Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D...
Transcript of Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D...
![Page 1: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/1.jpg)
Geometric Review and Design (GRAD)
Horizontal
Alignment
3
![Page 2: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/2.jpg)
32 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Identify the Design Elements of Horizontal Alignments
Understand how to Design Horizontal Alignments to a Given Design Speed
Understand how to design appropriate superelevation design
Learning Objectives
![Page 3: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/3.jpg)
33 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Tangents
Circular Curves
Spiral (Transition) Curves
Superelevation
Elements of Horizontal Alignments
![Page 4: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/4.jpg)
34 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Sect 202
Maximum Deflection without
Horizontal Curve
Angle varies with the design speed of the roadway
Recommended Minimum Distance
between Consecutive Horizontal
Deflections
High speed / Low speed
Horizontal Alignments - Curves
![Page 5: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/5.jpg)
35 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Horizontal Alignments - Curves
![Page 6: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/6.jpg)
36 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Horizontal Alignments - Curves
![Page 7: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/7.jpg)
37 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Types of Curves
Simple Curves
Compound Curves
Reverse Curves
Spiral Curves
Horizontal Alignments - Curves
![Page 8: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/8.jpg)
38 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Key Elements of a Horizontal
Curve
Simple Curves
![Page 9: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/9.jpg)
39 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Degree vs. Radius
Degree of curve is the central angle subtended by a 100-foot arc for a given radius.
Example: Degree of curve for R = 1909 feet
Simple Curves
![Page 10: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/10.jpg)
310 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Degree vs. Radius
Degree of curve is the central angle subtended by a 100-foot arc for a given radius.
Example: Degree of curve for R = 1909 feet
D = 3°
Simple Curves
![Page 11: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/11.jpg)
311 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Degree vs. Radius
Degree of curve is the central angle subtended by a 100-foot arc for a given radius.
Example: Degree of curve for R = 1909 feet
D = 3°
Example: Radius of curve for D = 9.5°
Simple Curves
![Page 12: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/12.jpg)
312 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Degree vs. Radius
Degree of curve is the central angle subtended by a 100-foot arc for a given radius.
Example: Degree of curve for R = 1909 feet
D = 3°
Example: Radius of curve for D = 9.5°
R = 603 feet
Simple Curves
![Page 13: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/13.jpg)
313 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
2 horizontal curves in the same
direction
Utilize a common tangent
From AASHTO: It is preferable that the
ratio of the flatter radius to the
sharper radius not exceed 2:1 *
Should be used with caution!
Compound Curves
* A Policy on Geometric Design of Highways and Streets, 7th
Edition (2018) - Section 3.3.7.3
![Page 14: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/14.jpg)
314 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
2 horizontal curves in opposite directions separated by a tangent with sufficient length to rotate superelevation from one curve to the next.
Superelevation - The cross slope of the pavement used to compensate for the effect of centrifugal force on horizontal curves
Reverse Curves
![Page 15: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/15.jpg)
315 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Combination of high speed and
sharp curvature leads to longer
transition paths, which can result in
shifts in lateral position and
sometimes actual encroachment
into adjacent lanes.
Should be used on new alignments
based on the maximum degree of
curve as shown in Figure 202-11.
Length of spiral should be equal or
greater than superelevation runoff
length for the curve.
Spiral Curves
![Page 16: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/16.jpg)
316 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Spiral Curves
Key Elements of a Spiral
Curve
![Page 17: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/17.jpg)
317 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Sect 202.4
Increasing the cross slope to
keep vehicles on the road
through the horizontal
curve
Implemented by raising the
pavement outer edge with
respect to the inner edge.
Superelevation
![Page 18: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/18.jpg)
318 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Recommended rates
Rural Highways (0.08 max) –
Figure 202-7
Urban Highways (high speed – 0.06
max) – Figure 202-8
Urban Ramps and Interchange
(low speed – 0.06 max) – Figure
202-10
Urban Highways (low speed – 0.04
max) – Figure 202-9; Figure 202-9a
Superelevation
![Page 19: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/19.jpg)
319 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Can be difficult to apply
recommended superelevation rates
on urban roadways because of:
Wide pavements
Adjacent development
Drainage conditions
Frequent access points
In these cases, may use reduced or
no superelevation although Crown
Removal is recommended min.
Superelevation – 0.04 Figure
![Page 20: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/20.jpg)
320 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Required whenever rate specified in Figures 202-7 through 202-10 is not provided.
Not required if a higher superelevation rate than what is specified in Figures 202-7 through 202-10 is provided as long as the rate doesn’t exceed the maximum superelevation rate for that given figure.
Superelevation – Design Exceptions
![Page 21: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/21.jpg)
321 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Maximum curvature (minimum
curve radius) that doesn’t
require superelevation based on
design speed and rural/urban
condition (Figure 202-3)
Can also use Figures 202-7, 202-
8, and 202-9 to determine these
values.
