Cost allocation study for the Maryland Transportation Authority


In 1997 the U.S. Federal Highway Administration (FHWA) released the results from its latest Federal Highway Cost Allocation study. This cost allocation study employed the cost-occasioned approach based on the underlying philosophy that each user should pay the highway costs that it creates or “occasions.” The cost recovery objective is similar to a user fee principle in which each vehicle class pays for maintenance and preservation of highway infrastructure in proportion to the share of the costs for which the vehicle class is responsible. The1997 Federal Highway Cost Allocation Study (FHWA, 1997) found that pavement and bridge rehabilitation and reconstruction costs are most closely correlated with the characteristics of different vehicle classes.

The 1997 Federal Highway Cost Allocation Study summarized total vehicle miles traveled (VMT) by vehicle class for 2000. As shown in Table 1, passenger vehicles account for about 93 percent of total vehicle miles of travel (VMT) in the United States, while single unit trucks and combination trucks accounted for 3 and 4 percent of total VMT, respectively. Over two-thirds of single unit truck travel is by vehicles registered below 25,000 pounds while, among combination vehicles, 75 percent of travel is by vehicles registered between 75,000 and 80,000 pounds.
Table 2 shows the estimated cost responsibility of different vehicle classes and registered weight groups for Federal highway-related program costs funded from the Highway Trust Fund in 2000. Automobiles and combination trucks are responsible for the greatest shares of Federal highway costs, followed by pickups and vans, single unit trucks, and buses. There are large differences in cost responsibilities among single unit and combination trucks at different weights. The Federal cost responsibility per mile for single unit trucks registered at 25,000 pounds or less is only 13 percent of that for single unit trucks registered over 50,000 pounds. Combination trucks registered at 50,000 pounds have only 40 percent of the cost responsibility per mile as compared to combinations registered at 80,000 pounds, and less than 20 percent of the cost responsibility per mile as compared to combinations registered over 100,000 pounds. While combination vehicles of over 80,000 pounds registered weight account for only 3 percent of total truck travel, they are responsible for almost 8 percent of total truck cost responsibility. Single unit trucks registered at over 50,000 pounds account for 4 percent of total truck travel but 11 percent of total truck costs. In combination, the heaviest single unit and combination trucks account for 7 percent of truck travel but almost one-fifth of total truck costs.
In summary, while total VMT in the United States for passenger vehicles account for 93% and trucks accounts for 7%, the 1997 Federal Highway Cost Allocation Study apportioned only 60% of the cost responsibilities to passenger vehicles and the remaining 40% to trucks.

Table 1. Total 2000 Travel and Number of Vehicles by Class and Registered Weights (FHWA, 1997).
Vehicle Class/Registered Weight Vehicle Miles of Travel (millions) Number of Vehicles
Passenger vehicles Total Percent Total Percent
Autos 1,818,461 67.5% 167,697,897 70.0%
Pickups/Vans 669,198 24.8% 63,259,330 26.4%
Buses 7,397 0.2% 754,509 0.3%
Total 2,459,056 92.6% 231,711,736 96.7%
Single Unit Trucks
≤25,000 pounds 56,451 2.1% 4,126,241 1.7%
25,001 – 50,000 pounds 18,631 0.7% 1,352,441 0.6%
>50,000 pounds 8,018 0.3% 491,745 0.2%
Total 83,100 3.1% 5,970,431 2.5%
Combination Trucks
≤50,000 pounds 6,744 0.3% 253,022 0.1%
50,001 – 70,000 pounds 16,685 0.4% 225,347 0.1%
70,001 – 75,000 pounds 5,926 0.2% 94,509 0.0%
75,001 – 80,000 pounds 86,176 3.2% 1,295,973 0.5%
80,00 – 100,000 pounds 3,879 0.1% 64,365 0.0%
>100,000 pounds 2,279 0.1% 37,788 0.0%
Total 115,689 4.3% 1,971,435 0.8%
Total Trucks 198,789 7.4% 7,941,435 3.3%
Total All Vehicles 2,693,845 100% 239,653,170 100%


Table 2. 2000 Federal Highway Cost Responsibilities by Vehicle Class and Weight Group ($ Millions; FHWA, 1997).
Vehicle Class/Registered Weight Total Cost Responsibilities Cents per Mile Shares of Total
Autos $11,898 0.65 43.8%
Pickups/Vans $4,198 0.65 15.4%
Buses $190 2.57 0.7%
All passenger vehicles $16,287 0.66 59.9%
Single Unit Trucks
≤25,000 pounds $985 1.75 3.6%
25,001 – 50,000 pounds $842 4.38 3.1%
>50,000 pounds $1,083 14.60 4.0%
All single units $2,910 3.51 10.7%
Combination Trucks
≤50,000 pounds $187 2.78 0.7%
50,001 – 70,000 pounds $454 4.25 1.7%
70,001 – 75,000 pounds $370 6.25 1.4%
75,001 – 80,000 pounds $6,103 7.08 22.5%
80,001 – 100,000 pounds $484 12.50 1.8%
>100,000 pounds $378 16.60 1.4%
All combinations $7,978 6.90 29.4%
All trucks $10,888 5.48 40.1%
Total $27,175

Purpose of the Study

The Maryland Transportation Authority (the Authority) currently owns, operates and maintains 7 facilities comprised of various types and combinations of highway structures (bridges) and pavement.  Structural inventory statistics of these seven facilities are listed below:

Table 3. Structural Inventory Statistics.
Name No. of Major Structures* No. of Small Structures*
JFK 58 38
FMT 95
BHT 65 13
FSK 19

* Major structures are primarily bridges; small structures are primarily culverts.

The magnitudes of the tolls and discount options vary among the Authority’s facilities.  However, the basic formula for the toll rates is the same for all facilities, i.e., the first axle is free and then “x” dollars are charged for each additional axle.  Compared to the Federal Highway Cost Allocation Study’s allocations of cost responsibilities for passenger vehicles at 60% and trucks at 40%, the Authority’s net adjusted revenue percentage from trucks of 31% appears low.

The objectives of the proposed study are as follows:

  1. Develop an analytical model based on current and accepted best practices to evaluate the relative cost of system degradation attributable to each vehicle class in the Authority’s vehicle tolling structure. This cost allocation model must be sufficiently robust to be applicable for the entire diverse composition of the Authority’s facilities and should use methodologies appropriate for assessing costs to individual vehicle classes.
  2. Apply the cost allocation model to each toll facility individually to assess the infrastructure degradation attributable to each vehicle class and the corresponding share of maintenance and rehabilitation costs. This will require that the study team compile relevant Authority data for vehicle characteristics (e.g., classification and axle load distributions) and facility features (e.g., number and type of structures, length and type of paving, etc.).

This study shall focus only on determining a rational distribution of the costs of system preservation and system development attributable to each vehicle class for the vehicle mix and asset mix at each toll facility. The study will not include specific recommendations for remedying any current toll inequities should they exist.