LOGAN CANYON STUDY
INTERDISCIPLINARY TEAM MEETING
July 31, 1987
UDOT District Office
Additional data for agenda items:
Accident data summary for curve at
MP 384 and Logan Cave area. Also
alternative details Logan Cave area.
Rideability--definition and also
Listing of ID team requests and
6/10/86 LOS description
Maps of proj. area
Public info placed
in Logan & USU lib
Field Studies & data
6/23/86 Sampling methodology
7/14/86 2/86 daily traffic
7/28/86 Population data
Detail maps - visual
9/8/86 Daylnight accidents
Accident quick list
9/22/86 Gen. desc. of envir.
10/6/86 Letter to UDOT -
10/20/86 Visual criteria
11/3/86 1979 alternatives
& USFS evaluation
Criteria for climb. lane
11/17/86 Speed profile for canyon
Requirements for vertical
12/8186 Scorecard of tech memos
Review of Pub. Mtg.
12/22/86 Parking area standards
Parking area mapping
FHWA/UDOT EIS documents
1/15/87 Comments on notice
1/26/87 Break section 2 into subsect.
Forecast increases for
BY TO COMPLETE
Research and Development Unit
Utah Department of Transportation
Volume II of the state-wide pavement survey prioritizes highway
sections from the worst to the best for ride, cracking, rutting, structural
adequacy, friction index and an overall condition rating.
These priority listings are intended as a tool to be used in the
selection and programming of rehabilitation and maintenance activities.
Where data concerning the condition of a specific section is needed,
reference should be made to the Detailed Data Sheets in Volume I.
Final rehabilitation decisions obviously should not be made strictly
on the basis of these listings. More detailed analysis should be done to
accurately select a rehabilitation strategy. More frequent deflection
testing (every 0.1 mile) should be requested where appropriate, and a more
detailed distress analysis may be necessary.
The following discussions outline the intended use of each printout,
and provides an example of each.
Title: AVERAGE RI
Description: Sections are prioritized (from worst to best) by the
average of the Rideability Indexes*(RI) measured for
each mile. (Figure lA)
Use: The sections near the top of this listing are the
poorest riding sections based on average values.
Title: MINIMUM RI
Description: Sections are prioritized by the mlnlmum RI value
measured within the section. (Figure lB)
Use: Identifies sections containing a shortt poor riding
area that needs correction t but may be adequate based
on the Average RI listing.
Title: RI FAILURES
Description: Lists sections where the RI has reached th Terminal
Serviceability Index (TSI). (Figure 1C)
Use: These sections have reached the minimum allowable
rideabilitYt and should be considered for improvement.
4.4 to 5.0
3.6 to 4.3
2.B to 3.5
1.9 to 2.7
Title: DISTRESS ANALYSIS
Description: Sections are prioritized by the distress index, which is
based on cracking, and patching. * (Figure 2)
Use: The sections at the top of this listing are highly
distressed, and are in need of rehabilitation or maintenance.
*Note - Distress Index = 5.0 - 0.13 ~
Title: STRUCTURAL ANALYSIS
Description: Sections are prioritized by the structural index* which
is related to the number of years remaining prior to
fatigue failure. (Figure 4)
Use: The sections with structural indexes below 2.0 are very
near fatigue failure, or have already cracked in the
wheel paths. Preventive rehabilitation could prevent
the development of fatigue cracking if it has not
SURFACE FRICTION R4NKINGS
Title: FRICTION AVERAGE
Description: Sections are prioritized by the average friction index
measured at each milepost. (Figure SA)
Use: Pavements that are identified with a friction number below
35 should be programmed for a surface seal, and "Slippery
When Wet" signs should be posted until the work can be done.
Friction numbers between 35 and 45 are considered to be
marginal, and above 45 are generally adequate. Pavements
with significant rutting can cause hydroplaning during wet
weather, which could compound skidding problems when combined
with a low friction number.
Title: FRICTION MINIMUM
Description: Sections are prioritized by the mlnlmum friction index
measured within the section. (Figure 5B)
Use: Identifies sections containing a short, slippery area
that needs correction, but may be adequate based on the Friction Average listing OVERALL RANKING Title: FINAL SUMMARY TABLE Description: Sections are prioritized by the Final Index* which is realated to the structural indenx, the distress index and the averaage R.I. the final index is weighted more heavily toward the structural index where high truck traffic exists, and weights the R.I. value more heavily where a high ADT (see definitions) is present. Use: This listing basically identifies the worst overall sections. It also cam be used to obtain a general indication of the type of rehabilitaion (or maintenance) activity which may be needed since the technique selected should correct all of the existing deficiencies. the final index is intended for prioritization only, and should not be used in any other way since it does not represent any single pavement condition.
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