Configurations for Analysis in the Comprehensive Truck Size and Weight Limits Study

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The MAP-21 Comprehensive Truck Size and Weight Limits Study (Section 32801) requires USDOT to evaluate the impacts of vehicles currently operating above baseline Federal gross weight and axle weight limits as well as to assess the safety and infrastructure impacts of "six-axle and other alternative configurations of tractor-trailers" if they were allowed to operate above current weight regulations. USDOT determined that up to six configurations could be examined as part of the Study in the timeframe established in MAP-21. USDOT initially identified specific truck configurations at the outset of the Study and solicited input from stakeholders regarding the selection of additional configurations. Commercial motor vehicles currently designated as Surface Transportation Assistance Act (STAA) vehicles will serve as baseline vehicles needed to conduct the comparative analysis required in the Study. The following identifies all the configurations to be studied.

Configuration	# Trailers or Semi-Trailers	# Axles	Gross Vehicle Weight (pounds)
1. 5-axle vehicle	1	5	80,000 [baseline]
1. 5-axle vehicle	1	5	88,000
2. 6-axle vehicle	1	6	91,000
2. 6-axle vehicle	1	6	97,000
3. Tractor plus two 28 or 28 ½ foot trailers	2	6	80,000 [baseline]
4. Tractor plus twin 33 foot trailers	2	6	80,000
5. Tractor plus three 28 or 28 ½ foot trailers	3	7	105,500
6. Tractor plus three 28 or 28 ½ foot trailers	3	9 or 10	129,000