There's been a large influx of food trucks appearing over the past few years. PBS's Need to Know did a story about it in October 2010 (~8 mins):

http://www.pbs.org/wnet/need-to-know/culture/street-smarts-t...

Restaurants hate them, since they don't have to pay the overhead of rent/property taxes. Plus, they can park directly outside a restaurant and steal their business. No need to deal with any landlord. It's getting political though; brick & mortar restaurants are very much against them for obvious reasons.