Module 3: Road and Traffic Considerations Flashcards
Purpose of road?
Primarily a function of the immediate land use
Provide connections to locations outside of immediate area
Road classifications?
Local
Street providing land access with little or no provision for through traffic
Design speed of 40km/h
Low density areas
Generally lower density areas, stop signs, parked cars, kids
10% absolute maximum grade
Pavement structure varies across municipalities, within them; look at successfully existing adjacent pavement structures
Low quality materials in aggregate standards due to scarcity of resources, unless near a good source
No good common standard for wheelchair ramps
Collector
Performs dual function of land access and distribution of traffic between local and arterial streets
1000-12,000 daily volume
Design speed of 60km/h
Medium and high density areas
12% absolute maximum grade
Pavement structure varies across municipalities, within them; look at successfully existing adjacent pavement structures
Low quality materials in aggregate standards due to scarcity of resources, unless near a good source
No good common standard for wheelchair ramps
Arterial
Provides continuous route primarily for through traffic with land across a secondary consideration
5000-30,000 daily volume
15% absolute maximum grade
Pavement structure varies across municipalities, within them; look at successfully existing adjacent pavement structures
Low quality materials in aggregate standards due to scarcity of resources, unless near a good source
No good common standard for wheelchair ramps
There are others, but not important here (possibly forest service?)
18% absolute maximum grade?
Pavement structure varies across municipalities, within them; look at successfully existing adjacent pavement structures
Low quality materials in aggregate standards due to scarcity of resources, unless near a good source
No good common standard for wheelchair ramps
Road and right-of-way widths? Determined by?
Determined by density
Low: <16 dwellings/ha
Medium: 16-30 dwellings/ha
High: >30 dwellings/ha
More dense = more wide
Greater land slope = more wide right-of-way for local streets
No less than 20m for right-of-way (roads are actually less wide)
However, there have been provisions made in standards for right-of-ways widths less than 20m
see https://docs.google.com/document/d/13QjXslbKcm56KCcnbQaC6OebBPX7u248o9cNfhDDHKQ/edit
remember: local roads in hillside locations (so that means greater slope) will need wider SRW
What generally governs absolute maximum grade in BC? Why will they have to be increasingly used in the future?
Snowfall, heavy snowfall
Due to the Agricultural Land Reserve (ALR), more housing will be developed on hillsides
2 types of storm drainage design. they consist of?
conventional method
storm water management method
Substantial amount of engineering design work for each development proposal and formulation by the municipality of overall watershed design criteria
consist of
They should consist of a minor system component and a major system component (both)
Needed because there is increasing exposure to flooding
Water Distribution: main and service connection location? Hydrants? How are hydrants standardized?
Main and service connection location
Must be separate from sanitary sewer mains and service connections (Ministry of Health and Environment)
Saves costs
Hydrants
3-4 hydrant types
80% produced by Vancouver company
Variety of municipal specifications
Sliding gate vs compression type
Type of pumper connection
Main spindle rotation
Municipalities try to standardize hydrants by
Manufacture
Type
Pumper connection
Spindle rotation
Who sets out the standards of right-of-way and pavement widths? What do the standards include?
Transportation Association of Canada
Widths, geometric design standards, coding for road standards
What ultimately governs design? What plays a large role? What must be reduced?
Its use
Its purpose, with a minimum of disruption and waste
Road must be built to serve its purpose
Engineering knowledge and judgement is needed in preparing transportation and land use plans
Must reduce dislocation of people and business
Traffic factors that can be anticipated based on a good plan?
Traffic volume
Vehicular type (truch, bus, car)
Trip type (commuter, local, through, shopping, sightseeing, recreational)
Public transportation needs (future traffic protection)
Functional classifications of road
Rural
Freeway
Arterial
Collector
local
Urban
Freeway
Arterial
Collector
Local
Remember: rural and urban refer to the predominant characteristics of adjacent land use, NOT jurisdictional boundaries
see https://docs.google.com/document/d/13QjXslbKcm56KCcnbQaC6OebBPX7u248o9cNfhDDHKQ/edit
describe freeways
Heavy volume
High speeds (80-100km)
Free flowing conditions
Long trip traffic
8000 - 20000 (rural to urban)
limited access roads
opposing traffic lanes seperated
overpasses and bridges
restrictions on parking, pedestrains and cycling
connects to freeways, arterials and collectors only
describe arterials; primary functions
major routes in networks
connect industrial and commercial centres, concentrations of residential development
use arterials if freeways are not warranted
1000 - 12000, 500-30000 daily users (rural - urban)
usually uninterrupted flow; controlled intersections
public transportation loading zones, turning lanes
restricted parking
50-90km
connect to all other road types, even local, industrial or commercial
describe collector streets; primary function
Collect traffic from local roads and distribute it to other local roads, arterials, sometimes freeways
Service land, permitted full access to adjacent land usually
200-5000, 1000-12000 (rural - urban)
flow interrupted by stop conditions at intersections and turning movements at land access points
connect to all other road types, usually not freeways in urban settings; rarely found in central business districts
describe local streets; primary function
provide land access
Trips on local roads have their origin or destination within the length of the road
interrupted flow
20-50-80km
mostly passenger vehicles or light service trucking
connect to arterials, collectors, locals; only collectors and locals in urban setting
Preliminary and Secondary Groups
Some jurisdictions divide the major classification into primary or secondary
Secondary urban local
A short crescent or cul de sac
Primary urban collector
A collector serving primarily industrial area
Extra width and strength needed to handle trucking
What are the design elements for each basic classification of road?
