Effects of Increased Weights of Alternative Fuel Trucks on Pavement and Bridges: Long-haul electric trucks with a range of 300 miles are expected to be 5,328 pounds heavier than fossil-fuel versions in 2030, in 2050 they will be 1000 pounds less

Effects of Increased Weights of Alternative Fuel Trucks on Pavement and Bridges. Harvey, John, Saboori, ArashMiller, Marshall, Kim, Changmo, Jaller, Miguel, Lea, JonKendall, Alissa, Saboori, Ashkan. Univ of California Institute of Transportation Studies, report no. 2020/19, Nov 2020. https://doi.org/10.7922/G27M066V

Abstract: California’s truck fleet composition is shifting to include more natural gas vehicles (NGVs), electric vehicles (EVs), and fuel cell vehicles (FCVs), and it will shift more quickly to meet state greenhouse gas (GHG) emission goals. These alternative fuel trucks (AFTs) may introduce heavier axle loads, which may increase pavement damage and GHG emissions from work to maintain pavements. This project aimed to provide conceptual-level estimates of the effects of vehicle fleet changes on road and bridge infrastructure. Three AFT implementation scenarios were analyzed using typical Calif. state and local pavement structures, and a federal study’s results were used to assess the effects on bridges. This study found that more NGV, EV, and FC trucks are expected among short-haul and medium-duty vehicles than among long-haul vehicles, for which range issues arise with EVs and FCs. But the estimates predicted that by 2050, alternative fuels would power 25–70% of long-haul and 40–95% of short-haul and medium-duty trucks. AFT implementation is expected to be focused in the 11 counties with the greatest freight traffic—primarily urban counties along major freight corridors. Results from the implementation scenarios suggest that introducing heavier AFTs will only result in minimal additional pavement damage, with its extent dependent on the pavement structure and AFT implementation scenario. Although allowing weight increases of up to 2,000 lbs. is unlikely to cause major issues on more modern bridges, the effects of truck concentrations at those new limits on inadequate bridges needs more careful evaluation. The study’s most aggressive market penetration scenario yielded an approximate net reduction in annual well-to-wheel truck propulsion emissions of 1,200–2,700 kT per year of CO2 -e by 2030, and 6,300–34,000 kT by 2050 versus current truck technologies. Negligible effects on GHG emissions from pavement maintenance and rehabilitation resulted from AFT implementation.

1 lb is almost .5 kg

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Long-haul electric trucks with a range of 300 miles are expected to be 5,328 pounds heavier than fossil-fuel versions in 2030. Short-haul and medium-duty box delivery electric trucks are expected to weigh 1,400 extra pounds. Batteries are heavy because the chemicals and materials in battery cells are densely packed and have a good amount of mass. Based on average market penetration, the batteries on electric trucks in 2030 could collectively equal 59.3 million pounds. Future technology is expected to reduce that weight by almost 1,000 pounds by 2050. Also, adding tires and axles to the largest trucks could spread the load more evenly to reduce stress on roads and bridges.

4.3 Cost to Strengthen and Replace Bridges Due to a 2,000-Pound Truck Weight Increase

The MAP-21 study provided an estimate of $0.4 billion for the one-time costs to strengthen and replace bridges due to a 5axle, 88,000 lb. truck (Scenario 1 of the CTSWLS) across all states. The following is a top-down first-order calculation that translates that national-level cost to California alone.

• The MAP-21 study assumed that bridges with a rating factor (either flexure or shear) less than 1.0 will require rehabilitation.

• For this current study, it was assumed that the bridges in the structurally deficient category are those that had rating factors less than 1.0.

• California has 6.2 percent of all the bridges in the US that are structurally deficient and 3.9 percent of all the structurally deficient NHS bridges. It was assumed for this study that 4.5 percent of the bridges are structurally deficient. Bridges on the NHS system are longer and more costly to rehabilitate than non-NHS bridges.

• It was also assumed for this study that the 82,000-lb. GVW limit produces half (allowing for some illegal trucks over the 82,000-lb. limit) as many ratings less than 1.0 than the 88,000-lb. truck scenario (a conservative estimate).

• The estimated cost is then: 4.5% × 0.5 × $400 million = $9 million in 2011 dollars.

• This cost estimate does not include any increases in annual maintenance costs due to the heavier trucks.