A value, determined either by mathematical relationships or by experience, that represents the degree of excellence required for a particular application, acknowledged as appropriate for that application where prevailing conditions are normal and typical, recognizing that in atypical circumstances some variation may be appropriate. It may be regarded as a basis for assessing existing designs and formulating opinion on their quality, but is not treated as a rigid value to which there is any obligation for designs to conform.
Cross Fall (Cross Slope)
The average grade between edges of a cross section element.
Crossoverb
Any portion of a roadway distinctly indicated for pedestrian crossing by signs on the highway and lines or other markings on the surface of the roadway as prescribed by the regulations and the Highway Traffic Act, with associated signs Ra-4, Ra-4t, Ra-5L, Ra-5R, Ra-10, and Ra-11.
Cross Section
The transverse profile of a road.
Cross Street
A street of lower classification that crosses a roadway of higher classification, either at grade or passing over or beneath.
Crosswalka
Any portion of a roadway, at an intersection or elsewhere, distinctly indicated for pedestrian crossing by appropriate pavement markings and/or signs, or by the projections of the lateral lines of the sidewalk on opposite sides of the road.
Crown
The highest break point of the surface of a roadway in cross section.
Cul-De-Sac
A road opens at one end only.
Curb
A structure with a vertical or sloping face along the edge of a lane or shoulder strengthening or protecting the edge or clearly defining the edge.
Curb Drop
The transition length required to decrease the curb height to accommodate a driveway or sidewalk ramp.
Curb and Gutterb
Curb and gutter is placed adjacent to an outside lane or shoulder and is intended to control and conduct storm-water and also provides delineation for traffic. In some instances, curb is introduced without a gutter.
Curb Return
The curved section of curb used at intersections or driveways in joining straight sections of curb.
Curve to Spiral (CS)
The point of alignment changes from circular curve to spiral curve, in the direction of stationing.
Curvilinear Alignment
An alignment in which the majority of its length is circular and spiral curve.
Cutb
A roadway located below natural ground elevation is said to be in cut.
Cut Side Slopeb
Where the roadway is in cut, the slope between the road-way and drainage channel is referred to as a cut side slope.
D.
Deceleration Lanea
An auxiliary lane to enable a vehicle exiting from a roadway to reduce speed after it has left the through traffic lanes as applied at channelized intersections, or as speed-change lane at interchanges.
Decision
We post our decision and the approved comments made on our proposal after we finish our review. In our decision, we let you know:
- how your comments were taken into consideration
- the number of comments we received
- our decision on what we’re doing
Decision Sight Distance
The distance required for a driver to detect an information source or hazard which is difficult to perceive in a roadway environment that might be visually cluttered, recognize the hazard or its potential threat, select appropriate action, and complete the manoeuvre safely and efficiently.
Deflection Angle
The angle between a line and the projection of the preceding line.
Departure Taper
The taper required beyond a flared intersection to laterally shift the through lanes to the left, back to a normal alignment or cross section.
Design Consistency
An indication of the quality of design offered by a roadway.
Design Exception
A “Design Exception” is a documented decision to design elements of highway for criteria that do not meet minimum values or ranges established in the highway standards, policies or specifications.
Design Speeda
A speed selected for purposes of design and correlation of the geometric features of a road and is a measure of the quality of design offered by the road. It is the highest continuous speed at which individual vehicles can travel with safety on a road when weather conditions are favourable and traffic density is so low that the safe speed is determined by the geometric features of the road.
Design Hour Volume (DHV)
An hourly traffic volume selected for use in geometric design.
Designer Fill-in
Designer fill-in means an option the person putting together the specification can enter at their discretion. It is part of the specification where the text must be entered and is not always the same.
Desirable Valueb
The value at the top of a range of values in a design standard, or the discreet value when a range is not given in a design standard.
Desired Speed
The Operating Speed that drivers will adopt on the less constrained alignment elements of a reasonably uniform section of road (e.g., the longer straights and large radius horizontal curves) when other vehicles or users do not affect their speed choice.
Development Roadway
A roadway whose primary purpose is to provide access to undeveloped areas.
Double Left-Turn Lanes
A pair of adjacent lanes intended for the exclusive use of vehicles about to turn left. Interchangeable with dual left-turn lane.