Maximum Curvature without Superelevation
![Page 22: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/22.jpg)
322 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Figures also show maximum
curvature for given design speed
(confirmed in Figure 202-2)
Maximum Curvature without Superelevation
![Page 23: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/23.jpg)
323 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Four methods:
1. Revolve pavement about the
centerline (most commonly used)
2. Revolve pavement about the inner
edge of traveled way
3. Revolve pavement about the outer
edge of traveled way
4. Revolve pavement having a straight
cross slope (no crown) about the
outside edge of traveled way (ramps
typically)
Superelevation Methods
![Page 24: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/24.jpg)
324 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Key Terms:
Normal Crown (Point A)
Adverse Crown Removed (Point B; also known as “half flat”)
Crown Removal (Point C)
PC/PT of curve (Point D) Superelevation rate is 50-70% design rate
Full Super (Point E) Design superelevation rate
Tangent Runout Normal Crown to Adverse Crown Removed
Superelevation Runoff Adverse Crown Removed to Full Super
Superelevation Transitions
![Page 25: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/25.jpg)
325 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
With Spirals
Transition from Adverse Crown
Removed to Full Super shall occur
within the limits of the spiral.
Superelevation Position Spiral Length
![Page 26: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/26.jpg)
326 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
With Spirals
Transition from Adverse Crown
Removed to Full Super shall occur
within the limits of the spiral.
Simple Curves – No Spirals
50%-70% of maximum
superelevation rate is outside the
curve limits; 2/3 of
superelevation rate at PC and PT
Prefer to have full superelevation
rate maintained for 1/3 of curve
length
Superelevation Position
2/3 (e(des) rate)
![Page 27: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/27.jpg)
327 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Determine width of pavement
that is being rotated
Superelevation Transitions
![Page 28: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/28.jpg)
328 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Determine width of pavement
that is being rotated
Identify Adjustment Factor (bw)
“Credit” for rotating more than
one lane
Superelevation Transitions
![Page 29: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/29.jpg)
329 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Determine width of pavement
that is being rotated
Identify Adjustment Factor (bw)
“Credit” for rotating more than
one lane
Identify Equivalent Slope Rate (G)
For the given Design Speed
Superelevation Transitions
![Page 30: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/30.jpg)
330 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Determine width of pavement
that is being rotated
Identify Adjustment Factor (bw)
“Credit” for rotating more than
one lane
Identify Equivalent Slope Rate (G)
For the given Design Speed
Calculate Superelevation Runoff
(Lr)
Superelevation Transitions
![Page 31: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/31.jpg)
331 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Determine width of pavement
that is being rotated
Identify Adjustment Factor (bw)
“Credit” for rotating more than
one lane
Identify Equivalent Slope Rate (G)
For the given Design Speed
Calculate Superelevation Runoff
(Lr)
Calculate Tangent Runout (Lt)
Superelevation Transitions
![Page 32: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/32.jpg)
332 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Example - Determine Superelevation
Degree of Curve = 3.0°
Design Speed = 60 mph
Urban Location
Superelevation
![Page 33: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/33.jpg)
333 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Example - Determine Superelevation
Degree of Curve = 3.0°
Design Speed = 60 mph
Urban Location
Radius of Curve = 1,910 feet
Superelevation
![Page 34: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/34.jpg)
334 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Example - Determine Superelevation
Degree of Curve = 3.0°
Design Speed = 60 mph
Urban Location
Radius of Curve = 1,910 feet
e(des) = 0.055 ft/ft
Superelevation
![Page 35: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/35.jpg)
335 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Example - Determine Superelevation
Radius of Curve = 1,550 feet
Design Speed = 50 mph
Urban Location
Superelevation
![Page 36: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/36.jpg)
336 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Example - Determine Superelevation
Radius of Curve = 1,550 feet
Design Speed = 50 mph
Urban Location
Degree of Curve = 3°42’
Superelevation
![Page 37: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/37.jpg)
337 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Example - Determine Superelevation
Radius of Curve = 1,550 feet
Design Speed = 50 mph
Urban Location
Degree of Curve = 3°42’
e(des) = 0.050 ft/ft
Superelevation
![Page 38: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/38.jpg)
338 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Example – determine
superelevation rotation
placement
Design Speed = 50 mph
Undivided Highway
Rotate 2-12’ lanes
PC Station = 100+73.35
e(des) = 0.050 ft/ft
Superelevation Transitions
![Page 39: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/39.jpg)
339 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Example – determine
superelevation rotation
placement
Design Speed = 50 mph
Undivided Highway
Rotate 2-12’ lanes
PC Station = 100+73.35
e(des) = 0.050 ft/ft
Superelevation Transitions or
![Page 40: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/40.jpg)
340 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Example – determine
superelevation rotation
placement
Design Speed = 50 mph
Undivided Highway
Rotate 2-12’ lanes
PC Station = 100+73.35
e(des) = 0.050 ft/ft
Superelevation Transitions or
![Page 41: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/41.jpg)
341 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Example – determine
superelevation rotation
placement
Design Speed = 50 mph
Undivided Highway
Rotate 2-12’ lanes
PC Station = 100+73.35
e(des) = 0.050 ft/ft
Superelevation Transitions
![Page 42: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/42.jpg)
342 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Example – determine
superelevation rotation
placement
Design Speed = 50 mph
Undivided Highway
Rotate 2-12’ lanes
PC Station = 100+73.35
e(des) = 0.050 ft/ft
Superelevation Transitions
![Page 43: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/43.jpg)
343 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Example – determine
superelevation rotation
placement
Design Speed = 50 mph
Undivided Highway
Rotate 2-12’ lanes
PC Station = 100+73.35
e(des) = 0.050 ft/ft
Superelevation Transitions
![Page 44: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/44.jpg)
344 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Example – determine
superelevation rotation
placement
Design Speed = 50 mph
Undivided Highway
Rotate 2-12’ lanes
PC Station = 100+73.35
e(des) = 0.050 ft/ft
Superelevation Transitions
![Page 45: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/45.jpg)
345 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Example – determine
superelevation rotation
placement
Design Speed = 50 mph
Undivided Highway
Rotate 2-12’ lanes
PC Station = 100+73.35
e(des) = 0.050 ft/ft
Superelevation Transitions
![Page 46: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/46.jpg)
346 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Example – determine
superelevation rotation
placement
Design Speed = 50 mph
Undivided Highway
Rotate 2-12’ lanes
PC Station = 100+73.35
e(des) = 0.050 ft/ft
Superelevation Transitions
![Page 47: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/47.jpg)
347 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Each curve has its own superelevation runoff value
New Alignments
PT and PC should be separated enough
for a smooth transition at a rate not
to exceed “G” value in Figure 202-4.
