Once again today I took my life in my hands by attempting a left-hand turn from northbound Table Rock Road onto westbound Vilas Road. Why does southbound traffic merit a protected left-turn arrow while northbound traffic is resigned to the indignity of only a flashing arrow with nary a safe opportunity to turn left during the entire light cycle?

Once again today I took my life in my hands by attempting a left-hand turn from northbound Table Rock Road onto westbound Vilas Road. Why does southbound traffic merit a protected left-turn arrow while northbound traffic is resigned to the indignity of only a flashing arrow with nary a safe opportunity to turn left during the entire light cycle?

Inquiring minds want to know!

— Connie M., Central Point

You know that I'd noticed the same exact thing just a few days before your letter, but hadn't thought too much about it until receiving your letter, Connie. So I went to Mike Kuntz, one of the engineers at Jackson County Roads and asked him about it. Here's what he had to say:

"When protected left turns are provided at an intersection, the left-turn arrow is programmed as either a 'leading' or a 'lagging' arrow. The majority of left-turn arrows are 'leading arrows,' meaning that the green arrow comes on first as it leads the through movement in the signal cycle. The subject left turn (at Table Road and Vilas) has a 'lagging' arrow, meaning the green arrow comes on last as it lags the through movement in the signal cycle. If a motorist is not able to make their left turn during the flashing yellow arrow, the green arrow will then come on at the end of the signal cycle to provide for the turn movement. If the motorist is able to make the left-turn movement during the flashing yellow, the signal will skip the green arrow movement and increase the efficiency of the intersection. Other 'lagging arrows' in the valley include eastbound Pine (Street) at Penninger (Road) and southbound Depot (Street) at the I-5 southbound ramps in Rogue River."

So now all of us inquiring minds know.

Dace Cochran, a patrol sergeant with the Jackson County Sheriff's Department, writes a weekly Q&A column on police issues for the Mail Tribune. Have a question for him? Write to Mail Tribune Newsroom, P.O. Box 1108, Medford, OR 97501, or e-mail cochradc@jacksoncounty.org.