DRAFT Comprehensive Transportation Plan Update: February 23, 2018 version

MULTI -USE PATH

DESIGN

GUIDELINES

Figure F-1: AASHTO Guide to Bicycle Facilities Typical Cross Section of Two-Way, Shared Use Path on Independent Right-of-Way

HORIZONTAL OFFSETS Horizontal offsets need to be used in locations where the multi-use path is adjacent to parallel bodies of water (outside of the floodplain) or

on a downward slope. Table F-2 presents the projected slopes to provide horizontal offset ratios from the bottom of a designated bank.

Refer to the Drainage and Erosion Section of the AASHTO guide for additional horizontal offset for paths within a floodplain.

Guidelines:  When the projected slope is 1V:3H or steeper, the multi-use path must have a reasonable offset from the top of the bank or hinge

point.

 The edge of the shoulder must be 5 feet from the top of the bank/hinge point or the projected slope ( Table F-2 ), whichever is

greater.

 Depending on the bank height and conditions at the bottom of the bank, a physical barrier, such as a fence, railing, or dense

shrubbery, may be necessary.

 If a minimum 5-foot recoverable area (i.e., the distance between the edge of the path and the hinge point) cannot be achieved, a

physical barrier or rails are recommended.

Table F-2. Projected Slopes to Provide Horizontal Offset

CONDITION

PROJECTED SLOPE FROM BOTTOM OF BANK 1

1.5:1

Bank in residual soils

2:0:1

Bank in fills soils

2:5:1

Bank in coastal plain soils

Bank in alluvial soils 2 3:0:1 1 Only valid if bank height is 15 feet or less. Anything greater than 15 feet need to be assessed individually. 2 Assume this condition if no other information is available.

HORIZONTAL CURVES

The horizontal curve radius must be based on the chosen design speed, typically assumed for multi-use paths to be between the 18-and

30-mph case. The multi-use path alignment must follow the contours of the land closely and, to the extent possible, preserve the natural

terrain and vegetation. Meanders can be evaluated to provide potential tree preservation.

Guidelines  Installation of signage warning of sharp turns needs to be implemented if sharper radii are used.

 Meanders in the path must be limited and appear to have a purpose.

 The NCDOT desired minimum horizontal curve is 60 feet, (18 mph design speed) but when ample room exists curves greater than

60-foot radii need to be implemented.

F-3 | P A G E D R A F T | 0 2 / 2 3 / 2 0 1 8