Drainage Channela
A drainage channel is placed adjacent to an outside lane or shoulder and is intended to control and conduct storm-water runoff. A shallow drainage channel is sometimes referred to as a swale.
E.
Earth Roadway
A roadway that has a driving surface consisting of subgrade material.
Easement
A right acquired by public authority to use or control property for a designated purpose.
Effective Wheelbase (EWB)
The distance from the centroid of the front axle group to the centroid of the rearmost axle group, which significantly influences the turning envelope. For two-axle vehicles, total and effective wheelbase are the same.
End Treatment
The method by which the end of a barrier facing on-coming traffic is treated to minimize its hazard.
Energy Attenuator
See “Crash Cushion”.
Entrance
The general area where turning roadway traffic enters the main roadway.
Entrance Terminal
The part of an entrance comprised of acceleration lanes or speed change lanes, including the ramp proper up to the ramp controlling curve.
Exception Notice
Exception notices skip the consultation and commenting stage and go right to our decision. We post exception notices in the following situation. When there's an emergency. If we wait for public consultation, there could be the risk of:
- danger to public health or safety
- injury or damage to property
Exit
The general area where turning roadway traffic departs from the main roadway.
Exit Terminal
The part of an exit comprised of deceleration lanes or speed change lanes, including the ramp proper up to the ramp controlling curve.
Express Lanesa
Managed lane that restricts access or a ML that employs electronic tolling in a freeway right-of-way with or without access restrictions. Express lanes can be located within tolled or non-tolled facilities and may be operated as reversible flow or bi-directional facilities to best meet peak demands.
Express-Collector System
A freeway in which the through or express lanes are physically separated from the collector lanes.
Express toll lane (ETL)b
ETL is a limited access managed lane employing electronic tolling that charges users’ toll, and they do not exempt high occupancy vehicles.
Expressway
A divided arterial road for through traffic with full or partial control of access and with some interchanges.
F.
False Grading
The practice of distorting the profile of a roadway, relative to the top of curb, so as to avoid flat grades in order to effect drainage.
Fillb
A roadway located above the natural ground elevation is said to be in fill.
Fill Side Slopeb
Where the roadway is in fill, the slope between the roadway and the natural ground is referred to as the fill side slope or sometimes the fill slope.
Flare
The variable offset distance of a barrier to place it further from the travelled way.
Flexible Barrier
A form of the longitudinal barrier that is intended to redirect an errant vehicle by rail tension, usually through a system of cables installed in tension.
Four-Lane Divided Highwayb
A highway consisting of four (4) through lanes total, with two (2) through lanes in each direction which are separated by an unpaved area or physical barrier, including but not limited to a curbed island.
Four-Lane Roadb
A road that provides two through lanes of traffic in each direction.
Frangible
Readily or easily broken upon impact.
Freewaya (Multi-Lane Freeway)
A multi-lane, divided highway with more than four (4) through lanes total (two (2) through lanes in each direction) with a continuous dividing median. This highway is a fully controlled access road limited to through traffic, with access through interchanges and a posted speed of greater than 90km/h.
See also “Staged Freeway”
Friction Factor
The coefficient of friction between tire and roadway, measured either longitudinally or laterally.
Front Overhang (FOH)
The distance from the front bumper of a vehicle to the centroid of its front axle group.
Frontage Roadway
A road contiguous to a through road so designed as to intercept, collect and distribute traffic desiring to cross, enter or leave the through road and to furnish access to property.
G.
Geometric Design
The selection of the visible dimensions of the elements of a road.
Gore Areaa
Area between edge of highway, edge of ramp and bullnose.
Grade Separation
Vertical separation of two intersecting roadways or a roadway and a railway.
Gradient (Grade)a
The rate of rise or fall with respect to the horizontal distance; usually expressed as a percentage.
Gravel Road
A road that has a driving surface consisting of granular material.
Guiderail (Guardrail)
See “Barrier”.
Guidelines
Outlines of acceptable practice.
Gutter
A paved shallow waterway provided for carrying surface drainage.
Gutter Line
The bottom of the curb face where it meets the concrete gutter, or the paved surface where a gutter is not employed.
Gutter Lip
The edge of a concrete gutter opposite the curb where it meets the paved roadway.
H.
