Use your mobile phone in a school zone in Dallas and get a $200 ticket.

The city just passed that ordinance today, following others.

A mobile phone ban in Dallas amounts to a major expansion in the number of school zones where you can no longer use a hand-held phone.

Before today, it was just the Park Cities, with about seven school zones.

Now, with Dallas, add another 230 school zones.

Parents we spoke with today were pleased with the new ban.

"You need to be focusing on driving. Not talking on the phone. So, it's a good idea. It's a minor inconvenience to keep from hurting a child," said Ashely Roman.

It's a politically popular measure that's quickly spread beyond the Park Cities where police have already written about 600 tickets since early January.

Flower Mound, Duncanville, Irving and Dallas all plan to roll out their bans in the coming months.

Dallas councilman Mitchell Rasansky says the ban in a no-brainer.

"You have it here, you're driving with one hand, and you're holding the phone. You know, it doesn't make sense. You're going to have an accident," he said.

Research, however, has shown that handheld phone bans are not effective.

Scientists say using an earpiece is no safer then holding the phone since it is the conversation itself that distracts drivers.

"If you talk to people in law enforcement they will tell you anecdotally and beyond that, that when you see somebody that's engaged in this sort of thing, it distracts them," said Dallas Mayor Tom Leppert.

The City will spend about $145,000 installing signage to alert drivers to the changes.