Determine physical limitations of the route
Know anticipated traffic
What do physical limitations govern in design?
Grades
Design speeds
Max width (existing/proposed right-of-way)
What does traffic govern in design?
Pavement width
Shoulder width
Number of lanes
How are roads coded?
Location
Class type of road
Type
Divided vs undivided
Design speed
Ex:
RLU = rural local undivided. 80km/h. So, code is RLU80
see https://docs.google.com/document/d/13QjXslbKcm56KCcnbQaC6OebBPX7u248o9cNfhDDHKQ/edit
What identifies the external access and circulation needs of the neighbourood? How?
Site analysis process
Locates the internal circulation pattern to suit the density and type of development being accommodated
What aspects of circulation have planning implications?
Vehicles
Trucks
Emergency vehicles
Transit vehicles
Snow plows
Bicycles
Pedestrians
Which is planned first: arterial road or neighbourhood? Why? Recommended design features?
Arterial road
They are to provide direct routes for traffic PAST residential neighbourhoods to destinations >2km away
Design features
Widely spaced intersections (250m apart)
No direct access to adjacent land (unless land has internal road system)
Pedestrian crossing only at intersections
Land uses should be buffered by landscaping, berms, fences
Discourage residential parking
What do collector roads serve to do? Design considerations?
Distribute vehicular traffic throughout neighbourhood
Design
Intersections should meet at between 70-110 degrees, final alignment maintained for a distance of 30m from the centre of intersection
see https://docs.google.com/document/d/13QjXslbKcm56KCcnbQaC6OebBPX7u248o9cNfhDDHKQ/edit
Discourage intersections of more than 2 streets
Intersections on residential streets should not be closer then 60m between the limits of street right-of-ways
T intersections are preferable to cross roads
Access to land uses should not interfere with intersections (>25m away)
Parking only on one side
What do local roads do? What should design ensure?
Provide direct access to residential properties
Channel local traffic onto collector roads within the neighbourhood
Design
Access to residences is more than 25m from centre of intersection of a collector road with a local road
Width, minus permitted parking, should be able to accommodate turning delivery vans, garbage trucks
Driveways may help with this
Emergency circulation; characteristics?
Characteristics
2 access points for residential neighbourhood into adjacent arterial road system
Secondary access should be 4m wide
Dont need to be paved (grass, gravel etc is ok)
When neighbourhood is built in phases, create one access in each one
On long cul de sacs, P streets or loops (over 150m) a secondary access route for emergency vehicles should be provided
see https://docs.google.com/document/d/13QjXslbKcm56KCcnbQaC6OebBPX7u248o9cNfhDDHKQ/edit
Transit vehicles: what do roads need to do for them
Provide direct route through each neighbourhood
Only on collector, arterial streets (not local); what about freeways?
Minimize left turns
No loops or switchbacks
Same route in both directions
Transit route characteristics
Designed within 500m of residential development (May be less with high density areas)
Accommodate present and future service
Min 150m between stops
Max 360-400m distance between stops
Bus shelters with densities >32 dwellings/ha
Arterial roads may warrant bus bays
when :
only one moving lane in each direction
Transit vehicles have layovers to meet schedules
Anticipate traffic lineups
Implications of Snow plows and road maintenance vehicles
If snow is expected to be on ground for long,
6.75 of pavement free of parked cars
Min turning radius of 11m
If snow is expected to accumulate for longer
Designate snow storage locations within neighbourhood, like
Boulevards
Parks, open spaces
Median strips on collectors
Street pavement with increased width roads
Easements on lots
Implications of bicycle circulation? For low density? Medium? High?
Low
Bikes can be on local roads
Medium
Traffic is too heavy for bikes
Need separate right of way
Should connect residential groupings to major activity areas (parks, recreation facilities)
Less changes in elevation
Bicycle storage?
Protective barriers for arterial bridges
High
Traffic is too heavy for bikes
Need separate right of way
Should connect residential groupings to major activity areas (parks, recreation facilities)
Less changes in elevation
Bicycle storage?
Protective barriers for arterial bridges
Implications for pedestrian circulation? 3 types of walkways? What must the 2 larger types include? When can sidewalks on only 1 side of a collector be considered? When are sidewalks not needed?