Hazard
Any obstacle or other feature such as an embankment, or a body of water of depth greater than 1 m which, without protection, is likely to cause significant injury to the occupants of a vehicle encountering it.
Heuristic
An aid to design based on experience - a "rule of thumb".
High-Occupancy-Toll (HOT) Lane, also referred to as Value-Priced lanesb
HOV lane that is electronically tolled for single- or lower occupancy vehicles and free to higher-occupancy vehicles
High-Occupancy-Vehicle (HOV) Lanea
Managed lane restricted primarily to high-occupancy vehicles (no tolling applied)
Highway
Synonymous with roadway but generally limited to higher-speed roadways in rural areas.
Horizontal Alignmenta
The configuration of a road or as seen in plan, consisting of tangents, lengths of circular curve, and lengths of spiral or transition curves.
Horizontal Curve
A circular curve to plan to provide for change of direction.
I.
Independent Alignment
A divided highway in which each roadway is designed independently both in horizontal and vertical alignment, to take advantage of topographical features.
Infrared Joint Heater
Infrared joint heater is a machine with infrared as heating element to heat up both adjacent edges of the pavement during construction to prevent longitudinal cracking or separation between lanes.
Inside Lane
The left lane in one direction of a roadway with two or more lanes in that direction also referred to as an inner lane.
Interchange
A grade-separated intersection with one or more turning roadways for travel between the through roads.
Intersection (At-Grade)
The general area where two or more roads join or cross, within which are included the roadway and roadside facilities for traffic movements.
Intersection Approach
That part of an intersection leg used by traffic approaching the intersection.
Intersection Sight Distance (ISD)
The sight distance to left and right available to a driver intending to execute a maneuver onto a through roadway from an intersecting roadway.
Island
A defined area between traffic lanes for control of vehicle movements or for pedestrian refuge and the location of traffic control devices.
K.
King's Highwayb
An administrative classification referring to all Provincial numbered lower than 500, and including the Queen Elizabeth Way (Q.E.W.). While “Freeways” fall under the administrative classification of a King’s Highway, they have their own functional classification that differs from other King’s Highways.
L.
Lane (Traffic Lane)
A part of the travelled way intended for the movement of a single line of vehicles.
Lane Kilometre
One kilometre of a single lane of highway.
Lane Kilometres
A linear measurement on the length of a highway, accounting for each single lane.
Left-Turn Lane
A lane added on the approach to an intersection for the exclusive use of left-turning vehicles.
Length of Need
Total length of a longitudinal barrier needed to shield an area of concern.
Local Roadway
A road intended to provide access to development only.
Long Combination Vehicle (LCV)
A combination of a tractor and trailer(s) used for special purposes, with an overall length greater than 25 m. Examples are 'triples' and 'turnpike doubles'.
Longitudinal Barriera
A barrier placed adjacent to a roadway, intended to contain a vehicle leaving the normal travel path, by re-directing it.
Low Volume Roadwaya
A road with average daily traffic of 200 vehicles per day of less, and whose service functions are oriented toward rural road systems, roads to or within isolated communities, recreation roads and resource development roads.
LRT
Light rail transit.
M.
Mainline
The principal route.
Mediana
The area that laterally separates traffic lanes carrying traffic in opposite directions. A median is described as flush, raised or depressed, referring to the general elevation of the median in relation to the adjacent edges of traffic lanes. The terms wide and narrow are often used to distinguish different types of median. A wide median generally refers to depressed medians sufficiently wide to drain the base and subbase into a median drainage channel. Flush and raised medians are usually narrow medians.
Median Barriera
A longitudinal barrier placed in the median to prevent a vehicle from crossing the median and encountering oncoming traffic or to protect a vehicle form a fixed object in the median.
Merging-End
The physical end of an entrance terminal between the outer travel lane and the ramp, beyond which traffic merges. Also known as the painted wedge.
Minimum Passing Sight Distance
The least visible distance required by a driver in order to make a passing manoeuvre safely, based on a given set of circumstances.
Minimum Stopping Sight Distance
The least stopping sight distance required by a driver to come to a stop under prevailing vehicle, pavement and climatic conditions.
Minimum Turning Radius (TR)
The radius of the path of the outside of the outer front wheel for the minimum radius turning condition. In former TAC Design Guides, this dimension was used to denote the minimum design turning radius.
