New York has outlawed texting or talking on handheld cell phones by commercial drivers at stoplights or in traffic jams, restrictions that don't apply to other drivers.
The law that took effect Monday brings the state into line with federal regulations for interstate trucking that took effect in 2012. Violations carry fines.
All states that issue commercial driver licenses must do the same by the end of next year.
Commercial drivers can use hands-free phones, as well as two-way or CB radios, even though they require one hand to operate.
Trucking association officials say they back measures like this that promote safety.
Distracted driving was blamed in 153 fatal New York crashes last year.
The state Senate in June voted to extend the restriction to other drivers. The measure didn't move in the Assembly.