Cold temperatures mixed with snow made for some adventurous driving in the upper elevations of the foothills Thursday, transportation officials said. A couple of minor traffic accidents occurred near the intersection of Highway 20 and Interstate 80 due to snow accumulation in the upper elevations of the foothills, causing Caltrans to implement chain requirements on the highway 9.3 miles east of Nevada City, from Vista Point to Interstate 80. At 3:30 p.m., a minor injury accident transpired at Lake Spaulding Road, and another accident took place on the eastbound off-ramp connecting Interstate 80 to Highway 20, said Curtis Fouyer of …