Minimum Valueb
The value at the bottom of a range of values in a design standard.
Multi-Lane Roadsb
Roads having more than two through lanes of traffic in each direction. In the Traffic and Capacity chapter Multilane refers to four lanes or more.
Multi-Use Path (MUP)
A path with multiple users of different types (e.g., pedestrians, bicycles, and similar user types); a MUP may be shared (all users share the same pathway space, with or without a marked centre line) or may be separated (i.e., the pathway is separated into parallel travelled ways, e.g. one exclusively for pedestrians and one exclusively for bicycles).
Multi-Use Trail (MUT)
See “Multi-Use Path”.
N.
Narrow Medianb
A median without an unpaved area or physical barrier between opposing through lanes.
Noise Berm/Barrier
A physical barrier, consisting of compacted earth in a trapezoidal shape, used as a means of minimizing the transmission of traffic sounds.
Normal Crown
A cross section in which adjacent surfaces slope in opposite directions from the centre line or a lane edge to effect drainage to the sides.
Nominal Safety
Nominal safety is a consideration of whether the highway design elements meet minimum design criteria. For example, if design features such as lane width, shoulder width, lateral clearance, etc. meet the minimum values or ranges, the highway proposed design is considered to have nominal safety.
O.
Obstaclea
Any fixed object which is likely to cause significant injury to occupants of a vehicle encountering it.
Or
Any non-breakaway and non-traversable feature within the roadside environment greater than 100mm in height that can increase the potential for personal injury and vehicle damage when struck by an errant vehicle leaving the roadway.
Offset Mid-Block Crossing
A pedestrian crossing on a divided roadway in which the alignment of the crossing is staggered at the median.
One-lane One-way Road
A road with one lane that carries one-directional traffic.
One-lane Two way Road
A road that provides sufficient roadway width for the safe passing of opposing vehicles.
Operating Speed
The 85th percentile speed of vehicles at a time when traffic volumes are low and drivers are free to choose the speed at which they travel.
Outer Separationa
A reserve on freeways (including shoulders) between lanes carrying traffic in the same direction.
Outside Lane
The right lane in one direction on a roadway with two or more lanes in that direction (also referred to as an outer lane).
Overall Length
The distance between the front bumper of the power vehicle and the rear bumper on the rear unit of a vehicle or trailer combination. It equals the sum of its effective wheelbases, front overhand and rear overhang.
Overpass (vehicle)
A grade separation in which the subject road passes over an intersecting road or railway.
P.
Painted Wedge
See “Merging-End”.
Parameter
A quantity that is a variable in the general case and is constant in the specific case under consideration. (Radius of circular curve is an example, in which radius varies from one curve to another but for one particular circular curve is the same at any point on the curve.
Parclo
An abbreviation for the PARtial CLOverleaf interchange, a grade separation having loop ramps in fewer than all four quadrants.
Parking Lane
A supplementary lane intended for parking.
Passing Lane
A supplementary lane intended for passing.
Passing Opportunity
The distance ahead required to be visible to a driver to initiate a passing maneuver safely.
Passing Sight Distance
The distance ahead visible to the driver available to complete a passing maneuver.
Perception Timeb
The time that elapses from the instant that a driver observes an object for which it is necessary to stop, until the instant that he decides to take remedial action.
Performance Graded Asphalt Cement (PGAC)
PGAC means an asphalt binder that is produced from petroleum residue, either with or without the addition of non-particulate modifiers, according to AASHTO M 320. It is used as a general term encompassing the methodology for selecting the grade of asphalt cement binders based on fatigue, rutting, low temperature cracking and moisture damage.
Platform Intersection
An intersection in which the area common to the two roadways is at the same elevation as the top of curb or sidewalk.
Policy
Principle, course of action, or strategy adopted by government, government agency or technical organization that reflects prevailing community values, intended to provide direction and guidance in the selection of technical and non-technical criteria for general application, and specific dimensions in the planning and design process. Policy necessarily incorporates some element of political or other non-technical community viewpoints.
Posted Speed
A speed limitation introduced for reason of safety, economy, traffic control and government regulatory policy aimed at encouraging drivers to travel at an appropriate speed for surrounding conditions.
