Transportation and Geometrics Flashcards
What does PT stand for, where is is and what is it?
what is jam density and what is the equation for it?
what is free flow speed and how is it calculated
how do you fins capacity of a highway section?
by determining the peak of the speed-flow or flow density curves - qCAP
In a horizontal curve formulas what point is PC also called?
BC, begining of curve equal point of curve
In a horizontal curve formulas what point is PC also called?
BC, beginning of curve = point of curve PC
In a horizontal curve formulas what point is PT also called?
EC, ending point of curve = PT point of tangenet
In a horizontal curve formulas what point is PT also called?
EC, ending point of curve = PT point of tangent
What is PI ?
point at which the two tangents meet
For intersection of freeway ramp terminals with aerial crossroads geometrical design, what type of vehicle would be a good design vehicle?
Interstate semitrailer
For intersection of freeway ramp terminals with aerial crossroads geometrical design, name 3 types of vehicles that would be bad design vehicle?
passenger car, Single unit Truck, City transit bus
Define headway
the time interval between two consecutive vehicles
Define Saturation Headway
is the headway when traffic volume reaches the freeway capacity
Define Freeway Capacity
this is the maximum # of vehivles that can pass through the freeway section in *1 hour (check 1 hour)
Equation for Station of PT?
Sta PT= sta PC + L ( not given)
Equation for station of PC
Sta PC = Sta PI -T
How do you convert D° M’ S’’ to just degrees
D°+ (M/60)+(S/3600)
how to convert feet to a station
feet/ 100 = X.00
convert “.” to “+”
Equation for station PVC?
Sta PVC = Sta PVI - (L/2)
PVC station + Xm =?
The station of the point of max elevation on the vertical curve
what is an equation of the point at the same horizontal distance as PVC but on the back tangent line*
=PVC elevation + g1 (L)
what is The vertical distance from the previous point to PVT, and the equation
vertical distance of Tangent outset = Y
y=((g2-g1)/2L)*L^2
how to find the elevation of PVT given y and***
using the Curve elevation equation, where is the maximum curve elevation?
where X = Xm
for horizontal curves what does M represent?
