section 2.0 Policy Implications; section 2.6 Turner Trucks

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Comprehensive Truck Size and Weight (TS&W) Study

Phase 1—Synthesis

Working Paper 3—Pavements and TS&W Regulations

2.0 Policy Implications

2.6 Turner Trucks

In 1984, former Federal Highway Administrator Francis Turner proposed a new approach to truck size and weight regulation. The objective of this new approach, which became known as the Turner Proposal, was to reduce pavement wear caused by truck traffic while simultaneously improving the productivity of freight transportation. Truck operators would gain productivity through higher allowable gross weights, but would add extra axles to their vehicles to reduce the weights carried on individual axles.

Turner's original proposal was as follows:

Reduce legal axle loadings to a maximum of 15,000 pounds for single axles and 25,000 pounds for tandem axles

Allow greater vehicle lengths

Raise maximum gross weights to as much as 112,000 pounds.

Turner proposed that these limits apply to all trucks, but that when axle weights could not practically be brought down to the indicated maximums, special permits with higher fees be issued.

The Turner Proposal was the subject of an extensive study by the Transportation Research Board, reported in TRB Special Report 227, New Trucks for Greater Productivity and Less Road Wear: An Evaluation of the Turner Proposal. That study retained the basic concept of a truck that would be both more productive and less wearing on pavements. However, rather than Turner's mandatory change applying to all trucks (with limited exceptions), it considered a voluntary system in which each truck operator would choose whether to comply with the new weight regulations or to continue to follow the previously existing rules. The study also broadened the scope of its evaluation beyond Turner's original proposal by considering ranges of possible values for axle weights, length limits, and other vehicle characteristics to find trucks that approach optimum overall performance, considering productivity, pavement, bridges, and safety.

The TRB study estimated that if Turner trucks were introduced on a nationwide basis, 23 percent of the freight carried in existing combinations would divert to these trucks. The most popular Turner configuration would be a nine-axle double with 32-to 34-foot trailers carrying 114,000 pounds maximum weight. Key impacts were estimated as follows:

$2.0 billion per year reduction in freight costs

Two percent increase in truck freight due to shift from rail. Rail would lose four percent of ton-miles and five percent of gross revenues

$729 million per year reduction in pavement costs

$403 million per year increase in bridge costs if all inadequate Interstate and primary bridges and one-quarter of inadequate non-primary bridges are replaced.

[continued on next page, Page 13, section 2.7-New Approach; TRB Truck Weight Study ]

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