Proposal
Most notices are in the development or revision stage when we first post them on this portal. It is called a proposal because we're proposing to change an existing one or make a new policy, standard or specification.
Most of our proposals:
- say what we're wanting to do
- give the details
- link to supporting material
- provide the option to comment
Public Lane (Alley)
A narrow minor street, usually without sidewalks, located at the rear of lots for vehicle access to garages or other parking spaces and which also serves as a utility right of way.
R.
Raised Crosswalk
A crosswalk on a curbed street whose elevation is the same as the top of curb or sidewalk.
Ramp
A turning roadway to permit the movement of traffic from one highway to another.
Reaction Time
The time that elapses from the instant a visual stimulus is perceived by a driver to the instant the driver takes remedial action.
Rear Overhang (ROH)
The distance from the rear bumper of a vehicle to the centroid of its rearmost axle group.
Recovery Area
Generally synonymous with clear zone.
Retrofit
The reconstruction of an existing roadway with geometric improvements.
Reverse Crown
A typical surface cross section in which adjacent surfaces slope in the same direction at the normal crown.
Reverse Curve
Two curves, curving in opposite directions from a common point.
Review
We review all the comments we receive and consider them before making a decision. It’s important to know that we consider the content of the comments as more important than the number of comments we receive. As the Ministry of Transportation is a public agency, all comments must be weighted equally. We’ll also decide whether your comment can be posted for others to see. We will not post your comment if it:
- contains inappropriate or offensive content (language or links)
- is off topic,
- contains personal information
Our decision will be noted in the comment status. There is no time limit for the review stage.
Right-Of-Way (ROW)
The area of land acquired for or devoted to the provision of a road.
Right-Turn Lane
A lane added on the approach to an intersection for the exclusive use of right-turning vehicles.
Right-Turn Taper
The taper from the edge of the through lane to the beginning of a right- turning roadway at an intersection, where an auxiliary lane is not used.
Rigid Barrier
A form of longitudinal barrier that is intended to redirect an errant vehicle with minimum deflection in the barrier system and usually consist of a continuous concrete mass.
Road
The entire right-of-way comprising a common or public thoroughfare, including a highway, street, bridge and any other structure incidental thereto.
Roadside
The area adjoining the outer edge of the roadway.
Roadside Barrier
A longitudinal barrier used to shield roadside obstacles or non-traversable terrain features. It may occasionally be used to protect pedestrians from vehicle traffic.
Roadside Environmentb
The portion of the ROW beyond the roadway, including medians, not designed for vehicular use. The roadside environment may include a variety of surfaces and slopes, fixed Obstacles (such as signs, poles, bridges piers, abutments, culverts, ditches, sideslopes, backslopes, barrier systems, crash cushions, etc) and natural features (such as water bodies, trees and other vegetation, boulders and rock outcrops, etc).
Roadway
That part of the road that is improved, designed or ordinarily used for the passage of vehicular traffic, inclusive of the shoulder.
Roadway Hump
A speed control device in which the roadway surface is raised over a length of about 3.5 to 4.0 m to a maximum height of 80 mm.
Roundabout
A channelized intersection in which traffic moves counterclockwise around a centre island of sufficient size to induce weaving movements in place of direct crossings. It is sometimes referred to as a rotary or traffic circle.
Roundinga
Width between edge of shoulder and cut or fill slope.
Rumble Strips
Indentations in the surface of a paved shoulder that provide an audible or tactile warning to a driver that the vehicle has left the travelled lane.
Runout Lengthb
The distance parallel to the roadway, measured from the object to the point of vehicle encroachment. This distance varies with design speed and traffic volume.
Rural Area
An area characterized by low density development on large parcels.
S.
Safety Zonea
An area officially established within a roadway for the exclusive use of pedestrians, protected or so indicated as to be plainly visible.
Sag Vertical Curve
A vertical curve having a concave shape in profile viewed from above.
Secondary Highwayb
An administrative classification referring to all 500, 600, and 700-Series Provincial Highways.
Semi-rigid Barriera
A form of longitudinal barrier that is intended to direct an errant vehicle by a system of steel beam action to adjacent posts.
Service Road
Same as frontage road but not necessarily contiguous with the through road.
