Lock Rehabilitation, A Public Infrastructure Problem: The Value of Increased Productivity in Mean Lockage Performance.

Productivity increases are measured in terms of decreases in the mean time it takes tow to transit a lock. The analysis develops a dynamic model for estimating these values. The quantity of public infrastructure capital, i.e., lock capital cannot be estimated by any of the commonly accepted price or quantity methods due to lack of data. Lock capital is estimated with price data and estimates of asset depreciation functions. A recursive system of equations with exogenous demand for lockages at the lock to be rehabilitated is estimated to show the effect of lock capital on transit time. An increase in lock capital is shown to decrease mean values of 1 the time it takes to service a tow 2 queue length and, 3 the total transit time required to pass through a lock. The model is solved for Lock and Dam 13 on the Mississippi River. The value of the improved productivity is minimal and relatively insensitive to variations in model assumptions or the estimation of the quantity of capital. Results indicate a need for data on the physical characteristics of public infrastructure capital so its quantity can be estimated. The value of improvements in infrastructures mean productivity appear to be insignificant when compared to the value of preventing economic losses which could result from failure or loss of the infrastructure. The importance of an empirical basis for estimating the probability of infrastructure failure is pointed out as is the current lack of data to do this.