Arizona officials report success with an experiment requiring trucks to stay in the right-hand lane on an uphill section of Interstate 17 near Mesa.

In December, signs were put up telling truckers of the right-lane requirement on the often congested 6-mile section of I-17 between Black Canyon City and the Sunset Point rest area. Last week, authorities said the restriction appears to have traffic moving more quickly and safely, according to published reports.
It's not clear whether the restriction will be used on other highways in Arizona. It is expected to take a year or more before officials will have enough data to make a decision. However, officials say it will never be implemented on Phoenix-area freeways, because lines of trucks in the right lane would interfere with traffic at entrance and exit ramps.