Table of Contents:
The mission of the Bureau of Street Services (BSS) is to maintain all improved streets, alleys, and related throughways in a perpetually good to excellent condition while providing desirable standards of safety, appearance, and convenience to the residents and the traveling public within our jurisdiction. With a street network comprised of approximately 6,500 centerline miles of streets and 800 centerline miles of alleys, the City of Los Angeles not only has the largest municipal street system in the nation, but also the most congested.
To monitor, maintain, and manage this street network, the BSS utilizes MicroPAVER™, a state-of-the-art Pavement Management System (PMS) that not only provides a systematic and consistent method for assessing maintenance and rehabilitation needs, but also determines the optimal time of repair by predicting future pavement condition.
The information provided by the Bureau’s PMS is the basis for this report, titled “Street Infrastructure Condition Assessment.” In this report, the BSS identified the physical condition of the pavements and rated them from A to F, with “A” representing the streets in good condition and “F” representing the streets in very poor condition.
These condition levels were determined by using the internationally accepted Pavement Condition Index (PCI), a scale that rates the physical condition of the street by considering the pavement’s structural and surface operational condition. This numerical rating index ranges from 0 for a failed pavement to 100 for a pavement in perfect condition.
Calculation of the PCI is based on the methodologies and analyses recommended by MicroPAVER™ in which type of pavement distress, severity, and quantity are determined. The PCI provides an insight into the causes of such distresses and, additionally, is the basis for predicting future pavement deterioration.The results of the Street Infrastructure Condition Assessment are as follows:
A summary of the existing conditions of the street system is shown in Figures 1a and 1b.
The Bureau's on-going plan is to survey one third of the entire street system every year, and thus complete the survey of all city streets in three years. The third part of the most recent infrastructure analysis cycle was completed in September of 2007.
Based on the results of the Street Infrastructure Condition Assessment, the Bureau of Street Services recommends adopting the following policy:
The street system infrastructure of the City of Los Angeles shall be maintained at an average condition level of “B” or better, and no streets in the network shall have a condition rating below “C”.
In other words, all streets in the City of Los Angeles should have a PCI of 60 to 100, with the City’s goal being an average street network PCI of 80. Once this goal is reached, it will be more economically feasible to maintain the City streets in a perpetual good to excellent condition.
If a proposed budget of $2.85 billion to support a ten-year Maintenance and Rehabilitation Program is approved, the BSS will be capable of performing routine maintenance on the roadways while eliminating the current backlog generated from historical under-budgeting. As a result, the City's current average street condition level of C will improve to an average B level.
Like any other element of the City infrastructure, keeping the street network in good condition is time-dependent; portions of the street system that do not receive routine maintenance will transition to a lower condition value.
Therefore, routine maintenance and elimination of the current backlog are tasks that must be placed on high priority.
If the proposed budget cannot be secured and the current level of funding is maintained for the next ten years, the pavement condition of the City street network will rapidly decline from its current level of “C” to a projected ”D” level.
Primary, Secondary, and centerline miles of streets and 800 Collector Streets (also known as Non-Residential) are designed and constructed by this Bureau to last 15 to 20 years while Residential streets have a life expectancy of 30 to 35 years before their first major rehabilitation (maintenance overlay). The importance of providing the appropriate pavement preservation techniques before the streets reach the sharp decline in pavement condition (critical point) resides in the fact that repair savings of 50% can be achieved. Managers and engineers who have adopted pavement technology understand that pavement management is a matter of “Pay now, or pay much more, later.”
Historical changes in the size of the street system (Figure 2), in addition to insufficient funding, have resulted in a street system that has aged with minimum or no maintenance.
For several years, the State of California’s Gas Tax has been the City’s main source of funding to preserve the street network, at an average level of approximately $15 million per year.
During the fiscal year 2001-2002, monies from sources such as Metropolitan Transit Authority’s Proposition C, Traffic Control Relief Program (TCRP), Traffic Safety (TS), and General Fund (GF) increased the annual resurfacing budget to approximately $60 million. In subsequent years, the Annual Resurfacing Program (ARP) budget has significantly fluctuated and the current level of funding can neither improve nor maintain the current physical condition of the City’s street system.
The Bureau’s goal at the present time is to acquire sufficient resurfacing and maintenance funding to sustain the current average pavement condition of the street network until the time when there is adequate funding to improve it.
See Figures 3a and 3b for a summary of the Street Infrastructure Condition Assessment.
The City of Los Angeles has approximately 6,500 miles of improved streets divided into two geographic areas, Metropolitan (53 percent) and the San Fernando Valley (47 percent). It is the responsibility of the Bureau of Street Services to maintain all streets in a perpetual good to excellent condition.
