The 9 days is a good time to be careful as a Hachono for Parshas vaEschanan which states:- veNishmartem Meod leNafshoseichem.
Talking on blue tooth &/or cell phone, is not only dangerous for a driver, but also for a pedestrian, and not only during the 9 days, but all 365&1/4 days of the year.
But 9 days is also an excellent opportunity to stay safe & quit smoking because:- 1) 1 less danger during the 9 days; 2) It weans you of 1 addiction prior to Tisha b’Ov when smoking is Ossur; 3) Can save money wasted on cigar[ette]s to prepare your outfit & travel expenses for Bi’as haMoshiach.