Distance to be not less than 50% nor
greater than 70% of Lr1 + Lr2. 2/3
(67%) is preferred.
Existing Alignments
Conform as closely as possible to New
Alignments criteria.
Superelevation - Reverse Curves
![Page 48: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/48.jpg)
348 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Example – determine
superelevation rotation
placement
Design Speed = 50 mph
Undivided Highway
Rotate 2-12’ lanes
PC Station = 100+73.35
e(des) = 0.050 ft/ft
Superelevation Transitions
![Page 49: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/49.jpg)
349 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Superelevation Exaggerated Profiles
![Page 50: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/50.jpg)
350 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Superelevation Exaggerated Profiles
Y = (enc) X
(rotating pavement width)
![Page 51: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/51.jpg)
351 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Superelevation Exaggerated Profiles
Y = (enc) X
(rotating pavement width)
Y = (FS cross slope) X
(rotating pavement width)
Y = (-FS cross slope) X
(rotating pavement width)
![Page 52: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/52.jpg)
352 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Superelevation Exaggerated Profiles
Y = (enc) X
(rotating pavement width)
Y = (FS cross slope) X
(rotating pavement width)
Y = (-FS cross slope) X
(rotating pavement width)
![Page 53: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/53.jpg)
353 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Superelevation Exaggerated Profiles
Y = (enc) X
(rotating pavement width)
Y = (FS cross slope) X
(rotating pavement width)
Y = (-FS cross slope) X
(rotating pavement width)
PC = 2/3 x Superelevation Rate)
![Page 54: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/54.jpg)
354 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Superelevation Exaggerated Profiles
Y = (enc) X
(rotating pavement width)
Y = (FS cross slope) X
(rotating pavement width)
Y = (-FS cross slope) X
(rotating pavement width)
PC = 2/3 x Superelevation Rate)L = [(ePC/eDES) x Lr]
![Page 55: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/55.jpg)
355 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Superelevation Exaggerated Profiles
Y = (enc) X
(rotating pavement width)
Y = (FS cross slope) X
(rotating pavement width)
Y = (-FS cross slope) X
(rotating pavement width)
PC = 2/3 x Superelevation Rate)L = [(ePC/eDES) x Lr]
L = Lt L = Lt
![Page 56: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/56.jpg)
356 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Superelevation Exaggerated Profiles
![Page 57: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/57.jpg)
357 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Information reviewers
should look for:
Superelevation Rate
Transition Length
Transition Rate
Super Rate at PC
Super Rate at PT
Length of curve/time at full superelevation
Superelevation Review
![Page 58: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/58.jpg)
358 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
For horizontal alignment
design elements that
don’t meet standards
Chevrons
Rumble Strips
Curve Ahead Signage
Curve Widening
Place the wider shoulder on the left (instead of right) side
Safety Countermeasures
![Page 59: Geometric Review and Design (GRAD) 3...Spiral Curves 3 16| Module 3 –Horizontal Alignment ODOT L&D Vol. 1 –Section 200 Spiral Curves Key Elements of a Spiral Curve 3 17| Module](https://reader034.fdocuments.in/reader034/viewer/2022051607/603699eec33fc77d9a70b5b8/html5/thumbnails/59.jpg)
359 | Module 3 – Horizontal Alignment
ODOT L&D Vol. 1 – Section 200
Key Terms
Horizontal Alignments
Tangents
Curves
Spirals
Horizontal Curves
Simple Curves
Compound Curves
Reverse Curves
Spiral Curves
Tangent Runout (NC to ACremoved)
Superelevation Runoff (ACremoved to FS)
Module Review