Drivers passing emergency activity on the shoulder of a highway usually have the good sense to shift lanes to give it a wide berth, or, if they cannot shift lanes, slow down.

But some drivers lack that sense. They roar past police, ambulances and tow trucks, a few feet away from causing accident or injury. The Association of Chiefs of Police reports that about 700 officers nationwide were killed in line-of-duty traffic accidents from 2000 to 2009. In Maryland, officers were injured when hit on the roadside twice recently, in 2012 and 2013, both in Howard County.

Since it was passed in 2010, Maryland's "move-over law" requires drivers to avoid emergency responders. Maryland, however, is one of four states that does not extend this protection to tow trucks and their drivers. This was clearly an oversight, as tow truck operators face the same dangers as police and emergency medical technicians on the state's busy highways. In fact, a tow truck driver was struck and killed on a highway in Anne Arundel County in 2011.

Legislation pending in Annapolis would remedy this oversight. A bill before the General Assembly would make it a violation to blow past tow trucks with lights flashing without moving over or slowing down. As with the current law, violators would face fines up to $500.

State Police, who frequently enforce the "move over law," say one problem is that the public seems largely unaware of this rule. The fact that 2,400 citations were issued for violations of the law last year seems testimony to this.

Separate bills including tow trucks in "move over" have passed the state Senate and House of Delegates. it is likely that Gov. Martin O'Malley, who says he supports extending protection, will sign one of the bills. We hope he does.

But driver ignorance about this safety law may still linger. Maybe the state can help with public service announcements. Meanwhile, pass the word.