Evaluates the fastest path for an adaptive roundabout created with the Roundabout Wizard tool. The results are calculated and drawn in the roundabout, and can be saved to a file.

The fastest path is the largest possible radii centerline path approximated based on the critical offsets (median offset, edge offset, central island offset) for the through path or turn path (for more information on the fastest path, see Overview -> Fastest Path).

Evaluate Fastest Path - Adaptive Roundabout Dialog Box

Vehicle Section

Vehicle

Displays the name of the design vehicle that is used to create the fastest path movement. Initially, the list contains a default design vehicle. Vehicles specified via Select Vehicle are added to the list.

Button	Option	Click to...
	Select Vehicle	Open the Design Vehicles dialog box to specify a different design vehicle for the fastest path movement.

Hint: Ensure that you use appropriate design vehicles to govern the fastest paths.

Fastest Path Settings Section

Button	Option	Click to...
	Fastest Path Settings	Open the Fastest Path Settings dialog box to specify the acceleration/deceleration rates, superelevation, plan speed markers and distance settings.

Tire Track Offsets Section

The offsets are the minimum distances measured to the design vehicle's tire tracks. The fastest path is then derived from the center of the design vehicle's steering axle group as it navigates from the entry leg to the exit leg.

Entry Median Offset

Specify the entry median offset value. This is the distance from the entry-side splitter island envelope or reference geometry to the tire tracks of the fastest path design vehicle.

Entry Edge Offset

Specify the entry edge offset value. This is the distance from the entry-side right turn edge to the tire tracks of the fastest path design vehicle.

Central Island Offset

Specify the central island offset value. This is the distance from the central island to the tire tracks of the fastest path design vehicle.

Exit Median Offset

Specify the exit median offset value. This is the distance from the exit-side splitter island envelope or reference geometry to the tire tracks of the fastest path design vehicle.

Exit Edge Offset

Specify the exit edge offset value. This is the distance from the entry-side right turn edge to the tire tracks of the fastest path design vehicle.

Apply to All Fastest Paths

Click this button to apply the currently displayed Approach Offset values to all approaches.

Fastest Path Results Section

Draw

Turns fastest paths on/off. This option is useful when you want to view certain fastest paths independently.

Note: All through fastest paths are drawn by default for Adaptive Roundabouts.

Entry Leg

Displays the name of the entry approach leg.

Exit Leg

Displays the name of the exit approach leg.

VEntry, VInt. (VIntermediate), VExit

Displays the fastest path speed values that TORUS calculates for the corresponding travel path radii.

REntry, RInt. (RIntermediate), RExit

Displays the travel path critical radii:

• REntry - the entry path radius, which is the minimum radius on the fastest through path of a vehicle traveling prior to the inscribed circle.
• RInt. (RIntermediate) - the circulatory path radius, which is the minimum radius on the fastest through path of a vehicle traveling around the central island.
• RExit - the exit path radius, which is the minimum radius on the fastest through path of a vehicle traveling into the exit.

Annotations Section

Speed Based on radii

Select this check box to display the speed and radii of the fastest paths.

Speed Based on acceleration/deceleration

Select this check box to display the plan speed markers along the fastest paths.

Display Options Section

Highlight selected fastest path

Select this check box to highlight the selected fastest path in the adaptive roundabout drawing.

Preview tire tracks

Select this check box to view the tire tracks of the selected fastest paths.

OK & Hide

Click this button after evaluating the fastest path to hide the fastest path in the drawing and from other editing tools. The fastest paths will be turned on again as soon as the Evaluate Fastest Path tool is used on the adaptive roundabout again.