Five incidences within five days involving people driving automobiles in the wrong direction on freeways in the Phoenix area raised questions about the cause of such mishaps. Some voiced concerns that local freeway designs could be contributing to the problem. But Fulton Schools Associate Professor Yingyan Lou, an expert in intelligent transportation systems and the modeling and optimization of those systems, says Arizona’s freeways — particularly busy Interstate 10 — adhere to the some of the best design codes. Better visibility of road signage might help reduce wrong-way driving, Lou says, but studies show driver impairment remains the biggest cause of such incidents.