Even if total compliance with bans on drivers' hand-held cell phone use can be achieved, crash risk will remain to the extent that drivers continue to use or switch to hands-free phones. Although the enactment of laws limiting drivers' use of all phones is consistent with research findings, it is unclear how such laws could be enforced. At least in the short term, it appears that drivers' phone use will continue to increase, despite the growing evidence of the risk it creates. More effective countermeasures are needed but are not known at this time.

Graduated licensing laws that include strong nighttime and passenger restrictions and laws that delay the learner's permit age and licensing age are associated with lower teenage fatal crash rates. States that adopt such laws can expect to achieve substantial reductions in crash deaths.

We evaluated the effects of temporary, prominently displayed signs in reducing deer‐vehicle collisions (DVCs) during mule deer (Odocoileus hemionus) migrations. To conduct the study we selected segments of 5 highways in 3 western states that were crossed by mule deer during seasonal migrations. Using local input and historical DVC data, we identified migration corridors used by deer. We separated these migration corridors into sections of equal length. Each section was separated by a buffer zone. We randomly assigned each section into treatment or control areas. In treatment areas we erected temporary warning signs equipped with reflective flags and solar‐powered flashing amber lights. To evaluate the effectiveness of signs in reducing DVCs, we monitored deer mortalities during migration periods before and after signs were placed. We also monitored vehicle speeds to determine whether the signs affected motorist behavior. DVCs in the treatment areas were reduced by 50%. Vehicle speeds also were reduced, but evidence suggested that the effect eroded during the second year of the study. Study results indicated that temporary signing can be a cost‐effective technique when used on roads where DVC peaks occur in conjunction with seasonal migration periods and are isolated to narrow corridors.