Transportation Flashcards
Explain the concept of sight distance in highway design and its importance in ensuring safe driver visibility.
Sight distance in highway design refers to the length of road visible to a driver, and its importance lies in ensuring safe driver visibility by providing adequate distance for drivers to perceive, react to, and stop for obstacles or changes in the road environment.
Discuss the factors influencing horizontal and vertical alignments in highway geometric design.
The factors influencing horizontal alignments in highway geometric design include design speed, sight distance requirements, topography, and driver expectations, while vertical alignments are influenced by factors such as terrain, drainage considerations, and the need to balance earthwork, collectively ensuring safe and efficient highway operation.
Define the terms “density,” “flow,” and “speed” in the context of traffic flow theory.
In traffic flow theory, density represents the number of vehicles per unit length of road, flow is the rate of vehicles passing a point per unit of time, and speed is the average rate of motion of vehicles, forming the fundamental parameters that characterize traffic behavior.
Define the terms “trip generation,” “trip distribution,” and “mode choice” in transportation planning.
In transportation planning, trip generation refers to the estimation of the number of trips generated by a land use, trip distribution involves determining the destination pattern of these trips, and mode choice is the decision process where travelers choose the transportation mode for their trips, collectively forming key components of the transportation planning process.
Horizontal Curve
STA @ PC= PI -T
STA @ PT= PC + L
Vertical Curve STA @ PVC
STA PVI - L/2
Vertical Curve STA @ PVT
STA PVI + L/2
Vertical Curve EL @ PVC
ELPVI -g1(L/2)
Vertical Curve EL @ PVT
ELPVI -g2(L/2)
Highest point on curve
STA PVC + Xm
