Pavement Preservation Index

OBJECTIVE

• Manage UDOT pavements to provide a sustainable pavement condition.

STRATEGIES

• Select a mix of treatments that provide a sustainable pavement condition.

• Each Region to calculate surface area benefit years and divide by total surface areas to yield pavement preservation index.

MEASURE

• Pavement Preservation Index

TARGET

• Achieve 100% replacement benefit each year.

• Replace 19,000 HV Surface Areas Years each year.

• Replace 4,600 LV Surface Area Years each year.

Consider that our 23,600  Surface Areas of pavement age 1 year, each year, for a loss in pavement condition measured in units of Surface Area Years.  For us to have a sustainable condition level we need to replace those 23,600  Surface Area Years of pavement life. 

The Pavement Preservation Index will be the ratio of the work done (planned) to the work required – measured in units of surface area years.  This Index will provide an indication of our future condition.  Values less than 100% would forecast a decline in condition, while values greater than 100% would forecast an improvement in condition.

Pavement Preservation Index = SA Years replaced / SA Years lost

This takes our current Surface Area of work measure to the next level, where we associate a benefit to each project in terms of years of added/ replaced life.  This also changes the reporting from a 4 year average to an annual value, although looking at multiple years is still important.

Initial assumptions:

• All projects are the right treatment on the right road at the right time.

• Ongoing maintenance with patching & crack sealing is included in the project benefits.

• Lane leveling before a treatment doesn’t add any thickness for calculating benefit years.

• Chip seals or micro surfacing after a treatment doesn’t add any thickness for calculating benefit years.

• Thickness for cold in place recycling is reduced 50% for calculating benefit years.

Initial Project Categories & Benefit Years:  

These benefit years will be adjusted over time to calibrate the Index.

PROJECT CATEGORY                BENEFIT YEARS

Chip seal                                                                 7

Micro Surface                                                     7

1" Treatments (BWC & OGSC)               10

1 1/2" Treatments (HMA & SMA)         10

Preservation - unspecified                        10

2" Treatments (HMA & SMA)                  12

3" Treatments (HMA)                                   15

Rehabilitation - unspecified                     15

4" Treatments (HMA)                                  18

Major Rehabilitation - unspecified      20

> 4" Treatments (HMA)                              20

Reconstruct - unspecified                         25

Concrete Repair                                               8

Concrete Repair with Grind                    15

New PCC                                                            40

The following chart shows an annual comparison between our current Surface Area measure and this Surface Area Year measure.  Both data sets are shown as a percent of their Goal.  The 2018, 19 & 20 Areas were based on projects funded with $ 190 million/ year.  These programs are in the process of being adjusted to $ 160 million/ year.

The Surface Area Goal was based on an 11 year project cycle (19,045/11).  The Surface Area Year Goal was based on a SI of 100% (19,045 Surface Area Years).

 This incorporates our current High Volume system Surface Area reporting criteria.

• Calculate surface areas for each calendar year using the EPM substantial completion date.

• Only include surfacing work on exiting pavement for widening projects.

• Surfacing work on ramps is not included.

• Include surfacing work for all projects:  Preservation, Rehabilitation, TIF, Asset, Code 1, Choke Point & other large paving projects over 1 surface area.

• Report 4 year average and 3 year projection. 

 It is important to recognize these measures are independent of funding, they focus on how much surfacing work should be done to sustain the condition, not how much it will cost.