The Arizona Department of Transportation is negotiating with construction and engineering firms about a massive project aimed in helping traffic flow on Interstate-17 between Phoenix and Flagstaff. ADOT says the 23-mile project will contain eight-miles of “flex lanes,” which will be two lanes that would run next to southbound I-17. The lanes could be used for either north or southbound travel, depending on the need at the time. The lanes could be used to divert traffic from an accident, wildfire or a medical emergency. The over $360-million project will expand a 23-mile stretch of highway from Anthem to Sunset Point. The project and the flex lane idea was born out of the need for improvement on I-17 as traffic can back up for miles heading north on a Friday or heading south on a Sunday. Flex lanes are being used in Texas, California and Florida. Construction of the project is expected to begin next year and last for three years.