Severity Indexb
A number from zero to ten used to categorize the potential severity of an encroachment or impact by an errant vehicle for a range of design speeds over a variety of surfaces and slopes, fixed objects and natural features within the roadside environment. The number is used for evaluating alternative safety treatments.
Shared Street
A street designed to be shared by pedestrians, cyclists, and slow-moving motorists, with no physical separation of modes and typically an emphasis on use as a livable public space.
Shielding
The introduction of a barrier or crash cushion between a vehicle and an obstacle or area of concern to reduce the severity of impacts of errant vehicles.
Shouldera
Areas of pavement, gravel or hard surface placed adjacent to through or auxiliary lanes. They are intended for emergency stopping and travel by emergency vehicles only. They also provide structural support for the pavement.
Shy-Line Offset
A distance beyond which a roadside object will not be perceived by a driver to be a threat, to the extent of changing lane position or speed.
Sidewalk
A travelled way intended for pedestrian use, following an alignment generally parallel to that of the adjacent roadway.
Sight Distance
From any given point, the unobstructed distance a driver can see, usually along the roadway ahead.
Sight Distance at Intersectionb
See “Intersection Sight Distance”.
Sight Triangle
The triangle formed by the line of sight and the two sight distances of drivers, cyclists or pedestrians approaching an intersection on two intersecting streets.
Simple Open Throat Intersectiona
A simple or un-channelized intersection where additional area of pavement may be provided for turning of large vehicles.
Slot Left-Turn Lane
On a divided roadway, a left-turn lane which is angled and situated entirely within a wide median to accommodate a divisional island between the left- turn lane and the adjacent through lane.
Speed Hump
See “Roadway Hump”.
Speed Change Lane
A deceleration or acceleration lane.
Spiral Parameter (A)a
“A” designates the sharpness of the spiral. It is a measure of the flatness of the spiral, the larger the parameter, the flatter the spiral.
Spiral to Curve (SC)
The point of change form spiral curve to circular curve, in the direction of stationing.
Spiral to Tangent
The point of change from spiral curve to tangent, in the direction of stationing.
Spline
A flexible drafting tool used to draw curved lines of varying radii.
Staged Freewayb
A freeway (typically rural) that is planned to be a multi-lane dived freeway that is built using staged construction. In the plans for each stage of development, provisions should be made to adapt each stage to the next or the ultimate stage (completion). The transition should be made with minimum waste of the exiting plant and minimum interference to traffic. Typically, this might include treatments such as interim at-grade intersections in lieu of interchanges.
Standard
A value for a specific design feature, which practice or theory has shown to be appropriate for a specific set of circumstances, where no unusual constraints influence the design.
Steering Angle
The angle between the longitudinal axis of the vehicle and the direction of the steering wheels, limited by the dimensions of parts of the steering mechanism.
Stop Blockb
Pavement marking to indicate where vehicles are required to stop for a traffic control device.
Stopping Distance
The distance travelled by a vehicle from the instant the driver decides to stop, to coming to a stop.
Stopping Sight Distance
The distance between a vehicle and an object, for which the driver decides to stop, to the instant the vehicle begins to come into view.
Street
Synonymous with road, but generally limited to lower speed roads in urban areas.
Street Furniture
Practical and decorative features introduced into the streetscaping, intended to enhance the comfort, convenience and aesthetic quality of the roadway environment.
Streetscaping
The practice of applying aesthetic treatments to the street and its facilities, intended to enhance the quality of the roadway environment.
Suburban Area
An area characterized by larger scale developments. Building coverage and development density can vary, but typically are less than in Urban Areas.
Substantive Safety
Substantive Safety is the expected or estimated long-term average, safety performance of a roadway. The concept of substantive encompasses methods for estimating the following expected quantitative measures: • Collision Frequency • Collision types • Collision severity
Summer Average Daily Traffic (SADT)b
The average 24-hour, two-way traffic for the period July 1st to August 31st including weekends.
Superelevation
The gradient measured at right angles to the centre line across the roadway on a curve, from the inside to the outside edge.
Superelevation Runoff
The gradient measured at right angles to the centre line across the roadway on a curve, from the inside to the outside edge.
Surfaced Roadway
A roadway in which the travelled lanes have been hard surfaced, usually by some form of bituminous or concrete surface.
Swale
A shallow drainage channel.
T.
