interstate 435 and front street interchange improvements
Download
Skip this Video
Download Presentation
Interstate 435 and Front Street Interchange Improvements

Loading in 2 Seconds...

play fullscreen
1 / 29

Interstate 435 and Front Street Interchange Improvements - PowerPoint PPT Presentation


  • 89 Views
  • Uploaded on

This presentation will probably involve audience discussion, which will create action items. Use PowerPoint to keep track of these action items during your presentation In Slide Show, click on the right mouse button Select “Meeting Minder” Select the “Action Items” tab

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Interstate 435 and Front Street Interchange Improvements' - libitha


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
interstate 435 and front street interchange improvements

This presentation will probably involve audience discussion, which will create action items. Use PowerPoint to keep track of these action items during your presentation

  • In Slide Show, click on the right mouse button
  • Select “Meeting Minder”
  • Select the “Action Items” tab
  • Type in action items as they come up
  • Click OK to dismiss this box
  • This will automatically create an Action Item slide at the end of your presentation with your points entered.

Interstate 435and Front Street Interchange Improvements

purpose and need for this project
Purpose and Need for this project

To provide safety improvements at the northbound and southbound exits from I-435, within the interchange on Front Street and the entrance ramp onto southbound I-435.

slide5

Initial Concepts We Reviewed

Single Point (SPUI)

Half-Cloverleaf

Roundabout

Tight Urban Diamond (TUDI)

problems with a single point design
Problems with a Single Point design

Required extensive reconstruction of I-435.

Costs for additional right-of-way and construction were very high, about$31 million.*

We had concerns about how long it would take trucks to clear such a large intersection.

*Based on 2002 estimates.

problems with a half cloverleaf design
Problems with a Half- Cloverleaf design

Required large amounts of new R/W.

Costs for additional right-of-way and construction were very high, about$37 million.*

We had concerns about the trucks being able to accelerate from the loop ramps onto the freeway.

*Based on 2002 estimates.

problems with a roundabout design
Problems with a Roundabout design

Did not perform as well as other alternatives.

We had concerns about the operation of the trucks in the roundabout (two trucks likely would not enter a roundabout at the same time, reducing capacity).

Costs for additional right-of-way and construction, about $10 million.*

*Based on 2002 estimates.

problems with a tight urban diamond design
Problems with a Tight Urban Diamond design

Required considerable reconstruction of I-435.

Did not work as well as the SPUI or half-cloverleaf.

Costs for additional right-of-way and construction were high, about$28 million.*

*Based on 2002 estimates.

initial design
Initial Design

The existing interchange is very similar to a TUDI, with I-435 over Front Street.

The initial preliminary design included:

Adding lanes to the off ramps with double and triple left turn lanes.

Adding lanes to Front Street between Universal and Corrington with traffic lanes behind the bridge piers.

problems with the initial design
Problems with the initial design

The life of the capacity improvements were limited. This design would probably fail within 10 to 15 years.

The Levels of Service were D, E and F.

Costs for additional right-of-way and construction were still somewhat high, about $11 to $12 million.*

This design has 45 conflict points within the entire interchange.

*Based on 2005 estimates.

problems with the initial design1
Problems with the initial design

Triple left turn lanes were needed for the northbound to westbound movement. This is not desirable with 11% trucks during peak hour. (Off peak has about 30% trucks.)

Seven lanes were needed under the bridges, requiring construction of lanes and retaining walls behind the bridge piers in existing sand fills. This would be difficult to build.

The trucks required large turning radii to achieve capacity improvement. This limited vehicle storage between the signals.

a practical design solution
A Practical Design Solution

A Diverging Diamond Interchange or DDI

slide20

Diverging Diamond Design

Link to DDI overhead video

Link to one of the drive thru videos

advantages of using a ddi at this location
Advantages of using a DDI at this Location

The DDI doubles the capacity of the left turn lanes and eliminates the need for the triple left turn. The double left turn should be safer than a triple with high truck volumes.

Levels of Service are A, B and C.

This design reduces the number of lanes required under the bridge to four, eliminating the need to build retaining walls.

advantages
Advantages

This also reduces the number of lanes needed on Front Street beyond the interchange.

This DDI design has more storage room between the ramp signals.

(550’ vs 350’)

This design will also provide better sight distance. Drivers on the ramps don’t have to look through bridge columns to see on-coming traffic.

advantages1
Advantages

It incorporates roadway features which calm traffic and reduce speeds while maintaining capacity. This should result in fewer and less severe crashes.

Although wrong way entry into opposing lanes is possible, wrong way entry onto the ramps and the interstate will be almost eliminated.

The DDI has 21 conflict points compared to 45 with the initial design.

advantages2
Advantages

The smaller ramp intersections mean vehicles will have shorter clearance times resulting in less exposure and safer conditions.

The DDI design has reduced the cost of the project.

estimated costs initial ddi
Estimated Costs*InitialDDI

Construction

MoDOT $ 6,763,000 $4,097,000

Kansas City $ 103,000 $ 71,000

Right of Way

MoDOT $ 1,823,000 $ 625,000

Kansas City $ 2,045,000 $ 667,000

Utility Relocations

MoDOT $ 600,000 $ 312,000

Total Costs$11,334,000 $5,772,000

*Based on 2005 estimates.

disadvantages of a ddi
Disadvantages of a DDI

Driver expectations.

We need more extensive public involvement.

Pedestrians have to cross free-flowing ramps (or the crossings need to be signalized as at this location).

There is very limited accident history available.

We need additional signing, lighting and pavement markings.

slide28
DDI

Length of Construction

TUDI

One construction season

Two construction seasons

conclusion
Conclusion

The DDI will improve safety and capacity of the existing interchange, at less cost and with a shorter construction schedule.

It will also provide valuable information on function and safety that will allow MoDOT and FHWA to determine if use of the DDI design at other locations is feasible.

ad