Prefeasibility Access Road Design-Revised
7
The requirements for sight distance are based on AASHTO design standards. The
following tables show the required sight distances:
Design
Speed
(mph)
Stopping Sight Distance (ft.)
Downgrades
Upgrades
3%
6%
9%
3%
6%
9%
30
205
215
227
200
184
179
35
257
271
287
237
229
222
40
315
333
354
289
278
269
Design
Speed
(mph)
Decision Sight Distance (ft.)
Avoidance Maneuver
A
B
C
D
E
30
220
490
450
535
620
35
275
590
525
625
720
40
330
690
600
715
825
Avoidance Maneuver A: Stop on rural road t=3.0s
Avoidance Maneuver B: Stop on urban road t=9.1s
Avoidance Maneuver C: Speed/path/direction change on rural road t varies between 10.2s and 11.2s
Avoidance Maneuver D: Speed/path/direction change on suburban road t varies between 12.1s and 12.9s
Avoidance Maneuver E: Speed/path/direction change on urban road t varies between 14.0s and 14.5s
The Hydromet plant is on Buffalo Creek Road in the Upton Regional Industrial Site in
Upton, Wyoming. There are two different routes that lead to the site: one from US
HWY 16 and one from WY HWY 116.
When accessing Buffalo Creek Road from US HWY 16, there are two railroad
crossings and both are at grade. The approach and intersection with US HWY 16 has
adequate sight distance, curve radii, and is illuminated. There is a building at the
intersection of US HWY 16 and WY HWY 116 which obstructs sight distance prior to
approaching the stop controlled intersection; however, the sight distance is not
obstructed when positioned at the stop sign.
Accessing Buffalo Creek from WY HWY 116 utilizes a bridge to cross the railroad
tracks. This route will require about two more driving miles on Buffalo Creek Road
than if accessing from US HWY 16. The approach and intersection of Buffalo Creek
Road and WY HWY 116 has adequate sight distance, curve radii, and is not
illuminated. Improvements will need to be made to the Buffalo Creek Road to meet
the design requirements and incorporate the design typical section.
