The IL 13 intersection at Norman Road/East Main Street in Marion has experienced numerous severe crashes in recent years resulting in numerous severe injuries. Safety improvements are needed to reduce the occurrence of these crashes and injuries. An informational meeting was held on September 29, 2015 to introduce the concept of Restricted Crossing U-Turn (RCUT) Intersections to interested stakeholders. The RCUT is an innovative intersection design that improves safety and operations by changing how minor road traffic crosses or turns left at a major road. The RCUT does not change any of the movements that are possible from the major road.
Note: IDOT projects typically have three distinct phases. Phase I (or the project Study) consists of developing the project scope, environmental studies and preliminary design of a project. Phase II (Design) consists of refining the design to develop contract plans and land acquisition. Phase III (Construction) consists of the actual construction of the project.
The project is currently in the planning stages. Two alternates were presented at the informational meeting.
Alternate 1 converts both the north leg (Norman Road) and the south leg (East Main Street) to an RCUT intersection.
Alternate 2 converts only the north leg (Norman Road) to an RCUT configuration. The south leg (East Main Street) is not affected.
Safety Four lane partially access controlled divided highways such as IL 13 are an economical and efficient design for rural areas. Compared to two-lane undivided rural highways, four lane divided highways have much lower rates of sideswipe, rear-end and head-on crashes. However, crash rates at four lane divided highway intersections are markedly higher than at two lane undivided highway intersections. This is often because of conflicts between the side road left turn or through movements and mainline through traffic on the far side of the intersection. A table summarizing the most recent 5 years of crash data available (2009-2013) is shown in the following chart.
As depicted in the chart, crashes involving left turn or through movements from the side roads comprise 41% (7 of 17) of the total crashes. These same crashes account for 27% of the total reported injuries with 1 A (severe and incapacitating), 1 B (moderate injury), 1 C (minor injury) and 1 fatality. These crashes often occur in the lane farthest from the STOP sign, that is, when a driver on the minor road, attempting to cross or make a left turn, crosses over the first pair of lanes to the median and then is struck by a vehicle traveling in out outside lane of the second pair of lanes.
The causes of these crashes could be a combination of factors. Drivers entering the IL 13 from the side road might misjudge the gaps between vehicles on the major road. The driver on the minor road also might expect that the drivers on the major road will slow down upon seeing the new vehicle entering the intersection from the minor road. A third factor could be that drivers on the major road expect that the driver entering the expressway will yield the right-of-way.
Regardless of the cause, an effective solution to minimize angle crashes is the restricted crossing U-turn intersection. To make the movement for a left-turn or to cross the major highway, drivers would first turn right on the main road and them make a U-turn some distance downstream where designated. With this design, the conflicts that can lead to angle crashes are reduced. Case studies show that RCUTs can reduce fatal and injury crashes by 40 percent to 70 percent.
The chart also depicts a high number of crashes involving left turns from IL 13 (5 of 17, 30% of the total). However the percentage of injuries related to these crashes are quite high (10 of 15, 67%) with 6 A injuries (severe and incapacitating), 2 B (moderate injuries) and 2 C (minor injuries). Through field inspection an issue with sight distance has been discovered. At times where there are EB and WB cars storing in the left turn lane they block the vision of the opposing through or left turning traffic. The condition is exacerbated if there is a vehicle that has pulled into the median from the side road trying to make a left or through movement. By relocating Norman Road to the west and not allowing through movements from the side roads the sight distance shielding problem should be solved.
This site will be updated periodically as the project progresses. The Illinois Department of Transportation (IDOT) wishes to thank you for your support and patience.
A meeting was held on September 29, 2015 at the Marion Senior Citizens Center. The exhibits that were presented can be viewed under the Resources Tab. Any further questions can be addressed by calling (618-549-2171) or visiting the IDOT Region 5, District 9 Headquarters at 2801 West Murphysboro Road on the west edge of Carbondale.
Accident and ADT Diagrams
FHWA case studies
IDOT is currently at the early stages of Phase I for this project. As we make changes, this website will be updated accordingly.