“If a job is worth doing,  it is worth doing right!”

Many municipalities have limited resources and cannot allocate a significant portion of those resources to implementing a complex pavement management system.  Therefore, this article will outline a simplified approach for those who cannot devote a lot of time to implementing a pavement management system, but who recognize the need for a systematic approach with documented results.  For this article, it will be assumed that municipalities are using a pavement management software program (PMSP).

The following is a list of the basic steps necessary to build a road surface management program.  Each of the steps is discussed briefly in the following sections.

Road Inventory Survey
Road Surface Condition Survey
Repair Strategies
Determining Network Needs
Developing a Budget

ROAD INVENTORY SURVEY

A road inventory survey is the process of collecting the information necessary to adequately describe the roads in the local network (all municipal streets). The information to be collected would include:

Section Description 
Functional Classification
Type of Pavement
Length and Width
Construction History
Traffic

Since the inventory process is the most time-consuming step, it can be completed over time.  The process of assembling inventory information should be accomplished in three phases:

1. Determine the types of data needed.

2. Determine which data currently exists in office records.

3. Determine the remaining data that must be gathered by the survey team.

SURFACE CONDITION SURVEY

The purpose of the condition survey is to determine the condition of each segment by visually observing any surface distresses that are present.  The condition survey is a crucial part of any PMSP since certain distresses are very much related to particular causes of pavement deterioration.   Due to this direct correlation, a PMSP will link distress types to repair strategies.  Therefore, ensuring that the proper repair strategy is selected for each road segment requires an accurate condition survey.

The surface condition survey is a visual inspection of 100 percent of the street system.  The survey is conducted in a vehicle traveling at a very slow speed (approximately 5 - 15 miles per hour).  Since the data from this survey is used for planning purposes, a detailed survey of each street is not necessary.

It is necessary that the personnel performing the condition survey be properly trained to produce correct, consistent results.  Since the data from the distress survey serves as the basis for a PMSP to determine which repair strategies will be used, it is imperative that this data be accurate.  The use of  inaccurate condition survey data leads to inappropriate repair strategies that ultimately will result in the inefficient use of funding.

The following is a list of recommended distresses to be included in the condition survey for the average municipality with asphalt concrete pavements.

Alligator cracking
Longitudinal/transverse cracking
Edge cracking
Potholes/patching
Roughness
Rutting
Raveling/Oxidation

REPAIR STRATEGIES

This step requires a municipality to decide which repair alternatives are going to be considered.  Some municipalities may only want to patch, overlay and reconstruct.  Other municipalities may decide that they are willing to consider many options including micro-surfacing and cold in-place recycling.  Once the initial set of repair alternatives is selected, they are not “set in stone.”  Additional alternatives can be added in the future.  As time goes on, a municipality with only a few alternatives will probably determine that they should consider other options which may be more cost-effective.

Once the repair alternatives are decided upon, each alternative must be grouped into major categories referred to as repair strategies.  This is necessary because a PMSP first selects a repair strategy based upon the distresses found during the road condition survey and the related decision trees.  After the repair strategy is selected, then the PMSP will determine which repair alternative should be used for each road segment.  The role of the decision trees provide a link between the type, severity and extent of a distress and the recommended repair strategy.  Decision trees are a very important part of a PMS will be discussed in more detail in Part III of this series.

It is generally accepted that there are five repair strategies that should be considered for road surfaces:

  1.  Routine Maintenance - usually includes local patching, crack sealing, and other relatively
        low cost actions.  Localized distresses, such as isolated severe bumps or potholes are 
        usually corrected first.  If at all possible, all routine maintenance needs should be  
        funded each year.

  2.  Preventive Maintenance  - includes techniques such as surface treatments that are 
        designed to stop deterioration before it becomes a serious problem.

  3.  Deferred Action  -  road sections which fall into this category receive minimum funds for 
        the current budget year.  These sections are beyond the point where preventive 
        maintenance will be effective but have not yet deteriorated to the point of needing 
        rehabilitation.  When an agency defers action, it must be prepared to fund rehabilitation 
        or reconstruction when it becomes necessary.

  4.  Rehabilitation  - usually includes overlays or recycling.  Funding for completion of these 
        major projects may depend upon long range planning and careful scheduling of 
        improvements to be done in stages.

  5.  Reconstruction  - involves complete removal and replacement of a failed pavement.  It 
        may also involve features such as widening, improved alignment, grade changes, guard 
        rail, and major drainage work.  Lead times of several years may be required because of 
        the more costly nature of full reconstruction and the time required to develop a 
        complete plan of action, to secure any permitting required, and to establish special 
        funding needs.
 

DETERMINING NETWORK NEEDS

In this step, a PMSP will analyze all the data entered and will determine the most cost-effective type of repair alternative for each road segment in the municipality’s network.  The reports generated will include the recommended repair alternative and the estimated repair costs to improve each road segment, as well as, the total cost to repair all streets.  

The reports generated by the initial analysis simply list each street in alphabetical order.  In other words, this analysis does not consider priorities. Most municipalities do not have the funds necessary to repair all streets in one year.  As such, additional analyses must be performed to prioritize the needs of the network.  Based on a prioritization scheme within a PMSP, reports will be generated that will list the streets in the order that they should be repaired.  

Prioritization uses either the worst-first method or the best-first method.  The worst-first method will select the streets in worst condition to be repaired first.  The best-first method will select the street in good condition first.  The T2 Center strongly recommends that all municipalities utilize the best-first policy described in the last issue of the Travel Log.
 

DEVELOPING A BUDGET

At this point, the municipality must make the tough decision of how much funding should be allocated to repairing its streets.  It must be remembered that the total cost of repairs for the network is not stagnant.  As time goes on, roads that need to be repaired will continue to deteriorate.  Also, roads that are currently in good shape will continue to deteriorate and require repairs in the future.  If the maintenance and rehabilitation budget is under-funded, the total cost of repairs for all streets can rise drastically.  Therefore, not only is it important to develop a short-term plan, but to consider developing a long term plan as well.

Once the streets that are to be repaired have been selected, they must be examined more closely, to determine the exact scope of work.  Upon completion of the detailed survey of the selected streets, a more accurate cost estimate can be developed.  The detailed survey of the selected streets is necessary because the initial condition survey does not measure exact quantities of repairs. Performing a detailed survey of every street in the network would be extremely time consuming and is normally not necessary at the network planning stage.

For municipalities who would like more information about the pavement management process, please contact Kercher Engineering, Inc.