A river of chocolate was flowing in the westbound lanes of I-40 at milepost 211, east of Flagstaff Jan. 14 after a tanker truck carrying 40-thousand gallons of liquid chocolate rolled over, according to DPS.A river of chocolate was flowing in the westbound lanes of I-40 at milepost 211, east of Flagstaff Jan. 14 after a tanker truck carrying 40-thousand gallons of liquid chocolate rolled over, according to DPS.