Safety is important
Separate right of ways from vehicles
Types
Paths approx 1m wide from individual dwellings to parking, bins, open space, or wider pathways
paths/sidewalks 1-1.5m wide connecting dwellings or groups of residential units
No barriers for wheelchairs/baby carriages
Walkways 1.5-2m wide between groups of dwellings and community, recreation or commercial facilities
No barriers for wheelchairs/baby carriages
Only 1 side
Low traffic volume
Internal paths are provided within neighbourhood
Housing mix favours households without children
Activity centers are grouped in a favourable way (on same side)
Not needed on short cul de sacs and P loops (<150m long) if they are not part of pedestrian routes to parks, schools, community facilities
Accepted max length of road prior to a secondary access requirement? What about in rural? Who needs to be consulted about standards?
150m, 220m in rural
Local fire chief
What makes secondary roads not practical? What is a way to maximize land efficiency?
Rural settings, where there is no nearby hydrants or water supply
country/rural roads can be long narrow dead ends leading to a farm or ranch
Road must be able to handle a fire truck
Combine alternate access routes with walkways and sewer right of ways
Normal drivers must not use it
What else should local roads accomplish? What do collectors/ major local roads accomplish in this context? Arterial roads?
rovide direct access to land and Prevent through traffic in neighbourhoods
collectors / majors collect traffic from local roads and disperse it throughout community
Also channel the traffic towards arterial roads
Arterial roads connect to other communities
see https://docs.google.com/document/d/13QjXslbKcm56KCcnbQaC6OebBPX7u248o9cNfhDDHKQ/edit
2 basic road patterns? Advantages of cul de sacs?
GRID
Most common
More efficient
90 degree intersections
Numerous cross intersections which have 2 and 4 way stops
Most compatible to the subdivision of land based on existing land ownership
Can be tedious, monotonous
Can deviate to provide opportunities for more open space
Meandering or flowing
Can still be planned
Avoids conventional grid
Utilizes curved roads and cul de sacs
Cul de sacs are a viable alternative to basic grid
Creates more family friendly neighbourhoods with kids
Opportunities for parks and open spaces
More T intersections (due to curved roads
they create mini neighbourhoods
There is also a compromise
What ultimately dictates road placement?
Topography, public demand and the sequence of development will dictate future road placement and trend of preferred layouts
Reflected through lot and house sales
Most cities existing grid consists of what? What is needed to create an entire neighbourhood? What makes their development harder?
Basic roads and large parcels of land
Development must be large enough to accommodate a conceptual neighbourhood plan
Difficult to create when staged development occurs involving different developers of small parcels of land over a long term approach
Reason for naming roads and streets related to what? How are grid roads named?
Underlying hierarchy of street system
Governed by policy
A major consideration in the naming of roads is a clear distinction of location for rapid response by emergency vehicles
Place same named roads close together!
Ex: Birchwood Drive, Birchwood Crescent, Birchwood Place
Grid roads are named either street or avenue
Definition of street? Avenue? Boulevard? Drive? Crescent? Place and Close?
Street
Road which runs in a north south direction, or at right angles to avenues in a grid system
Avenue
Road which runs in east west direction, or at right angles to streets in a grid system
Boulevard
Residential collector meandering through or separating 2 residential areas
May commence and end on the same or different arterial road
Drive
Local road which begins on one collector and ends on another
Crescent
Local road that begins and ends on the same collector
Place and close
Local road which dead ends in a cul de sac or P loop
When developing a community plan, explain why arterial roads are established first. How does this control the pattern for future neighbourhood planning?
Arterial roads are routes for residential neighbourhoods to reach places more than 2km away
neighbourhoods are bounded by arterial roads?
Land access is only secondary for arterial roads
Collectors and locals must stem from arterials to provide land access
Intersections placed 250m or more apart
No parking on arterials
Landscape buffers arterials
Commercial and service development will be on these roads to service the local areas
Placement of arterial influences shape of division of remaining land, determine location of required collectors and locals
When establishing zones or land uses, which are the most dependent on the arterial roads, and why?
High density residential areas and commercial and industrial centres
High volume of traffic
Type of flow (uninterrupted)_
Vehicle type: more trucks, transit vehicles
Intersections and their location are important for the safe and efficient circulation of traffic. Give the primary considerations for intersections in each of these classes of roads.
Local road
Stop signs
70-110 degrees
T intersections only
Access to residences more than 25m away
Connection
Intersections at 70-110 degrees; final alignment maintained for a distance of 30m from centre of intersection
Only 2 streets intersecting
T intersections preferable, with locals
25m away from land accesses
90 degrees to arterials
Stop signs at local roads
Arterial
Widely spaced (250m apart)
Traffic should be less interrupted
Cross intersections
Traffic control devices
90 degrees
