It took a Titanic to create a law that there needed to be enough lifeboat space for all passengers...
https://en.wikipedia.org/wiki/Caldecott_Tunnel_fire
https://www.sfgate.com/bayarea/article/40th-anniversary-of-Caldecott-Tunnel-fire-17037648.php
"For what it’s worth, one major law came out of the Caldecott Tunnel fire: Trucks carrying hazardous materials, such as gasoline, can only use the tunnel between 3 a.m. and 5 a.m. each day."