In 1982, the BSS created an in-house Pavement Management System (PMS) to monitor and maintain the City’s 6,500 centerline mile street system. At the time, it was determined to utilize a “windshield survey” method to rate the pavement condition of the streets. The extremely large size of the street network, in addition to the Bureau’s limited resources, only allowed the BSS to complete the street survey of the network every five years.
Although the in-house PMS provided maintenance and historical information of the streets, it did not produce meaningful and/or repeatable condition values usable for budget allocation. Therefore, the BSS decided in 1998 to adopt the MicroPAVER™ System, which allows the selection of the most economical maintenance and rehabilitation strategy based on the Pavement Condition Index (PCI) of the streets.
Developed at the U.S. Army Construction Engineering Research Laboratory, the PCI is obtained by analyzing the type, severity, and quantity of pavement distresses identified during a pavement condition survey. The use of PCI has been adopted as standard procedure by the American Society of Testing Materials (ASTM) and is being used by numerous municipalities and airports worldwide.
Pavement Management data indicates that repair savings of 50 percent can be achieved if maintenance and rehabilitation are performed during the early stages of deterioration preceding the sharp decline in pavement condition. Consequently, it is crucial to use a PMS in order to alert managers about this critical point in a pavement’s life cycle.
Projection of future condition requires the ability to measure condition in an objective, repeatable scale, such as the Pavement Condition Index as illustrated in Figure 4.
The first three classifications are considered “non-residential” streets and primarily are throughways that connect distant locations. This group of streets represents approximately 2,600 miles of the street network and generally speaking, they are wide streets (between 45 feet and 100 feet) that carry heavy volumes of traffic. Primary, Secondary and Collector streets are designed and constructed with thicker layers of asphalt to last approximately 15 to 20 years. (Figure 5a)
Residential roadways represent approximately 3,900 miles of the street system and their width varies between 15 feet and 45 feet. They carry local and light traffic but are sporadically exposed to heavy traffic such as refuse collection trucks, buses and/or construction trucks. The Bureau of Street Services expects this class of roads to last 30 to 35 years. (Figure 5b)
The street network can also be classified by surface type. Mainly, two types of surface are typical in the City streets: Asphalt Concrete and Portland Cement Concrete. (Figures 6a and 6b)
Asphalt covers approximately 5,840 miles of the network while concrete covers 493 miles of streets. Other types combined represent 107 miles of the street system.
|METHODOLOGY AND CRITERIA|
The primary tool used by the BSS to complete this Street Infrastructure Condition Assessment was the Bureau's Pavement Management System.
As previously mentioned, the Bureau of Street Services has adopted the Micro PAVER™ System to monitor and maintain the City’s 6,500 centerline mile street system and to select the most economical maintenance and rehabilitation strategy based on the Pavement Condition Index of the streets.
Using current information, streets were identified and rated from A to F, with A representing streets having the best pavement conditions and F the poorest. In addition to the PCI, the condition levels A through F also describe further characteristics, as explained below:
Streets in Condition A (Good) have the following characteristics:
Streets in Condition B (Satisfactory) have the following characteristics:
Streets in Condition C (Fair) have the following characteristics:
Streets in Condition D (Poor) have the following characteristics:
Streets in Condition F (Very Poor) have the following characteristics:
Figures 3a and 3b show a summary of the condition assessment for non-residential and residential streetsrespectively.
|CONDITION ASSESSMENT PROCESS|
To calculate the average Pavement Condition Index (PCI) of the entire street network, the Pavement Management Section of the Bureau of Street Services followed the typical Micro PAVER™ five-step methodology:
Inventory: The entire City’s street network , which includes over 69,000 pavement segments, was inventoried and entered into a computer database.
Routing: Prior to performing the survey of the pavement sections, all 69,000 segments were routed manually. Routing of the streets in the network ensures the most time efficient way for the survey teams to capture accurate pavement data.
Survey (Gathering of Data): The Bureau of Street Services currently utilizes an automated van to collect pavement distress data. This van is equipped with a computerized work station, cameras to take digital images of the street surface, and lasers to capture roadway roughness and rutting data.
Data Processing: The surface distress information captured by the City van is processed at two workstations in the office. Laser data and digital images are analyzed using custom software. The distresses on each one of the 69,000 street segments are identified and evaluated for type, quantity and severity.
Micro PAVER™ Analysis: The processed information is imported into Micro PAVER™, which analyzes the distress information and calculates a PCI for the pavement. Life Cycle curves are developed and the critical PCI established. By using the critical PCI method , an optimum maintenance/rehabilitation strategy can be developed, budget needs can be determined, and future roadway conditions can be projected based on different budget scenarios.
|CONDITION ASSESSMENT RESULTS|
As previously explained, the Bureau of Street Services utilized PCI as the primary factor to determine the current condition of the street infrastructure.
