Category: Smart Path
Topic: Smart path speed vs Speed report speed
Answer: The speed input in the SmartPath tool influences the minimum radius for the trajectory of the vehicle (maximum turning angle, or the tightest possible arc path that can be achieved).
However, when generating a Speed Profile Report, it generates the ‘maximum’ speed that the vehicle can travel at any given point. The speed calculated in the Speed Profile Report is based on the vehicle’s trajectory that has been drawn, using the equation:
| Metric | |
| Imperial |
R = Radius (m or ft)
V = Speed (km/h or mph)
e = Superelevation (m/m or ft/ft, e.g., 0.02 = 2/100)
f = Friction (e.g., 0.03)
(Reference to AASHTO Green Book).
This will draw a graph for the value V in the formula, and will take the radius (R), superelevation (e) and coefficient of lateral friction (f) into account, and the values for acceleration and deceleration as set in the configuration dialog box for Speed Profile Report.
The Speed Profile Report will display the highest achievable speed up to the Vmax value, not the speed used to create the original arc path.
Minimum turn speed (Smart Path tool) vs Maximum achievable speed (Speed Profile)