Unit 7. Intro to Route Surveys Flashcards
is a survey for the design and construction of linear works, such as roads and pipelines.
ENGINEERING (ROUTE) SURVEYING
establish the location of transportation routes such as highways and roads, railways, rapid transit, canals, pipelines, and transmission lines.
ENGINEERING (ROUTE) SURVEYING
are information about the elevation of the surface of the Earth.
Topographic data
The “shape” or “geometry” of any transportation route.
ALIGNMENT
are horizontal tangents (straight roadway sections), circular curves, and spiral transitions.
HORIZONTAL ALIGNMENT
consists of gradients (straight lines in a vertical plane) and vertical curves typically represented by a profile.
VERTICAL ALIGNMENT
A straight-line section of a road or railway alignment.
TANGENT
The rate of rise or fall along the length of the road with respect to the horizontal.
GRADIENT
A set of points whose horizontal locations and interrelationships have been precisely determined in order to serve as stable references for positioning and correlating map features.
HORIZONTAL CONTROL
Determines the elevation above sea level.
VERTICAL CONTROL
A situation in which one party utilizes another party’s property in exchange for a fee paid to the property owner in exchange for the right of easement.
EASEMENT
ROUTE SURVEY REPRESENTATION (2)
INSTRUMENT SURVEYING
EXPLORATORY SURVEYING
is that condition where highway sight distances, as governed by both horizontal and vertical restrictions, are generally long or could be made to be so without construction difficulty or major expense
LEVEL TERRAIN
having cross slope varying from 0% to 10%
LEVEL TERRAIN
is that condition where the natural slopes consistently rise above and fall below the road or street grade and where occasional steep slopes offer some restriction to normal horizontal and vertical roadway alignment
ROLLING TERRAIN
having cross slope varying from 10% to 25%
ROLLING TERRAIN
generates steeper grades, causing trucks to reduce speeds below those of passenger cars
ROLLING TERRAIN
is that condition where longitudinal and transverse changes in the elevation of the ground with respect to the road or street are abrupt and where benching and side hill excavation are frequently required to obtain horizontal and vertical alignment
MOUNTAINOUS TERRAIN
having cross slope varying from 25% to 60%
MOUNTAINOUS TERRAIN
aggravates the situation, resulting in some trucks operating at crawl speeds
MOUNTAINOUS TERRAIN
determined by dividing a count of the total yearly traffic volume by 365. Units are vehicles per day.
AADT - Annual average daily traffic
results from dividing a traffic count obtained during a given time period by the number of days in that time period.
ADT - Average daily traffic
A survey that identifies the legal boundaries between public and private lands.
Cadastral Survey
The maximum safe speed that can be maintained when conditions permit the design features of the highway to govern.
Design Speed
The percentage of the two-way traffic volume traveling in the direction of interest, expressed as a decimal.
D - Directional distribution
The two-way traffic volume that is determined by multiplying the ADT by a percentage factor called the K-factor.
DHV - Design hour volume
expressed as vehicles per hour.
DDHV - Directional design hour volume
The classification of roadways by operational status such as freeway, arterial, collectors and local.
Functional Class
The proportion of daily traffic occurring during the peak hour, expressed as a decimal.
K-factor
For design purposes, K represents the proportion of AADT occurring during the ___ peak hour of the year.
thirtieth highest
A survey of the centerline of a planned or existing highway.
Located Centerline Survey
Illustrates features such as roads, buildings, water, fences, vegetation, bridges, railroads.
Planimetric Map
Points along a line (usually a survey line) of equal distance designated either in feet or meters. Points at multiples of 100 meters or feet are typically called full stations.
Stations
Illustrates elevation with the use of contour lines and spot elevations.
Topographic Map
A survey that establishes the configuration of the ground and the location of natural and man-made objects.
Topographic Survey
Purpose of preliminary survey (3)
- To survey the various alternative alignments proposed after the reconnaissance and to collect all the necessary physical information and detail of topography, drainage and soil.
- To compare the different proposals in view of the requirements of the good alignment.
- To estimate quantity of earthwork materials and other construction aspect and to work out the cost of the alternate proposals.
METHODS OF PRELIMINARY SURVEY (2)
Conventional approach
Modern rapid approach
The survey party carries out surveys using the required field equipment, taking measurements, collecting topographical and other data, and carrying out soil surveys.
Conventional approach
It is done by aerial survey taking the required aerial photographs for obtaining the necessary topographic and other maps, including details of soil and geology.
Modern rapid approach
is the viewable distance required for a driver to see so that he or she can make a complete stop in the event of an unforeseen hazard.
Stopping Sight Distance (SSD)
SSD is made up of two components: (1) ___ and (2) ___.
Braking Distance
Perception-Reaction Time
is the minimum distance required for the driver to stop a vehicle moving at design speed, without colliding with an obstruction.
Stopping sight distance
SSD = ___ distance + ___ distance
Lag
Braking
