I believe Superior introduced the crossing arm around 1963 and may have actually discontinued it as an option because it had such a low take rate from customers. Interesting how things change over time and innovation is often not rewarded.
I don't necessarily have an opinion on crossing arms either way, except that the reliability is questionable at best in poor weather conditions, particularly those with severe winters. One of the things that I've heard brought up as a point is if the crossing arm fails to deploy, some students may cross directly in front of the bus as opposed to walking the ten feet. The other thing that I've heard brought up is that a crossing arm can give drivers a false sense of security.
I would also argue that front loading zone deaths have gone down due to improved training and the huge improvement in crossview mirrors technology, not necessarily just crossing arms.
Cost is right on around the $200-400 mark depending on what type of crossing arm and whether or not you order the interrupt switch to pull the arm back in when loading behind other buses.
They have been standard equipment here in Va, since 1988 I believe. As a private operator we dont have to have them but I believe they are valuable to keeping the danger zone to a minimum but driver training is a must. The driver has to be the key to a safe operation.
I believe crossing arms are one of those things that allow the driver to be lazy about checking mirrors and enforcing safe crossing practices from students. A driver that has properly trained students on crossing, and will always check cross-view mirrors will never have a problem when it comes to the front danger zone. I feel the same way about child check systems. A driver is EXPECTED to do these things..if you can't trust someone to do them, they shouldn't be driving a school bus. -Sid