Chapter 4 - Elements of Design
4.2. Horizontal Alignment
4.2.3. Pavement Widening on Curves
On modern highways and streets that feature 12-ft. lanes and high-type alignments, the need for widening on curves has decreased considerably in spite of high speeds. In many cases, degrees of curvature and pavement widths established by policies in this Design Manual preclude the necessity of pavement widening on roadway curves. This is especially true if the alignments are as directional as practical, consistent with the topography, and developed properties and community values are preserved (see Section 4.2.1. General Considerations). However, for some conditions of speed, curvature, and width, it may still be necessary to widen pavements. Widening should be evaluated at the following locations:
- low speed roadways with near maximum curvature
- ramps
- connecting roadways
- where curves sharper than those specified in this Manual are used
Specific values for pavement widening in curves are shown in Table 4.2. Pavement Widening on Curves on Two-Lane Roadways. For additional discussion and widening values, refer to the AASHTO Green Book, Chapter 3. Elements of Design – Traveled Way Widening on Horizontal Curves. Widening less than 2-ft. is considered impractical and will not be required.
Table 4.2. Pavement Widening on Curves on Two-Lane Roadways |
Degree Curve |
Radius (ft.) |
24-ft. Roadway |
22-ft. Roadway |
20-ft. Roadway |
30 (mph) |
40 (mph) |
50 (mph) |
60 (mph) |
70 (mph) |
30 (mph) |
40 (mph) |
50 (mph) |
60 (mph) |
70 (mph) |
30 (mph) |
40 (mph) |
50 (mph) |
60 (mph) |
1.00 |
5,729.58 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.5 |
0.5 |
0.5 |
1.0 |
1.0 |
1.5 |
1.5 |
1.5 |
2.0 |
2.00 |
2,864.79 |
0.0 |
0.0 |
0.0 |
0.5 |
0.5 |
1.0 |
1.0 |
1.0 |
1.5 |
1.5 |
2.0 |
2.0 |
2.0 |
2.5 |
3.00 |
1,909.86 |
0.0 |
0.0 |
0.5 |
0.5 |
1.0 |
1.0 |
1.0 |
1.5 |
1.5 |
2.0 |
2.0 |
2.0 |
2.5 |
2.5 |
4.00 |
1,432.39 |
0.0 |
0.5 |
0.5 |
1.0 |
1.0 |
1.0 |
1.5 |
1.5 |
2.0 |
2.0 |
2.0 |
2.5 |
2.5 |
3.0 |
5.00 |
1,145.92 |
0.5 |
0.5 |
1.0 |
1.0 |
|
1.5 |
1.5 |
2.0 |
2.0 |
|
2.5 |
2.5 |
2.5 |
3.5 |
6.00 |
954.93 |
0.5 |
1.0 |
1.0 |
1.5 |
|
1.5 |
2.0 |
2.0 |
2.5 |
|
2.5 |
3.0 |
3.0 |
|
7.00 |
818.51 |
0.5 |
1.0 |
1.5 |
|
|
1.5 |
2.0 |
2.5 |
|
|
2.5 |
3.0 |
3.5 |
|
8.00 |
716.20 |
1.0 |
1.0 |
1.5 |
|
|
2.0 |
2.0 |
2.5 |
|
|
3.0 |
3.0 |
3.5 |
|
9.00 |
636.62 |
1.0 |
1.5 |
2.0 |
|
|
2.0 |
2.5 |
3.0 |
|
|
3.0 |
3.5 |
4.0 |
|
10.18 |
562.64 |
1.0 |
1.5 |
|
|
|
2.0 |
2.5 |
|
|
|
3.0 |
3.5 |
|
|
12.24 |
488.04 |
1.0 |
2.0 |
|
|
|
2.5 |
3.0 |
|
|
|
3.5 |
|
|
|
15.30 |
374.48 |
2.0 |
|
|
|
|
3.0 |
|
|
|
|
4.0 |
|
|
|
19.35 |
296.10 |
2.5 |
|
|
|
|
3.5 |
|
|
|
|
4.5 |
|
|
|
22.42 |
255.59 |
3.0 |
|
|
|
|
4.0 |
|
|
|
|
5.0 |
|
|
|
26.44 |
216.69 |
3.5 |
|
|
|
|
4.5 |
|
|
|
|
5.5 |
|
|
|
Notes:
1. Values for widening (ft.) for two-lane roadways - one-way or two-way traffic
2. Disregard values less than 2.0-ft. (above heavy line and not within highlighted area) for two-lane (one-way or two-way traffic) pavements
3. For three-lane and four-lane undivided roadways multiply values by 1.5 and 2.0, respectively and round to the nearest 0.5-ft. If values are less than 2.0-ft., disregard
4. Pavement widening is intended for utilization where truck traffic is significant and the increase in pavement width is to be 2.0-ft. or greater
5. Locations for pavement widening shall be shown in the construction plans or specified by the Engineer
6. Pavement widening to occur along the inside of the normal curve. Additional width is to be shared equally by all lanes.
|
GDOT Design Policy Manual ver. 2.0 Revised 5/21/2007