The teachers have asked their union to authorize a strike if safety does not improve.

They first criticized themselves, then mentioned "safeties," things that could be done better to improve the safety of the show.

Since then, safety has greatly improved, and the airline ranks among the best in the 21st century.

Since the end of the 26-year separatist war, stability and safety in the country have improved.

Among students, there was both suspicion of the police and hopes that safety might improve.

Since the last fatality in 1999, safety has greatly improved.

A recent government review found that after five years there had been no increase in the numbers of women working and women's safety had improved.

Since the airline industry was deregulated in 1978, safety has improved.

Interoperability works, the systems are being harmonised and safety improved.

Esthetics and safety on the paths should improve as use increases, with call boxes planned for the future.