Innovative Intersections

Peter Allain, PE, PTOELouisiana Department of

Transportation and Development

BackgroundTheorySafetyCapacityRight of way and AccessOperationPublic Opinion

Airline Highway at Siegen/S. Sherwood Forrest

Let to contract November 2004 at a cost of $4.4M

Hurricane Katrina August 2005Open to traffic March 2006 Accepted November 2006

Actually a Displaced Left-Turn Lane Intersection (DLTLI?)

Left-turning traffic crosses over opposing lanes to the left side of the roadway in advance of the main intersection.

The turn to the cross street can then be made at the same time as the main thru movements.

Partial CFI

Traditional Intersection 32 Conflict Points

Partial CFI 30 Conflict Points

Right Angle Rear End Head on S Swipe Right Turn Left Turn Non collision TOTAL

2003-04 42 67 0 17 2 15 23 166

2007-08 12 65 2 25 4 11 7 124

-71% -3% N/A 47% 100% -27% -70% -25%

846

592

575

432

Free 1638 128

327 1022 285

57

428

361

1599 1634

1766

5845

North

• Power Failures• Timing• Signing

Question 5. Please indicate your level of satisfaction with the current traffic conditions of the intersection.

291

10063

2912

0

50

100

150

200

250

300

Level of Satisfaction Level of Satisfaction

59%20%

13%6% 2%

Extremely Satisfied

Somewhat Satisfied

Satisfied

Unsatisfied

Extremely Unsatisfied

92% 92% SatisfiedSatisfied

Safety – So far looks good, but not conclusiveNo issues with wrong way at

crossoversCapacity –

Fewer phasesCFI’s do have limits

Right of way and Access – Very wide width Access issues

OperationComplexNeeds to be engineered

Public OpinionVery good acceptanceNo problems with misuse

For more information:

peter.allain@la.gov

ABMB.com