FDOT Roadway Design and Geometric Standards 3 — Questions and Answers
Question 1: What is the minimum median width required for a raised median on a divided arterial to accommodate a left-turn storage lane per FDOT standards?
- 8 feet
- 12 feet (Correct answer)
- 16 feet
- 20 feet
Correct answer: 12 feet
FDOT requires a minimum 12-foot raised median width to accommodate a left-turn storage lane within the median, allowing vehicles to complete left turns safely.
Question 2: According to FDOT horizontal alignment standards, what is the minimum radius of curvature for a 60 mph design speed road with maximum superelevation of 8%?
- 855 feet (Correct answer)
- 1,000 feet
- 1,200 feet
- 1,500 feet
Correct answer: 855 feet
FDOT and AASHTO tables indicate a minimum horizontal curve radius of approximately 855 feet at 60 mph design speed with 8% maximum superelevation.
Question 3: What is the purpose of a 'deceleration lane' in FDOT intersection design?
- Allow through traffic to speed up before merging
- Provide a separate lane for turning vehicles to slow down without impeding through traffic (Correct answer)
- Mark the transition from freeway to arterial speeds
- Separate bicycle traffic from vehicular traffic
Correct answer: Provide a separate lane for turning vehicles to slow down without impeding through traffic
A deceleration lane provides turning vehicles a separate space to reduce speed without disrupting the flow of through traffic in the travel lanes.
Question 4: What FDOT document would a designer reference for standard pedestrian ramp (curb ramp) details?
- FDOT Plans Preparation Manual
- FDOT Design Standards Index 304 (Correct answer)
- FDOT ADA Transition Plan
- FDOT Pedestrian Safety Action Plan
Correct answer: FDOT Design Standards Index 304
FDOT Design Standards Index 304 provides standard curb ramp designs, dimensions, and detectable warning surface requirements for pedestrian accessibility.
Question 5: In FDOT pavement design, what does 'ESAL' stand for?
- Equivalent Single Axle Load (Correct answer)
- Estimated Surface Aggregate Loss
- Effective Structural Asphalt Layer
- Edge of Shoulder At-grade Level
Correct answer: Equivalent Single Axle Load
ESAL stands for Equivalent Single Axle Load, the standard unit for measuring pavement damage caused by different vehicle axle loads relative to an 18-kip single axle.
Question 6: What is the standard posted speed limit increment used on Florida State Highway System roads?
- 2 mph increments
- 5 mph increments (Correct answer)
- 10 mph increments
- Exact engineering calculations
Correct answer: 5 mph increments
Speed limits on Florida's State Highway System are posted in 5 mph increments (e.g., 25, 30, 35, 40 mph) following standard traffic engineering practice.
FDOT Roadway Design and Geometric Standards 3
What is the minimum median width required for a raised median on a divided arterial to accommodate a left-turn storage lane per FDOT standards?