Last year Bangkok became the first Thai city to ban (1.) hand-held cell phone use in vehicles, on the grounds that talking on a phone while driving can cause accidents, Meanwhile, similar 2.) are being debated in legislatures. Some experts said a ban on drivers use of cell phones might not make much difference anyway. Our best estimates of accident and fatality reductions do no unnecessary (3.) how drivers would alter their behavior in response to regulation; if police tried to enforce a ban. drivers might simply switch to other dangerous activities. Thus. the net reduction in accidents and fatalities(4) is likely to be overstated, so the measures (5.) of regulatory intervention could be quite small. Also. government regulations are sometimes slow to be take into account(6), wireless technology is advancing so fast that regulation could soon be unnecessary (7.)