The results of the Condition Assessment indicate that the Primary, Secondary, and Collector streets (Non-Residential) have an average condition level of C+, while the Residential street system has an average condition level of C-. Furthermore, it was determined that the combined average condition level of the entire street system is a C.
Figure 4 summarizes the condition of the streets in the City of Los Angeles.The better condition of the Primary/Secondary/Collector (Non-Residential) system is attributed to the types and level of funding the BSS has received in the last ten years. In general, the budget has helped to preserve this system rather than the Residential system.
It is imperative for the Bureau to not only receive the proper amount of funding, but also the right type. Restrictions and requirements from funds such as the MTA’s Proposition C, and others, impede the Bureau from utilizing these monies on residential streets; as a result, a non-equitable distribution of monies for the preservation of the street network occurs.
This Street Infrastructure Condition Assessment shows that special rehabilitation emphasis must be placed on residential streets.
With a street system comprised of approximately 6,500 centerline miles of roadways, the BSS depends on its Pavement Preservation Program to determine pavement condition, maintenance needs, and the optimal time for rehabilitation by predicting future pavement conditions. This sole principle allows the Bureau to perform cost-effective preventive maintenance and rehabilitation, and provides a strategy for maintaining the network, based on the level of funding available.
Currently, since there is insufficient rehabilitation funding to improve the average pavement condition of the street network, the Bureau’s strategy is focused on “saving” as many streets as possible before they get to the point in their life cycle at which it will cost three to five times more to repair them. The Bureau has adopted a “sustainability mode” until the right level of resurfacing funding is available.
The Pavement Preservation Program utilized by the BSS is comprised of the following components:
A major challenge faced by the BSS is the dramatic rise of commodity prices over the last three years. This has resulted in substantial cost increases in asphalt, aggregate, and fuel oils. To exacerbate this situation, there is a chronic shortage of acceptable virgin aggregate materials in the Los Angeles area. In order to mitigate this trend of rising commodity prices, the Bureau has implemented an aggressive asphalt recycling program and has focused on solid pavement preservation techniques.
The Bureau is currently utilizing Cold In-Place Recycling (CIPR) technology to reuse asphalt concrete in l ocal street reconstruction projects. Implementation of this technology has substantially reduced asphalt concrete placement and transportation costs. In the future, the Bureau is looking to expand this program by adding a second CIPR paving machine to its fleet.
The Bureau’s two municipal asphalt plants are currently recycling about 20 percent of reclaimed asphalt concrete (RAP) and t he Bureau’s contracted asphalt plant is recycling about 50 percent of RAP. In order to further reduce the manufacturing cost of asphalt concrete and disposal fees, the Bureau will work to increase the recycling effort of both c ity- owned asphalt plants to a 50 percent capacity, each. This requires that b oth aged asphalt plants be replaced and upgraded to a state-of -the-art recycling facility.
Environmentally speaking, the increase of asphalt concrete recycling has significantly reduced air, noise, and traffic pollution. It also has decreased the dependency and the use of landfills required to dispose the milled street grindings. Furthermore, the use of a rubberized slurry seal mix has succeeded in recycling about 260,000 waste tires over the last three fiscal years, helping to improve environmental conditions and preserve valuable landfill space.
The BSS also continues to explore innovations and ways of greening the public right-of-way . Goals include identifying new construction techniques and materials with proven performance and lower annual cost and determining alternative designs and construction materials that are more environmentally conscious. Since the latter goal depends on new, emerging industr ies, objective performance data is critical for making informed decisions about greening strategies. To help produce that data, the Bureau of Street Services has partnered with several agencies to fund demonstration projects with porous concrete sidewalks, buried infiltration basins, stormwater diversions, and landscaped bioswales.
During the past decades, the Bureau of Street Services has faced constant resurfacing under funding. While the street system continued to increase its number of miles, the annual resurfacing budgets were not properly adjusted to the needs of the changing network. Therefore, the approved funds did not meet the maintenance and rehabilitation requirements, creating an existing backlog that currently requires $1.92 billion to eliminate.
During the last ten years, the Bureau’s average Annual Resurfacing Budget has been approximately $45 million , which only represents approximately 15.8 percent of the required network maintenance. These funding limitations have placed the average condition of the street system at the C level, and if the current budget levels continue, the street network will drop to a D- average condition within the next 10 years.
The current average network PCI for 2008 of 62 is equal to the one presented in the 2005 version of this report. The status quo is largely due to the 1,200 miles of slurry seal applied on residential streets in the last four years, which prevented the decline of the average network PCI. However, the existing network is expected to decline in the future, due to inadequate budget funding required to maintain the system.
