Operational Effects of Geometric Design Flashcards
What is the basis for classifying the highway and street network?
Land access and mobility
Road classifications
- Principal Arterial
- Minor Arterial
- Major Collector
- Minor Collector
- Local Road
Context Sensitive Design
Create projects that function safely and efficiently and are pleasing to users and neighboring community
Access Control
legal limitation or restriction of access to and from properties neighboring highway facilities
A person’s ability to recognize and respond to a situation that may require a decision and action
perception-reaction time
What PRT is used for calculating stopping sight distance?
2.5 seconds
Vulnerable Road User
a road user unprotected by an outside shield
includes pedestrians, bicyclists, person operating a personal mobility device, motorcyclists, etc.
Design speed
selected speed used to determine various geometric design features of the roadway
High and low speed design threshold
high-speed: 50 mph or greater
low-speed: 45 mph or less
Driver eye height
3.5 feet
Target height (SSD)
2 feet
Target height (PSD)
3.5 feet, represents upper portion of opposing car
L=KA
L = length of vertical curve (ft or m)
K = horizontal distance to affect one percent change in grade
A = absolute value of algebraic difference in grades (percent)
What criteria are used to establish length of sag vertical curves?
headlight sight distance
passenger comfort
drainage control
general appearance
Headlight height (sight distance for sag vertical curve)
2.0 feet
