Minnesota Department of Transportation House Transportation Policy

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Minnesota Department of Transportation House Transportation Policy & Finance Committee February 23, 2015

Truck Size & Weight (TS&W) Study (MnDOT, 2006) Study Purpose Evaluate the benefits and costs of alternative truck configurations, and recommend any changes in state TS&W laws, in response to: Requests from industry (shippers & carriers), especially transporters of bulk commodities Lack of uniformity with border states Complexity of TS&W laws in Minnesota Projected 40% increase in truck freight by 2040

Background Study only considered changes in allowable semitrailer truck weights (not length, width or height) Only considered state and local roads (Interstate highways governed by federal regulation) Road authorities can “post” roads and bridge to lower weight limits Current maximum Minnesota weight limit on all 10-ton paved roads is 80,000 lbs (typical 5 axle semi)

Background continued Studies conducted since have raised additional questions, particularly regarding safety: Can available crash data definitively relate truck weights to highway safety levels? Can roadway design and driver training adequately offset increased risk from changes in truck size or weight? Do heavier trucks have significantly lower crash rates but higher crash severities? Do higher centers of gravity on heavier trucks increase the number of rollovers and/or ramp-related crashes?

Approach Extensive stakeholder outreach Examined a variety of truck configurations (heavier weights, additional axles, required spacing): Truck traffic effects (including modal or system diversion) Transport costs Pavement costs Bridge impacts and costs Safety impacts Congestion Statewide system analysis considered industry acceptance of the new configuration and resulting changes in miles of travel by vehicle type by roadway type, including empty trucks and typical payloads

Pavement Impacts “Equivalent Single Axle Load” (ESAL) Additional axles spread the weight out and actually reduce pavement damage compared to conventional five-axle semis. 80,000 lbs. 12,000 lbs. 34,000 lbs. 53’ 34,000 lbs. Five-axles 2.4 ESAL 97,000 lbs. Seven-axles 1.5 ESAL 108,000 lbs. Eight-axles 1.8 ESAL 90,000 lbs. 12,000 lbs. 34,000 lbs. 53’ 44,000 lbs. Six-axles 2.0 ESAL 6

Study Findings: Truck Configurations Increased payloads fewer truck trips lower transport costs Additional axles & fewer truck trips less pavement wear Heavier Vehicles some additional bridge postings higher bridge design costs in future Heavier Trucks slightly higher crash rates but fewer overall trucks safety would improve slightly Proposed configurations for operations above 80,000 lb. GVW meet internationally accepted heavy vehicle safety performance standards

Study Recommendation: Change Truck Weight/Axle configurations Allow following configurations on all 10-ton roads (revocable permits with fees, added certified axles with brakes, must meet bridge formula, axle and tire weight limits) 80,000 lbs. single unit truck, seven axles 90,000 lbs. semi-trailer, six axles (winter to 99,000 lbs.) 97,000 lbs. semi-trailer, seven axles (winter to 99,000 lbs.) 108,000 lbs. twin semi-trailers, max. 28.5 ft. each semitrailer (no change), eight axles

Study Recommendation: Changes to Seasonal Load Restrictions All county roads default to 7 tons per axle rather than the current 5 tons per axle unless posted otherwise State trunk highways remain at 10 tons per axle unless posted otherwise City streets and township roads continue to default to 5 tons per axle unless posted otherwise Encourage uniform SLR timing across all jurisdictions within zones; SLR for gravel roads ends two weeks later than paved roads.

Study Recommendation: Change to 10-Ton Road Network Declare all state and county roads 10 tons unless posted down. Remove the 73,280 lb. GVW limit for 5 axle semi-trailer on 9-ton roads and allow axle weights and bridge formula to control up to 80,000 GVW. Both recommended changes were addressed in 2009, see Laws of Minnesota 2009, chapter 64, sections 6 and 18

Recent Studies Since the Truck Weight study was released in 2006, other research has raised concern about safety aspects (crash and rollover rates) related to higher truck weights: – 6 axle plus, 97,000 lb single trailers had higher fatality rates – higher center of gravity leading to more rollovers – Recommends more research before allowing more six plus axle trucks Moving Ahead for Progress in the 21st Century Act (MAP-21) required a Comprehensive Truck Size and Weight Limits Study – Investigated differences in safety risks and infrastructure impacts of truck size and weight limits. – Scheduled for release in 2015. MnDOT Study will be reviewed after findings and recommendations are published.

Minnesota Truck Size & Weight Project Web Site http://www.dot.state.mn.us/information/truckstudy/ William Gardner, Director MnDOT Office of Freight and Commercial Vehicle Operations [email protected] 651-366-3665

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