The Bureau of Street Services has prepared a 10-year plan to improve the street network. The primary focus of the plan is to attain an average network PCI of 80. The strategy consists in performing preventive maintenance ( small asphalt repairs, crack sealing, and slurry sealing) for an estimated cost of $31 million per year in conjunction to an annual $254 million for street rehabilitation (maintenance overlays, resurfacing, and reconstruction).
The total cost per year for routine maintenance and backlog elimination is $285 million; at the end of 10 years, the cost of this plan will be $2.9 billion. Since the methodology behind this Street Infrastructure Condition Assessment is time -dependent, streets in the system will continuously decrease in condition level if sufficient funding is not provided. Therefore, the maintenance and rehabilitation efforts must be carried out consistently, even after the backlog is eliminated.
Analysis of the assessed data determined that approximately 1,000 miles of streets require reconstruction, with costs averaging about $6 50,000 per mile. In addition, 3,000 miles of streets require resurfacing and have varying degrees of base failure removal with costs ranging from $ 250,000 to $ 400,000 per mile.
The BSS adopted a strategy to minimize the impacts created by inadequate funding . Basically, it consists in assigning no more than 20 percent of its resurfacing budget to street reconstruction. Spending more in reconstruction or using a “worst first” strategy would greatly reduce the number of streets resurfaced and cause an acceleration in the decline of the overall condition of the street system.
It is the mission of the BSS to ensure that the desired good-to-excellent pavement condition levels are reached and maintained indefinitely. The preceding not only provides the public with safe and comfortable transportation routes, but also guarantees that the street system can be preserved at a lower cost.
However, it is unrealistic to apply all the necessary money to elevate a pavement network to the desired status in one year. As a result, the BSS performed an analysis to determine what long - term programs can be implemented to reach the desired network conditions with attainable expenditure levels.
The time periods analyzed were one year, 10 years and 15 years. For the 10 and 15 year time periods, a scenario was developed to determine the annual budget requirements so the backlog of rehabilitation (maintenance overlay, resurfacing, and reconstruction) was eliminated in the respective 10 and 15 year time periods. For the one-year plan, an unlimited budget was used to determine the annual cost to maintain the entire street network at or above the desired average condition level of B.
Estimated Annual Expenditure Needed to
Estimated Annual Expenditure Needed to
Estimated Annual Expenditure Needed to
Considering the current Federal, State, and Local fiscal condition, it is difficult to predict the future levels of funding that will be allocated to the BSS’ Annual Resurfacing Program. Therefore, as part of this study, the Bureau analyzed different budget scenarios and predicted the future condition of the street network based on different levels of funding.
As mentioned before, the Bureau has been funded at a level of approximately $45 million per year in the last ten years. A projection using this allocation in the next ten years was performed and the results indicate that the current average PCI of 62 will decrease to 47 at the end of the tenth year as shown in Figure 7.
It is clear that failure to fund the Annual Resurfacing Program at the right level not only accelerates the deterioration of the City’s street system, but also significantly increases the future financial needs as shown in Figure 8. The key to successful Pavement Management resides in not allowing the pavement condition of the roadways to reach the “failed” status because once there, the rehabilitation cost increases by five to seven times and consequently, fewer miles can be resurfaced with the available funding.
In order to accomplish the objective of increasing the current average PCI of the street network to the desired PCI of 80, the City must allocate $285 Million per year for the next ten years; this investment would also eliminate the current maintenance and rehabilitation backlog of $1.92 Billion . If the current $45 Million resurfacing budget was kept for the next ten years, the maintenance and rehabilitation backlog will swell to almost 3 .2 Billion by the end of the tenth year.
As stated in the Executive Summary of this report, the current funding level for street resurfacing is inadequate to improve or even maintain the street system in its current condition. The need to identify sustained funding for the improvement of the street system should remain one of the City’s top priorities. However, the number one priority must be to identify additional funding to ensure that the current condition of the street system does not continue to deteriorate at its current accelerated pace.
Acknowledging that obtaining additional funding is unlikely as a result of the current fiscal deficit, the Bureau has proactively sought out and introduced new processes (Rubberized Slurry Seal) and technological equipment (Cold-In-Place Recycling Machine) that have allowed the BSS to reduce resurfacing costs and stretch the limited funding to provide additional miles of resurfacing. These actions, while positive, have had a minimum impact on slowing the decline of our street system.
The Bureau strongly recommends the following actions:
The pavement condition of our street system has a major impact on the quality of life of the City residents. Adopting the above recommendations would validate the City’s commitment to improving public works infrastructure.
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