تخمین هزینه حاشیه ای نگهداری و تعمیر بزرگراه تحت فعالیت های نگهداری چندگانه Estimation of Highway Maintenance Marginal Cost under Multiple Maintenance Activities

Introduction A typical highway agency uses multiple types of highway pavement maintenance, rehabilitation, and reconstruction
MR&R activities. Often, highway agencies have MR&R strategies that are condition responsive; in other words, a given MR&R activity is performed each time a given measure of pavement condition reaches a predetermined trigger level. Each type of activity can be triggered by a different type of pavement condition, such as rutting, alligator cracking, or roughness. As a result of such a condition-responsive strategy, an increase in traffic loading leads to an
indirect increase in the MR&R total cost incurred by the highway agency. An increase in traffic loading accelerates pavement deterioration, which brings forward all future MR&R activities which, in turn, increases their present value. The increase in the MR&R total cost resulting from an additional unit of traffic loading e.g., an additional equivalent single axle load
ESAL is the MR&R marginal cost. This is only one component of the marginal social cost. Other components of the marginal social cost include the private marginal cost
the increase in own vehicle operating cost and the highway user marginal cost
the increase in the cost of subsequent vehicles as a result of worse pavement condition. This paper only focuses on the MR&R marginal cost component. From an equity and economic efficiency point of view, it is desirable that each vehicle pays its marginal social cost. There is growing interest for implementing marginal cost pricing, which is a pricing strategy that sets price equal to the marginal social cost, one component of which is MR&R marginal cost. The lack of accurate estimates of MR&R marginal cost remains an important obstacle to such implementation. Much of this inaccuracy stems from unrealistic simplifying assumptions, such as the assumption that the only MR&R activity used by a highway agency is an overlay of constant intensity. Bruzelius
۲۰۰۴ surveyed the different approaches used in the literature to estimate MR&R marginal cost. Among these approaches, the perpetual overlay indirect approach is the most detailed because it explicitly models the steps that take place between the increase in traffic loading and the increase in MR&R cost. Bruzelius
۲۰۰۴ referred to it as the “indirect approach.” This approach assumes that pavement overlay
resurfacing costs dominate MR&R costs, and it ignores all other MR&R costs. It uses an infinite analysis horizon and assumes that a pavement is overlaid as soon as it deteriorates to a predetermined trigger level
Newbery 1988; Small et al. 1989. It first relates changes in traffic loading
additional ESAL to changes in overlay frequency
an additional ESAL brings forward the future overlays and possibly changes in the overlay intensity
thicker overlays in anticipation of higher traffic loadings in the future. Then, it relates these changes in overlay frequency
and intensity to MR&R marginal cost. Following Small et al.
۱۹۸۹, Vitaliano and Held
۱۹۹۰, and Lindberg
۲۰۰۲, an additional ESAL is defined as an event that recurs annually, and the MR&R marginal cost is defined as the change in the annualized cost of future overlays, as a result of increasing the traffic loading by 1 ESAL this year and every year in the future.
After the increase, all years have the same annual traffic loading, which exceeds the current annual traffic loading by 1. This is referred to as the recurring additional ESAL. The perpetual overlay indirect approach includes studies by Newbery
۱۹۸۸, Small et al.
۱۹۸۹, Vitaliano and Held
۱۹۹۰, Transportation Research Board
۱۹۹۶, Lindberg
۲۰۰۲, and Haraldsson
۲۰۰۷a. The basic formulation in the state-of-the-art proceeds as follows. Consider one lane of a flexible pavement section of a highway. Let constant L, such that L
۰, be the annual traffic loading for this section
ESAL/year. Also, consider a highway agency that uses a simple MR&R strategy with only one type of MR&R activity, namely, an overlay of constant intensity that is triggered by a specific pavement performance measure, M.