Tangent Runout
The length of road needed to accomplish the change in cross slope from a normal cross-section to a section with the adverse crown removed.
Tangent to spiral (TS)
The point of alignment change from tangent to spiral curve, in the direction of stationing.
Taper
Where an auxiliary lane is being developed or terminated, the straight-line transition from the edge of the through lane to the beginning of the full width auxiliary left- or right-turn lane.
Target Speed
The speed at which the designer intends for traffic to operate.
TCP Number
This is the unique, seven-number reference every notice gets in the portal (e.g. 123-4567)
You can use it to:
- search for a policy, standard and specification
- reference a policy, standard and specification when you submit a comment
Terminal
A crashworthy end treatment or crashworthy anchor used at the end of a barrier system.
Tertiary Highwayb
An administrative classification referring to all 800-Series Provincial Highways.
Throat Length
The provision of sufficient unobstructed on-site driveway length to prevent stopped vehicles from blocking the path of entering vehicles or vehicles travelling along the circulation roadways on site.
Through Lane
A lane intended for through traffic movement
Toll Lane (Toll Road)a
A road open to traffic only upon payment of a direct toll or fee; sometimes called tollway, throughway, turnpike or auto-route. (may not be a managed lane if travel benefits are not assured)
Total Wheelbase (TWB)
The centre-to centre distance from the front axle to the rearmost axle of a tractor-trailer combination. (The nomenclature used for design vehicles is based on total wheelbase, for example "WB-19" refers to a tractor-semitrailer having a total wheelbase of approximately 19 m.)
Traffic barrier/Barrierb
Traffic barriers are placed adjacent to a roadway to protect traffic from hazardous objects either fixed or moving (other traffic). Barriers placed in a median are referred to as median barriers and may be placed in flush. Raised or depressed medians.
Trail
A beaten or maintained path or track often for a specified type of traffic (e.g. ski trail).
Transit Lane
A lane intended primarily for public transit vehicles.
Transition
A method by which a change in longitudinal barrier type provides continuous protection to errant vehicles.
Transition (spiral) curve
A curve whose radius continuously changes.
Travelled Waya
That part of a roadway intended for vehicular travel. This includes through lanes, turn lanes, and other auxiliary lanes. This does not include shoulders or ancillary space. It may have a variety of surfaces but is most commonly hard surfaced with asphalt or concrete or gravel surfaced.
Truck Escape Ramp (TER)
A ramp provided on the right side of a long downhill section of roadway to allow vehicles (usually trucks) to escape in the event of brake failure.
Turning Roadway
A separate roadway or ramp to accommodate turning traffic at the intersection or interchange of two roads.
Turnout
A widened section of roadway provided for passing of vehicles travelling in opposite directions on a one-lane roadway, or in the same direction on a two-lane roadway.
Two - Lane Road
A road that provides for one lane of through traffic in each direction.
Two-Way Left-Turn Lane (TWLTL)
The middle lane on a two-way undivided street intended for the exclusive use of vehicles about to turn left from either direction into property accesses.
U.
Underpass
A grade separation in which the subject roadway passes under a roadway or railway.
Urban Area
An area characterized by extensive development and building coverage.
V.
Vertical Alignmenta
The configuration of a road or roadway as seen in longitudinal section, consisting of tangents and parabolic curves.
Vertical Curvature (K)
The horizontal distance along a parabolic curve required to effect a one percent change in gradient.
Vertical Curvea
A parabolic curve on the longitudinal profile or in a vertical plane of a road to provide for change of gradient.
W.
Warranta
A criterion that identifies a potential need or the justification for an addition to the highway such as traffic signals, traffic barrier, truck climbing lanes, passing lanes, left turn lanes etc.
Waterbodyb
Any natural or constructed body of water.
Watercourseb
Any stream, river, or channel in which flow of water occurs either continuously or intermittently.
Weaving
The condition in which vehicles move obliquely from one lane to another, and across the paths of other vehicles moving in the same direction.
Weaving Lane
A lane added to provide additional capacity and operational improvement in sections of roadway experiencing weaving.
Weaving Section
A section of roadway between an entrance and an exit, such that the frequency of lane changing exceeds that for open highway condition.
Wide Medianb
A median on a divided roadway and/or freeway consisting of an unpaved area or physical barrier between opposing through lanes.