• Marine highways – what are they?

    When asked to describe a highway most people will tend to describe a roadway that they drive their automobile on. But, did you know that there are other types of highways?

    “America’s Marine Highway System consists of the nation’s navigable waterways,” said Transportation Commissioner Mike Tagert. “These waterways play an important role in the logistics, safety and economic development of our state, and our nation.”

    Marine highways are navigable waterways that have been designated by the U.S. Secretary of Transportation and have the ability to provide additional capacity to relieve congested landside routes serving freight and passenger movement.

    “Each marine highway has a corridor designation that reflects the congested landside route it parallels,” Tagert said.

    In Mississippi, the Tennessee-Tombigbee Waterway is designated as M-65 because it is parallel to Interstate 65 in Alabama. The Mississippi River is designated as M-55 because of its relationship to Interstate 55.

    “These marine highway designations are important because they provide ways for goods and services to be moved from Mississippi throughout the region, and even internationally,” Tagert said. “Marine highways also reduce the number of heavy commercial vehicles traveling on our highways, which also increases safety for the traveling public.”

    The Mississippi Department of Transportation (MDOT) has installed signs throughout the state to show the marine highway designations of these navigable waterways. Motorists will notice the M-65 signs in northeast Mississippi at four Tennessee-Tombigbee Waterway Crossings: U.S. Highway 72, U.S. Highway 45, U.S. Highway 82 and Interstate 22.

    Additionally, signs for M-55 will be installed at four Mississippi River crossings throughout the state.

    For more information about Mississippi’s Marine Highway system, visit GoMDOT.com.

  • Mississippi Transportation Commission opposes longer, heavier big rigs

    There is proposed legislation in Congress to modify  vehicle weight limitations for the Interstate Highway System and the possibility of “Twin-33’s” being allowed on interstates. Supporters of the legislation claim that increased truck length and weight limits will increase efficiency and safety.

    Your Mississippi Transportation Commission (MTC) has sent a letter to Mississippi’s Congressional delegation showing that the proposed length and weight increases not only violate current bridge formulas but will also decrease safety and increase repair costs.

    The 1975 bridge formula used by the Federal Highway Administration (FHWA) protects the structural integrity of bridges from damage caused by heavy trucks. The six-axle configuration proposed in 2015, which has been proposed again this year, will violate this formula.

    FHWA tested one 91,000 pound six-axle combination in the Comprehensive Truck Size and Weight Limit Study, but the configuration tested could only carry up to 45,000 pounds on the three-axle and still be in compliance with the bridge formula.

    Last year, the U.S. Department of Transportation (USDOT) released its Final Truck Size and Weight Report to Congress, recommending there be no changes in current truck size and weight limits. The USDOT report concluded that there was not enough data to support the claims that bigger trucks would be safer.

    According to the American Society of Civil Engineers (ASCE), one in nine bridges is structurally deficient. In Mississippi, that number is one in eight. Overweight trucks cause a disproportionate amount of damage to the state’s deteriorating roads and bridges compared to passenger vehicles. An 18,000-pound truck axle does over 3,000 times more damage to pavement than a typical passenger vehicle axle. Increasing the weight of a heavy truck by only 10 percent, increases damage by 33 percent.

    “The limited data available actually shows that heavier trucks have higher crash rates and that longer trucks take 22 feet longer to stop, causing considerable bridge damage,” said the MTC in its letter to Congress. “Our maintenance efforts are already seriously underfunded. This type of legislation would further contribute to the destruction of bridges and to the cost of repairs and rehabilitation on states, and ultimately the public.”

    To view the full letter from the MTC to Congress, click here. For more information, visit GoMDOT.com.