1
FHWA
What is the Federal Highway Administration?
For passenger travel, highways account for about ___% of all passenger-miles
90
Effort vs Resistance
Tractive effort is simply the force
available at the roadway surface to
perform work (expressed in lbs [N])
Resistance (expressed in lbs [N]) is
defined as the force impeding vehicle
motion
Factors affecting rolling resistance
Rigidity of tire and roadway surface
Tire inflation pressure and temperature
Vehicle speed
Spiral Curve
is a curve of gradually increasing radius that allows an easy transition between a circular arc and a straight on a road or railway.
What is the Federal Aviation Administration?
Trucks account for about __% of the freight ton-miles and nearly __% of the value of all transported goods
37, 80
Aerodynamic resistance originates from a
number of sources
Turbulent flow of air around the vehicle body
(≈ 85%)
Friction of air passing over vehicle body (≈ 12%)
Air flow through vehicle components such as
radiators and air vents (≈ 3%)
PTSF
PSI
TSI
AASHTO
Percent Time Spent Following
Present Serviceability Index
Terminal Serviceability Index
American Association of State Highways and Transportation Officials
Superelevation
Superelevation is defined as the amount by which the outer edge of a curve on a road or railroad is banked above the inner edge.
FTA
What is the Federal Transit Administration?
1.New advances in traffic signal timing and coordination
2. New traffic controls, safety, navigation, and congestion-mitigation tech
3. system reliability, human response, and the human/tech response
Sources of Rolling Resistance
Primary source (about 90%) of this resistance is
the deformation of the tire as it passes over the
roadway surface.
Tire penetration/roadway surface compression
(about 4%)
Tire slippage and air circulation around tire &
wheel (about 6%)
Simple Curve
A simple circular curve is a curve consists of a single arc with a constant radius connecting the two tangents.
T or F
For a horizontal curve on a two-lane highway, Rv is equal to R plus half the lane width
False
NHTSA
National Highway Traffic Safety Administration
PC
PT
PI
PVI
PVC
PVT
Point of Curve
Point of Tangent
Point of Intersection
Point of Vertical Intersection
Point of Vertical Curve
Point of Vertical Tangent
Grade Resistance
The grade resistance is determined
simply as the component of the vehicle
weight acting parallel to the roadway
surface
Compound Curve
A compound curve is a curve made up of two or more circular arcs of successively shorter or longer radii, joined tangentially without reversal of curvature.
T or F
1 horsepower equals 550 watts
F
1 horsepower equals 550 lb*ft/s
Secretary of Transportation
Pete Buttigieg
AADT
CBR
LOS
PHF
PF
pcphpl
DHV
PCE
Annual Average Daily Traffic
California Bearing Ratio
Level-of-service
Peak-hour factor
Progression Adjustment Factor
Passenger Car per hour per lane
Design Hour Volume
Passenger-car equivalency
AASHTO Code for SSD
tr=2.5 sec
a= 11.2 ft/s2
f= 0.35
G= 5%
Reverse Curve
is a section of a horizontal alignment on highways or railroad tracks, produced by the joining of two curves that turn in opposite directions.
CBR Test
CBR is test is a penetration test used to evaluate the surface layer strength of roads and pavements.