In the summer of 2020, The Port of Los Angeles received 10 heavy-duty trucks, each having one defining component in common: a hydrogen fuel cell.

Just last month, a truck developed by the California-based autonomous-vehicle company TuSimple completed an autonomous 80-mile run from Tucson to Phoenix.

Jackknifing is a major cause of devastation in a traffic accident involving tractor-trailer trucks. Researchers in Greece have now designed a device to prevent this often lethal action. The team’s sliding kingpin device allows the so-called kingpin junction between the front tractor and...