Would you like to expand on it a bit?

Our business is signage for public transport http://www.twinvisionna.com/

When our company started out a public transportation bus had a sign - period.
Then came the automatic announcement - door activated
so far we could generate as much EMI as we saw fit.
Then came the radio communication with the dispatcher
Then came the GPS controlled announcement system
Then came the data messages e.g. oil is too hot to the dispatcher
Then came the AVL (automatic vehicle locator)
Then came the video monitoring of activates in the bus
....

So, today a typical public bus will have 5-20 radios receiving at as many frequency bands and the likelihood of some ENI affecting one or more of them is great.

What actually triggered the "get rid of EMI" campaign was some 12 to 24V converters we bought to equip some coaches that has 12V systems as opposed to the standard 24V. Those converters you could "hear" miles away.

one unfortunate side effect is that it is now possible to use a cell phone on a city bus.

Erik