Date post: | 30-Mar-2015 |
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I-26 Safety Project
Project CorridorI-26 between I-95 and Summerville• Number one and three ranked location for interstate safety
improvements• AADT = 32,433 • Posted S/L = 70 mph• Crash Stats: January 2007 through November 2011• Total Crashes = 1934• Total Fatalities = 44• Total Injuries = 709• 50% Run off Road Crashes
• Post and Courier coined the phrase “Corridor of Death” in 2010 articles
Project Corridor
Project Corridor Safety Data
• Existing Median Width = 84’ – 86’ • Existing Median Shoulder = 2’ - 3’ (paved)• Distance from travel way to tree line = 25’• Clear Zone Distance = 46’
Median Rt. Side Median Rt. Side0
1020304050607080
Incapaciting InjuriesFatalitiesCrashes
Berkeley Dorchester
Project Corridor Safety Data
Distracted / Asleep **
DUI Speeding Too Fast for conditions
(wet roadway) **
Tire failure ** Improper lane change **
Debris in roadway **
0
2
4
6
8
10
12
14
16
18
Berkeley
Dorchester
** Vehicular speeds were estimated by investigating officer to be within posted speed limits.
Project Corridor Safety Data
0
5
10
15
20
25
30
35
40
45
50
8
16
9
01
4 42 3
5
2 13 2 3 3
43 4 3
52 2
0
35 6
5
8
3 46 6
24
8
57
4 3
6
9
6
141416
8
25
12
23
11
7 8
17
13
28
16
25
12
42
11
20
1211
1615
8
11
14
37
21
14
2221
3
13
46
33
18
29
15
I-26 Tree Crashes Per Mile
State Average
0
I-77
US
601
I-95
FOU
R H
OLE
SW
AMP
US
17 A
LT
US
21
US
301
CYPR
ESS SW
AMP
I-26 Safety AlternativesRemove obstacles
Provide clear zone• clearing of median • Median consists primarily of
pines with light mixture of hardwoods
• environmental permit required• Standard cable rail to be installed
in center of median• Initial cost estimate of $5M• Would prepare median for future
widening
I-26 Safety Alternatives
• Cable would be required for both directions of I-26
• Initial cost estimate of $10M• Considerable maintenance, repair
and traffic impact concerns
Shield Obstacles
• High tension cable rail only feasible option due to close distance of trees and existing shoulder slopes
Project DetailsExisting Conditions
• Total Length of project corridor – 29.6 Miles• Total Length of Existing Guardrail along median– 2.2 Miles• Median Length with no existing trees – 2.6 Miles
• Median Length with existing median cable rail – 0.9 Miles• Median width occupied by trees – 36 feet maximum• Wetlands within Project Limits – 4.2 Acres• Overlap with Existing Projects
• Sheep Island Interchange• I-26 Widening (Jedburg Road)
Preferred Alternative DetailsAlternative Feature
• Exclude median areas protected by existing guardrail
• Extension of existing steel beam guardrail in areas of steeper slopes• 1.8 Miles of new steel beam
guardrail • Reduce tree impacts to only the
trees necessary to allow for the installation of the guardrail
• Wetland impacts reduced from 4.2 to 1.9 acres• SCDOT has received authorization
from the Army Corps of Engineers based on these conditions
Preferred Alternative DetailsAlternative Considerations
• No glare shield provided• Median width greater than 20
feet• Can accommodate emergency
crossovers and will bring up to standards with coordination with the local emergency agencies
Preferred Alternative DetailsAlternative Elements
• 23.0 miles of clearing, grubbing, dressing and grassing of the median ( 6 miles overlaps with the I-26 widening and Sheep Island Parkway Interchange)• 24.7 miles of median cable
rail• 1.8 miles of new steel beam
guardrail
I-26 Safety Project