Turn lane length reduction

[TEEI]

Here is the situation.
Posted Speed = 25 mph
Design Speed = 25 mph + 5 mph = 30 mph
Min. Deceleration length (based on local agency manual for 35 mph Design Speed)= 145'
Queue Length = 50 feet
Total right turn lane length = 145'+ 50' = 195'
Available length = 110'due to constraints.
Difference = 85'
How can we justify reduction of 85' in total turn lane length. The roadway has no major crash history, no safety issues. Appreciate any help with this.

 

[civilman72]

Does the 145' requirement include taper length? If so, what is the req. taper ratio?

Does the 110' include taper length constraints?

Is 50' queue length based on an intersection analysis, or minimum req'd by local agency manual?

 

[IRstuff]

Is this an existing turn lane? Or a new one?

TTFN
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[ACtrafficengr]

What is the prevailing speed of traffic? What is the effective design speed? Can you justify not adding the extra 5 mph?

Whart is the AADT? Can you use AASHTO's Guidelines for Geometric Design of Very Low Volume Roads (<400 vpd)?

 

[TEEI]

145' includes a 50' taper. It is a standard.
110' includes a 50' taper
50' storage is based on intersection analysis (95th percentile back of queue)

This is an existing turn lane
There is no posted speed limit, so we were requested to use 25 mph as posted speed.
AADT=2000 VPD

 

[civilman72]

If it's an existing intersection, why are these improvements necessary (i.e. more traffic is being added to intersection)?

What are the turn lane length requirements for a 25 MPH design speed? Maybe using a 35 MPH design speed is excessive, particularly considering this is existing with little safety concerns/incidents.