Current law is unclear in Tennessee as to when police have the right to stop you for unsafe driving. The state Supreme Court is hearing two cases that ask the question how many times a driver must cross the center line before they're stopped for a violation.

Attorney Sara Compher-Rice with Oberman and Rice in Knoxville says a clarification of the law is important. "It's impossible for every motorist at all times to drive in a perfectly straight vector down the center of the lane," she says. "If the court is going to allow for anyone who crosses the line to be stopped, you're virtually subjecting every motorist on the roadway to being stopped."

Compher-Rice adds that crossing a center line and putting other people on the road in danger should merit a stop by a police officer, versus the single act of crossing the line. Both cases involve drivers charged with DUIs after police observed them crossing the yellow line one time before stopping them.

Compher-Rice says it's important to remember that crossing the center line for a moment isn't always tied to alcohol consumption - and the interpretation of the law should reflect that. "If someone crosses over the lane one time, you're not likely to think, 'oh, there's a drunk driver,'" she says. "Something where someone touches a lane line once or crosses over once could be reaching to turn the radio.

They could have their kids in the car and be turned around to discipline them." While judges initially ruled in the cases that crossing the center line once was enough to merit a stop, judges in prior cases have dismissed charges, saying that crossing the line once wasn't enough to justify a stop. That includes the dismissal of DUI charges against state Representative Bill Beck of Nashville earlier this year, and Tennessee Titans quarterback Steve McNair several years ago.